)
Is the pressure difference between the oval and round
windows the effective acoustic stimulus for the inner ear?
by
Susan E. Voss
Submitted to the Department of Electrical Engineering and Computer Science
in partial fulfillment of the requirements for the degree of
Master of Science in Electrical Engineering and Computer Science
at the
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
February 1995
( Massachusetts Institute of Technology 1995. All rights reserved.
Author.....
Department of Electrical Engineering and Computer Sc..ience...............
Department of Electrical Engineering and Computer Science
January
20, 1995
"~
Certified by ......
John J. Rosowski
Associate Professor of Otology and Laryngology, Harvard Medical School
^ m :7 Supervisor
Certifiedby....
.....
...............................
...........
·
William T. Peake
Professor of Electrical and Bio-engineering, M.I.T.
Thesis Supervisor
¢\ n t , n A
Acceptedby...............
aU
Q\ \,-W
F. R. Morgenthaler
Chairman, Deartmental Cmmittee on Graduate Students
INSTITUTE
MASSACHUSETTS
APR 13 1995
Is the pressure difference between the oval and round windows the
effective acoustic stimulus for the inner ear?
by
Susan E. Voss
Submitted to the Department of Electrical Engineering and Computer Science
on January 20, 1995, in partial fulfillment of the
requirements for the degree of
Master of Science in Electrical Engineering and Computer Science
Abstract
This thesis experimentally tests the common assumption that the pressure difference
between the oval and round windows of the inner ear (cochlea) is the only acoustic
stimulus for cochlear response. The cochlear potential, recorded at the round windows
of anesthetized cats, is used as a measure of cochlear response. The sound pressures at
the oval and round windows are individually controlled. A linear model of the response
to the two input pressures estimates a complex common-modegain C and a complex
difference-mode gain D. The magnitude of the difference-mode gain IDI is found to be at
least 20 dB, and in some cases 40 to 60 dB, greater than ICI; to a first approximation the
pressure difference between the oval and round windows is the effective acoustic stimulus
for the inner ear. This result is relevant both to models of the inner and middle ear and
to clinical approaches to the improvement of hearing in ears with no ossicles.
Thesis Supervisor: John J. Rosowski
Title: Associate Professor of Otology and Laryngology, Harvard Medical School
Thesis Supervisor: William T. Peake
Title: Professor of Electrical and Bio-engineering, M.I.T.
Acknowledgments
I would like to thank my advisors Dr. John J. Rosowski and Professor William T.
Peake for their constant guidance and support through all phases of this project. The
three of us had numerous discussions concerning the experiments and data interpreta-
tions presented here. I learned a lot about science and the auditory system through
these meetings, and I appreciate all the time spent to meet with me. I also thank John
for teaching me to work with experimental animals. John spent several nights working
at EPL so that he would be available when I needed help.
Many members of the Eaton-Peabody
Lab helped with this project - I thank you
all! Animal surgeries were performed by Leslie Dodds, Debbie Flandermeyer, Kerstin
Jacob, and Tracy Liu. Debbie also assisted with several of the figures in chapters one
and two. Discussions with Bertrand Delgutte, Nelson Y.S. Kiang, Sunil Puria, and Bill
Sewell were particularly helpful. I thank Mike Ravicz for his assistance in teaching me
to use the chamber 2 equipment.
This work was supported by NIH grants T32 DC 00038 and R01 DC 00194.
4
Contents
1 Introduction
9
1.1
Ossicular versus non-ossicular coupling ...................
1.2
The pressure-difference assumption.
9
11
1.3 Experimental results relevant to the pressure-differenceassumption . . .
12
1.4
16
Common-mode and difference-mode responses ...............
2 Experimental methods
19
2.2
Stimulus paradigms.
.......... .19
...........19
2.3
Experimental configuration.
..........
.20
2.4 Probe-tube microphone calibration ............
..........
.20
2.5 Animal preparation .
..........
.23
2.1 Subjects ...........................
2.6
Computer measurements of sound pressure and cochlear potential
2.7
Cochlear potentials and TTX ...............
..........
.25
2.8
Definition of noisefloor ...................
..........
.26
2.9
Independent control of oval and round window sound pressures
. .
....
....
....
2.10 Frequency range.
5
25
27
27
3 Methods of estimating common and difference-mode gains, C and D
31
3.1
Linear fit to the data ..............................
33
3.2
Logarithmic fit to the data
35
3.3
Correlation coefficients.
.........................
.............
..............
36
4 Pressure measurement errors
4.1
39
Calibration errors ................
................
4.1.1
Stability of absolute and relative calibrations
4.1.2
Movement of acoustic assembly ...................
............
4.2
Spatial variations in pressure in the tympanic and bulla cavities .....
4.3
Summary of pressure error estimates
..
39
39
42
.
...................
5 Results: Stimulus to one window
45
47
49
5.1
Experimental results ..............................
49
5.2
Discussion ....................................
57
6 Results: Stimuli to both windows
65
6.1
Experimental results ..............................
6.2
Model fits to the data: Estimation of C and D
6.3
Discussion ...............................
77
6.3.1
General model behavior ........................
77
6.3.2
Why is it difficult to estimate C? ...................
85
6.3.3
How much is the estimate of C affected by small errors in pressure
measurements?
65
...............
............................
72
86
6.3.4
Comparison to Wever and Lawrence .................
90
6.3.5
Comments on the Bekesy result ....................
94
6
95
7 Summary
Appendices
A Summary of experimental animals and calibrations
97
A.1 Brief description of each experiment .........
. 97
A.2 Acoustic crosstalk for each animal
..........
. 102
A.3 Changes in microphone calibration
..........
. . . ..
. . . . 110
A.4 Noisefloor calculations.
............
123
A.5 Effects of TTX.
............
130
B Summary of results: Stimulus to one window
139
C Summary of results: Stimuli to both windows
175
Bibliography
227
7
...
8
Chapter 1
Introduction
1.1
Ossicular versus non-ossicular coupling
The auditory portion of the fluid-filledinner ear (the cochlea) is enclosed by a bony
capsule with two membrane-covered holes that face the middle-ear air space: the oval
and round windows. In a normal ear sound is transmitted from the tympanic membrane
(ear drum) to the oval window of the cochlea by the ossicles (malleus, incus, and stapes)
(Fig. 1-1A). The tympanic membrane and ossicular system act to increase the soundpressure level between the ear canal and the cochlea. This increase is generally presumed
to be a result of the large area ratio between the tympanic membrane and the stapes
footplate (Pickles, 1988). The round window acts as an outlet that releases the pressure
transferred to the oval windowby the ossicular motion. In pathological human ears with
the ossicles missing hearing sensitivity is greatly reduced but hearing is still possible.
In this case the sound pressure in the ear canal is neither magnified nor transmitted
selectively to the oval window of the cochlea; instead the ear canal sound-pressure wave
acts approximately equally on both the oval and round windows (Fig. l-lB).
9
MALLEUS
L
OW
RANE
W
WNE
LEA
-A
EAR C
EAR C
r
I
TYMPI
CAVI
B
A
Figure 1-1: A: Schematic of a normal human ear. A sound pressure at the tympanic
membrane, PT, is magnified and transmitted to the oval window of the cochlea through
the ossicular system (malleus, incus, and stapes). B: Schematic of a human ear missing
the tympanic membrane, malleus, and incus. PT is not magnified and acts approximately
equally on both the oval and round windows.
Peake et al. (1992) developed a model that predicts hearing levels in both cat and
human when the tympanic membrane, malleus, and incus are missing. They suggest
that an important mechanism for hearing in such pathological cases is direct coupling
of sound to the cochlear windows and that the cochlea responds to the pressure difference between the oval and round windows. Approximate agreement between model
predictions and hearing levels in pathological ears supports the conclusion "For ears in
which the tympanic membrane-ossicular chain mechanism has been disrupted available
evidence for cat and human is consistent with the hypothesis that the sound-pressure
differenceat the cochlear windowsis the dominant stimulus mechanism, at least for the
higher frequencies (i.e. above 0.8 kHz)" (Peake et al. p. 258). It is difficult to come to
a conclusion about the Peake et al. model fit to experimental data at lower frequencies
because there are few experimental data. The existing data are discussed in Chapter 1.3.
10
1.2
The pressure-difference assumption
The pressure difference between the oval and round windows is often assumed to be
the only acoustic stimulus to the cochlea. This assumption is prevalent in both basic
science and clinical explanations of cochlear function. Models of the inner and middle
ear usually assume that the cochlear fluid is incompressible and that the response of
the cochlea is proportional only to the pressure difference between the oval and round
windows (e.g. Zwislocki, 1965; Allen, 1985; Peake et al., 1992). Surgical approaches to
hearing improvement in ears without tympanic membrane, malleus and incus attempt
to maximize the window pressure difference (e.g. Wullstein, 1956; Peake et al., 1992;
Merchant et al., 1995; Rosowski et al., 1995). For example, in the type IV tympanoplasty
procedure the surgeon places a facia or cartilage graft across the middle-ear air space to
act as a shield that isolates the round window from sound pressure in the ear canal; it
is assumed that the graft functions to increase the pressure difference between the oval
and round windows and thus improve hearing. The best surgical results yield hearing
losses of about 20 dB. However, the surgical results are extremely variable; only 50%
of the surgeries yield hearing losses of 30 dB or smaller, and post-surgical hearing losses
of 40 - 50 dB are not uncommon (Wullstein, 1956; Lee and Schuknecht, 1971; GotayRodriquez and Schuknecht, 1977).
If the cochlea is assumed to be a linear system the pressure-difference assumption
can be expressed as
Cochlear Response = D(Pow- PRW)
(1.1)
where D is a complex constant and Pow and PRW are the complex amplitudes of the
sinusoidal sound pressures at the oval and round windows (Fig.1-2). If Equation 1.1 holds
11
"C··lil··"sDXIILI······LIIID'i·l·l·i
and the cochlear system is also reciprocal then a volume velocity at the oval window,
Uow, produces a volumevelocity at the round window,URW, such that Uow = -URW.
1
Acous
shield
betwe
oval
and
round
windo
Figure 1-2: A schematic showing Pow and PRW, the pressures at the oval and round
windows, respectively. Uow and URW refer to the volume velocities at the oval and
round windows. It is commonly assumed that Uow = -URw.
1.3 Experimental results relevantto the pressure-difference
assumption
There is little experimental support for the pressure-difference assumption expressed by
Equation 1.1. In fact, it has been suggested that the cochlea responds even when the
lIf the cochlea is a linear, reciprocal system and if the response for all Pow and PRW is proportional
to (Pow - PRW), then Uow = -URW. Proof: Use a linear two-port network to represent the pressures
and volume velocities at the oval and round windows.
Uow = Y11 Pow + Y12 PRW
(1.2)
(1.3)
It is assumed that the response of the system, here the volume velocity,is proportional to the difference
URW = Y21 Pow + Y22 PRW
in pressure between the two windows.
Uow = Y11POW + Y12PRW = a (POW - PRW)
(1.4)
URW = Y21 POW + Y 22 PRW = b (POW - PRw)
(1.5)
Equation 1.4 shows that Y11 = -Y12 = a, and Equation 1.5 shows that Y21 = -Y 2 2 = b. Reciprocity
requires that Y21 = Y12 which sets a = -b. Since a = -b, Equations 1.4 and 1.5 show that Uow = -URw.
12
co
.
20..
40
6 0
-: ......
I
..:
2
4
0.01
2
4
0.1
2
4
1
Frequency (kHz)
Figure 1-3: Result taken from B:k:sy (1936a; 1960, Fig. 5-10). Mean hearing thresholds
from five cases with unilateral loss of the eardrum, malleus, and incus" (B6ksy, 1960).
Hearing levels indicate hearing thresholds in dB relative to the mean hearing threshold
on the normal side on which an "otological examination had shown that the inner ear
was normal" (Bksy, 1960); a hearing level of 40 dB corresponds to a hearing loss of
40 dB. The results shown here suggest that hearing improves as frequency decreases for
ears missing the tympanic membrane, malleus, and incus.
pressure difference between the oval and round window is zero. Bk6sy (1936a) reported
average hearing levels from five patients with unilateral missing tympanic membranes
and ossicles. He assumed that their cochleas were normal since the patients had normal
hearing on the nonpathological side. Bk6sy concluded that the results shown in Fig. 13 appear to be inconsistent with Equation 1.1 through the following argument. At
low frequencies the wavelength of sound is much greater than the distance between the
oval and round windows (and the dimensions of the middle-ear cavity). Thus, at low
frequencies the spatial variation in pressure between the oval and round windows is
expected to be small and the pressure difference between the oval and round windows
should decrease as frequency decreases. As a result the pressure-difference assumption
expressed by Equation 1.1 predicts that hearing sensitivity in ears with no tympanic
membrane, malleus, and incus should decrease as the frequency lowers. Instead Fig. 1-3
reports an improvement in hearing as frequency (and presumably pressure difference)
13
Uc
-1---".---"1111----___
·
decreases.
Based on the results shown in Fig. 1-3 Bk4sy hypothesized that the cochlea may
appear to be compressibledue to fluid flowthrough the endolymphatic and perilymphatic
ducts or compressibility of cochlear blood vessels. Shera and Zweig (1992) developed a
model in which the scala media is assumed to be compressible; they conclude that such
a model matches the Bekesy result shown in Fig. 1-3.
Other evidence has some consistencies with the pressure-difference assumption expressed by Equation 1.1. Wever, Lawrence and Smith (1948) showed in cat that sound
applied to the cochlea at the round window produces a cochlear-potential magnitude
similar to that produced by the same sound applied to the oval window (the angle of the
cochlear potential was not reported). Wever and Lawrence (1950) applied tonal stimuli to the oval and round windows simultaneously and measured the cochlear-potential
response. (The oval-window stimulus was applied at the tympanic membrane through
the ossicular chain whilethe round-windowstimulus was applied through a tube coupled
directly to the round-window membrane.) The stimuli were balanced such that each of
them produced the same cochlear-potential magnitude when applied alone. Wever and
Lawrence (1950, p. 462) described the response when the two stimuli were presented
simultaneously and the angle between them was varied over one cycle: "the cochlear
potentials vary in magnitude according to the phase relation between the sound waves
entering by the two pathways. Under usual conditions a phase relation can always be
found at which this response is just double what it would be for either pathway alone.
This is a maximum value for these stimuli; the response falls off if the phase is altered
in either direction from this setting. As the phase is further altered the response falls
rapidly, and it approaches a value of zero as the phase is changed 180 degrees from the
14
maximum setting".
Fig. 1-4 shows the only example of such a measurement that was
published by Wever and Lawrence (1950).
20
._
4-'
0
10
CL
a)
_r
0.
0
O
-90
0
90
180
270
PHASE - DEGREES
(arbitraryreference)
Figure 1-4: Result taken from Wever and Lawrence (1950). The cochlear-potential
magnitude was measured as the oval and round windows were simultaneously stimulated.
The phase of one of the stimuli was varied. This plot shows the cochlear-potential
magnitude as a function of the phase of the varied stimulus. The value 0 degrees was
arbitrarily chosen and does not mean that the two stimuli had a phase difference of 0
degrees at that point on the axis.
In another set of experiments, stimuli balanced as described above were delivered
directly to the oval and round windows and the angle between the stimuli required for a
minimal magnitude response,
,bMIN,
Was plotted as a function of frequency. The result
is shown in Fig. 1-5. At frequencies below 1000 Hz and above 4000 Hz the data in Fig. 15 are clearly inconsistent with Equation 1.1. Even though IPowl and PRwI are not
known, Equation 1.1 requires the difference in angle between Pow and PRW to be zero
when the cochlear-response magnitude is a minimum. The angle differences reported in
Fig. 1-5 range from 0.03 to 0.09 cycles (11 to 34 degrees) for frequencies below 1000 Hz
while at frequencies above 4000 Hz the angle differences range from 0 to 0.5 cycles (0 to
15
0.5
180
0.4
C,
,
0.3
z
0.2
135
-
z
90
a
(D
(a
45
0.1
CD
CD
0.0
102
103
10
Frequency (Hz)
Figure 1-5: Result taken from Wever and Lawrence (1950). The oval and round windows
were stimulated simultaneously and the phase relation between the stimuli was varied
until a minimum cochlear-potential response was obtained. The phase difference between
the oval and round-window stimuli required for this minimal cochlear-potential response,
bMIN, is plotted here as a function of frequency.
180 degrees). At frequencies between 1000 Hz and 4000 Hz the data shown in Fig. 1-5
are consistent with Equation 1.1 because the differences in angle between Pow and PRW
are nearly zero. However,it is impossible to relate directly the data in either Fig. 1-4 or
Fig. 1-5 to Equation 1.1 because IPowl and IPRWI were not measured.
1.4
Common-mode and difference-mode responses
A general linear system description of the cochlear response includes a "common-mode"
term. In the cochlea common-mode mechanisms might include effects of cochlear fluid
or blood vessel compressibility and flow through cochlear ducts. However, compressibility of cochlear contents need not produce a common-mode response; a symmetrically
compressible cochlea may have no common-mode response.
Common-mode mechanisms can be included in Equation 1.1 by adding a common16
mode term to the difference-modeterm.
CochlearResponse =
.~
~'- ~
difference-mode response
(Pow - PRW)
+
1
C(POW + PRW)
(1.6)
common-mode response
The gain constants D and C are the difference-modegain and the common-modegain,
respectively. Equation 1.6 reduces to Equation 1.1 when C = 0.
The aim of this thesis is to determine the relative importance of the difference-mode
and common-mode terms to the cochlear response. The cochlear response to direct
simultaneous stimulation of the oval and round windowsis examined in a manner similar
to that of Wever and Lawrence (1950). The cochlear-potential response is measured in
cat ears while the magnitudes and angles of the sound-pressure amplitudes at the oval
and round windows are controlled; these cochlear-potential measurements are used to
estimate the difference-modegain D and the common-modegain C. Comparison of D
and C determines the importance of the pressure differenceat the two windows relative
to the summation of pressure at the two windows. D and C are compared using the
common-mode rejection ratio (CMRR).
CMRR
= 20logiolj
_(
17
(1.7)
18
Chapter 2
Experimental methods
2.1
Subjects
Measurements were made on seven cat ears. The first three ears were used to develop
the experimental methodology; the pressure measurements in these animals were not
stable to within less than a few dB over long periods of time. Appendix A contains a
description of the measurements on each cat.
2.2 Stimulus paradigms
Two types of stimuli were used: "single-sided" and "simultaneous". The single-sided
level series are measurements of the cochlear potential, Vcp, made while either the
oval or round window was stimulated with a tone of increasing sound-pressure level.
The simultaneous-stimuli measurements refer to cochlear-potential measurements made
while the oval and round windows were stimulated simultaneously; sound pressures of
nearly equal magnitude (generally within 0.1 dB) were presented to the oval and round
windows (Pow and PRW) while the angle of one of the pressures was varied over one
19
cycle. Vp
was measured as a function of b, the phase difference between the sound
pressures at the two windows. A measurement "set" refers to the set of data points
collected as b varied from 0 to 1 cycle.
2.3
Experimental configuration
Fig. 2-1 shows a schematic of the experimental set-up. The tympanic membrane, malleus,
and incus were surgically removed from a Dial and sodium pentobarbital anesthetized
cat. A petroleum-jelly soaked piece of cotton was inserted into the foramen of the septum
so that the tympanic and bulla air spaces were isolated from each other. A calibrated
probe-tube microphone and sound-source assembly positioned in the ear canal both
delivered and measured the sound pressure in the space around the oval window, Pow.
A similar assembly positioned over a hole made in the bulla wall delivered and measured
the sound pressure in the space around the round window, PRW. The sound sources were
"Beyer dynamic " earphones and the microphones were "Larson Davis 2530" quarter inch
condenser microphones.
2.4 Probe-tube microphone calibration
The experimental measurements required two calibrated microphones. OWmic refers to
the probe-tube microphone which measured the sound pressure in the tympanic cavity
and RWmic refers to the probe-tube microphone which measured the sound pressure
in the bulla cavity. OWmic and RWmic were calibrated separately using a coupler and
reference microphone, REFmic.
A calibration source (Larson Davis) of 114 dB SPL at 250 Hz was coupled to REFmiC
20
MICROPHONE
OV
SOl
STAPES
PM
MI
. ROUND
WINDOW
MEMBRANE
TYMPANIC
CAVITY
7
BONY SEPTUM
BULLA
CAVITY
MICROPHONE
) WINDOW
)-SOURCE
AND
]E-TUBE
OPHONE
a
Figure 2-1: A schematic of the experimental set-up of the cat middle-ear. The inset is a
blowup of the petroleum-jelly soaked cotton plug in the foramen of the septum.
21
to determine the relationship between sound-pressure level and the voltage output of
REFmic. This measurement combined with a measurement of the frequency response
of REFmic provided the transfer function between sound-pressure level, SPL, and the
reference microphone voltage, VREFmic VFP ic
One at a time, each probe-tube microphone and sound-source assembly was coupled to REFmic for the calibration procedure (Fig. 2-2). To calibrate the oval-window
probe microphone, the transfer function between the voltage measured by the reference
microphone, VREFmicand the voltage into the earphone generated by channel A of the
was measured: VF-.
digital-to-analog converter, VDACOW,
'W,
Next the transfer function
VDACO
W
between the voltage measured by the oval-window probe-tube microphone, Vowmic, and
VDACow was measured: VOWMc These transfer functions yield the relation between
VDACow
was measured: VDACOW'
sound-pressure level and the voltage of the oval-window microphone.
SPL
VREFi.
VREFmic
1 [VDACow
VOW
VDACow
i
=
SPL
(2.1)
VOWmic
The transfer function between VRWmic
SPL was found in the same manner. The roundwindow earphone was driven by channel B of the digital-to-analog converter VDACRW.
The two microphones, OWmic and RWmi,, should measure the same sound-pressure
level because they were calibrated with a common reference microphone. The relative
calibration between the oval and round window microphones was checked periodically
during the experiments on Cats #5, #6, and #7. After each calibration a short brass
tube was used to couple the two probe-tube microphone and sound-source assemblies
together; the two probe-tube tips were less than 2 mm apart. A sound common to
both microphones was produced and it was confirmed that the calibrations of the two
22
To REFmic Amplifier
A--
REFmic
J
(Larson Davis 2530)
Brass
Couplin
Asseml
Davis 2530)
To OWmic Amplifier
From
Beyer Dynamic Earphone
DACow
Figure 2-2: The Beyer dynamic earphone is coupled to both REFmic and OWmicfor the
calibration procedure of the oval-window probe-microphone and sound-source assembly.
Experimental measurements were made with the same assembly,without REFmic. The
part of the assembly to which REFmic coupled here is where the assembly was attached
to the cat. A similar assembly is used to couple REF,mi and RWmic for the calibration
procedure of the round-window probe-microphone and sound-source assembly.
microphones were consistent.
The results of this procedure are further discussed in
Chapter 4.
2.5 Animal preparation
Cats weighing between 1.7 and 2.2 kg were anesthetized with Dial (between 1.25 cc and
1.65 cc) and sodium pentobarbital (between 0.83 cc and I cc); the doses depended on the
weight of the animal. Boosters of Dial (10% of the original dose) were given throughout
the experiments, as determined by a toe-pinch response or 20% increase in heart rate.
Most cats received 0.1 cc penicillin to fight infections.
Removal of the ossicles required several steps.
First, as much as possible of the
cartilaginous ear canal was surgically removed in order to increase visibility of the middle23
ear air space. Next, an approximately circular hole with a diameter of about 5 mm was
made in the dorsal-lateral-posterior
part of the widely exposed bulla in order to provide
visibility of both the round window and the foramen of the bony septum; this hole
was later used to couple the round-window probe-tube microphone and sound-source
assembly to the bulla cavity. Two methods were used to remove the ossicles; both
required a dissecting microscope.
The ossicles of Cats #1, #2, #3, and #4 were removed as follows.
1. The tympanic membrane was removed with a set of small forceps.
2. The manubrium was held with the forceps and gently wiggled until the lateral
process and sometimes other parts of the malleus came loose; the pieces were
removed. This made the incudo-stapedial joint partially visible.
3. The incudo-stapedial joint was disarticulated with the use of a "Schuknecht hook"
(Storz Instrument Co.), and the incus was either removed or left loose in the
tympanic space.
4. The foramen was plugged with petroleum-jelly soaked cotton by placing the cotton
in the foramen with an approach through the ear canal and tympanic cavity. This
approach was difficult due to poor visibility of the foramen through the earcanal.
A different approach was used to remove the ossicles from Cats #5, #6, and #7.
1. The tympanic cavity was visualized through the 5 mm diameter hole in the bulla
wall and the foramen. Either part of Spence's cartilage or the chorda tympani
branch of the facial nerve was immediately in sight through the foramen. This dis-
rupted the view of the incudo-stapedial joint. Any such "soft tissue" obstructions
were moved out of the way by breaking them with the Schuknecht hook.
2. The Schuknecht hook was introduced into the tympanic cavity through the bulla
cavity and the foramen; the incudo-stapedial joint was disarticulated. The visibility
during this procedure varied among cats.
3. The tympanic membrane and other ossicles were removed through the ear canal.
4. The stapes and incus disarticulation was visually confirmed, by looking through
the ear canal.
5. The foramen was plugged with petroleum-jelly soaked cotton through the bulla
cavity approach.
24
After the ossicles were removed, the round-window wire-electrode tip was positioned
near (Cats #1 to #4) or on (Cats #5 to #7) the round-windowmembrane. The electrode
was advanced through a small hole in the bulla cavity with a micro-manipulator;
the
process was visualized through the larger 5mm diameter bulla wall hole with a dissecting
microscope. The wire electrode was glued to the bulla wall to minimize movement and
seal the hole.
2.6
Computer measurements of sound pressure and cochlear
potential
The digital-to-analog converter on a computer generated a two second stimulus tone(s).
The two second amplified microphone-output(s) and cochlear-potential voltage responses
were measured using the computer's analog-to-digital converter that sampled each response on a different channel at 12 kHz. Each channel of the analog-to-digital converter
output was divided into 50 segments, and each segment was an integer number of periods in duration.
The segments were averaged and the magnitude and angle of the
fundamental component of the average is reported as the cochlear-potential response.
The averaged microphone voltages were converted into sound-pressure levels using the
previously measured microphone calibrations.
2.7 Cochlear potentials and TTX
The AC cochlear potential is composed of two dominant components: cochlear microphonic (CM) and compound action potential (CAP). CM refers to the response of the
cochlear sensory hair cells and is believed to increase linearly with sound-pressure level
25
over a large stimulus range (Pickles, 1988). The nonlinear CAP is generated by the
auditory nerve fibers.
The cochlear-potential response is represented as a linear-system response to the two
inputs Pow and PRW (Chapter 3). This model is not consistent with the nonlinear
CAP component in the cochlear response. Tetrodotoxin (TTX) was used to eliminate
the CAP in Cats #6 and #7. TTX pharmacologically blocks action potentials generated
by voltage-gated sodium channels; others have used TTX to block the compound action
potential of the auditory nerve (Kaplan et al. , 1983; Dolan et al. , 1989). Here 1 mg
of TTX (Sigma Chem. Co.) was mixed with 1 ml of artificial perilymph; a 3.13 mM
solution resulted. Eight l of this solution was dropped on the round-windowmembrane
from where it diffused through the round window-membrane into the cochlea over a
time course of a few hours. The cochlear-potential response to clicks and tone bursts
was measured pre and post TTX administration to confirm that the CAP response was
eliminated; these results are included in Appendix A.
2.8
Definition of noisefloor
Noisefloors are defined as follows for measurements on Cats #5, #6, and #7: M cochlearpotential measurements were made with no stimulus. The noisefloor is defined as the
mean of these M magnitude measurements plus two standard deviations (all in dB). In
most cases (but not all) M = 11. Such noisefloor measurements were not made during
the experiments on Cats #1, #2, #3, and #4. However,several measurements of Vcp
in response to a 1000 Hz stimulus were made. The mean plus two standard deviations
of the appropriate frequency component of these measurements (M > 11) were used as
estimates of the noisefloor. For these four animals, the noisefloor at 1000 Hz is defined to
26
be the same as the noisefloor at 800 Hz. Tables of noisefloor measurements are included
in Appendix A.
2.9
Independent control of oval and round window sound
pressures
The bony septum that divides the cat middle-ear air space provides some natural acous-
tic isolation between the oval and round windows. The petroleum-jelly soaked cotton
plug that was inserted into the foramen of the septum further isolated the sounds at
the two windows. A measurement of the acoustic "crosstalk" between Pow and PRW
from Cat #7 is shown in Fig. 2-3, and measurements from the other cats are included in
Appendix A. Such measurements of sound isolation with the plug in place demonstrated
that the isolation was generally greater than 40 dB between 75 Hz and 1000 Hz. This
amount of isolation allows for control of Pow and PRW through the separate sound
sources. Note that, since Pow and PRW are always measured, acoustic "crosstalk" between the oval and round window sound-pressure sources is accounted for in the analysis.
2.10
Frequency range
Measurements were made at frequencies between 75 and 1000 Hz. This low frequency
range was chosen because low frequency results from both Bkesy
and Wever and
Lawrence (Chapter 1) contradict the pressure-differenceassumption (Equation 1.1). It
was not possible to make measurements at frequencies below 75 Hz because the sound
sources did not generate enough pressure to produce measurable cochlear potentials at
these frequencies. The measurements were limited to low frequencies (< 1000 Hz) so
27
_Ll________(__plI_______y
I
____
OW SOURCE OFF
OW SOURCE ON
RW SOURCE OFF
RW SOURCE ON
0
A\
u
-20
-
VOWmic/VDACow
-20
-40 _
m
m
·+
.
4--1-
..............
-80
A
iallli
ll
''till-
00
.
2
. 4I ..6
1 00
-
U)
aD
>O
r,.
IVRWmicNDACRw I
''I'll
-60
-80
0.5
-40
......
"O
-60 _
-100
IVOWmNDACRw [
-
......... IVRW,,,c/VDACowI
1
1000
-100
2
4
~~,-nzcl~~~~~~;
I
'
100
VOwmic- ZVDAC
......... ZVRW
c
I
24 6 iI1
8
LVOWmc
......... ZVRW
- ZVDACow
1000
22
I4I4
ZVDACR
w
ZVDACRw
0.5
Cn
a,
0.0
0
0>I
0.0
-0.5
-0.5
100
1 000
Frequency (Hz)
A.1
100
1000
Frequency (Hz)
Figure 2-3: Measurements of acoustic crosstalk between the tympanic and bulla
cavities from Cat #7. LEFT: Measurement of the transfer function between the
oval-window microphone response Vowmic and the oval-window sound-source input
VDACOW, and measurement of the transfer function between the round-window microphone response VRwmic and the oval-window sound-source input VDACow. The
round-window sound-source was off. RIGHT: Measurement of the transfer function between the oval-window microphone response VowmiCand the round-window sound-source
input VDACRW, and measurement of the transfer function between the round-window
microphone response VRwmic and the round-window sound-source input VDACRW. The
oval-window sound-source was off.
28
that it is reasonable to assume that the pressure at each probe-tube-microphone input
is the same as the pressure at the respective cochlear window a few millimeters away.
At these frequencies the wavelengths are much greater than the distance between the
probe-tube and the window; the shortest wavelengths are more than 30X the largest
cavity dimensions. The validity of this assumption was tested (Chapter
29
4.2).
30
Chapter 3
Methods of estimating common
and difference-mode gains, C and
D
The cochlear potential measured at the round window, Vcp, is modeled as a linear
function of the sound pressures at the oval and round windows, Pow and PRW. A linear
system representation is shown in Fig. 3-1.
Pow
Linear System
-0 Vcp
PRW O-
4-
Figure 3-1: A general linear system representation of the cochlear response Vcp to the
pressures Pow and PRW. The system input is describe by acoustic variables, and the
system output is described by electric variables.
31
Since Pow and PRW are two independent inputs, the response Vcp must also be
described by two independent terms, as in Equation 1.6:
D(Pow- PRW) + C(POW+PW)
VCP
2
difference-mode response common-mode response
.
(3.1)
The two independent terms of this equation include a "difference-mode" term, the prod-
uct of the difference-modegain D and the difference-modeinput (Pow - PRW), and a
"common-mode" term, the product of the common-modegain C and the common-mode
input
(Pow + PRW).
The simultaneous-stimuli measurements of Vcp, Pow, and PRw (Chapter 2) are used
and C, using two separate fitting
to estimate the differenceand common-modegains,
procedures of Equation 3.1 to the measured data (Chapter 3.1 and Chapter 3.2). All
data points such that IVcpI > Noisefloor
are weighted equally in the fitting procedures;
data points below the noisefloor are not used.
A model prediction for each data point, VcP, is calculated from the estimates D and
C and the measured Pow and PRW for each measurement set.
= D(Pow - PRW)+ 2 C(POW+ PRW)
_cp
The relative sizes of
I
(3.2)
and ICI are described by the common-mode rejection-ratio
(CMRR).
D
CMRR = 20logiol-Correlation coefficients that describe the fit of Vf/
(3.3)
to the measured Vcp are calcu-
lated for each measurement set (Chapter 3.3). Experimental and model parameters axe
32
Experimental and Model Parameters
Symbol
Description
Pow
PRW
VCp
PDIFF = POW - PRW
PSUM = (POW + PRW)
VcP
Complex pressure at the oval window (N/m 2 )
Complex pressure at the round window (N/m 2 )
Complex voltage at the round window (cochlear potential)
Difference-mode pressure
Common-mode pressure
Model prediction of cochlear potential
Estimate of the difference-modegain (Volts !M')
Estimate of the common-modegain (Volts -N-)
Estimate of the common-mode rejection ratio
D
CMRR
Table 3.1: Experimental and model parameters.
summarized in Table 3.1.
3.1 Linear fit to the data
A linear-least-squares fit of Equation 3.1 is made to the data points of each measurement
set in the followingmanner. The notation in Equation 3.1 is simplified to express the
model as
VIp = DPDIFF + CPSUM
(3.4)
where PDIFF = POW-PRW and PSUM = (POW+PRW). Equation 3.4 can be expressed
as
VCpa= D PDIFF,+ C PsuM,
(3.5)
where the subscript i refers to a specific data point. Each measurement set consists of a
series of N such data points and can be expressed in matrix format as
VcP = Pp3
where
33
(3.6)
/r
vCp2
VCp =
(3.7)
VCPN
-~ ~ / I Ic
VrGP.,
J
/
P=
rPDIFF
PSUM1
PDIFF2
PSUM2
(3.8)
PDIFFN PSUMN
(f D
(3.9)
A)
The estimate of /, ,, that minimizes the expression
N
X2
=
i=l
I(D-PDIFF +-CPSUM)-VCPij
= IP'/-Vcp'I
(3.10)
is found using singular value decomposition (SVD) techniques to solve Equation 3.6 for
p (Press et al. , 1992). This method is used to eliminate undesirable effects of singular or
nearly singular matrices. The NX2 matrix P defined by Equation 3.8 can be expressed
in terms of the product of three new matrices:
P =U. W .VT
(3.11)
where U is an NX2 orthogonal matrix (UT U = 1), W is a 2X2 diagonal matrix,
and V is a 2X2 orthogonal matrix (VT
V = 1). The
that minimizes X2 from
Equation 3.10 can be expressed as
/i
_
=P-Vcp
=
= V [diag(
34
)] U T . Vp
(3.12)
where [diag(
)] refers to the diagonal matrix comprised of the reciprocal of each ele-
ment of the diagonal matrix W defined by Equation 3.11. The solution of Equation 3.12
can be equivalently written as
=V=
(3.13)
where the subscript (i) refers to the vector which comprises the ith column of U and V
and wi refers to the diagonal element W(i, i) (Press et al., 1992).
3.2 Logarithmic fit to the data
All data points are equally weighted in the linear-least-squares fit described above (Chapter 3.1). However, the measurements of Vcp made while the oval and round windows
were simultaneously stimulated with variations in the relative phases of the stimuli have
a dynamic range of about 40 dB; equal weighting of data points puts an emphasis on
the regions where Vcpl is largest. To increase sensitivity to the points where Vcp is
small, estimates of D and C are found with a least-squares fit to
log(Vcp) = log(D_PDIFF+ CPSUM),
(3.14)
which requires the minimization of
N
2
x2= Ilog(b
,
PDIFF
+ PSUM)-(CP)
-*
(3.15)
i=P
Since Equation 3.15 is nonlinear it is not possible to use the method of Chapter 3.1.
Instead, a four dimensional space is searched to find values of D[, ZD, Cj, and
C that
minimize X2 .
The search procedure employs the "fmins" function in Matlab (Macintosh version 4.1,
The Mathworks, Inc.) to find a local minimizer of Equation 3.15. The "fmins" function
35
uses a "simplex" method (Nash, 1979; Press et al., 1992) to search the four dimensional
space. In this case the "simplex" is a four dimensional geometric shape which must
contain the desired values of IJD, D, C, and LC. The values of D,
D, CJ, and ZC
that were found using the least-squares fit of Equation 3.4 are used as an initial guess
to center the simplex. The four dimensional simplex is defined by five vertices which are
determined using the nonzero initial guess; each element of each vertex is between 0.9
and 1.1 times the initial guess. Next, Equation 3.15 is evaluated at each vertex of the
simplex. The vertex that produces the largest value when Equation 3.15 is evaluated
is replaced; it is reflected about the centroid of the other three vertices and through
steps of reflection, expansion, reduction, and contraction (Nash, 1979) the vertex with
a maximum function value (Equation 3.15) is replaced. This process is repeated until
the simplex has shrunk to a size such that the evaluation of Equation 3.15 at all vertices
differs by less than 0.0001. The estimates of IDJ, LD, C, and ZC at this local minimum
of Equation 3.15 are used as the "logarithmic" model fit.
3.3
Correlation coefficients
Two correlation coefficients are computed for each measurement set; PMAG describes the
model fit IfcpI to IVcpl, and pz describes the model fit ZLcp to LVcp. The difference
between the variance of the measured magnitude and angle data,
MAG
1
N
N- 1 [Illog(cP
-
2
lg(V)cp)11
(3.16)
1N -
(3.17)
2 = N l E VCP-LVCP,
and the variance of the mean squared error between the data and model prediction,
2
1
N
aMAG-ERROR= N-2[Iollo(Vcp)1N - 2 i=l1
36
log(Vcp)I)]
(3.18)
1
2
N
VcP
I-ERROR= N-2 i
i=_
2,
- lVCp]
(3.19)
is used to calculate the correlation coefficients
PMAG =
M--AG-
AG-ERROR
oMAG
(3.20)
and
a2 _ a2
P =-E
L
b-ERROR
O
(3.21)
In order to compare the two model fits, linear (Chapter 3.1) and logarithmic (Chapter 3.2), the correlation coefficients for both models are based on Equation 3.14; additionally all data and model fits are plotted on logarithmic scales. Vcp and LVcp refer
to the mean value of the measurement set and N is the total number of data points in
the measurement set. IV'cpl and LVcp, refer to the model prediction at the ith data
point.
37
__·1_··1_1____1___^_^___-·-___
38
Chapter 4
Pressure measurement errors
Categories of potential errors in the measurements of Pow and PRW include: errors in
the calibration of the microphone systems and pressure variations within the tympanic
and bulla cavities, which make the measured pressures differ from the pressures at the
oval and round windows. This chapter discusses these errors and estimates their sizes.
4.1 Calibration errors
4.1.1 Stability of absolute and relative calibrations
The exact calibration of each microphone is not critical for the experiments presented in
this thesis. However, the relative calibrations of the two microphones used to measure
Pow and PRW must be determined precisely. For example, if a common tone is presented
identically to both microphones it is critical that the calibrated sound-pressure response
be the same in magnitude and angle for both microphones.
Changes in temperature and humidity may affect each absolute microphone calibration. However, such changes are likely to be correlated between the two microphones
39
and probably do not introduce significanterrors.
The calibration procedure (discussed in Chapter 2.4) determines the ratio between
the sound pressure at the microphoneinput and the voltage generated at the microphone
output, i*.
The calibration procedure was repeated several times during the experi-
ments on Cats #4, #5 , #6, and #7 and the changes in Pi
as a function of time are
Vmic
used as one measure of error that exists in the measurements of Pow and PRW. The
changes in -
for all the cats are included in Appendix A. The largest variations in
v-c for Cats #4 to #7 occurred in Cat #7; these variations are presented here as an
example.
Changes in the magnitude and angle of inVm,(iinitial
Pmic(initial calibration) as a function of time
calibrationa
are shown in Fig. 4-1 for the measurements made on Cat #7. The maximum change in
calibration during the experiments is used as a "worst-case" estimate of the error that
exists in any given calibration.
This estimate is plotted as a function of frequency in
Fig. 4-2. The error estimates are not constant with frequency and they are not the same
for the four cats. The oval-window microphone was consistently more variable than the
round-window microphone. The maximum change in calibration during the experiment
on Cat #7 was nearly 0.8 dB in magnitude at 100 Hz and nearly 0.015 cycles in angle
at 1000 Hz. The maximum calibration changes seen in Fig. 4-1 probably over-estimate
errors in Pow and PRW.
The relative calibration between the oval and round window microphones was further checked periodically during the experiments on Cats #5, #6, and #7. After each
calibration a short brass tube was used to couple the two probe-tube microphone and
sound-source assemblies together; the two probe-tube microphone tips were less than
2 mm apart so the inputs to the microphones would be identical. When the calibrated
40
A Magnitude
A Angle
from Original
Calibration (cycles)
from Original
Calibration (dB)
0.4
0.005
1000 Hz
0.0
0.000
-0.005
20
30
40
0.4
20
30
40
20
30
40
20
30
40
0.000
300 Hz
-0.002
0.0
20
30
40
0.004
0.4
0.002
100 Hz
0.000
0.0
20
30
40
Time (hours)
Time (hours)
Figure 4-1: The differences in
between the initial calibration and subsequent calibrations during the experiment on Cat #7. Note expanded vertical scales. The first
measurement of Emr. is used to normalize all succeeding measurements of AuP; magnitudes (in dB) and angles (in cycles) of the ratios are plotted. Time of day = 17 hours is
the time of initial calibration.
-j
Maximum Phase
Difference (cycles)
Maximum Magnitude
Difference (dB)
A
.J
p
id
.6-
.4.20O
'·
.015
p
[
t RWI
I
I
400
800
.01
.005
400
Frequency (Hz)
Frequency (Hz)
Figure 4-2: The maximum changes in
iment on Cat #7.
as a function of frequency during the exper-
41
.r
l~~s~~~,-arr~
o~
lssa
_
arr~~~
800
_
.-
d
_,--
microphone outputs differed by more than 0.1 dB in magnitude or 0.002 cycles in phase
the microphones were re-calibrated and any measurements that relied on the faulty calibration were discarded.
4.1.2
Movement of acoustic assembly
Additional measurements weremade in a brass tube to understand better the microphone
variations that occur over time and that occur as a result of coupling and decoupling to
and from the cat head. In the tube, as in the cat head, the response of each microphone
contains two sources of variability: variation in the microphone response and variation in
the sound-source output. The variability in the two microphone responses was quantified
by making repeated measurements in the brass tube assembly. Changes in the source
output should cause correlated changes in the output of both microphones. Changes in
microphone sensitivity could also be correlated if they result from changes in temperature
or absolute pressure.
50 consecutive measurements were made with a 1000 Hz tone stimulus while the
two sound-source and microphone assemblies were coupled together; the time between
the first and 50 th measurement was about 5 minutes.
The sound pressure measured
by the two microphones and the differences between the two microphone measurements
are shown in Fig. 4-3A and C, respectively.
Fig. 4-3A illustrates that the outputs of
both microphones changed with time by about 0.15 dB in magnitude and 0.003 cycles
in angle. The difference between the microphone outputs changed less with time; the
variation was only 0.04 dB in magnitude and 0.0003 cycles in phase (Fig. 4-3C). These
data can be interpreted to show that small changes occur in both sound-source output
and microphone sensitivity over time, and the larger change is apparently in sound-source
42
output.
Next, 50 consecutive measurements were made in which the two sound-source and
microphone assemblies were uncoupled from and then recoupled to the brass tube between each measurement; the time between the first and 50th measurement was about
10 minutes. Such a procedure mimics the uncoupling and recoupling of the sound-source
and microphone assemblies to the cat. The sound pressure measured by the two microphones and the differences between the two microphone measurements for this case are
shown in Fig. 4-3B and C. The uncoupling-recoupling results (Fig. 4-3B) show changes in
microphone output that have a range of about 0.3 dB in magnitude and 0.005 cycles in
angle. The variation in the difference between the microphone outputs is about 0.1 dB
in magnitude and 0.003 cycles in angle (Fig. 4-3C).
The measurements in Fig. 4-3 indicate that the system is less stable when movements
of the sound-source and microphone assemblies are made. The large correlation between
the two microphone outputs clearly demonstrates that most of the observed variation
is the sound-source output.
The variations observed in the microphone outputs when
movements of the brass-tube assembly are made are appreciably smaller than the total
calibration variations in the cat ear observed when the system was recalibrated during
the experiments (Fig. 4-1); the changes caused by movement of the system are likely to
be a part of the total calibration changes (Fig. 4-1).
43
1
-11I1·-II--·--1II1111·
·Il·IUI·l·llll*LIII1II
MAGNITUDE
1
4
(dB SPL)
ANGLE (cycles)
0.296 -r-
,\
1 U. - I'
------
.. .
0.295
Mic A
...... Mic B
110.2
-Mic
110.1
I..
†.....
!
_. _ _
!
_
I
l
50
25
0
p]
0.294
A
Mic B
110.2-
25
0
I\
5
50
4,\n
U. JUU -
Mic A
...... Mic B
110.1.,,.A
.
Mic B
110.0-
109.9-
-Mi
i .··-
1%
a n
A'
25
0
50
r
0
0.001 - -
:
.:~~
I
i
25
50
|~~~~~~
Difference no recoupling
------Differencewith recoupling I
V
0-
0.05 0.00 -
.
:4
0.290-
-- Difference no recoupling
......Difference with recoupling
U. IU'
-
0.295 -
¥''~i.
,
I
,t
-0.001
-
0
'?: X
·
ir '~~~~~jibv~~.
-0.05
-
-0.002 -
I
I
I
_I
25
50
0
25
Sample number
..
!
50
Sample number
Figure 4-3: (A) 50 consecutive measurements by both microphones of a common 1000Hz
tone within a tube. Here the system was not touched between measurements. The
time between the first and
5 0 th
measurement was about 5 minutes. (B) 50 consecutive
measurements by both microphones of a common 1000 Hz tone within a tube. Here
the system was decoupled and recoupled between each measurement. The time between
the first and 5 0th measurement was about 10 minutes. (C) The difference between the
measurements shown in (A) and the difference between the measurements shown in (B).
This difference is a measure of the variation of the microphone responses.
44
4.2
Spatial variations in pressure in the tympanic and
bulla cavities
Pow and PRW are the measured pressures at the medial end of the ear canal and at the
bulla wall. Differences may exist between these measured pressures and the pressures
at the oval and round windows. To estimate these differences, pressure measurements
were made at different locations in the bulla cavity (of a dead cat). The round-window
sound-source and probe-tube microphone assembly was coupled to the bulla cavity as
shown in Fig. 2-1. A second probe-tube microphone, mounted on a manipulator,
was
introduced into the bulla cavity near this assembly. This second probe-tube microphone
was systematically moved across the bulla cavity from the bulla wall toward the round
window, and the responses of both microphones to tonal stimuli were recorded. The
calibration for the moving microphone was defined by assuming that the pressures measured by both microphones were the same when the moving microphone was positioned
at the bulla wall.
Fig. 4-4 shows the ratio of the two pressure measurements, as a function of distance
from the movable probe tube entrance at the bulla wall, for measurements at 1000Hz.
The 0 mm position defined the bulla wall position, and the opening of the round window
niche was at the 4.6 mm position.
A total of five measurements was made at each
position during three trials; a trial consisted of calibrating the moving microphone by
making a measurement while the probe tube was at the bulla wall and then making
one to three pressure measurements at each location as the probe tube was advanced
systematically toward the round window. These measurements and their averages are
shown in Fig.4-4. The probe moving toward the round window measured slight variations
45
in the pressure magnitude relative to the round-window microphone; these variations
were on average less than 0.05 dB different from the pressure magnitude at the bulla
wall. There were also variations in the pressure angle relative to the round-window
microphone output; advancing the moving microphone led to a lag or decrease in angle
relative to the pressure at the bulla wall. On average, the angle at the round window
niche lagged the angle at the bulla wall by about 0.0008 cycles; this lag is only 6% of the
phase lag of 0.013 cycles predicted theoretically for unidirectional uniform plane wave
propagation. 1 The presence of the probe-tube microphone in the bulla cavity had little
or no effect on the pressure magnitude measured by the round-window microphone; while
the measurements shown in Fig. 4-4 were made, the largest magnitude changes in the
pressure at the bulla wall were less than 0.02dB in magnitude. The presence of the probe
tube may have affected the pressure angle measured by the round-window microphone;
the maximum change in these angle measurements was 0.001 cycles.
However, such
variations in angle measurement are smaller than the variations that result in movement
of the acoustic system (Fig.4-3B). The measurements of Fig.4-4 support the assumption
that there is little spatial variation in the pressure in the bulla cavity; therefore the
pressure measured at the bulla cavity wall is an accurate representation of the pressure
at the round window (Chapter 2.10).
Pressure variations in the bulla cavity at 100 Hz were also measured; these variations
were smaller than those shown in Fig. 4-4 at 1000 Hz.
The differences between the
pressure at the round window and the estimated PRW should be largest at 1000 Hz
since the shortest wavelength involved in all experiments is at 1000 Hz.
Additionally
'If the speed of sound is 345- and the distance traveled is 4.6 mm then the phase lag for a uniform
plane wave would be o.o46m
=0.013 cycles.
1000
sec
- -1
46
the differences between the measured pressure and the actual pressure at the oval or
round window should be greatest in the bulla cavity since this cavity is larger than the
tympanic cavity.
IPPROBE / 1PR
I
PPROBE -PW
0.0004
8
0.10-
o
o Individualmeasurements
0.00.0000
-00 Ag
o
o
-0.00
o
-0.0008
-0.10-
-0.10
0
1
2
3
4
5
- o Individualmeasurements
Average
0
1
2
3
4
5
Distance (mm)
Distance (mm)
Figure 4-4: The reported pressures are measured as a function of distance from the
bulla wall and are relative to the pressures measured simultaneously at the bulla wall.
A probe tube microphone was advanced from the bulla wall (Distance=0 mm) to the
round window niche (Distance=4.6 mm) .
4.3 Summary of pressure error estimates
Changes in the calibrations of the acoustic systems over the course of an experiment are
the largest errors discussed here (Fig. 4-1). The contribution to these errors caused by
movements of the system are clearly smaller than the total errors (Fig. 4-3). Errors due
to spatial variation in pressure within the cavities are negligible compared to the total
errors.
The total errors observed for the measurements on Cats #1, #2, #3 were much
greater than those observed for the measurements on Cats #4, #5, #6, and #7 (Appendix A). The measurement system was improved by altering the components of the
sound-source and microphone assemblies to have tighter fits. For this reason the results
47
and discussion presented in the body of this thesis emphasize results from Cats #4 to
#7; results from Cats #1 to #3 are similar and can be found in the appendices.
48
Chapter 5
Results: Stimulus to one window
5.1 Experimental results
Single-sided cochlear-potential
measurements were made as a function of increasing
sound-pressure level while either the oval or round window was stimulated. The pressure
at the unstimulated window was effectively zero because the foramen plug was in place.
Examples of such measurements made on Cat #6 at 100 Hz, 300 Hz, and 1000 Hz are
shown in Fig. 5-1, 5-2, and 5-3. These results are characteristic of results from all other
cats (Appendix B).
The cochlear-potential response is described by its magnitude and angle. A linear
dependence requires:
1. The cochlear-potential magnitude must increase with stimulus level with a slope
of 1 with dB scales.
2. The cochlear-potential angle must be independent of stimulus level.
Nonlinear features can be seen in the pre-TTX measurements shown in Fig. 5-1, 5-2,
and 5-3. The cochlear-potential magnitude does not always increase linearly with a slope
of 1, even at levels well above the noisefloor; Fig. 5-3 provides the clearest example of
49
*r___UIIII__II____I_·-··I·IYI·IIIUII
-
CAT #6
100 Hz
.50
-80
.25
-100
W
()
a,
0to
L
m
-120
-
-
0
a.
0
0
N
-. 25
-140
-160
40
4
-.
0r
-
0
-
60
80
-.50
100
0
-41
60
80
-io
Pre-TTX
I
i
40
60
80
120
- - Pre-TTX
I I~
.00
Post-TX
.
Post-TTX
I
100
co
a.
o
.t
't
I
I'
.
.5
n
i
a-
40
120
.
a.
100 120
zA;
I
i
.
I
I
I
I
I
40
60
80
I
1I
I
100 120
LEVEL (dB SPL)
LEVEL (dB SPL)
Figure 5-1: CAT #6: 100 Hz. TOP: Magnitude and angle of Vcp as a function of
sound-pressure level both before and after the application of TTX. Either the oval or
round windowwas stimulated. BOTTOM: Ratio between the oval-windowresponse and
the round-window response from the plots shown at the top.
50
CAT #6
300 Hz
.50
-80
.25
-100
,
0)
ar
0
a
-120
0
0
0
N
-140
-.25
-160
-.50
40
60
80
100
120
40
60
80
c,
a)
a,
4
--
-&
.55
Pre-TTX
Post-TTX
-
I
O
--. ---
=
,
.
A
>
!
i
I-r' I ,
.A
40o
60
80
I
100
.45
- 120
120
Prp-TTX
Post-TTX
.5
.c)
-
-a
:o
-
1
.
100
>
40
3;
i
I
.I
I
I
I
60
80
100
I
120
LEVEL (dB SPL)
LEVEL (dB SPL)
Figure 5-2: CAT #6: 300 Hz. TOP: Magnitude and angle of Vcp as a function of
sound-pressure level both before and after the application of TTX. Either the oval or
round window was stimulated. BOTTOM: Ratio between the oval-window response and
the round-window response from the plots shown at the top.
51
CAT #6
1000 Hz
-80
-1
-·*..
-'*-O-A----
.25
OW Pre-TTX
RW Pre-TTX
OW Post-TTX
RW Post-TTX
noisefloor
slope=1
0
00
a)
0
m
a- -. 25
1-
-120
>
0
C
G.
N
-. 50
1 40
-. 75
-160
40
60
80
I
I
I
60
80
100 120
-
Post-TTX
............. - a
I
-. -. Prm-TT
.55bb
. -. Pre-TX
.
0
40
100 120
I
--
4
-
~I
I
Post-TX
r
.5
_-------~r,
_f__---------
.>
1
o
-4 -
I
I
I,
40
60
80
I
.45
I
100 120
>
_I
40
LEVEL (dB SPL)
I
I
I
80
I
120
LEVEL (dB SPL)
Figure 5-3: CAT #6: 1000 Hz. TOP: Magnitude and angle of Vcp as a function of
sound-pressure level both before and after the application of TTX. Either the oval or
round window was stimulated. BOTTOM: Ratio between the oval-window response and
the round-window response from the plots shown at the top.
52
this nonlinear feature. At the stimulus levels between 60 and 80 dB SPL the cochlear-
potential magnitude both increases and decreases with increasing stimulus level. The
cochlear-potential
angle varies over the entire stimulus range; pre-TTX 100 and 300
Hz measurements (Fig. 5-1 and Fig. 5-2, pre-TTX) have cochlear-potential angles that
increase with stimulus level over much of the stimulus dynamic range. (Many of the
other 100 and 300 Hz measurements included in Appendix B have cochlear-potential
angles that decrease with increasing stimulus level.) The cochlear-potential
angle at
1000 Hz (Fig. 5-3) increases with increasing stimulus level except for a sudden quartercycle decrease at a mid-stimulus level. This type of transition is evident in all of the
1000 Hz measurements on the other six animals (Appendix B).
TTX was added to the cochleas of Cat #6 and Cat #7 (Chapter 2.7) to reduce
the nonlinear component of the cochlear-potential response. The effect of TTX on Cat
#6 is shown in Fig. 5-1, 5-2, and 5-3, and the effect of TTX on Cat #7 is shown in
Fig. B-7, B-16, and B-34. TTX had larger effects on the Cat #6 results compared to
the Cat #7 results. The 1000 Hz cochlear-potential magnitude nonlinearity described
above (Fig. 5-3) is essentially eliminated after the application of TTX. TTX also appears
to reduce nonlinearities present in the cochlear-potential magnitude response at 100 and
300 Hz (Fig. 5-1 and 5-2).
The ratio between the response to the oval-windowstimulus and the round-window
stimulus is also plotted in Fig.5-1, 5-2, and 5-3 and in the Appendix B figures. In general,
the cochlear-potential response magnitude is nearly independent of the stimulated window while the angle is nearly 0.5 cycles different for the two windows. The difference in
magnitude (in dB) between the cochlear-potential response to the oval-window stimulus
and the round-windowstimulus is often greater at lower stimulus levels than at higher
53
^___II
· _I___·___^___I________·____·_O___UIPI_
stimulus levels; however, the difference rarely exceeds 2 dB and is often less than 1 dB
(Appendix B). The difference in angle between the cochlear-potential response to the
oval-window stimulus and the round-window stimulus is usually 0.5 4 0.05 cycles; the
largest deviations from 0.5 cycles occur most at the lower stimulus levels (Appendix B).
Cochlear-potential magnitude sensitivities from all seven cats are compared in Fig. 54. These results are interpolated from the plots in Appendix B. The top plot shows
the sound pressure required to produce a cochlear-potential magnitude of 10V
when
the stimulus is delivered to the oval window, and the middle plot shows the sound
pressure required to produce a cochlear-potential magnitude of 10AuVwhen the stimulus
is delivered to the round window. The bottom plot is the dB difference between the sound
pressure required with an oval-window stimulus and the sound pressure required with a
round-window stimulus to produce a 10lV cochlear-potential magnitude response; the
difference is never more than 2.5 dB SPL.
Cochlear-potential angle measurements from all seven cats are compared in Fig. 5-5.
These results are also interpolated from the plots in Appendix B. The top plot shows
the cochlear-potential angle, relative to Pow, which corresponds to a cochlear-potential
magnitude of 101V when the stimulus is delivered to the oval window. The middle plot
shows the cochlear-potential angle, relative to PRW, which corresponds to a cochlear-
potential magnitude of 10V when the stimulus is delivered to the round window. The
bottom plot is the difference between the two cochlear-potential angles. The difference
is near 0.5 cycles in most cases and is always 0.5 ± 0.07 cycles.
54
IVCpl=10 gV
130 r-
a
a
Stimulus to Oval Wind( OW
0
120
A
0a
.J
V
-o0
0 110
V
'O
100
v
o
Wv
V
A
o
0
V
A
0f
8Kr
o
O
A
V
0
0
N
X
Cat #1
Cat #2
Cat #3
Cat #4
Cat #5
Cat #6 Pre-TTX
Cat #6 Post-TTX
Cat #7 Pre-TTX
Cat #7 Post-TTX
$
90
_
__
I
I
'
200
I
I
600
800
'
400
I
'
1000
Frequency (Hz)
.dl
_'
l
I;OU
.J
03
CO
co
m
120
Stimulus to Round Window
0
a
A
a
V
V
110 -4
0
100 _
V
A
v
V
a
o
0
V
A
&
A
a
*
o Cat#1
O Cat#2
A
V
O
O
b4
X
Cat#3
Cat#4
Cat #5
Cat #6 Pre-TTX
Cat #6 Post-TTX
Cat #7 Pre-TTX
Cat #7 Post-TTX
O
E
A
V
0
o
N
X
Cat#1
Cat#2
Cat#3
Cat#4
Cat #5
Cat #6 Pre-lX
Cat #6 Post-TTX
Cat #7 Pre-TTX
Cat #7 Post-TTX
4
90
I*
I
200
200
'
400
I
I
600
800
.
I
1000
Frequency (Hz)
dB Difference
0
2
4
a_
Cn
OW more sensitive
0
o
aO
±1
0
V
V
V
V
a
a]
....................... .. ..........
...........
V
A
W
A
a
A
u
a
V
-2
-A
V
V
RW more sensitive
III
I
'
......
I
,
J
I
200
400
'
.
.
.
I
i
I
I
I
'
I
600
800
1000
Frequency (Hz)
Figure 5-4: TOP: Sound-pressure levels required for a 10upVcochlear-potential magnitude response when the oval window was stimulated. MIDDLE: Sound-pressure levels
required for a 10LV cochlear-potential magnitude response when the round window was
stimulated. BOTTOM: The dB difference between the top and middle plots.
55
'----- '--·----·---···1"*-`·I-r·r-r-·ll·
-
al-
IVCpl=10 VV
hl-
U.,
r
U)
a)
O
Stimulus to Oval Window
o Cat#1
A
o
.4
A
v
V
0.0
o
V
Q,
0
V
V
6i
\l
V
v
A
aP
IS
-0.5
I
200
I
I
'
400
I
8
1000
600
800
1000
o
o
o
m
x
Cat #2
Cat #3
Cat #4
Cat #5
Cat
Cat
Cat
Cat
#6
#6
#7
#7
Pre-TTX
Post-TTX
Pre-TTX
Post-tTX
Frequency (Hz)
1 .U
_
Stimulus to Round Window
a)
co
0
9
o Cat#1
-A
U)
I
0.5
.=
a.
o Cat#2
VV
a V
0
A
Cat #3
v Cat#4
o
v
o
*
o
m
Cat #6 Pre-TTX
Cat #6 Post-TTX
Cat #7 Pre-TTX
z
Cat #7 Post-TTX
v
v
\
0.0
Cat #5
v
-
I
I
I
I
200
400
600
800
'
I
1000
Frequency (Hz)
0.55
Difference
Ao
OW leads
v
0.50
a,
o(D
0
v
V
A
OW lags
v v
0.45
o
Cat #1
o
A
v
-
Cat #2
Cat #3
Cat #4
Cat #5
o
o
m
x
Cat
Cat
Cat
Cat
#6 Pre-TTX
#6 Post-TTX
#7 Pre-TTX
#7 Post-TTX
V
0.40
200
400
600
800
1000
Frequency (Hz)
Figure 5-5: TOP: Cochlear-potential angle when the cochlear-potential magnitude re-
sponse was 10/tV and the oval window was stimulated (relative to angle of Pow).
MIDDLE: Cochlear-potential angle when the cochlear-potential magnitude response was
10,uV and the round windowwas stimulated (relative to angle of PRW). BOTTOM: The
difference between the top and middle plots
56
5.2
Discussion
If the common-mode gain C is negligibly small in magnitude (pressure-difference assumption), when only the oval window is stimulated
Vcp = DPow,
since PRw
(5.1)
0. Likewise, when only the round window is stimulated the pressure-
difference assumption can be expressed as
Vcp = -D PRW,
since Pow
(5.2)
O. Equations 5.1 and 5.2 show that the pressure-difference assumption
requires the cochlear-potential magnitude to be independent of the stimulated window
and the cochlear-potential angle to be dependent on the stimulated window such that
the difference between the cochlear-potential angles when the oval and round windows
are stimulated is 0.5 cycles.
= IDI IPowl
JVcpI = ID IPRw
(5.3)
(5.4)
Vcp = LD+ LPow
/Vcp = ZD + LPRW+ 0.5 cycles
(5.5)
(5.6)
Stimulus to oval window:
Stimulus to round window:
IVcpl
and
Stimulustooval window:
Stimulus to round window:
Fig. 5-4 and 5-5 show that these requirements of the pressure-difference assumption
are approximated when IVcpt =. 10pV. Fig. 5-4 shows that the ratio between the ovalwindow and round-window sound pressures, when Vcpl = 101&V,is never greater than
2.5 dB and this ratio is often ±0.2 dB. Fig. 5-5 shows that the difference in cochlearpotential angle between the responses obtained from an oval-window and round-window
stimulus is nearly 0.5 cycles.
57
Differences between the results shown in Fig. 5-4 and 5-5 and the pressure-difference
assumption can be interpreted as a combination of measurements errors and contributions of the common-mode response. A general representation of the single-sided stimuli
responses uses Equation 3.1 when the oval and round windows are stimulated, respectively.
Stimulus to oval window: Vp = D Pow + 2C Pow
(5.7)
1
Stimulus to roundwindow: Vcp = -D PRW + -C
PRW
(5.8)
Equations 5.7 and 5.8 could be solved simultaneously to give estimates of D and C.
However, the methods of the next chapter are more robust in the estimates of C. The
single-sided measurements presented here do not control for small amounts of acoustic
crosstalk through the foramen plug; instead the unstimulated window pressure is assumed
zero. Additionally, the cochlear-potential measurements are taken at different times, not
simultaneously, and small changes in cochlear sensitivity can occur and cause small
changes in the measured cochlear-potential response.
If ICI << D I we can ignore the common-mode component and estimate D based on
the pressure-difference assumption and the single-sided stimuli measurements discussed
in this chapter.
Stimulus to oval window): D -
Stimulus to roundwindow:
=
VCP
P
Pow
Vcp
PRW
(5.9)
(5.10)
Estimates of D as a function of stimulus level are shown in Fig.5-6 for the single-sided
measurements of Fig. 5-1, 5-2, and 5-3. Estimates of D as a function of stimulus level for
all other single-sided measurements are included in Appendix B. These estimates of D
can be used as a measure of the linearity of a single-sided cochlear-potential measurement;
if the cochlear response is linear then both ID1 and ZD are independent of stimulus level.
58
Fig.5-6 showsthat the estimates of D are dependent on sound-pressure level;therefore
Vc p is not linear. The variations in D are largest at the lower sound-pressure levels.
The dependence of D on level at 1000 Hz is prominent in both magnitude and angle;
this dependence is much reduced after the application of TTX. The level dependency at
300 Hz is small compared to those at 1000 Hz and 100 Hz and it too is reduced after
the application of TTX. At 100 Hz, nonlinearities in Vcp are present both before and
after the application of TTX; the level dependence of LVcp seems to be reduced after
the application of TTX.
Level dependencies in D shown in Appendix B are not consistent for one frequency
across cats or for one cat at all frequencies. In several cases the estimate of DI varies
by one to two orders of magnitude and the estimate of ZD varies by nearly 0.5 cycles
as a function of sound-pressure level (Fig. B-3, B-4, B-6, B-9, B-10, B-29 and B-33, pre-
TTX). In other cases the estimates of IDI and LD are nearly constant as a function of
sound-pressure level (Fig. B-7, B-18, B-19, B-27, B-31 and B-33, post-TTX).
The difference-mode gain D appears to be level dependent, at least in some cases.
At 1000 Hz the nonlinearities may be a result of the CAP contribution to the cochlear
potential since D becomes nearly independent of level after the application of TTX.
But the source of nonlinearity at 100 Hz is not clear. It could be argued that the TTX
was not as effective for the lower frequencies because the TTX did not permeate the
entire cochlea; neurons with the ability to phase-lock to a 100 Hz tone extend further
toward the apex of the cochlea than neurons with the ability to phase-lock to a 1000 Hz
stimulus. It is possible that the lower frequency stimuli evoked responses from apical
neurons whose CAP's were unaffected by the TTX. It is also possible that the more
apical hair cells have a nonlinear response.
59
Br*r
I~I--Il~l--r~---r
-----
~-----
~I
ZD Estimate
IDI Estimate
100 Hz
2
_
-5
10
^'^
/~1
1'1.
U
I
'V
I-
4
0U)
I
2
Cs
a)
0 -.5
0
-6
10
_
100 Hz
4
*-- /LU UVV: 'OSt- I I A
ZD RW: Post-TTX
2
-
I
I
I
I
60
80
100
120
-1
I
60
1I
80
I
100
120
0
I .
Z
v
10
4
0C0
2
2
7
10
80
80
60I
60
4
4
-
o
~~
'
2
-..IDI:OW Pre-TTX
10:
l---RW Pre-TTX
--. . IDi:OW Post-TTX
IDI:RW Post-TTX
I
i i
I
I
60
80
100
120
i
r,,"
~~I
,-,
c)
a,
OW: Pre-TTX
RW: Pre-TTX
OW: Post-TTX
RW: Post-TTX
*
I
0
0
(L 10
ZD
--- ZD
..o. ZD
ZD
*..
-1
-1000 Hz
2
300 Hz
_
__1
120
120
100
100
-.5
0
IDI: OW Pre-TTX
-..- IDI: RW Pre-TTX
*.. IDI: RW Post-TTX
IDI: RW Post-TTX
-...
4
10
a)
300 Hz
6
0C 10
O
4
C)
:
E'a
---1nn'
· · II II
J
·
LI
,L
..z. D OW: Pre--TTX
--- ZD RW: Pre- TTX
. D OW: Posit-TTX
ZD RW: Pos :-TTX
.5
\.e
4
2
106
-
60
80
I
I
100
120
-1
-
I
I
I
I
I
I
I
I
60
80
100
120
Level (dB SPL)
Level (dB SPL)
Figure 5-6: Estimates of D from the single-sided cochlear-potential measurements on
Cat #6 both before and after the application of TTX. TOP: 100 Hz. MIDDLE: 300 Hz.
BOTTOM:
1000 Hz.
60
Fig. 5-7 and 5-8 summarize the estimates of D found from measurements on all seven
cats. The estimate of D is reported for the level at which the interpolated cochlearpotential magnitude was 10u/V. There are not large differences between the estimates
of D found from the stimulus to the oval window and stimulus to the round window
cases. Inter-frequency variations for one cat are larger than inter-cat variations for one
frequency. In general, IDI increases with frequency and LD decreases with frequency.
This result is further discussed in Chapter 6.
61
_UC__II___Unl__ll1__11
· UI
IC
·-I ·
V-l-----
I._-
IVCpl=10 RV
Stimulus to Oval Window
I
1 0-5
9
0
4
(1
Nv
2
9
CI
1 0-6
v
o
0
A 'Cat #3
v Cat #4
Cat #5
o Cat #6 Pre-TTX
o Cat #6 Post-TTX
4 Cat #7 Pre-TTX
X Cat #7 Post-TTX
0
o Cat#2
A
V
0
V
4 -V
-a
2 -a
7
a
A
0
·
2 I
·
200
·
I
r
400
I
I
I
600
800
Cat #1
I
A
[
0
50
10
v
I
·
I
1000
Frequency (Hz)
Stimulus to Round Window
2
5
1 0cS
4
0.o
Iv
2
0
'
10 6
V
a
o
[
A
V
o
O
4
X
A
M
0
a
0
0
v
a-
Vo
A
50
41 'V
0
13a
Cat #1
Cat #2
Cat #3
Cat #4
Cat #5
Cat #6 Pre-TTX
Cat #6 Post-TTX
Cat #7 Pre-TTX
Cat #7 Post-TTX
A
10
.
,
.....
.
,
I
I
I
200
400
600
I
.
I
I
800
1000
Frequency (Hz)
10
_m
Difference
0
5
co
VV
9
0
V
o
-5
-10x10 7
a
0
A
V
VV
I
I
I
200
400
600
I
I
800
A
V
0
o
o
m
X
Cat #1
Cat #2
Cat #3
Cat #4
Cat #5
Cat #6 Pre-TTX
Cat #6 Post-TTX
Cat #7 Pre-TTX
Cat #7 Post-TTX
'
1000
Frequency (Hz)
Figure 5-7: Estimates of ]IDtfound from Equations 5.9 and 5.10 at a sound-pressure level
such that IVcpl = 10rtiV.
62
IVCi=l10 gV
,\r
U.53
Stimulus to Oval Window
m
A
z
CD
0
0.0 I
V31
O v
211
V
\l
V
v
T
A
0
-0.5
·I ' . ,
200
A
U.0
a
, . I ,..
I
I
I
400
600
800
Frequency (Hz)
1000
Stimulus to Round Window
7-
o Cat#1
-A
VV
C3
0.0
V
m
0
Mv
g
v
V
v
,q
z
a
-0.5
_
O
A
V
0
o
N
X
Cat#2
Cat#3
Cat#4
Cat #5
Cat #6 Pre-TTX
Cat #6 Post-TTX
Cat #7 Pre-TTX
Cat #7 Post-TTX
__
I
I
I
200
'
I
I
400
600
800
Frequency (Hz)
0.05
C,
C.)
O Cat #1
O3 Cat #2
A Cat#3
V Cat #4
- Cat #5
o Cat #6 Pre-TTX
o Cat #6 Post-TTX
M Cat #7 Pre-TTX
X Cat #7 Post-TTX
1000
Difference
o Cat#1
O
A
V
O
o
N
x
0.00
6
$
0
(9
v
_v
(3 -0.05
V
vv
v
Cat #2
Cat#3
Cat#4
Cat #5
Cat #6 Pre-TrX
Cat #6 Post-TTX
Cat #7 Pre-TTX
Cat #7 Post-TTX
-0.10
I
200
I
'
400
I
,
600
I
i
800
1000
Frequency (Hz)
Figure 5-8: Estimates of the angle of D found from Equations 5.9 and 5.10 at a
sound-pressure level such that
Vcpl =- 10y
63
4"IIII"~""~""""""UI"~"~~-11111
· liL-·~·~·I~·SIBII~·I
-- LI-
-
64
Chapter 6
Results: Stimuli to both windows
6.1
Experimental results
Simultaneous-stimuli measurement sets were made by stimulating both the oval and
round windows and varying the phase difference b between the two stimuli over one
cycle. All such measurement sets are shown in Appendix C. The discussion in this
chapter emphasizes measurements from Cats #4, #5, #6, and #7 because errors in the
pressure measurements of Pow and PRW were smaller during these later experiments.
Fig. 6-1 and 6-2 show simultaneous-stimuli measurement sets made at 1000 Hz on
Cat #7 with sound-pressure level as a parameter; the data in Fig. 6-1 were taken before
the application of TTX and the data in Fig. 6-2 were taken after the application of TTX.
The cochlear-potential magnitude and angle measurements are plotted as a function of
'b, the phase difference between the oval and round-window sound pressures. The left-
hand plot is the cochlear-potential magnitude, the middle plot is the cochlear-potential
magnitude in the region around ,b
0, and the right-hand plot is the cochlear-potential
angle. Data points where Vcpl > Noisefloor
65
·i___lU__rr__UMUU_··--··--L·-··-*IUU
are represented by open circles and data
IVCPI
(dB re 1V)
IVcpI (dB re 1V)
/Vcp
(cycles)
0.5
-80
-80
o Data points
-100
-100 _
-120
-120
Linear fit
--- Logarithmicfit
0
-140
.........................
I 1I
-0.5
I
1 1 1 1 I
-140
...................
1 1 1 1 I
0
...............................
r
-
-
- -
-0.01
0.5
.9.
I
1
0
0.01
-0.5
-0.5
0
0.5
-80 _
-80
-100
-
-100
A
0
-120
-120
-140
-140
0
0.5
yi (cycles)
-0.5 I
|
I
-0.5
5..
................................
I
-0.01
0
Vy (cycles)
-.
0.01
-0.5
·
.
°
·
'
!
I
o
0
·
i
I
0.5
Vi (cycles)
Figure 6-1: Simultaneous-stimuli measurement sets and model fits at 1000 Hz on Cat
#7 before the application of TTX.
66
/Vcp (cycles)
IVcpl (dB re 1V)
IVcpl (dB re 1V)
U.
-80
_
-80
,
m
o Data points
Noisy data points
Linear fit
- -- Logarithmicfit
-
-100
-100
-120
-120 _
4,
0
10O0e_7
-140
-.... noisefloor...
'I
i
.
-..
.
.
.
-0.5
89dB SPL
.......................
I
.
.
.
.
-
.
-
0
-140
I
0.5
e,,,,
. ... .........
..... ............
l
-0.5
I ,·
-0.01
0
l
-0.5
0.01
l
l
l
L
l :
II
l
l
0
l
I
II
l
0.5
0.5
-80
-80 _
-100
-100 I0
-120
-140
-120
1000_7
99 dB SPL
......................................
.
.
.
.
.
.
a
,
.
.
.
.
.
.
-
.
-
.
.
0
-0.5
-140
.....
.
-
1.I
""
0.5
*
-0.01
.
I.
"""a
0
-0.5
""
-0.5
0.01
i 2 0 M 1-4
0
0.5
0.5
-80
-80
-100
-100 I-
-120
-120
'"-0.5
0
'L
-140
..............................................
I1
-
-0.5
.
.
II
II
.
0
.
.
-140
0,0~1 "
.....................................
l
I
!
,
·
!
-0.01
0.5
0
·
,
I
0.01
-0.5
0
0.5
0
0.5
0.5
-80 I
-80
-100
-100 _-
-120
-120
-140
-140
_
_
.
0
-.
J
-0.5
0
0.5
-0.01
I.I
.
..
0
Nf (cycles)
NY(cycles)
'
I
.
0.01
-0.5
-0.5
N(cycles)
Figure 6-2: Simultaneous-stimuli measurement sets and model fits at 1000 Hz on Cat
#7 after the application of TTX.
67
nirrzrr,,lmr·rrur*rXr*uglg·uqunr
·
------
points where Vcp < Noise floor are represented by open ovals. Each plot has a label
associated with it to identify the measurement order; for example the label "1000e_7"
refers to the fifth measurement made on Cat #7 at 1000 Hz. The measurement sets
are plotted in order of increasing stimulus level and not chronological order, and the
sound-pressure level printed on the magnitude plot is the measured sound-pressure level
of both IPowl and IPRwl.
Several features of the measurement sets shown in Fig.6-1 and 6-2 are seen in all of the
measurements shown in Appendix C. The cochlear-potential magnitude plots are roughly
symmetric about Ob= 0. A magnitude minimum occurs at an inter-window stimulus
phase differenceObMIN - Ocycles. A magnitude maximumoccurs near
= 0.Scycles and
is always close to the sum of the two cochlear-potential response magnitudes recorded
when the oval and round windows are individually stimulated.
The dynamic range
of a given measurement set, the dB difference between the maximum and minimum
cochlear-potential
magnitude, is roughly 40 dB when IPowl z IPRwl. The dynamic
range is sometimes limited by the noisefloor, especially when Powl and IPRwI are at
lower values.
In general, the cochlear-potential angle data points increase with increasing values of
b0except for a sudden 0.5 cycle shift at p t 0. However, for some of the ears deviations
from this pattern occur, especially at the lower frequencies, as illustrated in Fig. 6-3 with
examples from five of the seven experimental animals. Between 'b = -0.5 and b = 0
the cochlear-potential angle increases with increasing Oiand shifts by about 0.5 cycles at
b = 0. But between pb= 0 and b = 0.5 the cochlear-potential angle does not increase
at the same rate as it increased between b = -0.5 and 0b= 0. In fact, the cochlearpotential angle remains roughly constant between ,b = 0 and 0b = 0.1 for the examples
68
_
=
fs
m
U.O
_
0O
=
75a_4, 124 dB SPLI
75b_4,120dB SPL
U.D~~~~
IA
I[
03
z
0
0~
A
-0.5
0
(D
0
0
N
E
ka a o
A
a
-1.0
-0.5
- - - - - - - - i
-0.5
0
0.5
I
F.5
0.5
-0 .5
A1 300c_5, 10dBSPL
0
0.5
I A Post-TTX: 300d?, 121 dB SPLI
i
1.0
Pre-TTX: 100b_7, 127 dB SPLI
Post-TTX: 100d_7, 126 dB SPL
iI L
1.0
I
A
A
in
co
C,,
A
0
A
A
A
A
__
0.5
\ia.
0.5
A. AA
AA
N
&AAAAAAAA
I
0
.
.-
I
.
0
I
-0.5
0.5
0
0
~
_
~~_"._.
1 .U
IJ
L_
I
-0.5
A
A40
0.5
0
_
400d_3, 114 dB SPL I
&
,
co
<D
0
A
A
A
-0.5
0.5
a-
F-^
JAA A
0
.AI
^A
A
LA
N
&AAA
A&
'L A
A 400a.2, 114 dB SPL
-1.0 -0.5
T1
-0.5
.
.
.
.
I
.
.
0
r{
0
.
-0.5
0.5
,
,
|l
0
.
I
0.5
v (cycles)
yV (cycles)
Figure 6-3: Cochlear-potential angle measurements as a function of b, the phase difference between the pressure at the oval and round windows. These measurements were
selected to demonstrate an asymmetry around b = 0. The legends identify the frequency
of the measurement, the measurement order on a given cat, and the cat on which the
measurement was made.
69
"~""l~""~""-~"~~p"~~"~W~~~"U····-----_
I
shown in Fig. 6-3. To test if this asymmetry about b = 0 is a result of the order in which
the data points were collected, data points from Cat #5 were collected both in order of
increasing b and in a random order; there was no appreciable difference in the shape
of the curve. The asymmetry could also be a result of nonlinear behavior of the neural
component of the cochlear potential. The example from Cat #7 at 100 Hz in Fig. 6-3
shows that TTX did not affect the asymmetry, but TTX did not have large effects on
the single-sided cochlear potential measurements at 100 Hz on Cat #7 either (Fig. B-7).
The cause or mechanism of the angle asymmetry is not known.
There are not large differencesbetween the pre-TTX measurement sets and the postTTX measurement sets on either Cat #6 or Cat #7. The biggest differences occur at
1000 Hz; 1000 Hz pre and post-TTX measurement sets are compared in Fig. 6-4. Differ-
ences between the pre and post-TTX measurement sets were expected to be most obvious
around ~p= 0 because single-sided level series measurements showed that TTX had the
biggest influence on Vcp at the lower stimulus levels or when VcPI < -120 dB re 1V
(Fig. B-33 and B-34). The only pre-TTX simultaneous-stimuli measurement set at 1000
Hz on Cat #7 which includes data points such that IVcp < -120 dB re 1V is shown
in Fig. 6-1 and is labeled "1000b_7". Comparison of this pre-TTX measurement with
the post-TTX measurement set in Fig. 6-2 labeled "1000d_7" shows nearly equivalent
results in the region around ~p= 0, the region where the TTX was expected to have
the biggest effect on the result (Fig. 6-4). Instead, the biggest difference between the
pre and post-TTX measurements is an approximate 5 dB decrease in cochlear-potential
magnitude after the application of TTX; this decrease is most easily seen in regions
where
4p;
0.5 and in the single-sided measurements of Fig. B-34. Fig. 6-4 also compares
the pre and post-TTX simultaneous-stimuli measurements from Cat
70
6 at 1000 Hz;
A
a000000
IVcpI (dB re 1V)
(cycles)
ZVcp
0.5
-80 _
[00On-
100
A
A 10
-
L0&3
ooo·
Lo
0 -
1 20
Ar
-140
I
noisefloor
......
Pre-TTX: 1000b_7
Post-TX : 1000d_7
Pre-TTX: 1000b_7
0 Post-TTX: 1000d_7
-0.5
!
0
-C).5
,13
~~i~o°°°
-D
130-Dj
A
...........................................
II
00.5
-
-
-
-
0.5
-100
0
-
-
0. 5
0
0.5
-120
.OO
.
0
1aep
O0r[ ]
-140
-
-0.5
-0.02
0.02
0
OQO
I
i
!
I
-0.02
-0.02
v (cycles)
0.02
0
m (cycles)
LVcp (cycles)
IVcpl (dB re 1V)
0.5
-80
I
&6666666
3A
-100
0
-120
Pre-TTX: 1000a_6
o Post-TTX: 1000c_6
A
-140
-noisefloor
._
.
.
-0.5
-100
-140
.
I
.
.
.
-0.5
-0.5
0.5
0.5
0
A
.
I
0.!5
0
0.5
a 0 0
0
-120
Pre-TTX: 1000a_6
o Post-TT(: 1000c_6
.................................
A
0
... ................................
I
..................
I
-0.02
0
V
-0.5 _
I
0.02
-0.02
(cycles)
.d
.
-~~~~
0
I
0.02
,W (cycles)
Figure 6-4: Comparison of pre and post-TTX cochlear-potential measurements as a
function of 7b,the phase difference between the pressure at the oval and round windows,
when the oval and round windows were stimulated with nearly equal sound-pressure
levels. TOP: Cat #7 measurements at 99 dB SPL. BOTTOM: Cat #6 measurements
at 104 dB SPL.
71
~~LI~--I~IX
II l~
l
lr-I· II~U·-IC~·--··l·
·sl
-
~
------
there are slight differences in the cochlear-potential magnitude and angle around 0b= 0.
These differences could be a result of the TTX, or differences between pre and post-TTX
measurements could also be caused by slight changes or imbalances in IPowl and IPRwl.
6.2
Model fits to the data: Estimation of C and D
We estimate the difference-mode and common-mode gains using the methods described
in Chapter 3. The measured values of Vcp, Pow, and PRW at each and every data point
are used to determine the estimates D and C that produce the least-squares difference
to Equation 3.4 ("linear fit") or Equation 3.14 ("logarithmic fit") for each measurement
set. The model fits to the cochlear-potential data, Vcp, obtained from Equation 3.4 and
Equation 3.14 are included on the plots of the simultaneous-stimuli measurement sets
in Appendix C and Fig. 6-1 and 6-2. There are not large differences between the results
of the two fitting procedures; the discussion here will concentrate on the linear fit of
Equation 3.4.
Many general aspects of the model fits are consistent with the data: the magnitude
maxima from both the fits and the data are nearly the same and both occur at b - 0.5,
the magnitude minimum from both the fits and the cochlear-potential data all occur at
b -_0, and the angles of both the models and the cochlear-potential data change rapidly
by about 0.5 cycles at b b 0. Differencesbetween the linear and logarithmic fits are so
small that in most cases the two plots are nearly indistinguishable. The major difference
is illustrated in Fig. 6-1 (measurement "1000a_7") and Fig. 6-2 (measurement "1000f_7").
The largest deviation between the linear model fit and the cochlear-potential data occurs
near
= 0 because the magnitude of the cochlear potential is small in this region and
large fractional differences are not weighted strongly in the linear-least-squares fit of
72
Equation 3.4. The logarithmic fit does a better job fitting Vcp to the data points near
b = 0 but the fit near p = 0.5 is not as good as the linear model fit.
The linear model predictions of D and C from Equation 3.4 are summarized in Fig.65 for all measurement sets on Cats #4 to #7. The estimates of IDI are more than an
order of magnitude greater than the estimates of C, and the magnitudes of both gains
increase by approximately an order of magnitude as frequency increases from 75 to 1000
Hz. The estimates of IDI have a smaller standard deviation than the estimates of CI
on a logarithmic scale, and the estimates of LD have a much smaller standard deviation
than the estimates of LC.
The common-mode rejection-ratio (CMRR) is calculated for all measurement sets
using Equation 3.3: CRR
= 20logo- D . CRR
values are shown in Fig. 6-6 and
do not appear to be a function of frequency. The mean values of CMRR
range from
27.5 dB (75 Hz) to 34.5 dB (800 Hz). The lowest CIMRR is 18.6 dB at 300 Hz and the
highest CMRR
is 53.8 dB at 100 Hz. The variation in CMRR
is not surprising since
the standard deviation of C is large and CMiRR is calculated from C.
The correlation coefficients calculated for the model fit to each measurement set using
Equations 3.20 and 3.21 are shown in Fig. 6-7. In general, the magnitude correlation
coefficients are higher than the angle correlation coefficients. With the exception of
the two measurement sets at 75 Hz, the mean magnitude correlation coefficients are
all greater than 0.95, and the mean minus the standard deviation of all magnitude
correlation coefficients is greater than 0.9. The mean angle correlation coefficients are
all greater than 0.85, and the mean minus the standard deviation of all angle correlation
coefficients is greater than 0.7 (with the exception of the two measurement sets at 75
Hz). The angle correlation coefficients are more difficult to describe and less meaningful
73
-vA
o
o
o
10
Mean and std of IDI (shifted -20 Hz)
Cat #4 IDi (shifted -10 Hz)
Cat #5 IDI (shifted 0 Hz)
Cat #6 IDI (shifted 10 Hz)
Cat #7 IDI (shifted 20 Hz)
co
0
1 06
--
Mean and std of ICI (shifted -20 Hz)
Cat #4 ICI (shifted -10Hz)
* Cat #5 ICI (shifted OHz)
* Cat #6 ICI (shifted 10Hz)
* Cat #7 ICI (shifted 20Hz)
A
cr
(I,
10
7
o
CO
1 0 '8
I
i
I
_I
-
0
~~~ ~ ~
.
200
400
.
ii
ii
- '
0
I
I
600
800
1000
1.5
to
0
-0
1.0
0.5
I
-w*
*
*
*
r
N
Mean and std C (shifted -20 Hz)
Cat #4 ZC (shifted -10 Hz)
Cat #5 C (shifted 0 Hz)
Cat #6 C (shifted 10 Hz)
Cat #7 ZC (shifted 20 Hz)
0
-0.5
I
I
0
*
I
I
200
.
*
I
I
I
400
600
.
'
I
I
800
.
I
I
-v-Mean and std D (shifted -20 Hz)
A Cat #4 D (shifted -10 Hz)
o Cat #5 D (shifted 0 Hz)
o Cat #6 D (shifted 10 Hz)
o Cat #7 ZD (shifted 20 Hz)
1000
Frequency (Hz)
Figure 6-5: Estimate of D and C for each measurement set from Cats #4 to #7. D
estimates are represented by open symbols and C estimates are represented by closed
symbols. Because most of the measurements were at 100, 300, or 1000 Hz the plotted
points tend to overlap. To increase legibility, points for a given cat are shifted right
or left by a small amount, as indicated in the keys. TOP: Magnitudes of D and C.
BOTTOM: Angles of D and C.
74
ju -
A~
-V-
Mean and std (shifted -20 Hz)
A
Cat#4 (shifted-10 Hz)
o
o
o
O
O
Cat #5
Cat #6
Cat #7
50 - I-
(shifted 0 Hz)
(shifted 10 Hz)
(shifted 20 Hz)
o
o
.-
o
40-
C.
Do
O
300]
,o
20-
I-
13
o
0
0
10- l
-
II
I
I
I
I
0
200
400
600
800
1000
Frequency (Hz)
Figure 6-6: Calculation of the common-moderejection-ratio (CMRR) from the estimates
of D and C for each measurement set from Cats #4 to #7. Because most of the measurements were at 100, 300, or 1000 Hz the plotted points tend to overlap. To increase
legibility, points for a given cat are shifted right or left by a small amount, as indicated
in the keys.
75
3·ll---·-S
·
ll1llC-·1 -
_
1.0
r-'
-7
AO
~
£0~
0
o
CD
0.8
A
I.
0o
4qm
0Q
Q-
0.6 _
-VA
Mean and std (shifted -20 Hz)
Cat #4 (shifted -10 Hz)
o
Cat #5 (shifted 0 Hz)
O
0
Cat #6 (shifted 10 Hz)
Cat #7 (shifted 20 Hz)
0.4
-
II
1.0
400
200
0
I
600
800
1000
m
0
0.8
I--'
N
a-
0
0.6
03
I.A
0
O
o
Cat #5 (shifted 0 Hz)
Cat #6 (shifted 10 Hz)
Cat #7 (shifted 20 Hz)
0.4
a
[]
_
0
0
.i.
ii
200
400
600
800
1000
Frequency (Hz)
Figure 6-7: Correlation coefficients calculated for each model fit from Cats #4 to #7.
Because most of the measurements were at 100, 300, or 1000 Hz the plotted points tend
to overlap. To increase legibility, points for a given cat are shifted right or left by a small
amount, as indicated in the keys.
76
than the magnitude correlation coefficients because the angle data is periodic with a
period of 1 cycle and the computed angle correlation coefficients can change when the
angle data takes different values, or is "unwrapped" around different points.
Fig. 6-8 compares the estimates of D found in Chapter 5 to those found here. The
analysis in Chapter 5 assumes C = 0 and D is estimated as a function of level from the
single-sided level-series measurements. The estimates plotted in Fig. 6-8 are the means
computed from Cats #4 to #7 using the results of Fig. 5-7 and 5-8. Pre and post-
TTX measurements for Cat #6 and #7 were made; only pre-TTX measurements are
included in the mean estimates shown in Fig.6-8 so that the results from these cats don't
dominate the results. Standard deviations are not included because each mean estimate
from Chapter 5 is computed from only one to four data points.
The simultaneous-
stimuli measurement points in Fig. 6-8 are the mean values previously shown in Fig. 6-5.
There do not appear to be large differencesbetween the two methods of estimating the
difference-mode gain D.
6.3
6.3.1
Discussion
General model behavior
In the model described by Equation 3.1 Vcp depends on both the magnitudes and angles
of the two complex constants D and C. This section illustrates how the model's behavior
depends on these quantities; the magnitudes and anglesof D and C are specificallychosen
and Response defined by Equation 6.1 is computed. The signals "waveA" and "waveB"
are sinusoids of the same frequency and the variable Obdescribes the phase difference
77
-lll·--·-·IUIIIIIU··l
_I_----
-- IL__
10
5
co
CO
c()
Q.
O
10
n
0
200
400
600
800
1000
U.0
-V-- o-
Mean ZD:
Mean ZD:
simultaneous stimuli
single-sided stimuli
o)
0
,\
0
-0.5
·
0
.
!
I
!
200
!
!
!
400
.
!.
I
!
!
600
I
!
800
.
!
1
1000
Frequency (Hz)
Figure 6-8: Mean estimates of D using single-sided stimuli (Chapter 5) and simultaneous
stimuli (Chapter 6). The single-sided mean values of D are computed from the data
shown in Figures 5-7 and 5-8; only data from Cats #4 to #7 are used, and for Cats #6
and #7 only the pre-TTX single-sidedstimuli measurements are used. The simultaneous
stimuli mean values of D were previously shown in Figure 6-5.
78
between them.
Response = D(waveA - waveB) + IC(waveA + waveB)
(6.1)
Common-mode gain of zero
A simple form of Equation 6.1 is to assume C = 0.
Response = D(waveA - waveB)
(6.2)
Equation 6.2 is the pressure-difference assumption of Equation 1.1; three interesting
cases of Equation 6.2 are illustrated in Fig. 6-9.
1. Fig. 6-9A shows the case of IwaveAl = waveBI and D = 1. Responsel goes to
zero at bp= 0 and LResponse shifts from -0.25 cycles at
= 0- to -0.75 cycles
at ' = 0+.
2. Fig. 6-9B shows the case of IwaveAl = IwaveBI and D = j.
IResponsel goes to
zero at p = 0 and ZResponse shifts from 0 cycles at 4p= 0- to -0.5 cycles at
4p= O+ .
3. Fig. 6-9C shows the case of IwaveAl = 2waveBI and D = 1. Responsel goes to
a nonzero minimum of IResponsel = IwaveA - waveBI at 4' = 0 and LResponse
shifts from -0.25 cycles to 0.25 cycles near 4 = 0, but the phase shift is more
gradual than the cases where IwaveAj = IwaveBI.
To summarize, C = 0 requires Responsel to be a minimum at 4 = 0. This minimum is zero only when IwaveAl = IwaveBI. When IwaveAl = IwaveBI,
Response is
undefined at 4b= 0 because Responsel = 0. In general, ID affects IResponsej, and LD
affects LResponse. Differences between the magnitudes of the two input waves, IwaveAl
and IwaveB}, can have big effects on Responsel at values of b near zero; when these
magnitudes are not equal it is impossible for Responsej to reach zero.
To connect these examples to the experiments of this thesis, suppose that Pow =
waveA, PRW = waveB, Vcp = Response, and the common-mode gain is zero. This
79
_IlR__
III
1111111
*11---___·11
IResponsel
ZResponse
0
1 01
D=1
IwaveAl = IwaveBI = 1
: f = / (waveA) -
1 00
r .
"
\
(waveBl
1)
U)
-1
10
c
O
0n
0c) -0.5
-2
10
rC
oU
Ul
-3
10
-4
10
-
.
.
.
...r
-0.5
.
1
.
.
.
-1.0
I
!
Fm·
!
. !
-
-0.5
0.5
0
L
. . . . I
-
-
-
0.5
0
V
y (cycles)
:
(cycles)
0
1 01
1 00
()
c0
a)
-4
10
D=j
IwaveAl = IwaveBi = 1
-6
.3
10
-0.5
U)
o
-2
10
nC
0
-1
10
= Z (waveA) - Z (waveB)
. . . .
-0.5
.
.
.
.
·
;
I..
!
: -
!_
0.5
0.5
r
(D
C:
c
-1
0
rcoN.
0
(D,
U
0 -2
CD1 0
D=1
N
IwaveAl =2*lwaveBI = 2
= Z (waveA)- Z (waveB)
10 - 3
.
4
.
-0.5
-
f (cycles)
0
10
...
-
.
-
0
(cycles)
1 0°
c: 1 0
F--,
-0.5
1 01
0
I - - - -
.
0.5
0
V
-1 .
I
.
. .
.
.
-
-
0
.
.
.
-0 5 I E. . . .
.
V.w
-0.5
0.5
y (cycles)
.
.
.
r
0
.
.
I
.
0.5
xV (cycles)
Figure 6-9: Model behavior when C=0 and (A) D=i, IwaveAl = IwaveBI; (B) D=j,
IwaveAI = IwaveBI; (C) D=I, IwaveAI = 21waveBI .
80
situation is described by the pressure-difference assumption (Equation 1.1). Under these
conditions Vcpl should be limited by the noisefloor at b = 0 whenever IPowl = IPRwI.
During most of the measurements, attempts were made to keep IPowI = IPRwI, but it
was not uncommon for IPowl to differ from IPRWI by about 0.05 to 0.1 dB SPL (the
resolution of the attenuators which set IPowl and IPRWI was 0.1 dB). If IPowl
IPRwI,
the dynamic range of the magnitude response is limited
Maximum
Response
Dynamic Range = Minimum Response
IVcpl-o=0.5 IPOW+ PRWI
IVcPI,=O
IPow - PRWI
(6.3)
The following example illustrates the effect of a small difference between IPowl and
IPRwI on the total dynamic range of the response. Suppose
IPowl = 2 Pa = 100dB SPL
(6.4)
IPRwI= 2.01 Pa = 100.05dB SPL.
(6.5)
and
The maximum response is proportional to the maximum effectiveinput stimulus
I(Pow-
PRW)Jp=0.5= 4.01 Pa ~ 106 dB SPL
(6.6)
and the minimum response is proportional to the minimum effectiveinput stimulus
I(Pow - PRw),0=o = -0.01 Pa z 55 dB SPL.
(6.7)
The total dynamic range is the ratio of these two values.
Dynamic Range = 51 dB
(6.8)
IPowI and IPRwI differ by only 0.05 dB SPL in this example, but the dynamic range
is 51 dB.
Most of the measurement sets shown in Appendix C have dynamic ranges
between 40 and 50 dB.
The observed dynamic range is limited not only by our ability to set IPowI = IPRWI,
but also by our ability to measure a response at exactly b = 0. If IPowI = IPRWIbut
the measurement made closest to LPo w = LPRW is really LPow = LPRw + 0.01 cycles
81
rUII__·__N_______C_____I_·IIU·IIY·-PI
such that ,p = +0.01 cycles, the maximum dynamic range of Vcpl is limited to 26 dB.
Here is an example to illustrate this limitation. Suppose
IPowl= 2 Pa = 100dB SPL
(6.9)
IPRWJ= 2 Pa = 100dB SPL.
(6.10)
and
The maximum response is proportional to the maximum effective input stimulus
I(Pow - PRw)I0=o.5= 4 Pa - 106dB SPL
(6.11)
and the minimum response is proportional to the minimum effective input stimulus
I(Pow - PRW)I,=O.Ox
= 12- 2e001 'j Pa - 0.13 Pa m 80 dB SPL
(6.12)
The total dynamic range is the ratio of these two values.
Dynamic Range = 26 dB
In the same way, a measurement made such that
measurement made to
4' =
(6.13)
= +0.001
±
cycles is the closest
0 gives a maximum dynamic range of about 55 dB.
It is clear that mismatches in magnitude as small as 0.05 dB in magnitude and
0.001cycles in angle can have severe effects on the minimum Ivcl
value that is measured
in a given measurement set, if C = 0.
Non-zero common-mode gain
This section presents examples constructed to examine the behavior of Equation 6.1
when both IDI and ICi are nonzero. Only cases where IDI >> CI are presented because
the experimental results and model predictions shown earlier in this chapter suggest that
IDI >> jCl for the cat cochlear system. The examples here use DI = 1 and ICl = 0.1
which corresponds to CMRR
= 20 dB. Smaller values of CJ are not used because as the
difference between IDI and ICI increases (as CMRR increases) it becomes more difficult
to observe visually the effects of C on Response in Equation 6.1. Three interesting cases
are illustrated in Fig. 6-10.
82
1. Fig. 6-10A shows that when D and C have the same angle, and ID} >> C,
IResponsej is a minimum at Ob= 0 and LResponse makes a 0.5 cycle transition
near b = 0. The difference between this case and the one shown in Fig.6-9A, where
C = 0, is that at 0b = 0 the minimum in magnitude is limited by the commonmode component to be C(waveA + waveB) and can never be zero, and the angle
changes more slowly around
= 0.
2. Fig. 6-10B shows that when D and C differ in angle by 0.25 cycles the minimum
value of Responsel does not occur at Ob= 0, the 0.5 cycle transition in angle is
not centered at ~b = 0, and the minimum of IResponsel is zero. For this special
case Responsel = 0 at b = 0.016 cycles (see discussion below). Additionally, the
dynamic range of IResponsel is infinite (only 70 dB shows due to finite sampling
resolution), but CMRR is still 20 dB.
3. Fig. 6-10C shows that when D and C have angles that differ by amounts other
than ±j, the minimum value of Responsel does not generally occur at b = 0, the
0.5 cycle transition in angle does not generally occur at b = 0, and the minimum
of Responsel is not generally zero. For this case the minimum value of IResponsej
occurs at b = 0.01 and the minimum of IResponse is 0.07.
To summarize, when IDI >> ICI and LD = LC, IResponsel goes to a minimum at
00b=
and this magnitude minimum is determined by {C. When LD and LC are not
equal the magnitude minimum does not occur at -b= 0 and Responsel can have a larger
dynamic range than when
D = LC. For the special case of ZD differing from
C by
±0.25 cycles there exists a value of b, 0b0 , such that Responsel goes to zero. If
Response = 0 = D(waveA - waveB) + C(waveA + waveB)
the ratio
can be determined as
D
1 1+
C 2
where
(6.14)
waveA
__,
__-
1
14+Xej-6
(6.15)
(°
1,, 2 1-XeJ
eA = Xej'o, X is the ratio between {waveAI and IwaveBi, and
0
is the
phase difference between waveA and waveB when Responsel = 0. When X = 1, as in
Fig. 6-10B, the solution of Equation 6.15 can be approximated as
i -1 O
CCD =_ jsin(,bo)
83
(6.16)
lResponsel
ZResponse
0.5
01
1 00
()
0C. 10
0,
CE
26dB
1
r
I
00
0,
2
10
10
-3
10
4
0)
01
D=1
C=0.1
IwaveAl = IwaveBI = 1
yr= Z (waveA) - Z (waveB)
__ .__
=
.
-0.5
..
.
...
- -
-n,.,v
!
.
i
-0.5
0.5
0
_,
!I
;
_._,
0.5
0
-W (cycles)
-r (cycles)
1 01
0
1 00
(C,
co
-1
0. 10
0
a)
0,
Cc
-
10 2
CE
-0.5
D=j
C=0.1
N
10
3
10
-4
IwaveAl = IwaveBI = 1
= Z (waveA) - Z (waveB)
-1.0
-0.5
0.5
0
i
L...
. ..
I
-0.5
0
I
0
0.5
y (cycles)
Nf (cycles)
1 01
0.5
-I1 00
0
0CE
10
a)
c,
29 dB
-1
0r
CEL
0
1 0-2 r-
N
i =IwaveB
.
V
= 1
NaveA)- Z (waveB)
1 0'
-4 F _·
-0.5
.
·
-
-
0
-
-
-0.5
!
-0.5
0.5
v (cycles)
0
0.5
xr (cycles)
Figure 6-10: Model behavior when waveAl = IwaveBI and (A) D=1, C=0.1; (B) D=j,
C=0.1; (C) D = (1+j), C=0.1. In all three cases CMRR=20 dB.
84
or
1
,bo= sin
.C
(j3)
(6.17)
Equation 6.17 has solutions only when ZD differs from LC by +0.25cycles; thus Responsej
can go to zero only under this special condition.
6.3.2
Why is it difficult to estimate C?
We have seen that the dynamic ranges of the experimental measurement sets can be
limited by several factors.
1. Small deviations from IPowl = PRw]
2. The inability to make measurements at exactly bMIN
3. Noisefloors
4. Contributions of a common-modecomponent to the response
It is difficult to separate the effects of these factors from each other and from measurement errors in Pow and PRW.
To better understand the contribution of the difference-mode and common-mode
components to the total cochlear response, as a function of 0b,Equation 3.1 is decomposed. If Powl and IPRwl ae exactly equal then D can be found directly when Ob= 0.5
and C can be found directly when 4b= 0.
VCP
D
Pow - PRW
C
2
VCP
1 C(POW + PRW)
2 POW - PRW
POW
+PRW
D(POW - PRW)
Pow + PRW
VCP
POW - PRW
=2
VCP
(6.18)
VP
2POW
VCP
Pow + Pw I=0= Pow I=o
(6.19)
Equation 6.18 can yield a robust estimate of D even when pbonly approximates 0.5 cycles
because IlcpI is large and does not change rapidly when 'b = 0.5, and the term
is much larger than the term
(PO-W+PRW).
P-PRW However, when
85
VCp
POW-PRW
ICJ << IDI and there are
just slight deviations from Pow = PRW in either magnitude or angle, Equation 6.19
can make large errors in the estimates of C because VcpJ changes rapidly when 'b ~ 0,
and the term 2 Pow+PRW
+P is on the same order as the term D(POW-PRW) Therefore,
Pow+PR
when
ICI<<
IDi, the common-mode response only dominates Vp when Pow = PRW
and the difference-mode response is much less than the common-mode response. It is
difficult to make the difference-mode component of the response go to zero, or at least
become smaller than the common-mode component of the response, because b is never
exactly zero and IPowl is never exactly equal to IPRwJ. As a result, the estimate of C
is highly dependent on both the resolution of the measurement system and errors in a
single measurement, while the estimate of D is not significantly affected by such factors.
6.3.3
How much is the estimate of C affected by small errors in pressure
measurements?
The discussion in Chapter 4 suggests that errors in the measurements of Pow and PRW
are probably less than 0.5 dB in magnitude and 0.01 cycles in angle; here we examine
the effects of such errors on the estimates D, C, and CbMRR. To examine the effects of
the errors in IPowi, IPRWI,LPow, and LPRw, the measured Vcp and PRW values from
the measurement set labeled "1000f7" shown in Fig. 6-2 are held constant while errors
that range from -0.5 to 0.5 dB in magnitude and -0.01 to 0.01cycles in angle are added
to the measured value of Pow. Newestimates of D, C, and CMRR are computed from
Equation 3.1 for each combination of magnitude and angle error.
Fig. 6-11 shows effects on D and C of small errors in the measurement of Pow. The
errors have little effect on DI or ZD but there are large changes in C and LC. The ratio
between the maximum and minimum values of IDI is nearly 1 (1.07), and the difference
86
log
10
log
IDI
10
ICI
-5.36
-5.38
0.01
t6o0
6i
ZC (cycles)
ZD (cycles)
Figure 6-11: Estimates of D and C made for combinations of small errors in the magnitude and angle of Pow. The errors in pressure magnitude range from -0.5 to 0.5 dB
and the errors in pressure angle range from -0.01 to 0.01 cycles.
87
Co
Er
0.5
i d05
Figure 6-12: Estimates of CMRR made for combinations of small errors in the magnitude and angle of Pow. The errors in pressure magnitude range from -0.5 to 0.5
dB and the errors in pressure angle range from -0.01 to 0.01 cycles. Contour lines for
CMRR = 50,40,30,25 are drawn in the CMRR = 0 plane.
88
between the maximum and minimum values of LD is less than 0.01 cycles. However, the
ratio between the maximum and minimum values of C[ is infinite; if the plotted points
had been sampled more densely this would be visible from Fig. 6-11. The angle LC takes
values from -0.5 to 0.5 cycles. Since CMRR
is computed directly from D and C, it is
not surprising that CMRR shows the same type of variation as I;
and angle error where [_C[goes to zero, CMRR
at the magnitude
goes to infinity (Fig. 6-12).
The procedure illustrated here, introducing errors in the measured values of Powl
and LPow and calculating D, C, and CMRR from each synthesized value of IPowl and
ZPow, was performed on all measurement sets from Cats #4 to #7. A plot of CMiRR
such as the one shown in Fig. 6-12 was formed with ranges of ±0.5 dB in magnitude
and ±0.01 cycles in angle from the original measurement.
In most cases a large peak
occurred at some point on the plot (the location varied) while the minimum CIMRR
value was never less than about 20 dB. In a few cases the maximum peak of the mesh
was not contained within
0.5 dB in magnitude and
0.01 cycles in angle from the
original measurement, but part of the peaked area always existed within this range.
The position of the peak in the CMRR vs. Pow error analyses did not stay constant
among measurement sets. In some cases consecutive measurement sets made at the
same frequency and level, and with no movement of the microphone and sound-source
assemblies, predict peaks in the CMRR
plots that are in different quadrants.
This
suggests that something about the cochlear-potential response changed with time; based
on the result shown in Fig. 4-3 it does not seem possible that the microphone responses
could change by up to 0.2 dB in magnitude and 0.005 cycles in angle in a small amount
of time when the microphone and sound-source assemblies were not touched.
To summarize, small errors in Pow and PRW, and possibly small changes in the
89
cochlear-potential
sensitivity, can cause large variations in the estimate C and thus
CMRR. The upper-bound of C, or the lower bound of CMRR, remains approximately
constant for the error range examined here; CMRR
is rarely less than 20 dB at any
frequency for any combination of magnitude and angle error introduced here. On the
other hand, the lower-bound of C, or the upper bound of CMRR, is more difficult
to define. CMRR
has a peak value of infinity (or CI has a minimum value of 0) for
some combination of magnitude and angle error introduced here in almost all of the
measurement sets. These large dependencies of CMRR
and C on the precision of the
pressure measurements coupled with a possible change in cochlear sensitivity over time
makes it impossible to determine an upper bound for CMRR other than infinity from
our measurements.
6.3.4
Comparison to Wever and Lawrence
The experimentally measured minimum of Vcpl occurs at a difference in phase between
the oval and round-window sound pressures b = IbMINdat,a- IMINdata is an interesting
quantity because it helps describe D and C. IfC = 0, ,bMINd,t must equal zero, but more
generally bMINv,,d is also equal to zero when LD = LC (Chapter 6.3.1). In some of the
measurements
bMINda, occurs when Vcpl is below the noisefloor, and the precise value
is not known. However,the minimum magnitude of the model prediction,
of 0bMINdata
is always known. A t-test of the null hypothesis "the
Vcp, which occurs at bMINmodeL,
and the mean value of
mean value of 0bMINdata
kbMINm,de,
are the same", shows that there
are not statistically significant differences between these two mean values at 100, 300,
and 1000 Hz (p = 0.01). Additionally, t-tests of the null hypotheses "the mean value
of bMNdta is equal to zero" and "the mean value of 0MINoe,,
90
is equal to zero", show
that there are not statistically significant differences between the mean value of OMINdat,
and MIlNdata= 0 and the mean value of MINdata and IMINmodel = 0 at 100, 300, and
1000 Hz (p = 0.01). Since the minimum magnitude of the model prediction, Vcp, occurs
at '? =
/MINmodel
O, we use OMINnmdel to represent the experimental
?MINdt.
VbMINdota results.
0.02
*
uI--
a)
0.01
o
0
0
C
r0
4-
0o
_0
._
0
0
o
E
zZ
-0.01
-A
O
O
O
Mean and std (shifted -20 Hz)
Cat #4 (shifted -10 Hz)
Cat #5 (shifted 0 Hz)
Cat #6 (shifted 10 Hz)
Cat #7 (shifted 20 Hz)
-0.02
0
400
200
600
800
1000
Frequency (Hz)
Figure 6-13: ,bMINmodel,the difference in phase between the oval and round-window
pressures at which the minimum magnitude of the model prediction Vfp occurs, for
each measurement set from Cats #4 to #7. To increase legibility, points for a given cat
are shifted right or left by a small amount, as indicated in the keys.
Fig.6-13 plots
1MINmOdel
as a function of frequency;
91
.
_._
.`~"""~~~~"~~-I"~"
?IMINmodel
is within O.02cycles of
0.5
0.4
co
0.3
C.),
z
~.
0.2
0.1
0
8
Z
100
21
4
1b
Z
/U
1000
J
4
3
I/I
10000
Frequency (Hz)
Figure 6-14: Comparison of ObMINdaafrom Wever and Lawrence (1950) with the model
prediction ,bMINmodel from the data presented here. There are minor differences in
,MINmodel and OMINdta found in this thesis; see text for details.
92
IVcpl (dB re 1 V)
ZVp (cycles)
-80 -
.5I-
-90
CMRR =14.05
IDI = 5.63e-6
/D = -0.446
ICI = 1.12e-6
/C = 0.291
-100
-110
040
-
_
-
-140r
:: : a a ::
-0.5
0.0
I1
1
~ r- -~~~~~~~~·,\
, ,
MINIVIUUel= V.V 318
:I
0.5
-0.5
W (cycles)
Figure 6-15:
Pmag
= 0.996
a, = 0.973
MI
ta_ .03;-,,,o~
MIN Data = 0.031(05
tN
-120
Data from measurement
0.0
0.5
Mi(cycles)
"1000c_7" of this thesis shifted such that
4
'MINdat = 0.03 cycles in order to correspond to the result of Wever and Lawrence
(1950). The linear fit to this shifted data results in CMiRR = 14dB, a decrease of 21dB
from the result found in this thesis.
; = 0 for all measurement sets from Cats #4 to #7. Fig.6-14 compares the means values
of
bMIN,Ode,
found here to the values of
IbMINd,a measured by Wever and Lawrence
(1950). The Wever and Lawrence values appear significantly different from ObMINd,ta 0
for frequencies between 100 and 1000 Hz, but the measurements reported in this thesis
suggest that
IMINdata
and ?bMINmodeloccur at k
0.
Differences between the results found in this thesis and those found by Wever and
Lawrence are illustrated as follows. The Obvalues from the data of measurement set
"1000c_7", shown in Fig. 6-2, are shifted by 0.03 cycles (the ObMINda,treported by Wever
and Lawrence, 1950) and the least-squares fit is again applied to the data. This result is
shown in Fig. 6-15; the shifted data is barely distinguishable from the result in Fig. 6-2.
However the shift of only 0.03 cycles in ibMINd,ta has a significant affect on the estimates
of C and CMRR;
this shift increases ICI from 1.04 * 10- 7 to 1.12 * 10- 6 and reduces
93
CMRR from 35dB to 14dB. Thus the results of Wever and Lawrence suggest much lower
CMRR
values than those found here. The nonzero values of
OMIN
reported by Wever
and Lawrence between 100 and 1000 Hz are suggestive of a significant common-mode
component of the cochlear-potential response.
6.3.5 Comments on the Bekesy result
Audiometric results from B6kesy (1936a; 1960, Fig. 5-10) suggestive of a nonzero commonmode gain were discussed in Chapter 1.3. Briefly, using ears with no ossicles Bekesy
measured an increase in hearing sensitivity as frequency decreased; it is presumed that
this increased sensitivity was correlated with a decrease in the pressure difference between the oval and round windows. If this is true, such a result is not consistent with
the experimental results of this thesis. However, several factors can possibly explain the
Bk6sy result.
The threshold measurements performed on the ears with no ossicles do not necessarily
measure the threshold of hearing of the ossicle-less ear. Instead, the thresholds are
determined by the most sensitive sensation to an acoustic stimulus presented to the ear
with a head phone. One possibility is that a tactile sensation had a lower threshold than
the hearing sensation for the subjects tested. Between 5 and 20 Hz the average threshold
measured on these subjects is within one order of magnitude of one measure of tactile
thresholds to intense sound stimuli (B4kesy 1936b; 1960, Fig. 7-48). Another possibility is
that acoustic crosstalk" occurred between the earphone and the contralateral "normal"
ear. It does not appear that potential responses from the normal ear were masked.
94
Chapter 7
Summary
Experimental results which directly support the common assumption that the cochlea
responds to the difference in pressure between the oval and round windows were presented. The cochlear response was represented as two components: the difference-mode
response results from the difference in pressure between the oval and round windows
and the common-moderesponse results from the summation in the pressures at the oval
and round windows. The common-mode response was difficult to measure because it
was small compared to the total cochlear response.
A conservative summary of our
data is that the common-modegain is at least one order of magnitude smaller than the
difference-mode gain. However, most of our data is also consistent with a common-mode
gain of zero. Thus the ratio between the difference-mode gain and the common-mode
gain, CMRR, is between 20 dB and infinity.
It is not trivial to put a tighter bound on this large CMRR range. To decrease
the current range, the uncertainties in pressure measurements of less than 0.5 dB in
magnitude and 0.01 cycles in angle must be reduced. Also, further study of how the
cochlear-potential response changes with time is needed.
95
The importance of the difference-mode response to hearing suggests that procedures
such as the type IV tympanoplasty should improve hearing in ears with no ossicles.
Surgeons should continue attempts to maximize the pressure difference between the oval
and round windows.
96
Appendix A
Summary of experimental
animals and calibrations
Appendix A summarizes all experiments used to develop the methodology and to obtain
results for this thesis. Information specific to each cat is briefly discussed. Measurements
of the acoustic isolation between Pow and PRW, as shown in Fig. 2-3, are presented for
each experimental animal.
Also, changes in the calibrations of the sound-source and
microphone assemblies, as depicted in Fig. 4-1 and 4-2, are shown for each experiment.
Measurements used to define all noisefloors are displayed in tables. Responses from Cats
#6 and #7 to clicksand tone bursts are shownfor both pre and post-TTX measurements.
A.1
Brief description of each experiment
Cat#1: July 14, 1993
Both single-sided and simultaneous-stimuli measurements were made on the left ear.
The sound sources were not re-calibrated during the experiment. At the end of the
97
experiment a calibration was performed and the result was significantly different from
the calibration at the beginning of the experiment; the sound-pressure measurements
of magnitude and angle by the oval and round-window microphones are questionable
to within several dB in magnitude and several degrees in angle.
At the end of the
experiment the earcanal was found to be full of fluid a few minutes after the removal of
the oval-window sound source and microphone. It is not known how much of this fluid
was in the earcanal and middle-ear space during the experiment or how much of the
fluid seeped into the earcanal from the tissue surrounding the meatus after the removal
of the microphone.
Additionally, condensation was present on the diaphragm of the
earcanal microphone. There was no fluid in the bulla cavity and no condensation on
the round-window microphone. The round window looked opaque and vascular; it is
possible that an infection existed. In subsequent experiments the sound systems were
recalibrated several times over the course of the experiment, the middle-ear air spaces
were monitored and the cats were given penicillin to fight infections.
Cat#2: July 27, 1993
Severe bleeding occurred during the first attempt to plug the foramen of the left middleear space. The right ear was surgically prepared and more severe bleeding occurred when
the external carotid was cut. The cat survived and single-sided and simultaneous-stimuli
measurements were made but responses were not repeatable during the simultaneous
stimuli measurements. Additionally muscular activity superimposed on the cochlearpotential response was observed.
98
Cat#3: August 5, 1993
There were no physiologic problems with the cat. Numerous single-sided and simultaneousstimuli measurements were made on the left ear. In several cases the pressures at the
two windows were not equal in magnitude; instead the pressures were chosen such that
the resultant single-sided cochlear-potential magnitudes were equal. The system was
re-calibrated several times during the experiment. Variations in calibrations occurred
which were significantly greater than those in the final four experiments.
The stability of the acoustic systems was increased substantially after this experiment. Parts of the couplers between the sound-sources and microphones were modified
to have tighter fits. This alteration allowed the acoustic assemblies to be moved without
large changes in calibration (Chapter 4).
Cat#4: September 22, 1993
There were no physiologic problems with the cat. The acoustic systems were re-calibrated
several times during the experiment and the changes in calibration were much smaller
than previous experiments; these changes were on the order of a few tenths of a dB in
magnitude and a hundredth of a cycle in angle (Fig. A-12 and A-13). Measurements
were made at 75 Hz, 100 Hz, 250 Hz, 500 Hz, 800 Hz, and 1000 Hz.
Prior
to this
experiment the cochlear-potential electrode was coupled through a 1000 n resistor to
ground. Radiation from the sound sources at maximum input levels did not produce an
electrical artifact that could be recorded by the resistor - electrode system.
99
Cat#5: March 21, 1994
There were no physiologic problems with the cat. The acoustic systems were re-calibrated
several times during the experiment and the changes in calibration were less than 0.2
dB in magnitude and less than 0.003 cycles in angle (Fig. A-14 and A-15). After each
calibration a small brass tube was used to couple the two sound-source and microphone
assemblies together. A sound common to both microphones was produced and it was
confirmed that the two microphone calibrations were consistent.
This procedure was
repeated after the assemblies were decoupled from the cat. Measurements were made at
100 Hz, 300 Hz, and 1000 Hz on the right ear. The effect of artifactual coupling from
the earphones to the cochlear-potential electrode was not checked. The distance from
the oval window to the position of the probe tube in the earcanal was measured to be
4.9 mm, and the distance from the round window to the position of the probe tube on
the bulla cavity was measured to be 7.6 mm; the difference is 2.7 mm.
Cat#6: August 11, 1994
There were no physiologic problems with the cat. The system was re-calibrated several
times during the experiment and the changes were less than 0.2 dB in magnitude and less
than 0.004 cycles in angle (Fig. A-16 and A-17). The calibrations were checked with the
small brass tube described above. Measurements were made at 100 Hz, 300 Hz, and 1000
Hz on the right ear. TTX was applied to reduce the neural component of the cochlearpotential response (CAP). A significant electrical artifact from the sound source was
found at the end of the experiment. When the sound sources were plugged with cotton
and then recoupled to the cat the round-window-electrode response increased linearly
with input voltage. The highest levels were comparable to and possibly greater than
100
the lowest cochlear-potential measurements made during the experiment; it is likely that
the simultaneous-stimuli cochlear-potential measurements were contaminated by this
electrical artifact when Vcp| was near a minimum.
Cat#7:
September 8, 1994
There were no physiologic problems with the cat. The system was re-calibrated several
times during the experiment and the changes were less than 0.8 dB in magnitude and
less than 0.015 cycles in angle (Fig. A-18 and A-19). Measurements were made at 100
Hz, 300 Hz, and 1000 Hz on the right ear. The calibrations were checked with the small
brass tube described above. TTX was applied to eliminate the neural component of the
cochlear-potential response. All cables used in the experiments were shielded and no
electrical artifact was detectable.
101
A.2 Acoustic crosstalk for each animal
102
OW SOURCE OFF
OW SOURCE ON
RW SOURCE OFF
100
-
80
m
'O
RW SOURCE ON
......... IVRW.mNDACowI/
80
60
M
0
40
........A 4Arj.
. .t4
20
I
2
1
00
-
I
i
: f
I
I
4
I
I11
1000
2
I
I
. .=
40
A
.Ii
I
4
_
I
2
100
ZVOW - ZVDACow
.........
0.5
I
I
4
I
I Ii
l
6 8
1 000
I
I
1
2
4
4
4
VOW-VVDACRw
RW, c-
VDACRw
0.5
co
C
O1
o..................
60
VRW
.........-/V DACow
a)
W
-IVOWV.NDACRw
·
........
IVRW.VNDACRWI
.......................
.
20
?f
6 8
K
1 00
IVow,,DACow
cn
a)
)
0.0
0.0
>1
-0.5
100
-0.5
1000
100
Frequency (Hz)
1000
Frequency (Hz)
Figure A-1: Measurements of acoustic crosstalk between the tympanic and bulla
cavities from Cat #1. LEFT: Measurement of the transfer function between the
oval-window microphone response Vowm,, and the oval-window sound-source input
VDACOW, and measurement of the transfer function between the round-window microphone response VRWmiCand the oval-window sound-source input VDACow. The
round-window sound-source was off. RIGHT: Measurement of the transfer function between the oval-window microphone response Vow,ic and the round-window sound-source
input VDACRW, and measurement of the transfer function between the round-window
microphone response VRw,m, and the round-window sound-source input VDACRW. The
oval-window sound-source was off.
103
OW SOURCE ON
RW SOURCE OFF
OW SOURCE OFF
RW SOURCE ON
0
U
-20
m
0
-
-40
-
-60
-
-
IVOWmCVNDACOWI
.........
IVRW,. NDACowI
-20
..
-60
-80
I...........................................
v
100
I
I
2
4
ZV
.........
I
I I
_'"**"°"'"
I ]
'°°*'°°
6 8
1000
I
2
I
-100
.
I
4
I
1 00
2
4
6 8
1000
OWmic
..V-ZVDACow
OW
2
4
DACRW
ZVRWmiCZVDACRw
VRWmjcZV DACow
0.5
.......
0.5
a,
a)
<n
a)
Co
IVowmicNDACRw
IVRWmi/DACRWI
-40
E
-80
-10(To
_ .........
0.0
0
>1
0.0
0
0
-0.5
-0.5
100
Z
0
l4
Z
Z
4
1000
1 00
4
0
Z
4
1000
Frequency (Hz)
Frequency (Hz)
Figure A-2: Measurements of acoustic crosstalk between the tympanic and bulla
cavities from Cat #2. LEFT: Measurement of the transfer function between the
oval-window microphone response VOWmic and the oval-window sound-source input
VDACow, and measurement of the transfer function between the round-window microphone response VRWmic and the oval-window sound-source input VDACOw. The
round-window sound-source was off. RIGHT: Measurement of the transfer function between the oval-window microphone response Vow,mI and the round-window sound-source
input VDACRW, and measurement of the transfer function between the round-window
microphone response VRWmCand the round-window sound-source input VDACRw. The
oval-window sound-source was off.
104
OW SOURCE OFF
RW SOURCE ON
OW SOURCE ON
RW SOURCE OFF
0
U
-
-20 _
-40
m
a
- IVOWm DACRw
IVOWNVDACowI
-20
.--..... VRWVADACo
-
---
m
-60 _
-40
_ "I'",
IVRW, DACI
I
-60
-80
-80
,-A"
I
-100
---
I
100
-1in
Iy
2
4
6 8
1000
2
4
r
I
I
4
100
ZVow'ZVDACow
1111
68
2
1000
4
ZVOWmic
"VDACRW
......... ZVRWm= VDACow
--
0.5
U.5
A
I
2
......... ZVRW,,ZVDAC ..
en
(D
0cu 0.0
0
-0.5
-0.5
1000
100
100
4
6 8 -
1000
Z
4
Frequency (Hz)
Frequency (Hz)
Figure A-3:
Z
Measurements of acoustic crosstalk between the tympanic and bulla
cavities from Cat #3.
LEFT: Measurement of the transfer function between the
oval-window microphone response Vow,,c and the oval-window sound-source input
VDACow, and measurement of the transfer function between the round-window microphone response VRWm,i and the oval-window sound-source input VDACOW. The
round-window sound-source was off. RIGHT: Measurement of the transfer function between the oval-window microphone response Vowmjc and the round-window sound-source
input VDAC,w, and measurement of the transfer function between the round-window
microphone response VRWmi, and the round-window sound-source input VDACRW. The
oval-window sound-source was off.
105
OW SOURCE ON
RW SOURCE OFF
0
-20
m:
OW SOURCE OFF
RW SOURCE ON
0
VowmNDACowI
VRW.NDACOWI
.........
m
-80
-100
...
..
..........................................
2
1 00
-LVo
0.5
4
68
1000
2
-40
:,
-80
-100
..
........
.
.......
.""""
-60
...
.........
\ y..-,.%
V
6'8
IVOW. NDACRWI
-20
-40
-60
-
-
4
i
,,,
.
68
100
-ZLVDACW
-
......... /VRWmc -ZVDACOW
0.5
u,
a,
u,
01
C.
0 0.0
0
-0.5
2
I
I
I
.11111
4 68'
1000
I
2
I
I
4
ZVOW-ZVDACRw
RWm
cZVDACRw
.........
0.0
-0.5
100
1000
100
Frequency (Hz)
1000
Frequency (Hz)
Figure A-4: Measurements of acoustic crosstalk between the tympanic and bulla
cavities from Cat #4. LEFT: Measurement of the transfer function between the
oval-window microphone response VoWmic and the oval-window sound-source input
VDACOW, and measurement of the transfer function between the round-window microphone response VRWmc and the oval-window sound-source input VDACOW. The
round-window sound-source was off. RIGHT: Measurement of the transfer function between the oval-window microphone response VOWmicand the round-window sound-source
input VDACRW, and measurement of the transfer function between the round-window
microphone response VRWmic and the round-window sound-source input VDACRw. The
oval-window sound-source was off.
106
OW SOURCE OFF
OW SOURCE ON
RW SOURCE OFF
RW SOURCE ON
0
0
-20
-20
-40
-40
--
IVowN/DAC.WI
i....... iVRW NDACW
I
..
m
VD
m
a
-60
-60
-80
-80
-100
-100
.....
.l.
.
68
2
4
100
_ ZVOW,-VDACow
0.5
0.5
0.0
' 0.0
-0.5
-0.5
n
2
1000
4
......... ZVRWmc
-ZVDACR
a)
100
1000
100
1000
Measurements of acoustic crosstalk between the tympanic
cavities from Cat #5.
c
S
l
Frequency (Hz)
Frequency (Hz)
Figure A-5:
6 81
ZOWW -ZVDACRw
......... LVRW,, -LVDAw
0
.t.
......
and bulla
LEFT: Measurement of the transfer function between the
oval-window microphone response Vowc, and the oval-window sound-source input
VDACOW, and measurement of the transfer function between the round-window microphone response VRWmi, and the oval-window sound-source input VDACOW. The
round-window sound-source was off. RIGHT: Measurement of the transfer function between the oval-window microphone response Vowmtc and the round-window sound-source
input VDACRW,and measurement of the transfer function between the round-window
microphone response VRWmicand the round-window sound-source input VDACRW. The
oval-window sound-source was off.
107
OW SOURCE OFF
RW SOURCE ON
OW SOURCE ON
RW SOURCE OFF
-
-40
-60
m
'
-80
-1
IVOWm,,cVDACowl
-40
IVRW NDACowI
..........
IC,*
A
-60
-
m
-
00 _
-120
1111
6 8
100
2
- - - -_ _
I
I
4
I
6 8
2
1000
I
.........
VRWmic
I
I
4
I I1j
6 8
1000
I
2
I
ZVOWmi -ZVDACRw
......... ZVRWcZVDACRw
DACow
0.5
(I,
a0,
(,
c
2
1 00
U.b
a)
I
68
ZVVOWi-ZVDACow
-
..
~~~~224~~~~~~
I I1111
4
I
_~~~~~~~~~~'·
-80
-120
*
111111
IVRW NDAC
"""'"........_
-100
- _ _-, %:
IVOWm,,VDACRWI
-
.........
0.0
0.0
0
cJ
-0.5
-0.5
100
1000
I
Ir
100
1000
Frequency (Hz)
Frequency (Hz)
Figure A-6: Measurements of acoustic crosstalk between the tympanic and bulla
cavities from Cat #6. LEFT: Measurement of the transfer function between the
oval-window microphone response Vow,,ic and the oval-window sound-source input
VDACow, and measurement of the transfer function between the round-window microphone response VRWmic and the oval-window sound-source input VDACOW. The
round-window sound-source was off. RIGHT: Measurement of the transfer function between the oval-window microphone response VOWmicand the round-window sound-source
input VDACRW, and measurement of the transfer function between the round-window
microphone response VRWmi, and the round-window sound-source input VDACRW. The
oval-window sound-source was off.
108
I
4
OW SOURCE ON
RW SOURCE OFF
0
-
-O
0
IVOWmNDACowI
IVOWmCNDACRw
·.~...
'''.s..
'~'
.
| VRWmk/NDACowI
-20
m
OW SOURCE OFF
RW SOURCE ON
-40
-20
m
'O
-60 _
~~~~~~~~~~~:- i)C`yr,
~~~~.%..
~,¢: I!V
-80
-100
' 1 ' ' 111111
4 68
2
IlT'
68
100
I
a
2
......... IVRW,, NDACRw
-40
-80
-100
I
4
, liI
68
1000
ZVOW ZVDACow
... ... Z V RWm Z V DA...
C ow
1
2
100
,
I 1 ,II
4
6 8
1000
I
I
I
2
4
ZVVoWmli-VDACRW
......... ZVRWmic-ZVDACRw
0.5
0.5
()
a)
I-"
-60
(I)
a)
0.0
0
0)
c)
0.0
O
-0.5
-0.5
b
u
100
Z
4
t
b
Z
0
4
b
Z
100
1000
Frequency (Hz)
4
t
b
4
1000
Frequency (Hz)
Figure A-7: Measurements of acoustic crosstalk between the tympanic and bulla
cavities from Cat #7.
LEFT: Measurement of the transfer function between the
oval-window microphone response Vowmic and the oval-window sound-source input
VDACow, and measurement of the transfer function between the round-window microphone response VRwmic and the oval-window sound-source input VDACOW. The
round-window sound-source was off. RIGHT: Measurement of the transfer function between the oval-window microphone response Vow,,i and the round-window sound-source
input VDACRW, and measurement of the transfer function between the round-window
microphone response VRwmiCand the round-window sound-source input VDACRW. The
oval-window sound-source was off.
109
A.3
Changes in microphone calibration
110
-
A Magnitude
A Angle
from Original
from Original
Calibration (cycles)
Calibration (dB)
-43- OWM,,
0.0c
I
-0.4C
10
-0.010
20
I
10
0.020
0.010
0.000
1000 Hz
- RWMIC
0.4C
I
10
20
0.0c I
20
0.020
800 Hz
0.010
0.000
-0.2C
-0.010
I
10
10
10
20
0.00
-0.20
20
20
0.010
0.00ooo
600 Hz
-0.40
1
-0.010
I
I
I
10
20
10
0.00 I
0.000
400 Hz
-0.10I
20
-0.004
-0.008
-0.20I
20
10
10
0.05
0.00I
-0.05
20
0.000
200 Hz
-0.004 - - - - - - - -
-0.10I
I
20
10
.
.10
20
10
0.05
0.00
-0.05
I
I
0.002
100 Hz
0.000
I I
I
I
I
-0.002 - - - - - - - I
I
10
20
10
.
.
.
.
I
.
.
20
Time of Day (hours)
Time of Day (hours)
Figure A-8: The differences in SPL and SPL between the initial calibration and
Vomic
VRWmic
subsequent calibrations during the experiment on Cat #2. The first measurement of
SPL ( SPL ) was used to normalize all succeedingmeasurements of VSPL (VSPL );
OW.mic
Vmic
RW.,
Wm
magnitudes (in dB) and angles (in cycles) of the ratios are plotted. Time of day = 10
hours is the time of initial calibration.
111
Maximum Phase
Difference (cycles)
Maximum Magnitude
Difference (dB)
1.5
u.ut
-0- OWMIC
-43 OWMI I
I-0- RW., I
1.0
p--4
0.02
0.5
0.0
- .0- RWMIC
0.04
0.00
. .
I .. .. .. .. .I .. .. . . I
0
500
1000
0
Frequency (Hz)
Figure A-9: The maximum changes in
during the experiment on Cat #2.
,,
.
I
.
.
I,
..
.......
I
...
500
I
1000
Frequency (Hz)
SPL
Vow,. ti
112
ySPL
as a function of frequency
and VRW.i
c
A Magnitude
A Angle
from Original
from Original
Calibration (cycles)
Calibration (dB)
--
-- ow"'j
O0mjc
-o- RW,
1.0
1000 Hz
0.5
0.02
k~~d~~l?
0.0
0.00
A A
10
20
30
10
20
30
40
10
0.020
20
30
40
20
30
40
40
U.8
0.02
800 Hz
0.4
0.01
0.0
0.00
10
20
30
40
0.4
600 Hz
0.010
0.0
0.000
.
10
20
30
10
40
0.4
400 Hz
0.010
0.0
0.000
10
20
30
40
0.2
10
20
30
40
0.1
20
30
40
10
20
30
40
0.008
0.004
0.000
200 Hz
0.0
10
0.004
0.002
0.000 I-"
100 Hz
0.0
-0.1
I
10
20
30
40
10
Time of Day (hours)
'
I
20
'
I
30
'
I
40
Time of Day (hours)
Figure A-10: The differencesin VSPL and SPL between the initial calibration and
subsequent calibrations during the experiment on Cat #3. The first measurement of
vow. ( VR9W ) was used to normalize all succeeding measurements of VoSPL (VRWP);
magnitudes (in dB) and angles (in cycles) of the ratios are plotted. Time of day = 10
hours is the time of initial calibration.
113
Maximum Phase
Difference (cycles)
Maximum Magnitude
Difference (dB)
I.u
A
u.u4
to1
r
-1- OW . j
-- RW,,~
0.02
0.5
0.00
0.0 I
0
I
I
I
I
I
I
I
I
I
,I I
500
1000
Frequency (Hz)
Figure A-ll: The maximum changes in
during the experiment on Cat #3.
0
I
I
I
I
500
I
I
1000
Frequency (Hz)
SPL
114
and
SPL
as
VRWm.ic
a function of frequency
A Magnitude
A Angle
from Original
Calibration (dB)
from Original
Calibration (cycles)
--
-0- OWt
-o- RW,
OWm-
-0- RMH
1000 Hz
.004-
0
.002-
-. 2
0800 Hz
0
-.2
20
30
20
30
.002
0
20
30
.0025-
0
500 Hz
-.2
-
20
20
30
30
.0025-
0
250 Hz
o-
-.25
20
I20
30
30
20
30
.008-
.2
100 Hz
0
.004-
0-
-.2
20
30
75 Hz
20
30
20
30
.01
0
0
20
30
Time-of Day (hours)
Time of Day (hours)
Figure A-12: The
The differencesi
differencesin VwFigure
SPL and VRWc
SPL between the initial calibration and
A-12:
subsequent calibrations during the experiment on Cat #4.
SPL
SPL
Omi
(SRWiPL)
The first measurement of
SPL
RPmic
was used to normalize all succeeding measurements of VSPL
(VSPL
);
magnitudes (in dB) and angles (in cycles) of the ratios are plotted. Time of day = 12
hours is the time of initial calibration.
115
Maximum Magnitude
Maximum Phase
Difference (dB)
Difference (cycles)
.0
--O- MM,
.5
.0
.4
.0
.3
400
400
800
Frequency (Hz)
Frequency (Hz)
Figure A-13: The maximum changes in
during the experiment on Cat #4.
800
SPL
Vow.n
116
and
SPL
VRWmion
as a function of frequency
A Angle
from Original
A Magnitude
from Original
Calibration (dB)
Calibration (cycles)
OWic
1000 Hz
.1
.001
-o- RWmc
0
-.001
-.002
0
1I
0
5
10
15
.08
300 Hz
.04
I
0
5
10
15
0
5
10
I
0
5
10
15
I
I
I
I
0
5
10
15
0
-.0004
0
0
5
10
15
100 Hz
.04
0-.001-
-.002-
0
0
5
10
15
Time of Day (hours)
Time of Day (hours)
Figure A-14: The differencesin SPL and SPL between the initial calibration and
Vow.;i
VRWmisubsequent calibrations during the experiment on Cat #5. The first measurement of
PL (RP);
) was used to normalize all succeeding measurements of
VoPL (SPL
magnitudes (in dB) and angles (in cycles) of the ratios are plotted. Time of day = 0
hours is the time of initial calibration.
117
Maximum Phase
Difference (cycles)
Maximum Magnitude
Difference (dB)
.16
.1 6 -
-aw
4
- RWr~k
.002-
.12
\
Fm
.0015 -
.08
.001
.04
.0005
I
400
800
400
Frequency (Hz)
Figure A-15: The maximum changes in
during the experiment on Cat #5.
800
Frequency (Hz)
SwL
and
onCat#5.
theexperiment
oduring
118
as a function of frequency
A Angle
A Magnitude
from Original
Calibration (dB)
from Original
Calibration (cycles)
[.1- OW~
.RW_,_I
.05
1000 Hz
0
-.05
.001
0
-. 1
.05
.003
.002
20
20
30
30
.001
300 Hz
0
-.05
.0005
0
.05 -
20
30
.0005
0-
100 Hz
-.05
0
-.0005
20
30
20
Time of Day (hours)
Time of Day (hours)
Figure A-16: The differencesin Vow.i
SPL
30
and VRwmi¢
SPL between the initial calibration and
subsequent calibrations during the experiment on Cat #6. The first measurement of
SPL; (V P
) was used to normalize all succeeding measurements of VSPL
V iSPL
);
magnitudes (in dB) and angles (in cycles) of the ratios are plotted. Time of day = 18
hours is the time of initial calibration.
119
Maximum Magnitude
Maximum Phase
Difference (cycles)
Difference (dB)
-
OWic
-o- RWmw
15.1-
.003
rv
fly~~~~~~~~~~~~ .002
.001
.05
400
800
400
Frequency (Hz)
Figure A-17: The maximum changes in
800
Frequency (Hz)
PL
during the experiment on Cat #6.
120
and
RSPL as a function of frequency
VRwric
--
A Magnitude
A Angle
from Original
Calibration (dB)
from Original
Calibration (cycles)
W
0.4
1000 Hz
0.0
0.000
-0.005
20
30
40
0.4 +
0.0 -
0.005- oRe
20
I
30
30
40
20
30
40
20
30
40
0.000
300 Hz
I
20
-0.002
I
40
0.004
100 Hz
0.4
0.002
0.000
0.0
20
30
40
Time of Day (hours)
Figure A-18: The differences in VOL
Time of Day (hours)
and
SPL
between the initial calibration and
subsequent calibrations during the experiment on Cat #7. The first measurement of
SVP (SPgL;;) was used to normalize all succeeding measurements of owm
;
magnitudes (in dB) and angles (in cycles) of the ratios are plotted. Time of day = 17
hours is the time of initial calibration.
121
Maximum Magnitude
Maximum Phase
Difference (cycles)
Difference (dB)
.015.6.4-
{-
OWmic
-0-
RWmi
c
.01
-I-
OWm ic
-O-
RWmic
.005-
.2!
·
400
800
400
Frequency (Hz)
Figure A-19: The maximum changes in
during the experiment on Cat #7.
800
Frequency (Hz)
SPL
122
and
SPL
VRWmic
as a function of frequency
A.4
Noisefloor calculations
123
I
Table A.1: Measurements used to define the noisefloor of Vcp from Cat #1. The first 15
rows are the specified frequency component of the VcpJ response to a 1000 Hz tone, in
units of dB re 1 volt. These measurements are averaged and used as an estimate of the
noisefloor of Vcp. The noisefloor is defined as the mean plus two standard deviations
(also in dB re 1 volt). For simplicity the numbers have been rounded to the nearest
integer, however, the calculations used more significant digits.
124
NOISEFLOOR MEASUREMENTS: CAT #2
mean
std
Noisefloor
100 Hz
200
2
Hz
400 Hz
600 Hz
800 Hz
-115
-118
-128
-129
-135
-120
-132
-141
-146
-141
-115
-124
-130
-133
-135
-117
-120
-118
-122
-130
-125
-124
-128
-125
-131
-138
-135
-133
-137
-128
-148
-145
-140
-132
-131
-138
-136
-136
-137
-139
-136
-137
-158
-143
-145
-112
-119
-125
-132
-130
-123
-113
-124
-121
-117
-130
-114
-131
-113
-120
6
-108
-125
-135
-130
-131
-128
-149
-124
-130
-121
-129
7
-114
-141
-142
-131
-133
-130
-150
-130
-134
-126
-135
7
-120
-146
-141
-139
-141
-140
-148
-131
-137
-132
-137
6
-126
-138
-139
-141
-137
-138
-141
-133
-143
-132
-139
6
-127
Table A.2: Measurements used to define the noisefloor from Vcp of Cat #2. The first 15
rows are the specified frequency component of the Vcp response to a 1000 Hz tone, in
units of dB re 1 volt. These measurements are averaged and used as an estimate of the
noisefloor of Vcp. The noisefloor is defined as the mean plus two standard deviations
(also in dB re 1 volt). For simplicity the numbers have been rounded to the nearest
integer, however, the calculations used more significant digits.
125
NOISEFLOOR MEASUREMENTS: CAT #3
100 Hz
200 Hz 400 Hz
600 Hz
800 Hz
mean
std
Noisefloor
-131
-133
-144
-135
-146
-156
-135
-145
-138
-149
-137
-133
-133
-131
-136
-140
-151
-143
-140
-144
-139
-147
-143
-130
-136
-138
-139
7
-125
-135
-133
-134
-131
-138
-142
-135
-137
-136
-137
-136
-132
-133
-134
-134
-134
-135
3
-130
-139
-145
-142
-142
-146
-149
-143
-144
-147
-145
-144
-141
-146
-143
-145
-150
-144
3
-139
-146
-144
-142
-137
-143
-147
-144
-136
-150
-139
-135
-141
-142
-148
-142
-159
-143
6
-131
-145
-147
-140
-143
-148
-141
-147
-145
-147
-143
-149
-154
-147
-138
-148
-150
-146
4
-139
Table A.3: Measurements used to define the noisefloor from Vcp of Cat #3. The first 15
rows are the specified frequency component of the Vcp response to a 1000 Hz tone, in
units of dB re 1 volt. These measurements are averaged and used as an estimate of the
noisefloor of Vcp. The noisefloor is defined as the mean plus two standard deviations
(also in dB re 1 volt). For simplicity the numbers have been rounded to the nearest
integer, however, the calculations used more significant digits.
126
NOISEFLOOR MEASUREMENTS: CAT #4
mean
std
Noisefloor
75 Hz
-143
100 Hz
-142
250 Hz
-149
500 Hz
-159
800 Hz
-156
-132
-135
-145
-154
-160
-148
-131
-147
-159
-141
-129
-144
-144
-140
-134
-143
-133
-142
-165
-142
-151
-160
-146
-150
-150
-140
-137
-141
-140
-153
-154
-154
-156
-154
-158
-136
-148
-156
-155
-158
-124
-133
-133
-144
-137
-138
-134
-134
-142
-132
-142
-140
-144
-138
6
-126
-127
-131
-137
-144
-142
-132
-141
-151
-150
-142
-134
-141
-139
-139
6
-127
-141
-141
-152
-158
-151
-142
-151
-145
-150
-153
-152
-152
-164
-150
8
-135
-149
-141
-154
-165
-160
-163
-156
-152
-156
-160
-156
-162
-156
-155
6
-143
-149
-147
-162
-150
-157
-156
-151
-156
-154
-155
-151
-163
-169
-154
6
-141
Table A.4: Measurements used to define the noisefloor from Vcp of Cat #4. The first 22
rows are the specified frequency component of the Vcp response to a 1000 Hz tone, in
units of dB re 1 volt. These measurements are averaged and used as an estimate of the
noisefloor of Vcp. The noisefloor is defined as the mean plus two standard deviations
(also in dB re 1 volt). For simplicity the numbers have been rounded to the nearest
integer, however, the calculations used more significant digits.
127
I
Table A.5: Measurements used to define the noisefloor of Vcp from Cat #5. Either 11 or
6 measurements of Vcp (dB re 1 volt) were made with no stimulus. These measurements
are averaged and used as an estimate of the noisefloor of Vcp. The noisefloor is defined
as the mean plus two standard deviations (also in dB re 1 volt). For simplicity the
numbers have been rounded to the nearest integer, however, the calculations used more
significant digits.
NOISEFLOOR MEASUREMENTS: CAT #6
100 Hz
300 Hz
-149
-149
1000 Hz
-147
-148
-151
-155
-158
-147
-143
-159
-147
-154
-150
-151
-149
-145
-154
-148
-147
-143
-146
-148
-146
mean
-150
-153
-147
std
Noisefloor
5
-140
3
-147
2
-142
Table A.6: Measurements used to define the noisefloor from Vcp of Cat #6. Either 11 or
6 measurements of Vcp (dB re 1 volt) were made with no stimulus. These measurements
are averaged and used as an estimate of the noisefloor of Vcp. The noisefloor is defined
as the mean plus two standard deviations (also in dB re 1 volt). For simplicity the
numbers have been rounded to the nearest integer, however, the calculations used more
significant digits.
128
NOISEFLOOR MEASUREMENTS: CAT #7
mean
std
Noisefloor
100 Hz
300 Hz
-139
-155
1000 Hz
-132
-165
-158
-130
-131
-133
-154
-156
-143
-161
-150
-159
-141
-134
-139
-167
-138
-136
-138
-152
-155
-158
-164
-160
-160
-156
-148
-160
-155
-158
-148
-153
-154
-148
10
6
5
-118
-144
-144
Table A.7: Measurements used to define the noisefloor from Vcp of Cat #7. 11 measurements of Vcp (dB re 1 volt) were made with no stimulus. These measurements are
averaged and used as an estimate of the noisefloor of Vcp. The noisefloor is defined as
the mean plus two standard deviations (also in dB re 1 volt). For simplicity the numbers
have been rounded to the nearest integer, however, the calculations used more significant
digits.
129
A.5
Effects of TTX
TTX was added to the cochleas of Cat #6 and Cat #7 in order to eliminate the nonlinear
CAP component of the cochlear-potential response (Chapter 2.7). Cochlear-potential
measurements were made in response to click and tone-burst stimuli both before and
after the application of TTX.
Pre and post-TTX cochlear-potential responses to click stimuli (approximately 85
dB SPL) are shown in Fig. A-20 and A-21 for Cat #6 and Cat #7, respectively. In both
cases a small cochlear-microphonic response occurs at about 1 ms; the Cat #6 cochlear
microphonic is about 5 V (Fig. A-20), and the Cat #7 cochlear microphonic is about
2jV (Fig.A-21). The cochlear-microphonic component of the cochlear-potential response
is not affected by the TTX. The responses from both cats also have neural components
which occur between about 2 and 4 ms; the peak at about 2 ms is often referred to as
the N1 component. The N1 component from Cat #7 is about 20 ,V larger than the N1
component from Cat #6. The N1 and other neural components of the cochlear-potential
response are eliminated after the application of TTX; this suggests the TTX successfully
blocked at least some of the nonlinear neural response in these animals.
Pre and post-TTX cochlear-potential responses to 100 Hz and 1000 Hz tone-burst
stimuli (approximately 110 dB SPL) are shown in Fig. A-22, A-23, A-24, and A-25. The
Cat #6 cochlear-potential response to a 100 Hz tone burst shows a change after the ap-
plication of TTX; the pre-TTX response looks "noisy" and nonlinear whilethe post-TTX
response resembles the linear 100 Hz stimulus tone. The pre and post-TTX cochlear-
potential responses to a 100 Hz tone burst from Cat #7 are similar and neither response
looks as nonlinear as the pre-TTX 100 Hz response from Cat #6. The application of
TTX also affected the cochlear-potential response to 1000 Hz tone-burst stimuli. Both
130
the Cat #6 and Cat #7 pre-TTX responses show an initial increased response at about
2 ms; this increase is the neural component of the cochlear-potential response and it is
eliminated after the application of TTX. Additionally, the post-TTX 1000Hz tone-burst
responses are smaller than the pre-TTX ones.
These pre and post-TTX responses suggest that the TTX successfully blocked much
of the neural component of the cochlear-potential response. However, as discussed in
Chapter 5, some of the post-TTX single-sided level-series measurements made at the
lower frequenciesexhibited nonlinearities. It is possible that the TTX was not completely
effective at the lowest stimulus frequencies.
131
Click Stimulus
0
0
1
2
4
3
5
6
Time (ms)
Click Response
30-
20-
-
Pre-TTX
V)
:t
0
10-
0-
j
-r
-10-
ts
..
,
. . . . .
…
-
4
-
I
I
I
I
I
I
0
1
2
3
4
5
I
6
Time (ms)
Figure A-20: Cat #6. TOP: Click stimulus at about 85 dB SPL. BOTTOM: Response
to the click stimulus both before and after the application of TTX to the round window
membrane. Measurements made between 3 hours and 18 hours after the application of
TTX did not show large variations.
132
Click Stimulus
o-
...I
I
I
I
I
I
I'
1
0
1
2
3
4
5
6
Time (ms)
Click Response
30 -
20Pre-TTX
--- Post-TTX (shifted -101V)
a.
10-
;>O
0-
-10 .
.
I
I
I
i=
·
I
I
I
I
I
I
I
0
1
2
3
4
5
6
Time (ms)
Figure A-21: Cat #7. TOP: Click stimulus at about 85 dB SPL. BOTTOM: Response
to the click stimulus both before and after the application of TTX to the round window
membrane. Measurements made between 3 hours and 18 hours after the application of
TTX did not show large variations.
133
100 Hz Tone Burst Stimulus
0
0
20
40
60
Time (ms)
80
100
100 Hz Tone Burst Response
50
40
30
20
a.
0
--- Post-TTX (shifted +30pV)
Pre-TTX
10
0
-10
-20
0
20
40
60
Time (ms)
80
100
Figure A-22: Cat #6. TOP: 100 Hz tone-burst stimulus at about 110 dB SPL. BOTTOM: Response to 100 Hz tone-burst stimulus before and after application of TTX to
the round window membrane. Measurements made between 3 hours and 18 hours after
the application of TTX did not show large variations.
134
100 Hz Tone Burst Stimulus
0
100
80
60
40
20
0
Time (ms)
100 Hz Tone Burst Response
50 40-
30-
I
... !
I
:L
a.
o
0
.f ·
,4
i JI
I
i
I
I
· !
I
I· ·
·
iI
·
I.
V
I
·
*
59I
~,·
rr
20-
--- Post-TTX (shifted +301zV)
-
Pre-TTX
10-
0-10 -20
WVVVVVVV~h
lL
I
i
0
20
40
1I
I
I
I
60
80
100
120
Time (ms
Figure A-23: Cat #7. TOP: 100 Hz tone-burst stimulus at about 110 dB SPL. BOTTOM: Response to 100 Hz tone-burst stimulus before and after application of TTX to
the round window membrane. Measurements made between 3 hours and 18 hours after
the application of TTX did not show large variations.
135
1000 Hz Tone Burst Stimulus
o
0
2
4
6
8
10
12
14
Time (ms)
1000 Hz Tone Burst Response
400
300
200
a.
0
shifted +300ttV)
100
;>
0
-100
-200
0
2
4
6
8
10
12
14
Time (ms)
Figure A-24: Cat #6. TOP: 1000 Hz tone-burst stimulus at about 110 dB SPL. BOTTOM: Response to 100 Hz tone-burst stimulus before and after application of TTX to
the round window membrane. Measurements made between 3 hours and 18 hours after
the application of TTX did not show large variations.
136
1000 Hz Tone Burst Stimulus
0
I
I
I
_
I
0
2
4
1
I
·
·
I
6
10
8
Time (ms)
I
I
I
I
12
14
1000 Hz Tone Burst Response
400
300
:L
C.
O
200
fted +300pV)
100
0
-100
-200
0
2
4
6
8
10
Time (ms)
12
14
Figure A-25: Cat #7. TOP: 1000 Hz tone-burst stimulus at about 110 dB SPL. BOTTOM: Response to 100 Hz tone-burst stimulus before and after application of TTX to
the round window membrane. Measurements made between 3 hours and 18 hours after
the application of TTX did not show large variations.
137
138
Appendix B
Summary of results: Stimulus to
one window
Data from all single-sided level series measurements are contained within this appendix.
There are differences among the experiments (Cats #1 to #7) which are discussed in
Appendix A.
All of the figures in this appendix have the same layout.
* The top left hand plot is the magnitude of the cochlear-potential response as a
function of stimulus sound-pressure level for single-sided stimuli at both the oval
and round windows.
* The top right hand plot is the angle of the cochleax-potentialresponse as a function
of stimulus sound-pressure level for stimuli at both the oval and round windows.
* The middle left hand plot is the dB difference between the cochlear-potential mag-
nitude when the oval window is stimulated and the cochlear-potential magnitude
when the round window is stimulated, as a function of stimulus sound-pressure
level. This difference is the dB difference between the two responses in the top left
hand plot.
* The middle right hand plot is the differencein angle between the cochlear-potential
angle when the oval window is stimulated and the cochlear-potential angle when
the round window is stimulated. This difference is the difference in cycles between
the two responses in the top right hand plot.
139
* The lower left hand plot is an estimate of DI where D is obtained from the data
in the top two plots and Equation 1.1: VCP = D(Pow - PRW). Here it is assumed
that C = 0 and the pressure at the unstimulated window is zero.
* The lower right hand plot is an estimate of LD described above.
The figures are arranged first in order of increasing frequency. Within each frequency
the figures are arranged in chronological order of experimental cat. An attempt was made
to keep all axes ranges constant for each group of measurements at a specific frequency.
In a few cases this was not practical. When the phase angle plots have different absolute
ranges the relative range is constant.
140
100 Hz Cat #1
-80 _
an
.DU
.25 _
..o-- OW
-100 .
>^
0a,
to
0t
0
0
o.
-120
xN,
.25 _
-140 ,
I
I
I
I
60
80
100
120
-.50
W
I
I
I
60
80
100
120
80
100
120
-8
oa
.66
0
.65
-10
>-0-
-- .64
-12
60
80
100
N
120
60
.,
0I
o
01
...... IDI:OW
-IDI:
RW
........
0
107
r
-
D: OW
- LD: RW
N
I
60
.
80
.
o...........
I
,I
,
100
r
- - -·
.i
120
I-
I
I
I
I
I
I
60
80
100
120
_-
Level (dB SPL)
Level (dB SPL)
Figure B-1: TOP: Single-sided level-series measurements made on Cat #1 at 100 Hz.
Either the ovalor the round windowwas stimulated. MIDDLE:Ratio of the measurement
made while the oval windowwas stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that CI << IDI.
141
100 Hz Cat #2
-80 _
1
.50 _
0
--o-- OW
- RW
--- noisefloor
'Q
-100 _
25 _
a)
0
>.
a)
co
m
a1 20
-
0
>O
d
25 _
1 40
I
I
I
I
I
I
60
80
100
I
I
120
60
I60
1
3
2
0
",1
00
No
0
0
=
-2
a.
(.
n
(,3
03
a3.
60
10
100
100
120
120
0
o 10
-6
n
-7
10J
1
80
100
120
80
100
120
.5
.t
L
A
F~
60
-5
I
I
100
r
.
,,0CL
80
80
I
80
.5
------IDI:OW
IDI: RW
......-----D: OW
- D: RW
a,
0
o
0
0
I
_-
60
I
I
80
II
I
I
100
120
N
-.5
,,,,,,,,
60
Level (dB SPL)
80
100
120
Level (dB SPL)
Figure B-2: TOP: Single-sided level-series measurements made on Cat #2 at 100 Hz.
Either the ovalor the round windowwas stimulated. MIDDLE: Ratio of the measurement
made while the oval windowwas stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that C << ID1.
142
100 Hz Cat #3
,--_
.bU
-80 _
--o-- OW
-&- RW
---
-1 0o
vv
noisefloor
.25
-
-
c,
9>
c.
0
a.
0n
o -1 20
N
"
/
b
'.
-.25
i
-140
.
I
.I
I
80
100
120
I
30
-.50
I-
I
I
I
I
60
80
100
120
m
_
n-
0
0
a.
0
0
>
-
.D
.5
_
.-
------------
------
N
0~
l
o
2
-2
0
60
80
100
.>
',4
120
.4
_
60
I
I
I
80
100
120
1
..----- D: OW
-D: RW
--......IDI:OW
1 05
CZ
0c
1 06
n
1 0' 7
,
_
!B
60
I
I
I
80
100
120
N
.5
_
0
l'
60
Level (dB SPL)
80
100
120
Level (dB SPL)
Figure B-3: TOP: Single-sided level-series measurements made on Cat #3 at 100 Hz.
Either the oval or the round windowwas stimulated. MIDDLE:Ratio of the measurement
made while the oval window was stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that ICI << IDI.
143
100 Hz Cat #4
1.00
-80 _.-o--.OW
-&- RW
--- noisefloor
.75
-1 00
co
c)
0
0~
a-
a
1 20
a.
.50
0
N
.25
1 An
-Vj
0
!
I
I
I
I
I
I
I
60
80
100
120
60
2
a
80
100
120
.6
n0
0 - ---------------
a_
------
.5
u
0
0
-2
60
9
80
100
N
120
FA
- -- - - - - - - - ---
a.
.4
60
80
100
- -
120
.5
ILI
1 0-5
F
I
0
1 0_6
1
0' 7 I
630
...... ZD: OW
- D: RW
C3
0
N
I
100
120
Level (dB SPL)
80
;·i
60
_
60
I
I
I
80
100
120
Level (dB SPQ)
Figure B-4: TOP: Singe-sided level-series measurements made on Cat #4 at 100 Hz.
Either the oval or the round windowwas stimulated. MIDDLE:Ratio of the measurement
made while the oval windowwas stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that JCJ << ID1..
144
100 Hz Cat #5
I,,
-80 _
.DU
-
Q!Q
--o--OW
-A- RW
--- noisefloor
.25
-
100
b.
0
5a
b
,
0
'O
0
0
C.
-120
N
-.25
-140
-
-
-. 50
I
I
I
.
I
I
I
60
80
100
.
I
120
I
I
[[[
I
I
I
60
80
100
I~~~
I
120
c
2
r
0
-i
-i
.6
K
o .5
0
_'3
r
I
i
I
I
I
I
60
80
100
120
-f
-_
0
0
.4 II
60
I-
I
II
I
I
80
100
120
;
aL
.5
5
10
......-----ID: OW
-IDI:
RW
C,
a,
0
'
0 10 6
<: >
0
......-----ZD: OW
- D: RW
0
1 0-760
C
60
I
80
_I
100
N
120
Level (dB SPL)
-. 5
660
.t:O
80
100
120
Level (dB SPL)
Figure B-5: TOP: Single-sided level-series measurements made on Cat #5 at 100 Hz.
Either the ovalor the round windowwas stimulated. MIDDLE: Ratio of the measurement
made while the oval window was stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that ICi << ID.
145
100 Hz Cat #6
.50
-80
-----o--&---
-100
OW Pre-TTX
RW Pre-TTX
OW Post-TTX
RW Post-TTX
noisefloor
.25
CD)
0>
a,
a
m
0
-Q
0
-120
N
-.25
-
-140
60
I
I
I
80
100
120
-.50
60
2I
80
.1(
100
-V
-
0I
>
c
_._
C)
.
60
(0
U
/ Pre-TTX
- - Post-MX
.5
-2 2
80
100
n*3.
-- IDI:RWPost-TTX
10
1_
I
60
0 -.
I
I
I
80
100
120
_
_
DaO-
_
_-
a
-3- IDI: OW Post-TTX
-_n
,,
10
L_
r
60
120
-.- IDI:OWPre-TTX
-- IDI:RWPre-TTX
-L.-0
A
.
120
I
I
80
N
o
I
I
I
100
a -.5
C]
-1
--
Iffi
60
120
^.-- LD: OWPre-TTX
D: RWPre-TTX
\/ - D: OWPost-TTX
- LD: RWPost-TTX
/
l
l
Il
I
I
80
100
120
Level (dB SPL)
Level (dB SPL)
Figure B-6: TOP: Single-sided level-series measurements made on Cat #6 at 100 Hz
before and after the application of TTX. Either the oval or the round window was stimulated. MIDDLE: Ratio of the measurement made while the oval window was stimulated
and the measurement made while the round windowwas stimulated. BOTTOM: Estimate of D (difference-mode gain) from the single-sided level-series measurements. In this
estimation it is assumed that JIC << ID_.
146
100 Hz Cat #7
.50
-80 _
--e-- OW Pre-TTX
- RW Pre-TTX
--o-- OW Post-TTX
-- RW Post-TTX
--- noisefloor
100
.25
m)
V
00
0
0
>
-120
.25
140
a-
!
m
I
I
I
60
80
100
.50
1
120
60
V
2
.b
Pre-TTX
--- Post-TTX
a0
-
0
80
o0
- -- - -- - --
-
--
.-----
-2-2I 1=
i
i
i
60
80
100
120
10
---------------------
.5
.4
o 10
80
100
I
120
_,
C')
0
6
-A--.-
0
7
10I
03)
IDI:RWPost-TTX
'Zd
10
80
60
.b
-a- IDI: OW Post-TTX
-
-Pre-TTX
--- Post-TTX
,
-. IDI:OWPre-TTX
-- IDI: RWPre-TX
5'
120
r
0
00
100
r
I
I
I
60
80
100
120
N
-.5
r
60
I
ZD: OWPre-TTX
ZD: RWPre-TTX
ZD: OWPost-TTX
ZD: RWPost-TTX
I
I
I
80
100
!
I
120
Level (dB SPL)
Level (dB SPL)
Figure B-7: TOP: Single-sidedlevel-seriesmeasurements made on Cat #7 at 100 Hz
before and after the application of TTX. Either the oval or the round window was stimulated. MIDDLE: Ratio of the measurement made while the oval window was stimulated
and the measurement made while the round window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the single-sided level-series measurements. In this
estimation it is assumed that Ct << IDI.
147
170 Hz Cat #4
-80
.75
I--..-- OW
ARW
po
--- noisefloor
.50
-100
(0
a)
o
q)
m
a
tL
25
a:
o
-120
9~X~~ ----------..
QP.
0
>
0
140
m
!
I
I
I
I
I
60
80
100
-.25
I
1
120
60
100
120
100
120
1
2
.b
_
a
0
0
-
-2
>
0cn 1 0
a.
o 10
0
.3
o .5
X.-
-'A
lfl
I
60
ES
80
80
5
100
120
0o
.4
60
i
N
·
I.
I
.O
80
_
...----...IDI: OW
ID: RW
------ /D: OW
- D: RW
w
uC
C)
0
1 0 - 7 I r_
60
II
I
-
80
100
--
II
o
N
120
-.5
_
60
Level (dB SPL)
80
100
120
Level (dB SPL)
Figure B-8: TOP: Single-sided level-series measurements made on Cat #4 at 170 Hz.
Either the ovalor the round windowwas stimulated. MIDDLE:Ratio of the measurement
made whilethe oval windowwas stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that ICI << IDl.
148
200 Hz Cat #1
anl
.DV
-80 _
..o--OW
-A- RW
--- noisefloor
-100
.2 5 _
-
(,i)
i0
0
a.
1 20
oC.
-
,q
-.25
_
-.50
I
1 40
I
60
m
.,n
e
a-
".I
I
."
80
-
I
"
I
100
120
I
I
60
80
100
120
60
80
100
120
I
1
.6
__
a.
>1
0
0
0
.5
a.
-2
60
>L
10
,I IA
80
I
100
120
O
,,
.5
------IDI:OW
-IDI: RW
1 0' 6
..
n
7
L~
60
I
...... ZD: OW
D: RW
,
EDI
10
.4
c
5
co
a-
I.
0
\i -.5
60
L~
80
100
120
Level (dB SPL)
I
I
I
80
100
120
Level (dB SPL)
Figure B-9: TOP: Single-sided level-series measurements made on Cat #1 at 200 Hz.
Either the ovalor the round windowwas stimulated. MIDDLE:Ratio of the measurement
made while the oval window was stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that C << ID[.
149
200 Hz Cat #2
./5
,=
-80 _
--o-- OW
--- RW
--- noisefloor
50
i
_
100
a)
25 _
co
a)
-
o -120
--
_i
-
------
-----
.
>l.
,q
0
-140 _
I
I
I
I
60
80
100
120
-.255
?_
I
m
60
80
I
I
I
I
100
120
m
2
1 -
.0
-3a
0.
0 -------------------
----
.5
60
0 10
10
-
0a. .4
-2
0
5
w
a
80
100
120
N
5
80
100
120
i
....--. D: OW
ZD: RW
a,
6
60
------
_
......--IDI: OW
IDI: RW
1 0-7 1
---
I-6
60
.O
--- ----
0
II
80
-I-
II
- I
100
I
N
120
-. 5
[-
60
Level (dB SPL)
I
I
I
80
100
120
Level (dB SPL)
Figure B-10: TOP: Single-sided level-series measurements made on Cat #2 at 200 Hz.
Either the oval or the round window was stimulated. MIDDLE: Ratio of the measurement
made while the oval window was stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that ICI << IDI.
150
200 Hz Cat #3
-80
_,
.Z0
-
m
--o-- OW
0
1 00
m
o
"o
a.
0
1 20
0
-. 25
m
-.50
_
m
1 40
-
I..
I
60
.
I
.
I
80
100
I
-.755 '
I
,
1
II
I80
60
120
80
100
I
120
100
120
m
0
2
a:
rr
.6
0
0
0
0
NC>
.5
-------------
I
----------
O
-
0
1.
o
CO
-2 .60
,
.
80
100
I
...... ID: OW
IDI: RW
1 0-5
,qD_
o
....
N
A
. i
-
C30
120
i
I
I
80
100
120
.5
...... D: OW
_- LD: RW
0
an
O)
o> 1 06
0
1 0-7
60
I
I
I
80
100
120
0
N
o
v
r~
-.5
660
Level (dB SPL)
I
I
II
II
80
100
120
Level (dB SPL)
Figure B-11: TOP: Single-sided level-series measurements made on Cat #3 at 200 Hz.
Either the ovalor the round windowwas stimulated. MIDDLE: Ratio of the measurement
made while the oval window was stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that jIC << IDJ.
151
200 Hz Cat #4
'=
-80
./1
m
AI
.50
-100
(I,
co)
<,
-o
a-
-120
-
.25
C-
\
0
-140
I
I
I
II
I
I
I
60
80
100
120
60
80
100
120
m
I
a
-O
o
a
0
- 2-I
0a.
co
60
,
I
80
-5
100
120
...... IDI: OW
IDI: RW
1u
1
0
N
I
.4 1-
60
80
100
"
v,
.
I
120
...... LID: OW
~ z
D: RW
0
I
r)
10
-------
I
.0r
6
:r
5
------.
.5
C
0
0(/
_N
m
.b
7 i~
0
io
I
I
I
I
80
100
I
_
-. 5
120
m
60
Level (dB SPL)
80
100
120
Level (dB SPL)
Figure B-12: TOP: Single-sided level-series measurements made on Cat #4 at 200 Hz.
Either the ovalor the round windowwas stimulated. MIDDLE: Ratio of the measurement
made while the oval windowwas stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that IC << ID.
152
--
-80
250 Hz Cat #4
./5
- ,
.- o--OW
RW
--- noisefloor
-100
.50
(I,
0
.
co3
(,
-120
-
25 _
0
N
Q9
P--Q
0
-140
6
.
"- ..
'''.''_
.25
7
.'
_'
I
of ,
I
60
80
100
60
120
2
80
100
1
120
.6
_
-
0 - -----o
--------
0 .4
60
80
100
----- IDI: OW
IDI: RW
CO
a.
:-.
0
53
1 0-7
120
N
L H_
__
60
.o
I
I\
80
100
120
_
1 0-5
1 06
.5
a.
F
-2
20.3
.
.·
a,
0
0
a
I=.
60
80
100
120
,q
_
.
.5
m
60
Level (dB SPL)
D: OW
--.- I D: RW
m
I
Ii
80
100
120
Level (dB SPL)
Figure B-13: TOP: Single-sided level-series measurements made on Cat #4 at 250 Hz.
Either the oval or the round windowwas stimulated. MIDDLE: Ratio of the measurement
made while the oval windowwas stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that JIC << IDI.
153
300 Hz Cat #5
./O
'-=r
-80
_
--o-- OW
-A-
RW
--- noiseflo
-100
.50
_
.25
_
_
0,
0)
5n
-o
a-
0
-120
a-
\l
oo
0
Oq
Q.
-140
_
I
40
I
I
60
I
80
I
100
80
100 120
-. 25
I
120
'!
I
I
40
40
60
t0000
~
I
I
I
80
~~~I
I
1
100 120
co
A
.5
2
a
a
a
-
0 - ----------------- fll%_ - __
- --o.
-o
r
-C r
40
I
I
60
80
I
I
100 120
0
0 .4 c,_
N
40
.O
_
0C,)
10
-----------------\;r·-
.5
5
CO
0- 1 06
------IDI: OW
IDI:RW
1 0-7 I
40
\,
N
I
I
60
80
I
100 120
100 120
......-----D: OW
D: RW
0
m
-.5
40
3e
I
80
m
Cn
(d
60
I
I
60
80
I
I
100 120
Level (dB SPL)
Level (dB SPL)
Figure B-14: TOP: Single-sided level-series measurements made on Cat #5 at 300 Hz.
Either the oval or the round window was stimulated. MIDDLE: Ratio of the measurement
made while the oval windowwas stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that CI << IDI.
154
300 Hz Cat #6
-80
.50
-4- OWPre-TTX
- RW Pre-TTX
.-o-- OW Post-TTX
--- RW Post-TTX
--- noisefloor
-100
.25
m
0a.
-120
{-
0
N
-.25
140
-.50
40
60
80
100 120
40
2
-
ar
a.
Pre-TTX
--- Post-TTX
a.
i:
.b
80
100 120
_
Pre-TTX
-
_,, Drsv
- - - rUOt
--
I.
3 .5
0
60
.
-----
I IA
---
_-
3O
.4
-2
40
60
80
N
100 120
F
40
I
I
I
60
80
100 120
cI
0
0
1 05
o
n
co
a)
0
o
1 06
Z5
1 06
10~
-A- IDi:OW Pre-TrX
-- IDI: RWPre-T-X
-4o IDI:OW Post-TX
-IDI: RWPost-TTX
_II I
40
0
N
60
80
.5 _
100 120
Level (dB SPL)
-1
- ZD:
L- OWPre-TTX
-D: RW Pre-TTX
-0- ZD: OWPost-TX
- ZO: RWPost-TTX
I-
!
!
40
60
80
.
;,
I
i
I
i
I
100 120
Level (dB SPL)
Figure B-15: TOP: Single-sided level-series measurements made on Cat #6 at 300 Hz
before and after the application of TTX. Either the oval or the round window was stimulated. MIDDLE: Ratio of the measurement made while the oval window was stimulated
and the measurement made while the round window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the single-sided level-series measurements. In
this estimation it is assumedthat ICI << DI.
155
300 Hz Cat #7
.50
-80
--*-- OW Pre-TTX
-&-RWPre-TTX
--o-- OW Post-TTX
-- RW Post-TTX
--- noisefloor
.25
-1 00
ID,
Co
a)
0
a)
-
0
a_
-1 20
0
0
0
NcJ
L
-.25
-14C I
I
40I
40
2
cr
>O
0 -
-
0
-2
IL
40
I
I
I
r_
I
-. JU
80
100
120
60
80
100 120
F
I\
\-
. .--
_.
40
0
.
.5
,II
a-
I
80
.----
>1
I
60
------
0
0
I
100 120
.
,4
Y
N
[
F
40
100 120
Pre-TTX
--- Post-TTX
i
a-
/
/
80
.5
Pre-TTX
--- Post-TTX
--
60
-.
..
I
I I
I
I
I
I
I
60
80
I
1
100 120
0
10 -5
(.
c(
a)
0.
co
0
10
10
-6
7
----4v-B
I
40
I
!
I
60
!
!I
I
80
IDI: OW Pre-TTX
IDI: RW Pre-TTX
IDI: OW Post-TTX
IDI: RW Post-TrX
!I
I
-
.5
---
--
--
0
-1
I
!~~~
r
40
100 120
-
Q0/ \
I
60
80
ZD: OWPre-TTX
D: RW Pre-TTX
D: OW Post-TTX
LD: RWPost-TTX
I
I
100 120
Level (dB SPL)
Level (dB SPL)
Figure B-16: TOP: Single-sided level-series measurements made on Cat #7 at 300 Hz
before and after the application of TTX. Either the oval or the round windowwas stimulated. MIDDLE: Ratio of the measurement made while the oval window was stimulated
and the measurement made while the round window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the single-sided level-series measurements. In
this estimation it is assumed that ICI << ID1.
156
320 Hz Cat #4
.50
-80
--o- OW
RW
--- noisefloor
.25
_
-100
9
U,
0
a.
o
-120
o
0
9
-
,
\:---o-..
o a
d "o
'O..
O
.25
-140
-.50
60
a
80
100
120
2
ac
rc
T
I
I
I
60
80
100
120
.6
a.
o
:>
N
0
.5
---------------------------
0
-----
a
L
2
I
a.
o
60
(o
1 0'
0
(,
o
>
ES
10
1 0'
I
I
I
II
80
100
120
I
o
4.
m--
60
5
80
100
120
,.....
.b
-(6
------IDI:OW
o(
0
N
0
(3
------ ZD: OW
- D: RW
r
0
v
60
7
60
I
80
I
100
I
-.5
120
t-
60
Level (dB SPL)
I
80
I
I
100
120
Level (dB SPL)
Figure B-17: TOP: Single-sided level-series measurements made on Cat #4 at 320 Hz.
Either the ovalor the round windowwas stimulated. MIDDLE:Ratio of the measurement
made while the oval window was stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that ICj << DI.
157
400 Hz Cat #4
rn-_
.OU r-
-80 _
v
v
.- o--OW
-A RW
--- noisefloor
.25
00
-1
co
0
Q
a
0
a-
0
120
a
N
0
.i
-. 25
_ a.,
IO,.>
-140
I
60
I"·
I
I
I
80
100
120
'
r-
2
-.50 -I 60
80
I
100
I
120
60
80
100
120
I
I
I
I
I
I
80
100
120
3
cc
a.
0
.5
0.
-2
n0
c
I
I
60
80
I
I
100
120
N
.4
_.
--
:
60
,,q
.5
10-5
o
co
r
0
'O
0
f_
.0
(0
......--IDI: OW
IDI:RW
1 06
'
I. 1v
I
_.
I
!
I
I
I
I
60
80
100
120
r
I
o
-
...... LD: OW
ZD: RW
0
a
N
'.5
60
Level (dB SPL)
80
100
120
Level (dB SPL)
Figure B-18: TOP: Single-sided level-series measurements made on Cat #4 at 400 Hz.
Either the oval or the round windowwas stimulated. MIDDLE: Ratio of the measurement
made while the oval window was stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that CI << D[.
158
500 Hz Cat #4
-80
.50
_
---- OW
-, RW
--- noisefloor
-100
.25
-
m
cq
a)
'm
0
;>
c
a
-120
a.
0
d
-.25
-140
-
"-o
-o-o..
-
-.50
60
80
100
120
2
-I
I
I
60
80
100
120
60
80
100
120
.6
a.
co
'O
:
N3:
0
0a.
.5
0
o0
.4
-2
a>
0
60
1
cs 1 0
80
100
120
N
5
.5
r...... ZD: OW
- D: RW
0)
o-
a,
1
10
0
...... IDI: OW
-ID:
RW
-7
-
60
I
I
I
80
100
120
I
I
I
0
N
Level (dB SPL)
-.5
!1
I
..........
I
60
80
100
...
I
120
Level (dB SPL)
Figure B-19: TOP: Single-sided level-series measurements made on Cat #4 at 500 Hz.
Either the oval or the round windowwasstimulated. MIDDLE: Ratio of the measurement
made while the oval window was stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that CI << IDI.
159
600 Hz Cat #1
-80
-100
In _
_
.DU
m
.25
_
_
2
-c
0
0tO
_
0 -120
a
,q
.b
.25
1 40
_
q
'b-0--0-0-,0---0.,..0-
-
6
I
60
80
-. 50
1
1
100
120
I
I
.
I
.
I
.
I
60
80
100
120
I
I
.
80
100
120
m
.6
2
a.
-0.
a
.5
UI
-2 I
o
I1
60
0
10
I
80
I
100
120
-5
.4
-I
60
.5
0
O
>
,,
.------ D: OW
D: RW
0Cn
10
6
0
...... IDI:OW
-DI: RW
ES 1 0 7
0
N
60
80
100
120
Level (dB SPL)
0
-.5
I
I
I
I
60
80
100
120
Level (dB SPL)
Figure B-20: TOP: Single-sided level-series measurements made on Cat #1 at 600 Hz.
Either the oval or the round windowwas stimulated. MIDDLE:Ratio of the measurement
made while the oval window was stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that JIC<< ID.
160
600 Hz Cat #2
--
.bU
-80
--o-- OW
-- RW
--- noisefloor
.25
100
a
0
t_
r
-i
v
0
a.
0
-120
v
(.
N
-.25
40
1
'o
-
I I I I
I
I
I
80
100
120
I
60
-.50
-
I
60
I
I
80
I
I
1I
100
120
m
-13
2
.6
0 -----------
>c
-----------
-co
.
0
-2
a.
-1
I
60
o
.5 - ......
10
I
I
I
l
I
I
I--
80
100
120
N
.4 4_
60
60
\4
5
I
.;)
80
80
100
120
100
120
I--
CD
0
o 10
10
------IDI:OW
IDI:RW
7
I
.l
I
I
!
I
60
80
100
120
----- LD: OW
-LD: RW
0
0
N
\4
-.5
_1
60
Level (dB SPL)
I
I
I
80
100
120
Level (dB SPL)
Figure B-21: TOP: Single-sided level-series measurements made on Cat #2 at 600 Hz.
Either the ovalor the round windowwas stimulated. MIDDLE: Ratio of the measurement
made while the oval window was stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that ICI << IDI.
161
-----------
·---------·-----
·- ·----
-------
·------------ ---
600 Hz Cat #3
_ 1
-80
.DV
-o-- OW
RW
--- noisefloor
-1
w
_
.25 _
00
CO
c-
0
m
'a
0
a-
0
120
a.
o
N
,q
Q
.25 _
1 40
-
'.
I
I
I
I
60
80
100
120
-_rio
-. 50
-
2
I
!
I
80
100
120
1
60
1
0
:' 0
.6
0
-2
-
.5
-1
60
I
80
I
I
100
120
> 0 .4
N
5
1
60
60
1
.0i
80
100
......- D: OW
D: RW
,
1 06
1. -7_
120
.5
c)
5ni
1
a.
a:
0co
-I
-I
...... ID: OW
-IDI:
RW
_,
~:
60
ii
!
I
I
80
100
120
v
N
0
.5
60
Level (dB SPL)
I
I
I
80
100
120
Level (dB SPL)
Figure B-22: TOP: Single-sided level-series measurements made on Cat #3 at 600 Hz.
Either the oval or the round window was stimulated. MIDDLE: Ratio of the measurement
made while the oval window was stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that ICI << ID}.
162
600 Hz Cat #4
.50
-80
.25
1 00 I
0
0
a1.
-p
C,q
N"
o -1 20
a
-.25
-140
_
I
I
I
I
60
80
100
120
-.50
60
80
100
120
60
80
100
120
03
2
.6
o
>1
0
0
-
o
0
0-
-2
O
60
80
100
N
120
.5
.4
.5
1 0-
o
10
6
10
7
_
r-'
W
a,
[::
v
i
~
I
I
60
80
~
0
------IDI: OW
IDI: RW
0
~~~~~~~~~~~~~~~III
N
I
I
100
120
......-----D: OW
D: RW
-
- Z
-.5
--
60
Level (dB SPL)
.'
80
~
100
-' -
I
120
Level (dB SPL)
Figure B-23: TOP: Single-sided level-series measurements made on Cat #4 at 600 Hz.
Either the oval or the round windowwas stimulated. MIDDLE:Ratio of the measurement
made while the oval windowwas stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that CI << IDI.
163
800 Hz Cat #1
_,
.bU
-80 _
.25 _
1 00
-
c)
a)
(.
0
i_
-n
-
1 20
0
N
-
Q
_.
-. 25
-1401
a
-
60
80
100
I
60
80
100
120
o-do--o-o--"-c-
-. 50
2
_,
-o-
I
I
,
,
I
60
80
100
120
I
I
.tO
>
oN
0
.5 - --------
-------------
a.
4
-
60
10
aco
ES
10
10
-
80
100
120
N
-
- .I
60
5
------IDI: OW
IDI: RW
_
7 !
60
80
0
I
I
80
100
120
------ /D: OW
ZD: RW
I--..................
_-- .....
5
0
.
100
I
I
~~1 .
1
-6 _
I
I
3
120
60
Level (dB SPL)
I
!...I
Al
80
100
120
Level (dB SPL)
Figure B-24: TOP: Single-sided level-series measurements made on Cat #1 at 800 Hz.
Either the ovalor the round windowwas stimulated. MIDDLE:Ratio of the measurement
made while the oval windowwas stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that IC << IDI.
164
800 Hz Cat #2
7^
-80
/
_
-..o-- OW
-i-RW
--- noisefloor
1 00
.oo-o-.
.50 _
*0
_
a)
Io
pd
1
0
20
_
.25
>a
d
_
0
0
-140 _
60
60
80
100
120
80
100
120
-.
25
m!
I
*_
*
I
I
I
I
60
80
100
120
I
I
I
I
I
!
80
100
120
m
-
.or"_
2
0o
Q_
o
.5
UI
a-
0
o
a
-IleI
60
CZ
10
I
II
Ia
80
100
120
_
o .4
-
N
-5
III
....
I
60
1
---
eC
------ /D: OW
ZD: RW
1
Q)
o0
a)
1 0 '6
0
...... IDI:OW
IDI:RW
10
7
I
60
80
Level
I
II
100
120
.5
0
_-
a
N
0
-!
_,1
I
60
(dB SPL)
I.
I.
IB
80
100
120
I
Ii
Level (dB SPL)
Figure B-25: TOP: Single-sided level-series measurements made on Cat #2 at 800 Hz.
Either the ovalor the round windowwasstimulated. MIDDLE: Ratio of the measurement
made while the oval windowwas stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that JCI<< ID.
165
800 Hz Cat #3
./t
_
.,
CQb
_
-oU
-o--OW
&- RW
--- noisefloor
.50
00
-1
(/
ra)
v
.25
a
-o
-120
a.
O)
N
OI
0
-140
V
0
I
l
I
I
60
80
100
120
-.25
2
-
- a
I
I
I
I
60
80
100
120
r-
a
.0
0
.5 ----------
a:
0o
o - ---------------------
-v
-a.
N0
2
n
n-
.2
I
60
10
o0 1 0
II
80
I
100
120
O
. 4. -I
0
V
5-
I
I
I
I
I
I
60
80
100
120
1
------ ZD: OW
LD: RW
(C
6 _
-
10
I
>
7 _
--......
IDI: OW
IDI: RW
I
I
I
I
I
I
I
60
80
100
120
0
5
0
N
N
&
60
Level (dB SPL)
I
I
I
I
I
I
80
100
120
Level (dB SPL)
Figure B-26: TOP: Single-sided level-series measurements made on Cat #3 at 800 Hz.
Either the oval or the round windowwas stimulated. MIDDLE:Ratio of the measurement
made while the oval window was stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that CI << D1.
166
800 Hz Cat #4
nn
1 .UU
-80
--o.- OW
-&- RW
--- noisefloor
0..D
.75
'a
-100
(>
co
0
a.50
0o
a
o -120
.25
-140
-
,..o..O
0
60
80
100
120
60
r-
-o
2
--------
I
.5
0
-2 I
a.
0co 10
Cu
a0 10
5
120
0
-
>
100
r'
.t
a.
80
10
!I
I
I
I
I
I
60
80
100
120
A
>
N
-5_
v
.
LI
I
I
I
80
100
120
I
I
60
I
1
I
----- ZD: OW
ZLD: RW
a,
6
------IDI: OW
-IDI:
RW
7
60
I
I
I
80
100
120
o
.5 I
v
CD
0
0
N
0
-l
60
Level (dB SPL)
I
I
I
80
100
120
Level (dB SPL)
Figure B-27: TOP: Single-sided level-series measurements made on Cat #4 at 800 Hz.
Either the ovalor the round windowwas stimulated. MIDDLE: Ratio of the measurement
made while the oval windowwas stimulated and the measurement made while the round
window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the
single-sided level-series measurements. In this estimation it is assumed that KCI
<< ID1.
167
1000 Hz Cat #1
-r
/
_
0
-80 _
50 _
.-o-- OW
-*- RW
-1 00
---
_
6-.0.0-0-0--0-0--
nois
co
a)
-o
v
a .25 _
-120
>
,q
1 40
0
,----------
-160
I
I
I
40
m
co
l
I
80
-.25'
lI
I~~~~~
I
120
c
I
I
40
80
120
40
80
120
-
I
I
.55
I.
0
.5
'a-o
0
0
22
-14
40
-i0
0
10
4
0-
10
5
80
120
~q
.0
......---IDI: OW
IDI: RW
0
0co
> .45
I
I
(1)
-
0
5
E>
LD:
OWI
D: RW
r
1 06
I
40
-.5
I
I
80
--
II
=_
40
1 20
:
i
J
:
I
'_
80
_-
L
120
Level (dB SPL)
Level (dB SPL)
Figure B-28: TOP: Single-sided level-series measurements made on Cat #1 at 1000
Hz. Either the oval or the round window was stimulated. MIDDLE: Ratio of the
measurement made while the oval window was stimulated and the measurement made
while the round window was stimulated. BOTTOM: Estimate of D (difference-mode
gain) from the single-sided level-series measurements. In this estimation it is assumed
that Cj << ID1.
168
1000 Hz Cat #2
r'-f_
.DU
pro,oooo
9
-80
>
--o-- OW
- RW
--- nois
.25
-100
u,
a-
o
_ - - -- - -
/
0
-120
1
>
k
N
d
-. 25
-140
-.50
-1
an
vv
I
40
I
·I
120
40
I
I
·I
!
80
:
iI
·!
!I
!I
80
120
80
120
.bb
Cr
1-
0
>
0
'-
o
a.
0
-
cci
-I.
-2
I
_
40
10i'
6
1{¥
. v
I
_> 4S
.
.
80
120
.,,
N
I
_
I
'
40
I
80
7~~
.
40
-_:O
.3
------IDi: OW
ID: RW
C)
oQ- -1 5
- 10
0
_
I
I
......-----D: OW
- D: RW
a)
o
0
-N
_
I
rv
120
I
I
40
Level (dB SPL)
.
I
I
.
80
I
I
120
Level (dB SPL)
Figure B-29: TOP: Single-sided level-series measurements made on Cat #2 at 1000
Hz. Either the oval or the round window was stimulated. MIDDLE: Ratio of the
measurement made while the oval window was stimulated and the measurement made
while the round window was stimulated. BOTTOM: Estimate of D (difference-mode
gain) from the single-sided level-series measurements. In this estimation it is assumed
that IC << IDl.
169
1000 Hz Cat #3
0
-80
_
--o-- OW
-A-
-.25 _
RW
--- noise
100
_
Cal
0
rQ
1 20
-.50
.=1 --------------------------------
I
.
40
m
Q .
o-o44°-ve-
-.75 _
I
I
80
, I
120
-1.00
I
-
I
40
I
80
I
120
.55
2
a
a.
0
.5
0
0
_F
0
I
-2
j _
I
40
80
J
> .45 L
N
120
104
.
I
*I
80
i.
|~!
120
1 r
----- iDI: OW
IDI: RW
co
.5
r
10
_*
40
1 0-5
5
_
ao
_
-160 -
-0
o
0
-d
,
-1 40
a.
*
I
D
t
6
0
40
----......D: OW
D: RW
80
II
1- ;
40
120
I
I
80
120
I
Level (dB SPL)
Level (dB SPL)
Figure B-30: TOP: Single-sided level-series measurements made on Cat #3 at 1000
Hz. Either the oval or the round window was stimulated. MIDDLE: Ratio of the
measurement made while the oval window was stimulated and the measurement made
while the round window was stimulated. BOTTOM: Estimate of D (difference-mode
gain) from the single-sided level-series measurements. In this estimation it is assumed
that IC_<< DJl.
170
1000 Hz Cat #4
.25
-80
--..- OW
-4- RW
--- noisefloor
0
1 00
(o)
a)
r
p -.25
a
1 20
o
a0
N
-.50
-140
t)VU -
-I
J&0--0-00-0
I
40
m
I
I
.
80
0.1
CLa
-.75
I
120
80
40
120
l _
~= .5' 5 _r-L
-
5
>o
q
40
0
10
80
120
4
Co
0 10
10
,
I
I
I
I
I
'
.
40
80
120
1
......---IDI: OW
IDI: RW
C
25
0
>.4!
N
-2
- ----------
a)
5 -
0
v
.5
...... LD: OW
D: RW
0
6
N
~
40
0
80
120
_
40
Level (dB SPL)
I·
I
I
80
I
120
Level (dB SPL)
Figure B-31: TOP: Single-sidedlevel-series measurements made on Cat #4 at 1000
Hz. Either the oval or the round window was stimulated. MIDDLE: Ratio of the
measurement made while the oval window was stimulated and the measurement made
while the round window was stimulated. BOTTOM: Estimate of D (difference-mode
gain) from the single-sided level-series measurements. In this estimation it is assumed
that ICI<< DI.
171
1000 Hz Cat #5
./0
I-
-80 _
1 00
rn
--o-- OW
--- RW
--- noisefloor
0
_
a,
-.25 _
m
-1 20
-a.
o
a
_
N"
1 40
-.50 _
I
160
I
40
I
I
I
80
-. 75
I~~~~~~~~~
I
I
l
I
40
120
120
80
.5 5 r-_
2
V
- I
ra
-a.
o
0
oP
0
0.
-
1
0
5
I
I
40
80
2
·
- - - - - - - - - - - - - - - - - - - -
>a. .4[5 -_ 4,I
I
0
120
4
......----IDI:OW
IDI:RW
I
40
1
0co
+- 1 0
-
80I
I
120
80
120
...... /D: OW
D: RW
a)
0
5
:L
N
1 06
40
80
o.5
!I
40
120
I
80
I
120
Level (dB SPL)
Level (dB SPL)
Figure B-32: TOP: Single-sided level-series measurements made on Cat #5 at 1000
Hz. Either the oval or the round window was stimulated. MIDDLE: Ratio of the
measurement made while the oval window was stimulated and the measurement made
while the round window was stimulated. BOTTOM: Estimate of D (difference-mode
gain) from the single-sided level-series measurements. In this estimation it is assumed
that ICK << IDI.
172
1000 Hz Cat #6
.25
-80
--*-- OW Pre-TTX
-- RW Pre-TTX
--o-- OW Post-TTX
-&- RW Post-TTX
_
A-,,.
--- noisefloor
0
1 00 _
oa,
o -. 25
m
1 20 _
00
1 40
0
-.50
:0
-
-160
I
I
.
!
40
I
I
I
80
80
120
-.75
II
6,
I
I
I
,
40
120
El
,
80
I
120
oCr .55
2
a
o
a-
0
0
0
-2
a_
--
-
-
-'
.
I
0
----------
I
40
N4
0
0
Pre-TTX
--- Post-TTX
I
120
80
N
.45
6
---a-
Pre-TX
--- Post-TTX
I
II
;I_
40
Pre-TTX
80
1 20
h
-U
A:64
1 06
--
1
0
10
- ----- 4--
,o
q
1 04
0
.5
a,
.5
IDI:OWPre-TTX
IDi:RWPre-TTX
IDI:OWPost-TTX
IDI:RWPost-TTX
0
CD
I
I
40
80
I
0
I
-Z- ZD: OWPre-TrX
-- ZD: RWPre-TTX
-a- ZD: OW Post-TTX
D: RW Post-TTX
-[
40
120
.
.
I
80
II
I
1 20
Level (dB SPL)
Level (dB SPL)
Figure B-33: TOP: Single-sided level-series measurements made on Cat #6 at 1000 Hz
before and after the application of TTX. Either the oval or the round windowwas stimulated. MIDDLE: Ratio of the measurement made while the oval window was stimulated
and the measurement made while the round window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the single-sided level-series measurements. In
this estimation it is assumed that CJ << DI.
173
1000 Hz Cat #7
r
.zb
--.-- OW Pre-TTX
A RW Pre-TTX
--o-- OW Post-TTX
-- RW Post-TTX
--- noisefloor
-80
-1
0
00
co
1-
-.25
0
0
-1
_
0-
20
0
4
-. 50 _
-140
...
AV""
.
.. ,
.~------
ii
160
_ ,
I
:
40
I
-. 75
.
a
i
Z
I
I
40
80
;
120
80
CO
I
1
120
.55
I"
-
----- .5
0
o
-Pre-TTX
0o
-.- Post-TTX
-
a.
9
-
o:
1 04
I
.
I
I
40
80
I
'
--
IDI: RW Pre-TTX
-
IDI: RW Post-TTX
-
N
120
Pre-TTX
-.- Post-TTX
> .45
i
i
I
_
40
I
I
.
.
I
I
120
80
1
-&- IDI:OWPre-TrX
0
ao
\X
-a- IDI:OW Post-TTX
105
v .5
c)
N
10
6
_
I
40
I
I
80
0
I
120
Level (dB SPL)
-*- ZD:OWPre-TTX
-- ZD: RWPre-TrX
-.- ZD:OWPost-TrX
D: RWPost-TrX
-i
I
40
80
.
I
120
Level (dB SPL)
Figure B-34: TOP: Single-sided level-series measurements made on Cat #7 at 1000 Hz
before and after the application of TTX. Either the ovalor the round window was stimulated. MIDDLE: Ratio of the measurement made while the oval window was stimulated
and the measurement made while the round window was stimulated. BOTTOM: Estimate of D (difference-mode gain) from the single-sided level-series measurements. In
this estimation it is assumed that C <«< DL.
174
Appendix C
Summary of results: Stimuli to
both windows
Data from all simultaneous-stimuli measurements are contained within this appendix.
There are differences in each of the experiments (Cats #1 to #7) which are further
discussed in Appendix A; in general the results from Cats #1, #2, and #3 are not as
accurate as the results from the later cats.
The figures in this appendix compare the cochlear-potential magnitude and angle
measurements with model predictions. Each measurement set has three graphs associated with it; a cochlear-potential magnitude plot, a blow-up of the cochlear-potential
magnitude plot around
= 0,
0 and a cochlear-potential angle plot. Data points are rep-
resented with open circles and the model fits are drawn with solid (linear fit) and dashed
(logarithmic fit) lines. The description "linear fit" refers to the model fit obtained from
Equation 3.4 and the description "logarithmic fit" refers to the model fit obtained from
Equation 3.14.
The figures in this appendix are organized in order of increasing frequency. Within
175
each frequency group the figures are arranged in chronological order of experiment by cat
number. Measurement sets from a given cat at a given frequency are arranged in order
of increasing sound-pressure level. Each measurement set has a label which describes
the measurement frequency, cat number, and measurement order on the particular cat;
for example, measurement set 1000a_5 refers to the first measurement set made on Cat
#5 at 1000Hz.
There are two tables for each frequency group within this appendix. The tables give
model parameters for all measurement sets for the linear and logarithmic model fits.
176
Data set
75a4
7b-4
dB SPL
124
120
CMRR
24.52
30.83
IDI
1.95e-07
2.04e-07
Linear model parameters: 75 Hz
D
Icl
C
PMAG
0.181 1.16e-08 -0.090 0.917
0.227 5.88e-09 -0.192 0.751
P/
0.573
0.739
MIN Data
0.0035
-0.0136
f'MIN Model
0.0097
0.0027
Table C.1: Linear model parameters calculated from 75 Hz data.
Data set
75a4
75b_4
dB SPL
124
120
CMRR |
DI
22.20
2.72e-07
28.12
3.04e-07
Logarithmic model parameters: 75 Hz
ID
IC
C
PMAG
0.321 2.11e-08 0.036 0.979
0.321 1.19e-08 0.462 0.915
PI
P
0.884
0.873
MIN Data |MIN
Model
0.0035
0.0125
-0.0136
-0.0046
Table C.2: Logarithmic model parameters calculated from 75 Hz data.
IVcpl (dB re 1V)
-80
lVcpl
-80
-
o Data points
o Noisy data points
-Linear fit
-100
fit
-100 _ --- Logarithmic
-120
0 -0,
-120 -0
.......S_ ....3......
-140
-140
-
-0.5
0
I
.
I
-80
-80
-1 00
-100
-120
-120
-140
-140
0
0.5
I
I
'
0.02
0.5
0
0
-0.5
-o
P0
0.5
I
UV (cycles)
! .'
1.0
1.0
I ·
-0.5
I
-0.02 0
0.5
ZVcp (cycles)
(dB re 1 V)
I
o I
-0.02 0
V
.
I
I
0.02
(cycles)
0 I
-0.5
l
l
l.
'
.l
l
0.5
-~B~c
l
l
l
0
l
l
l
0.5
V (cycles)
Figure C-1: Simultaneous-stimuli measurement sets and model fits at 75 Hz on Cat #4.
177
Data set
100a_4
100b-4
100a..5
100b_5
100c.5
100d-5
100a_6
100b..6
100c_6
100d_6
100e_6
100f-6
100g_6
100h_6
100i_6
100a_7
100b_7
100c_7
100d_7
100e7
100_7
100g-7
dB SPL
121
120
118
124
120
125
121
126
121
126
116
116
100
110
121
119
127
102
126
118
108
98
CMRR
26.96
32.92
33.24
29.25
21.56
24.81
33.57
20.06
32.11
33.59
32.23
34.66
34.25
32.26
47.71
30.71
52.50
27.60
33.36
23.24
53.81
41.34
DI
3.97e.07
3.97e-07
1.26e-06
1.56e-06
7.29e-07
8.37e-07
1.81e-06
1.12e-06
1.86e-06
2.02e-06
1.68e-06
1.71e-06
1.56e-06
1.81e-06
1.85e-06
1.01e-06
1.17e-06
6.72e-07
1.19e-06
1.23e-06
1.06e-06
1.03e-06
Linear model parameters:100 Hz
LD
ICI
C
PMAG
1.78e-08 0.480
0.989
0.037
0.033
8.96e-09 0.371
0.812
-0.030 2.73e-08 -0.097 0.914
0.960
-0.094 5.38e-08 0.474
0.051
6.10e-08 0.271
0.843
-0.007 4.81e-08 0.347
0.982
-0.036 3.80e-08 0.421
0.978
0.841
-0.077 1.lle-07
0.268
-0.039 4.62e-08 0.297
0.965
0.967
-0.074 4.22e-08 0.447
-0.010 4.11e-08 0.232
0.972
-0.011 3.16e-08 -0.123 0.974
0.915
-0.042 3.03e-08 0.246
-0.008 4.41e-08 0.279
0.979
0.972
-0.036 7.60e-09 0.088
0.065
2.93e-08 0.206
0.985
-0.010 2.77e-09 0.271
0.975
0.117
2.80e-08 -0.419 0.970
-0.038 2.55e-08 0.152
0.985
8.47e-08 0.051
0.985
0.015
0.118
2.16e-09 0.307
0.998
0.098
8.83e-09 -0.302 0.991
PI
0.766
0.539
0.970
0.974
0.968
0.924
0.770
0.944
0.915
0.980
0.707
0.993
0.839
0.941
0.985
0.972
0.907
0.997
0.905
0.954
0.985
0.995
MIN Data
-0.0047
0.0024
-0.0270
-0.0088
-0.0014
-0.0002
0.0000
0.0038
-0.0004
0.0011
-0.0027
0.0007
-0.0114
-0.0058
-0.0009
-0.0196
0.0047
0.1580
0.0071
-0.0110
-0.0426
0.1341
bMIN Model
-0.0024
-0.0037
0.0018
0.0055
-0.0134
-0.0075
-0.0017
-0.0133
-0.0033
0.0001
-0.0028
0.0017
-0.0032
-0.0038
-0.0009
-0.0035
-0.0001
-0.0018
-0.0030
-0.0113
-0.0006
0.0006
Table C.3: Linear model parameters calculated from 100 Hz data.
Logarithmicmodel parameters: 100 Hz
Data set
100a_4
100b_4
100a.5
100b..5
100c.5
100d..5
100a-6
100b-6
100c.6
100d_6
100e_6
100f-6
100g_6
100h_6
100i_6
100a_7
100b_7
100c_7
100d_7
100e_7
100f_7
100g_7
dB SPL
121
120
118
124
120
125
121
126
121
126
116
116
100
110
121
119
127
102
126
118
108
98
CMRR
4.94
24.07
20.68
45.06
12.23
14.23
21.78
24.78
29.59
31.89
29.19
37.33
26.87
32.19
48.34
32.14
52.22
27.60
31.27
27.79
53.68
26.93
JID
2.67e-07
5.95e-07
1.18e-06
1.39e-06
6.88e-07
7.34e-07
1.00e-06
9.70e-07
1.45e-06
1.54e-06
1.21e-06
1.32e-06
1.31e-06
1.65e-06
1.38e-06
9.05e-07
9.62e-07
6.72e-07
1.14e-06
1.12e-06
1.05e-06
1.02e-06
LD
0.042
0.037
-0.037
-0.090
0.038
-0.002
-0.025
-0.086
-0.042
-0.073
-0.005
-0.037
-0.049
-0.007
-0.044
0.101
-0.000
0.117
-0.040
0.021
0.117
0.100
ICI
1.51e-07
3.72e-08
1.09e-07
7.78e-09
1.68e-07
1.43e-07
8.18e-08
5.60e-08
4.79e-08
3.92e-08
4.21e-08
1.79e-08
5.94e-08
4.07e-08
5.27e-09
2.24e-08
2.36e-09
2.80e-08
3.11e-08
4.59e-08
2.17e-09
4.61e-08
LC
-0.269
0.243
-0.002
0.180
0.180
0.172
0.158
0.292
0.296
0.449
0.210
-0.148
0.033
0.205
0.287
0.212
0.436
.0.440
0.068
0.058
0.309
-0.308
PMAG
0.741
0.867
0.948
0.972
0.946
0.947
0.893
0.923
0.974
0.980
0.975
0.994
0.966
0.979
0.980
0.992
0.984
0.969
0.990
0.989
0.998
0.991
/Z
0.298
0.756
0.973
0.973
0.972
0.967
0.720
0.953
0.927
0.980
0.653
0.996
0.820
0.907
0.975
0.983
0.923
0.997
0.903
0.962
0.985
0.994
OMIN Data
-0.0047
0.0024
-0.0270
-0.0088
-0.0014
-0.0002
0.0000
0.0038
-0.0004
0.0011
-0.0027
0.0007
-0.0114
-0.0058
-0.0009
-0.0196
0.0047
0.1580
0.0071
-0.0110
-0.0426
0.1341
OMIN Model
0.0827
-0.0094
-0.0030
-0.0008
-0.0303
-0.0275
-0.0116
-0.0064
-0.0052
0.0001
-0.0057
0.0014
-0.0032
-0.0038
-0.0009
-0.0025
-0.0001
-0.0019
-0.0030
-0.0113
-0.0006
0.0036
Table C.4: Logarithmic model parameters calculated from 100 Hz data.
178
ZVcp (cycles)
IVcpl (dB re 1 V)
IVcpl (dB re 1 V)
-8(
-80
-10(
-100
o Data points
e Noisy data points
Linear fit
--- Logarithmic fit
1.0
-!
0.5
-12(
................ ....... ..................
-14C D -
noisefloor
100b_4.
120 dB SPL
-120
-~
-0 00C.
_~~
-140
I
"
-0.5
0
0.5
0
-0.01
0
|
0
0.01
.
;
l~
~
l
l
lZ
0
-0.5
0.5
-
1.0
-80
-
-10C3l-O
-100
-
-12(
-120
-8C
o
0.5
I
D)~~
-14C
100a_4
121
dBSPL
-140
~1
.
..
-0.5
0
Ni (cycles)
0.5
-0.01
.
..
0
i (cycles)
.
..
I
..
0.01
0
=.
-0.5
.
.
.
.
.
.
0
.
0.5
I (cycles)
Figure C-2: Simultaneous-stimuli measurement sets and model fits at 100 Hz on Cat #4.
179
-80 I-
-80
-100
-120
o Data points
o Noisy data points
Linear fit
--- Logarithmic fit
-
-100
.................
noisefloor
................
I
100a_5
LVcp (cycles)
IVcpl (db re 1 V)
IVcpI (db re 1 V)
ato
0.5
0
-120
118 dB SPL
-140
-140
oI .
-
-
-
-
-
-0.5
II
-
-
l
-
0
lII
1
0
0.05
II
0.5
-0.05
-0.5
-0.5
0
0.5
0
0.5
0
0.5
0.5
-80
-80
-100
-100
-120
-120
-140
-140
-0.5
0
0.5
_
0..
i
I
I.
.
I' ..
-0.05
'
I,
**
I
0
..
0
-0.5
-0.5
0.05
0.5
-80
-80
-100
-100
....................
.........
-120
......
1004dBSPL5
124 dB SPL
-140
-120
_-
.i..
.......
0
1.
. .
........
...
-140
· I
-0.5
0.5
0
I
0
-0.05
,
1
0.05
-0.5
-0.5
0.5
-80
-80
-100
-100
50000
_
I
II
0
-120
-120
1OOd 5
I
125 dB SPL
-140
.
-0.5
-140
.
. .
. ..
0
yI (cycles)
I
I
0.5
I
-0.05
I
*
I
0
0.05
NM(cycles)
-0.5
.9.
-0.5
.
...
.
.
.
.
....
.
0
.
.
I
I
0.5
Ir(cycles)
Figure C-3: Simultaneous-stimuli measurement sets and model fits at 100 Hz on Cat #5.
180
ZVcp (cycles)
IVcpl (dB re 1V)
IVcpl (dB re 1V)
0
~~~~~~~~~~~~~~~~~~I
-
-80
-80
-100
-100
-120
-120
-140
-140
o Data points
-- Linear fit
----
Logarithmic
fit
f i oDa'a"°n'
!~P-3
I
I
-0.5
0
0.5
-0.02
0.02
0
A
-0.5
-1.0
r....;......
I-0.5
-0.5
·
·
·
0
II
I
I
0
0.5
U
0000
-80
-80 _
-100
-100
-120
-120
100b_6
126 dB SPL
-140
-140
01111
11111
-0.5
0
r (cycles)
0.5
-o~
0
0
..................................
1I ,
-0.5
·
I
a
-0.02
0.-
0
V (cycles)
.
I
0.02
-1.0
r,.. I..,
I
-0.5
II
0
I
0.5
yx (cycles)
Figure C-4: Pre-TTX simultaneous-stimuli measurement sets and model fits at 100 Hz
on Cat #6.
181
ZV,p (cycles)
IVcpl (dB re 1V)
1Vcp1(dB re V)
_
p
U
-80
__
ints
100
-1
120
100g 6
100 dB SPL
noisefloor
-140
t
I
-0.5
meet
-1
.I".
4-
-1
-
-.-
-0.5
-
- -
0
-
--
.
-
.
0
-
0.5.I
0.5
-0.02
0
0.02
-1.0 - -0.5
0
-80
-80
-100 I
-120
-120
-140
-140
0.5
0
0.5
m
I
I
-0.5
-
0
lI
II
-
- -
I-
-100
-0.5
II
I
-
-0.02
I
I
.
I
I
!
0
0.02
II
-1.0- .
-0.5
T
.
.
.
.
.
0
0
.
.
I
0.5
I
-80 _
-80
I
-100
-100
-120
-120
-140
-140
-4
-
-0.5
~a~-~p
~9~r
i·""
I
I
-1.0
.
0
0.5
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~I
4
I-
·
-0.5
4
-
-0.02
0
0.02
*
-
.
-
-
.
.
I I I i
0.5
0
0..5
-1.0
-0.5
0
0.5
0
-80
-80 I-
-100
-100
-120
-120
-140
-140
I-
-0.5
-
i
-0.5
0
v (cycles)
0.5
i
-0.02
i
0
B
i
0.02
,v(cycles)
v (cycles)
Figure C-5: Post-TTX simultaneous-stimuli measurement sets and model fits at 100 Hz
on Cat #6.
182
-/Vc(cycles)
IVcpl (dB re 1V)
IVcpl (dB re 1V)
o
-80 I
-80
o
---
-100
-100
-120
-120
Data points
Linear fit
Logarithmic fit
-0.5
0-
-140
100c_6
noisefloor
_..............
..............................
------ --- ----- --- --
-140
I
-0.5
I
1
I
I
0
0.5
-0.02
0
II
.
-1.0
0.02
-0.5
0
0.5
,\
U
-80
-80 _
-100
-100 _
-120
-120
-140
-140
i
.,,,,,,,y,
.............
0
0.5
,.......
I
I
-C3.5
2J
-0.5
I
-0.02
II
.
0
-1.0
0.02
-
-
-
·
l
-0.5
I
I
.II .
--
-
1
0
0.5
0
-80
-80
-100
-100
-120 =-140
~
_-
V100d
6
126 dB SPL
---
-0.5
-
VF(cycles)
0.5
-
-0.5
-120
_..I..............................
I
I
---.
0
0-
-140
...........................................
~I
-
I·
|
-
-0.02
I
0
vy
I
-.
(cycles)
0.02
-1.0
I.
I
I
-0.5
-
.
.
I
.
0
.
.I-
.
-A
I
0.5
4y (cycles)
Figure C-6: Post-TTX simultaneous-stimuli measurement sets and model fits at 100 Hz
on Cat #6.
183
0.0
r
-80
100
-120
ZVcp (cycles)
IVcpl (dB re 1 V)
IVcp, (dB re 1 V)
-80
I-
.. ,.
....
100c_7
102 dB SPL
-140
~·...
i
.
.
-100
-
-120
-0.5
.
I
.
.
.
-140
. _ O_I . ---.--_I
0
I
I
0.5
-0.02
.
-0.5
.....................................
.. . .e......I . . . I
.
o Data points
o Noisy data points
Linear fit
- - Loganrithmicfit
-
I
0
-1.0
-0.5
0.02
0
0.5
0.0
-80
-80
-100
-100 I-
-120
-120
_
-0.5
* 100a7
-140
S 119dBSPL
I:.::.:I:':::
-0.5
-140
...............
1
-
.
0.5
I
,
........
.
..
tI
;
0
0
2.
-0.02
0
0.02
1.
-1.0
.
.
-0.5
:
.
.'
.'
I
I
0
0.5
0
0.5
0.0
-80
-80
-100
-100
-120
-120
-140
-140
-0.5
-1.0
-0.5
0
xV (cycles)
0.5
-0.02
0
xV (cycles)
0.02
-0.5
V (cycles)
Figure C-7: Pre-TTX simultaneous-stimuli measurement sets and model fits at 100 Hz
on Cat #7.
184
IVcpl (dB re 1 V)
o Data points
-80
-80
-100
-120 ...-.....
·
d_7PL
140
2 a * a
i
-0.5
-80
-0.5
-120
.AtX
oisefloor
-140
0.0
- Noisy data points
Linear fit
--- Logarithmic fit
-
100
ZVcp (cycles)
IVcpI (dB re 1 V)
!
0
I
1
1
1
0.5
-0.02
0
0.02
-100
-100
4""B
-120
I1
-_
-140
I
000,0
I
-0.5
00f7
108 dB SPL
'
0
.
-120
-100
-100
-120
-120
-140
-140
0
0.02
0.5
'
..
I
I
·
0
l
-1.0
-0.5
0.02
0.0
-80
-100
-100
-120
-120
_
lira
-0.5
a
N(17
-140
-140
-0.5
0.5
'S
-0.02
-80
0
-0.5
.I---QQ-...
I
0
-1.0
-0.5
0.0
I-
I
-0.5
0.5
I
-0.02
-80
0
-0.5
-140
-80
0.5
.: ...................................
I
0.5
0
0.0
-80 _
_
-1.0
-0.5
I
0
Nf (cycles)
0.5
-0.02
0
VC(cycles)
.
I
0.02
-1.0
-
-0.5
-
-
-
-
!-
-
-
0
-
g
0.
0.5
V (cycles)
Figure C-8: Post-TTX simultaneous-stimulimeasurement sets and model fits at 00 Hz
on Cat #7.
185
Data set
200a-1
200b_l
dB SPL
124
125;122
CMRR
8.46
8.55
ID
3.49e-07
3.48e-07
Linear model parameters: 200 Hz
D
IC
ZC
PMAG
-0.113 1.32e-07 0.340
1.000
-0.114 1.30e-07 0.337 0.997
P/
1.000
0.996
PMIN Data |MIN
Model
-0.0218
-0.0177
-0.0167
-0.0188
Table C.5: Linear model parameters calculated from 200 Hz data.
Data set
200a_1
200b-1
dB SPL
124
125;122
Logarithmic model parameters:
D
C,
/C
3.51e-07 -0.111 1.33e-07 0.341
3.41e-07 -0.115 1.28e-07 0.330
IDI
CMRR
8.44
8.50
200 Hz
PMAG
1.000
0.985
P/
1.000
0.961
PMIN Data
-0.0218
-0.0167
PMIN Model
-0.0187
-0.0198
Table C.6: Logarithmic model parameters calculated from 200 Hz data.
IVcpl (dB re 1 V)
IVcpl
-80
Qn
-OU
-100
-100
_
-120
_
(dB re 1 V)
o Data points
o Noisy data points
Linear fit
--- Logarithmicfit
ZVcp (cycles)
1.0
---
-120
200a 1
noisefloor
124 dB SPL
.oseo
.. .............................
-140
.
.
.
.
,i'
-0.5
I
I
=
0
*
'
0.5
-140
I
I
·.
0.5
0n_
-du
r-'
-0.05
t,
.
0
.
0
0.05
-0.5
1.0
r
-?u
,0.
r_,
-I
. ..
....
II
0
0.5
0
0.5
-100 _-
100
-120
0.5
-120
OW 125 dB SPL
-140
RW 122 dB SPL
. ..........I ............
. . . . .I . .
-0.5
0
I1
I
..
-140
I
....
-!
y (cycles)
I_
I
0.5
-0.05
.........
'
I
'
0
0.05
f (cycles)
0
-0.5
V (cycles)
Figure C-9: Simultaneous-stimuli measurement sets and model fits at 200 Hz on Cat #1.
186
Data set
250a_4
|
r
Linear model parameters: 250 Hz
CMRR
IDI | D
Ic
C
I
C I PMAG
P/ I MIN Data
PMIN Model
30.73 | 2.11e-06 -0.009 1 6.13e-08 1 0.396 1 0.998 | 0.925 1 -0.0092
1 -0.0027
dB SPL
108
Table C.7: Linear model parameters calculated from 250 Hz data.
Data set
250a_4
Logarithmic model parameters: 250 Hz
CMRR
ID
I LD
IC
I LC
PMAG
PI I MIN Data
39.60 1 2.23e-06 1 -0.005 1 2.33e-08 1 0.415 0.997 1 0.941 -0.0092
dB SPL
108
{
PMI Model
-0.0012
Table C.8: Logarithmic model parameters calculated from 250 Hz data.
IVcpl (dB re 1 V)
/Vcp (cycles)
IVcpl (dB re 1 V)
1.0
-80
-80
-100
-100
-120
-120
o Data points
* Noisy data points
Linear fit
--- Logarithmic fit
0.5
-140
,
- noisefloor
'I
v1
-
-0.5
250a_4
108 dB SPL
0
........................
9
.
-
-
-
-
-
.
-
.
-
0
ry (cycles)
.
-
.
-
-140
I
0.5
.
-0.01
.
0
I
.
·
0.01
I
i (cycles)
0
-0.5
0
0.5
r (cycles)
Figure C-10: Simultaneous-stimuli measurement set and model fits at 250 Hz on Cat
#4.
187
Data set
300a.5
300b-5
300c_5
300d5
300e_5
300f.5
300a..6
300b..6
300c_6
300d_6
300e_6
300f_6
300g.6
300h_6
300i_6
300a_7
300b_7
300c_7
300d_7
300e_7
300f_7
300g_7
dB SPL
100
105
110
115
120
125
115
125
116
120
126
120
110
100
90
121
101
116
121
111
101
90
CMRR
24.36
26.18
34.40
33.89
33.51
37.08
33.11
28.53
31.24
35.58
34.83
39.62
42.89
49.11
31.42
31.78
39.41
47.32
36.65
35.27
18.60
32.38
IDI
6.20e-06
7.05e-06
6.82e-06
6.76e-06
6.41e-06
6.71e-06
1.20e-05
7.82e-06
1.05e-05
9.92e-06
7.35e-06
9.59e-06
9.50e-06
8.14e-06
7.82e-06
4.80e-06
4.21e-06
5.12e-06
5.74e-06
6.86e-06
4.94e-06
3.33e-06
Linear model parameters: 300 Hz
ZD
7
Id
LC PMAG
-0.093 3.75e-07 -0.433 0.922
-0.132 3.46e-07 0.453
0.950
-0.165 1.30e-07 0.248
0.990
-0.181 1.37e-07 0.291
0.890
-0.153 1.35e-07 0.212
0.936
-0.175 9.39e-08 0.303
0.959
-0.236 2.66e-07 0.270
0.980
-0.258 2.93e-07 0.177
0.979
-0.217 2.87e-07 0.336
0.988
-0.231 1.65e-07 0.228
0.976
-0.237 1.33e-07 0.242
0.988
-0.224 1.00e-07 0.174
0.993
-0.202 6.81e-08 0.272
0.989
-0.209 2.85e-08 -0.029 0.984
-0.228 2.10e-07
0.228
0.981
7
0.408
0.976
-0.221 1.24e-0
-0.159 4.51e-08 -0.492 0.995
-0.214 2.20e-08 0.403
0.985
-0.252 8.44e-08
-0.461 0.993
7
-0.228 1.18e-0
-0.431 0.992
-0.179 5.80e-07 -0.500 0.902
-0.147 8.01e-08 0.421
0.995
P/
0.769
0.564
0.499
0.512
0.847
0.865
0.982
0.960
0.964
0.882
0.970
0.994
0.962
0.879
0.969
0.960
0.990
0.874
0.989
0.993
0.571
0.984
'MIN Data
0.0104
0.0000
-0.0018
-0.0040
-0.0047
-0.0024
0.0014
-0.0003
-0.0007
-0.0016
-0.0012
-0.0011
-0.0006
-0.0001
0.0018
0.0015
0.0018
0.0011
0.0029
0.0026
0.0046
0.0034
'PMIN Model
0.0078
0.0036
-0.0011
-0.0011
-0.0029
-0.0002
0.0003
-0.0021
0.0007
-0.0011
-0.0007
-0.0011
-0.0005
-0.0008
-0.0009
0.0025
0.0015
0.0002
0.0020
0.0021
0.0170
0.0020
Table C.9: Linear model parameters calculated from 300 Hz data.
Data set
300a..5
300b.5
300c_5
300d.5
300e_5
300f_5
300a_6
300b..6
300c_6
300d_6
300e_6
300f_6
300g_6
300h_6
300i-6
300a_7
300b_7
300c_7
300d_7
300e_7
300f_7
300g_7
dB SPL
100
105
110
115
120
125
115
125
116
120
126
120
110
100
90
121
101
116
121
111
101
90
CMRR
25.18
31.12
32.77
29.75
30.88
32.29
32.91
32.21
31.10
35.73
39.64
39.23
43.87
41.11
29.10
38.06
39.73
38.87
34.78
33.90
22.04
29.19
IDI
6.35e-06
7.96e-06
6.68e-06
5.07e-06
5.33e-06
5.55e-06
9.04e-06
9.41e-06
8.46e-06
8.00e-06
7.86e-06
8.49e-06
6.08e-06
7.51e-06
7.88e-06
3.71e-06
3.66e-06
4.44e-06
5.49e-06
5.69e-06
5.86e-06
3.10e-06
Logarithmic model parameters: 300 Hz
D
IcI
C | PMAG |
-0.082 3.50e-07 -0.488 0.961
0.785
-0.108 2.21e-07 0.458
0.946
0.656
-0.134 1.54e-07 0.156
0.919
0.722
-0.137 1.65e-07 0.082
0.985
0.817
-0.073 1.52e-07 0.253
0.993
0.938
-0.115 1.35e-07 0.315
0.990
0.942
-0.263 2.04e-07 0.263
0.992
0.972
-0.242 2.31e-07 0.257
0.991
0.994
-0.283 2.36e-07 0.264
0.995
0.920
-0.227 1.31e-07 0.161
0.998
0.994
-0.219 8.19e-08 0.173
0.998
0.997
-0.215 9.28e-08 0.140
0.997
0.997
-0.160 3.89e-08 0.133
0.986
0.924
-0.220 6.61e-08 0.011
0.981
0.873
-0.257 2.76e-07 0.229
0.997
0.986
-0.153 4.64e-08 0.315
0.980
0.917
-0.141 3.78e-08 0.457
0.996
0.989
-0.183 5.06e-08 0.486
0.995
0.976
-0.225 1.00e-07 -0.465 0.998
0.994
-0.206 1.15e-07 -0.397 0.995
0.995
-0.197 4.64e-07 -0.496 0.923
0.715
-0.160 1.08e-07 0.240
0.987
0.960
PMIN Data | MIN Model
0.0104
0.0048
0.0000
0.0010
-0.0018
-0.0038
-0.0040
-0.0052
-0.0047
-0.0042
-0.0024
-0.0009
0.0014
0.0000
-0.0003
-0.0003
-0.0007
0.0007
-0.0016
-0.0021
-0.0012
-0.0012
-0.0011
-0.0011
-0.0006
-0.0005
-0.0001
-0.0010
0.0018
-0.0005
0.0015
-0.0004
0.0018
0.0007
0.0011
0.0011
0.0029
0.0025
0.0026
0.0031
0.0046
0.0119
0.0034
-0.0033
Table C.10: Logarithmic model parameters calculated from 300 Hz data.
188
-OD
-60
_
-80
ZVcp (cycles)
IVcpl (dB re 1 V)
1Vcpl (dB re 1 V)
_~f
o Data points
o Noisy data points
Linear fit
-80
1.0
--- Logarithmic
fit
-100
-100
-noisefloor
-120
100 dB SPL
._.... r...
.....
_
0.5
-120
0
-140
-140
ga
T
.
.
-,
-0.5
_ I I·
Ia
I
0.5
0
*
-0.01
n,
-Dv
-Dv r"
-80
-80 -
I
0
0.01
-100
I
I ._
-0.5
0
0.5
0a
-
0.5
-120
I
-1 A4
*7VI
0
1.0
I-
-100
-120
I
I
-140
l
l
l
I
l
l
l
I
0
0.5
0
-0.5
l
Ii
-0.01
-60
-60
-80
-80
-100
-100
-120 _
| 300c_5
-120
.................. ....i
-140
110 dB SPL
-140
......
11 . . . . -II ...--. . . . II
0
0.5
-0.5
n
n
n
I
yi (cycles)
I
I
0
0.01
0
-0.5
I
0
0.5
0
0.5
1.0
0.5
I
-0.01
I
I
0
0.01
lr (cycles)
0
-0.5
yv (cycles)
Figure C-11: Simultaneous-stimuli measurement sets and model fits at 300 Hz on Cat
#5.
189
IVcpl (dB re 1 V)
crn
-OU
_
-ouv
-80I
-80
-100 I
-100
-120
-140
300d_5
115 dB SPL
.......................
noisefloor
......................
1 1 1 1 1 I .
-0.5
. .
0
I.U
-
I o Data points
Linear fit
--- Logarithmic fit
_
0.5
-120
I
.
____
I
.
I
.
,i
.
.
0.5
-0.01
-60
-oU
-80
-80 I-
n_
0
300e_5
120 dB SPL
r
0-
0.01
-
I
-
-
...
-
i
!
i
i -
-0.5
0
0,!5
-0.5
0
0.!
1.0
r"-
-100
-120
I
-
-140
.
-100
ZV c p (cycles)
IVcpI (dB re 1 V)
0.5
-120
··············
"""""""··'······
-140
-140
.
·
.I
-0.5
0
0.5
-0.01
-60
-ou
-80
-80
-100
-100
300f_5
-120
125 dB SPL
.................................................
-120
-140
-140
I
I
.
I
Ii
0
0
0.01
_,
1.0
_
0.5
d
I
.
.
.
0 . . . . . . . . . .
-0.5
0
0.5
!
-0.5
0
Mf(cycles)
0.5
-0.01
0
0.01
l (cycles)
I
Ni (cycles)
Figure C-12: Simultaneous-stimuli measurement sets and model fits at 300 Hz on Cat
#5.
190
-IOU
-60
-80
-80
-100
-100
-120
-120
-140
300a_6
115 dB SPL
-
-0.5
-60
2
l
l
o Data points
!
Il
l
0
|
l
l
!
l
I
0.5
--- Logarithmic fit
I
........
.
.......
I
I
!
I
-0.01
-80
-80
-100
-100
-120
-120
-140
-140
I
'
0
0.01
Mf(cycles)
0.5
-0.5
0
0.5
-
0.5
-
-
!
0
0
1.0
-
II
-0.5
0.5
44~~ __
,,
-OU
1.0
- Linear fin
-140
noisefloor
.-
LVcp (cycles)
IVcpI (dB re 1V)
lVcpl (dB re 1V)
,,
1...................................
:
'
-0.01
.,
0
0 . . . . . . . . . .
:!
I
0.01
v (cycles)
-0.5
.
.
.
0
.
I
0.5
iv(cycles)
Figure C-13: Pre-TTX simultaneous-stimuli measurement sets and model fits at 300 Hz
on Cat #6.
191
IVcpl (dB re 1V)
IVcpl (dB re 1V)
-60
111_
-fou
r-
80 I
K
-80
-100
-100
-120
-120 _
300i6
-140
-
90 dB SPL
9
noisefloor
I.V
o Data points
Linear fit
--- Logarithmicfit
__
-140
A
·I
I
-0.01
0
-80
-80 _-
-100
-100 _
-120
-120
-140
-140
0.5
-80
-100
1 1 1 i
1.....................................
-140
-80
_-
.................................................
!
1··
·
-0.5
0
·
·
I
'
I
0
0.5
._
_
0. 5
0
II
II
0. 5
I
I
II_
s
0.5
I
0
-0.01
0
_
-0.5
0.01
0
0.5
0
0.5
1.0
f,\
-Du r'-
m-
-0.5
1.0
..
_
0
0
0.01
.....................................
I
I
!
: ;' i
- - - -
..
f
Qo
q
-
-140
1
-Ou
-OU
_,
r-
-120
.
0
-100 !3009_6
110 dBS PL
I
0.5
-0.01
_
-120
-- - -0.5
1.0
I
-60
U
0.01
r-
-DU
0
I
I
0.5
,
............
--9"k-v-
-60
-0.5
F
0.5
'I1.... .... . .1
. , 1 .....................
.1. .
0
-
_
I
-0.5
ZVcp (cycles)
-4
-80 _-
-80
-100
-100
-120
-
3- 00c_6
116 dB SPL
~
-140
~AA
-1
0.5
~~__
3,_ -~_
U t_
-140
................
I-0.5
-0.5
...........
I
I
0
0.5
V (cycles)
................
.....................
i I
I
I,
I
-0.01
,
I
0
0.01
v (cycles)
0
-0.5
i (cycles)
Figure C-14: Post-TTX simultaneous-stimuli measurement sets and model fits at 300
Hz on Cat #6.
192
en _
-OV
1.0
u_ r
-OU r'-
_
-80
-80
-100
-100
-120
Zvcp (cycles)
IVcpl (dB re 1V)
lVcpl (dB re 1V)
o Data points
Linear fit
--- Logarithmic fit
-
0.5
-120
300d6
120 dB SPL
-140
-140
- noisefloor
I......................................
-0.5
0
.
.
.
.
a
.
.
.
.
'..... ..... .....
*1
1
.
I
-0.01
0.5
A,,
*
1
1
0
i......................
0
1
a
-ou
-80
-80 _
~,t'
-100
-100
-120
-120
-140
-140
-0.5
0.01
1.0
-Ou
I4ak
111 1 1~
- - -l - -l -l
.....................................
-60
-0.01
,-OUD
-80
-80 _-
0
0.5
-100
-100
-120
-120
-140
-140
I
I
0
0.01
0
v (cycles)
0.5
I
-0.5
l
l
00
0.5
0.5
0
0.5
1.0
1!
0.5
-
I
-0.5
0.5
0.5
I
-0.5
0
_
-0.01
0
Ni(cycles)
I
.
I
I
0.01
0
-0.5
y (cycles)
Figure C-15: Post-TTX simultaneous-stimuli measurement sets and model fits at 300
Hz on Cat #6.
193
IVcpl (dB re 1V)
lVcpl (dB re 1V)
1-OUr1.0
-60
on
-80
-80
-100
-100
-120
-120
-140
-140
o Data points
Linear fit
--- Logarithmicfit
-
0.5
I
I
,,
-0.5
0
0.5
-tbU
-80
-80
100
-100
120
-120
140
-140
0
0.5
-80
I
0.01 !
0.0
0.01
-0.5
1.0
0
0.5
_
_
_
0.5
0-00010
i
i
.....................................
1
.'
.
*
I
0
I
I
0.0
!.
I
.
-0.5
0.01
.
.
.
.
. . .I-.. .
I
.
.
.
_
.
.
.
*
.
*
|.
n
.
0
0.5
0
0.5
1.0
7
-80 !-
-100
-100
-120
-120
-140
0
-0.01
-60
.
_,
II
-0.5
-60
I"
0I
0.01
-0.01
-OU
ZVcp (cycles)
_
300a_7
121 dB SIPL
!
-!
-0.5
I
I
Q~4O
-140
.................................................
:
0.5
-os
l'
0
Nf (cycles)
l
I
I
i
0.5
-0.01
ll
,
1
0
I
0.01
v (cycles)
0.0
-0.5
Nf (cycles)
Figure C-16: Pre-TTX simultaneous-stimulimeasurement sets and model fits at 300 Hz
on Cat #7.
194
IVcpI (dB re 1V)
_
on I"'
-OLv
enr
-Ou
-80 _-
-80
1.0
o Data points
. Noisy data points
Linear fit
--- Logarithmicfit
-
100 I
-100
120
-120 I-
140
*
90
dBSPL
noisefloor
........
a
a
.
.
-0.5
an
-ouDv
.
...................
.
.
a
0.5
140
. --
0
I
·
-0.01
0.5
-80
_
-100
-100
_
-120
-120
-140
-140
0
<b
-80
-80
t-
-100
-100 t111 dB SPIL
.................................................
I
-
-
-0.5
-OU
-
-
-
0
-
-Dv
0
0.5
I ·, 0.0
I
I
I
0
0.01
-0.5
I
~11B
~
...............................
.I'
II
'
I
|
0
|
*
0.01
0.0
. .. .. .. ..
-0.5
eoolo.
-
-
-.
0
0.5
1.0
m
-80 _
-80
-100
-100
-120
-140
-0.01
_
w
1
0.5
.,
0.5
0.5
I
......
-
0
8
-140
I
1
-
o
1.0
__
-120
·
-0.5
0.01
....................................
I--
-120
0.0
0.5
-Do
ore
0
I
1.0
I
-0.01
0.5
_
.-
·
m
-80
-140
I
-oun _
_
-0.5
-60
ZVcp (cycles)
IVcpl (dB re 1V)
-120
121
300d_7
121 dB SPL
..............................
1
.
.
.
...........
..
...
_
_
-0.5
vi
.
_
,
I
I_
0
0.5
(cycles)
-140
7v
I
I
-0.01
0
r (cycles)
0.5
0.0
0.01
W000010
a: a
-0.5
l
l
l
0
l
l
I
0.5
v (cycles)
Figure C-17: Post-TTX simultaneous-stimuli measurement sets and model fits at 300
Hz on Cat #7.
195
Data set
400aJl
400b_1
400a_2
400a_3
400b.3
400c.3
400d_3
400e.3
400f_3
400g.3
dB SPL
110
110;108.5
114;113
112
113
115;114
113;114
113;114
114
114
IDI
1.25e-06
1.24e-06
9.42e-07
1.26e-06
1.13e-06
1.08e-06
1.07e-06
1.08e-06
1.Ole-06
9.88e-07
CMRR
13.21
13.49
19.37
23.15
28.79
34.58
19.07
23.74
40.09
33.24
Linear model parameters: 400 Hz
D
CI
C
PMAG
-0.227 2.74e-07 0.342
0.999
-0.231 2.62e-07 0.342
0.999
-0.018 1.01e-07 -0.493 0.846
-0.189 8.79e-08 -0.472 0.983
-0.190 4.11e-08 -0.322 0.991
-0.195 2.01e-08 -0.338 0.993
-0.193 1.19e-07 -0.465 0.959
-0.188 7.00e-08 -0.403 0.970
-0.183 9.95e-09 -0.207 0.971
-0.183 2.15e-08 -0.213 0.992
P/
1.000
0.989
0.807
0.966
0.964
0.997
0.915
0.917
0.973
0.976
MIN Data
0.0159
0.0155
-0.0034
0.0118
0.0042
0.0130
0.0156
0.0085
0.0029
0.0019
MIN Model
0.0150
0.0152
0.0025
0.0109
0.0042
0.0027
0.0175
0.0105
-0.0001
0.0009
Table C.11: Linear model parameters calculated from 400 Hz data.
|
Data set
400al
400bl
400a_2
400a_3
400b_3
400c_3
400d_3
400e.3
400f.3
400g.3
dB SPL
110
110;108.5
114;113
112
113
115;114
113;114
113;114
114
114
CMRR
13.23
13.40
25.50
23.51
32.46
32.03
18.61
23.58
35.54
34.08
IDI
1.28e-06
1.28e-06
1.28e-06
1.32e-06
1.15e-06
1.11e-06
1.lOe-06
1.lle-06
1.15e-06
1.lle-06
Logarithmic model parameters: 400 Hz
D
IC|
C
PMAG |P/
|MIN
Data | MIN Model
-0.227 2.79e-07 0.343
1.000
1.000 0.0159
0.0150
-0.228 2.73e-07 0.348
0.999
0.997 0.0155
0.0152
-0.019 6.77e-08 0.403
0.939
0.848 -0.0034
-0.0035
-0.174 8.80e-08 -0.444 0.990
0.974 0.0118
0.0109
-0.169 2.73e-08 -0.324 0.995
0.983 0.0042
0.0018
-0.176 2.78e-08
-0.448 0.995
0.999 0.0130
0.0042
7
-0.465 0.954
-0.194 1.29e-0
0.925 0.0156
0.0185
-0.164 7.35e-08 -0.403 0.993
0.976 0.0085
0.0105
-0.165 1.92e-08 -0.182 0.990
0.980 0.0029
0.0009
-0.166 2.20e-08 -0.174 0.995
0.985 0.0019
-0.0000
Table C.12: Logarithmic model parameters calculated from 400 Hz data.
196
'3
-OU
-80
_
m
.
_
1 .U
7
_
400a_1
110 dB SPL
- noisefloor
.em
emN...
.
-U--T
-
laf...
.
&$
.
.........
e....E..E.E
.
-0.5
.
.
-
.
I 02
-1 20
-120
400b_1
OW110 dB SPL
RW 108.5 dlB SPL_ 1 4
.
...
.
.
.
.
.
--
-
-0.5
.
.
.
,
.
.
r
0
I
_
I
I
-0.02
-80
-100
.
.
I
I*
0.5
_-
0.5
-140
I
100
-140
i__111.-B-
.
.
0
-OUr-
B
o Data points
- I Linear
fit
...
___
.
.! I..I
I--- Logantnmic
='"1
-120
_
140
A
-100
100
120
LVcp (cycles)
IVcpl (dB re 1V)
IVcpI (dB re 1V)
0I
0
0.02
0
-0.5
1.0
I
I
0
0.5
0
0.5
0.5
0
0
I
.
.-
-0.02
0.5
0
0.02
-0.5
v (cycles)
i (cycles)
v (cycles)
Figure C-18: Simultaneous-stimuli measurement sets and model fits at 400 Hz on Cat
#1.
iVcpl (dB re 1V)
r-
_
tn
'-
-OU
-OU
-100
vff~~~~~~..
-120
-120
-140
noisefloor
-
1
-0.5
400a_2
OW 114 dS SPL
RW 113 dB SPL
* a 1
0
Mf (cycles)
o Data points
o Noisy data points
Linear fit
--- Logarithmic fit
-
o0
O-
0.5
-140
a1
I·
0.5
1.0
I
-
-100
ZVcp (cycles)
lVcpl (dB re 1V)
-0.02
°
0
r (cycles)
iI
0.02
0
-0.5
0
0.5
r (cycles)
Figure C-19: Simultaneous-stimuli measurement set and model fits at 400 Hz on Cat
#2.
197
IVcpl (dB re 1V)
_,
-100
-100
20
-120
112 dB SPL
..................
1 .. .
-0.5
-
1..
1I
0
0.5
I
I -0.5
,,
U
I
-140
0
lI
7
-0.02
,%n
-bU
r--
100
-100
_-
120
-120
400b_3
113 dB SPL
140
0
0.02
,
.
.
.
. .
.
I
.
-0.5
.
.
.
.
0
0.5
0
0.5
0
0.5
1.0
0.5
-140
- - - - - - - - - -0.5
0
0.5
l
!
1
l
l
r
QN _
-Or
1
I
1
I
-0.02
-ou
0
I
I
0.02
on
-100
0
-0.5
1.0
-100
p
400c_3
OW 115 dB SPL
RW 114 dB SPL
-120
-140
I........
1
I
.
.
.
*
.
1I
.
.
.
1
.
0
1
I
-100
....·.......
I
I
0.5
0
.VIIU.4J
0.5
-120
-140
....................................
-0.5
-80
·......................
·
I
0
-0.02
-80
·
I
0.02
OW 113 dEI SPL
RW114dE 3SPL
....................
-140
I ...................
L .
-0.5
.1 1. .1 1. 1. .1 1 1 1
!
I
0
0.5
N (cycles)
-0.5
0
0.5
-120
400d3
0
1.0
-100
-120
-140
J
0.5
400a_3
noisefloor
...................
-140
1.0
-80
-?U r--
-1
ZVcp (cycles)
IVcpl (dB re 1V)
_ . . . .I . . . .
-0.02
0
Mf (cycles)
0.02
-0.5
I
I
0
0.5
!
v (cycles)
Figure C-20: Simultaneous-stimuli measurement sets and model fits at 400 Hz on Cat
#3.
198
-80
on
-au
-100
-100
-120
0.5
tOW113dBSPL
-
RW114dBSPL
1 1 1 1 1
-0.5
-ou
1.0
-120
400e_3
nosiefloor
-140
-140
0
1 1 1 1 1
0.5
0
-0.02
0
0.C)2
-80
-100
-100
-120
-120
-140
-140
0.5
0
-80o
0.5
0
-0.5
I.U
0.5
1
-0.5
ZVcp (cycles)
IVcpl (dB re 1V)
lVcpl (dB re 1V)
-0.02
-80 -
II8
8
0
IJ
I
0.02
0I
-
I ....
.
-0.5
.
.
1
0.5
0
1.0
I
-100
-100
-120-
-120 q
-140 "
i 14 uOr OrL
..........................................
....
-0.5
-140
Il....
,
I
0
0.5
yr (cycles)
0.5
..................................
-0.02
0
N (cycles)
0ea""
0I
:
I
0.02
-0.5
i
0
0.5
A (cycles)
Figure C-21: Simultaneous-stimuli measurement sets and model fits at 400 Hz on Cat
#3.
199
Linear model parameters: 500 Hz
I
Data set
dB SPL CMRR I DI I
D I
CI
I
C I PMAG I
I MIN Data
500a4
1 97
1 28.82
4.45e-06 1 -0.230 1.61e-07 0.353 0.992
0.958 0.0026
MIN Model
0.0025
Table C.13: Linear model parameters calculated 500 Hz data.
Logarithmic model parameters: 500 Hz
Data set
dB SPL
500a_4 | 97
I
i
ICI
I
I MIN Data IMIN Model
C I PMAG I P/
1.49e-07 1 0.324 1 0.994
| 0.968 0.0026
1 0.0000
CMRR
ID] I
D
29.00 | 4.19e-06 1 -0.187
Table C.14: Logarithmic model parameters calculated from 500 Hz data.
(dB re 1 V)
IVcpl
ZVcp (cycles)
IVcpl (dB re 1 V)
1.0
-80
o Data points
-80
-100
-100
-120
-120
--
Linearfit
---
Logarithmic fit
0.5
-140
-m
X 500a_4
-_
noisefloor
B 97 dBSPL
.................................................
Ii
-0.5
::
.
.
I
I
0
xN(cycles)
:
:
'I
-140
0 0
-
D
.....................................
0
!
0.5
!
-0.01
0
x (cycles)
0.01
-0.5
0
r (cycles)
0.5
Figure C-22: Simultaneous-stimuli measurement set and model fits at 500 Hz on Cat
#4.
200
Data set
600a..1
600b..1
600c 1
dB SPL
106;105
113;112
100
CMRR
15.37
15.22
14.72
jDI
2.60e-06
2.40e-06
2.67e-06
Linear model parameters: 600 Hz
CI
[
C
PMAG
D
-0.331 4.43e-07 0.336 0.998
-0.344 4.16e-07 0.328 0.995
-0.330 4.91e-07 0.340 0.997
P
1.000
0.998
0.973
gIN Data
0.0196
0.0246
0.0224
MIN Model
0.0237
0.0245
0.0245
Table C.15: Linear model parameters calculated from 600 Hz data.
Data set
600a 1
600bl1
600c
dB SPL
106;105
113;112
100
CMRR
15.20
15.27
15.11
Logarithmic model parameters:
C
/D
ICI
2.74e-06 -0.329 4.77e-07 0.340
2.83e-06 -0.348 4.87e-07 0.325
2.70e-06 -0.324 4.74e-07 0.339
IDI
600 Hz
PMAG
0.999
0.999
0.999
P
I MIN Data
1.000 0.0196
0.998 0.0246
0.988 0.0224
PMIN Model
0.0237
0.0245
0.0239
Table C.16: Logarithmic model parameters calculated from 600 Hz data.
201
-ou
.1
-
QN _
-aU
m
0.5
_J
100
-100
20
-120
-1
zVcp (cycles)
lVcpI (dB re V)
IVcpl (dB re 1V)
o Datapoints
Linear fit
-- Logarithmic fit
0
600c 1
140
noisefloor
-
100dBSPL
-140
.................................................
I
r
. ·
-0.5
Q"
-OU
·
I
r
·
0
0.5
_
w
-0.05
-80
100
-100
120
-120
140
600a
OW 106 dE3 SPL
RW
..........
105dE3SPL
.
-
'I
1 1-
I1 .1 .
-0.5
Ore
-Ot
I
.. . .....................
I
I
0
0.5
m
20
-140
0
0.05
-0.5
-0.5
0.5
0
0.5
_
0
-140
-0.5
I
-0.05
-80
0
0.05
'l
l
l'
l
l'
-0.5
0.5
l'
!
l
l
l
0
l
l
!
0.5
-100
-100
-1
.....................................
·I
,'· , ,
·
1
·
0
-120
-
3 SPL
SPI
-
....
-140
I
...........................
Ad·
·
-0.5
·
*
·.
.*
.
I
·
x'
.
r
.
0
ir (cycles)
-0.5
I
I
0.5
-0.05
0
fr (cycles)
0.05
·
-0.5
l - .
l
l.l.l
I
0
l
I
0.5
Vr (cycles)
Figure C-23: Simultaneous-stimuli measurement sets and model fits at 600 Hz on Cat
#1.
202
Data set
800al1
800b1
800a.3
800a_4
800b_4
dB SPL
116
116
116
103
98
CMRR
16.55
16.31
19.82
31.56
37.12
IDI
3.25e-06
3.19e-06
2.34e-06
7.35e-06
6.76e-06
Linear model parameters: 800 Hz
/_C
PMAG
LD
I
0.999
-0.437 4.84e-07 0.260
0.998
-0.434 4.88e-07 0.271
0.968
-0.354 2.39e-07 0.387
0.995
-0.335 1.94e-07 0.446
-0.324 9.42e-08 -0.299 0.992
P
1.000
0.999
0.947
0.991
0.985
O3MIN Data
0.0228
0.0233
0.0164
0.0041
0.0006
'MIN Model
0.0227
0.0232
0.0159
0.0041
0.0001
Table C.17: Linear model parameters calculated from 800 Hz data.
Data set
800a1
800b
800a.3
800a_4
800b_4
dB SPL
116
116
116
103
98
CMRR
16.54
16.32
19.58
31.74
33.94
IDI
3.40e-06
3.41e-06
3.19e-06
7.40e-06
5.87e-06
Logarithmic model parameters: 800 Hz
/CPMAG
D
ICI'
1.000
-0.436 5.06e-07 0.261
0.999
-0.432 5.20e-07 0.272
0.989
-0.348 3.35e-07 0.426
0.996
-0.330 1.91e-07 0.477
-0.342 1.18e-07 -0.324 0.991
Data
P
IMIN
1.000 0.0228
0.999 0.0233
0.988 0.0164
0.993 0.0041
0.992 0.0006
'PMIN Model
0.0227
0.0232
0.0169
0.0041
0.0001
Table C.18: Logarithmic model parameters calculated from 800 Hz data.
IVcpl (dB re 1 V)
IVcpI
(dB re 1 V)
ZVcp (cycles)
0.5
-80
_
o Data points
Linear fit
--- Logarithmic fit
-80
_
-100
-100
-120
-120 .-
O
104 dB SPL
noisefloor
......................................
-140
1 1..1 . .
. . . . 1
0
0.5
-0.5
0
-140
0
.
5
. ... I
..... ...
.
.
0
.
.
-0.02
.
.
0.02
-0.5
-0.5
0
0.5
0
0.5
0.5
-80
_
-80
-100
-100
0
-120
~800b_
104
-140
I.
-0.5
.
-120
A..........L
W
_
.
.
.
! .. . .
0
. -
V (cycles)
dB
SPL
I
.
0.5
-140
I
I
1
I
-0 .02
0
0.02
xV(cycles)
-0.5
-0.5
V
(cycles)
Figure C-24: Simultaneous-stimuli measurement sets and model fits at 800 Hz on Cat
#1.
203
IVcpl (dB re 1 V)
IVcpl (dB re 1 V)
ZVcp (cycles)
0.5
-80
-80
-100
-100
o Datapoints
-Linear fit
--- Logarithmic fit
0
-120
800a_3
116 dB SPL
noisefloor
-140
'11
I
.
.. ..
.
11
0.5
E
-140
1 1 1 A1
0
-0.5
-120
...................
1
I
1
-0.02
1
I
1
0
1··············I
I
-0.5
I
0.02
.
"
....
'
-0.5
.
"'.
I
*
'
.
.
I
.1
0
0.5
v (cycles)
v (cycles)
v (cycles)
'
Figure C-25: Simultaneous-stimuli measurement set and model fits at 800 Hz on Cat
#3.
lVcpl (dB re 1 V)
ZVcp (cycles)
IVcpI (dB re 1 V)
AI
U.U
-80
-80
-100
-100
-120
-120
o Data points
- Linear fit
K
--- Logarithmicfit
0
-140
800b_4
noisefloor
98 dB SPL
.................. ........................
1
-0.5
*-. e.
-140
. . .
.
I
.
.
.B
,
0.5
/
..................................
1
0
.-
-0.02
0
I
-0.5
.
.
!
.
I
I .5
0.02
-0.5
0
0.5
0
0.5
0.5
-80
-80 I-100
-100
I-
0
-120
-120
-140
-140
-0.5
0
Vi (cycles)
0.5
. ........
. .............
'
I
-0.02
0
Ay (cycles)
·
I
0.02
-0.5
-0.5
i (cycles)
Figure C-26: Simultaneous-stimuli measurement sets and model fits at 800 Hz on Cat
#4.
204
I
-
Data set
dB SPL
1000la1
101
10OObl
100
1000OOa 101;99
10O0b.2
110;108
10OOc2
111;108
1000a-3
110
1000b3
110
1000c-3
111
1000d-3
111
10OOe.3 111
1OOOf_3 111
0l0g.3
112
1000h3
111
100Oi3
111
1000j-3
112
10OOk-3 112
100013
109;113
10OOm_3 113
1000n3
102
lOOO_4 106
lOOOb_4 98
10cOO_4 106
1OOOd_4 106
1000e_4 106
1000f_4
98
lOOOg_4 106
1000a.5
103
10OOb5 102.5;102.5
100lOOOc5103.2;101.9
1OOOd..5 103.7;101.2
10OOe_5 104.4;100.5
10OOf.5 103.0;102.3
1OOOg5 105
lOOOh..5 110
1000i5
115
1000j..5
100
10OOk.5 95
100015
110
10OOm5 105
O1OOn_5 100
10OOp.5 95
1000lq5
90
1000r..5
115
1000l 5
120
l000a6
104
10OOb_6 114
10OOc..6 104
10OOd-6 113
1000e_6 98
1000f_6
98
10OOg_6 110
10OOh_6 100
1000i_6
90
1000j_6
80
10OOk_6 120
10OOa_7 119
10OOb_7 99
1000c_7 109
10OOd-7 99
1000e_7 89
1000f_7
119
CMRR
17.85
17.77
13.36
12.33
12.43
16.30
16.42
20.15
20.49
18.61
16.88
21.81
15.68
46.08
23.64
17.37
12.21
15.23
14.88
31.23
32.97
33.64
28.80
44.01
44.63
44.95
25.45
31.81
24.68
29.62
29.43
27.07
26.83
25.94
25.21
29.02
33.94
25.65
25.77
23.30
29.04
21.86
26.70
22.65
36.78
34.17
28.06
30.97
37.10
33.82
32.45
32.33
33.81
21.43
29.09
31.96
33.25
34.67
35.04
35.15
37.49
-Di
2.84e-06
2.90e-06
5.63e-06
5.71e-06
5.58e-06
4.51le-06
4.43e-06
4.13e-06
4.1le-06
4.06e-06
3.90e-06
3.73e-06
3.94e-06
3.89e-06
3.78e-06
3.83e-06
3.35e-06
3.14e-06
3.64e-06
7.96e-06
8.29e-06
7.36e-06
7.43e-06
7.18e-06
7.42e-06
6.99e-06
1.71e-05
1..77e-05
1.78e-05
1.76e-05
1.77e-05
1.77e-05
1.76e-05
1.68e-05
1.71e-05
1.70e-05
1.63e-05
1.17e-05
1.22e-05
1.21e-05
1.24e-05
1.22e-05
9.34e-06
6.65e-06
1.70e-05
1.63e-05
1.45e-05
1.46e-05
1.39e-05
1.36e-05
1.43e-05
1.39e-05
1.40e-05
1.40e-05
1.22e-05
1.06e-05
1.31e-05
5.65e-06
5.64e-06
5.81e-06
4.24e-06
Linear model parameters: 1000 Hz
ZD
Ic,
LC
PMAG
-0.499 3.64e-07 0.264
0.999
0.499
3.75e-07 0.272
0.998
-0.383 1.21e-06 0.226
0.974
-0.396 1.38e-06 0.184
0.986
-0.395 1.33e-06 0.184
0.971
-0.394 6.90e-07 0.488
0.986
-0.395 6.70e-07 0.492
0.983
-0.385 4.06e-07 0.478
0.993
-0.387 3.88e-07 0.493
0.950
-0.388 4.76e-07 0.316
0.990
-0.393 5.59e-07 0.291
0.995
-0.390 3.03e-07 0.259
0.987
-0.372 6.48e-07 -0.157 0.980
-0.383 1.93e-08 0.032
0.989
-0.390 2.48e-07 0.289
0.965
-0.397 5.18e-07 0.281
0.998
-0.404 8.22e-07 0.272
0.996
-0.406 5.44e-07 0.281
0.986
-0.388 6.56e-07 0.308
0.986
-0.421 2.19e-07 0.244
1.000
-0.406 1.86e-07 0.303
0.998
-0.426 1.53e-07 0.066
1.000
-0.421 2.70e-07 0.096
0.999
-0.421 4.53e-08 0.345
0.999
-0.407 4.35e-08 0.400
0.998
-0.419 3.95e-08 0.196
0.999
-0.435 9.11e-07 0.394
0.974
-0.427 4.53e-07 0.450
0.965
-0.426 1.04e-06 0.347
0.989
-0.424 5.80e-07 0.376
0.997
-0.425 5.96e-07 0.398
0.999
-0.425 7.83e-07 0.366
0.988
-0.428 8.00e-07 0.474
0.928
-0.431 8.47e-07 0.430
0.982
-0.425 9.37e-07 0.433
0.961
-0.433 6.00e-07 0.298
0.878
-0.452 3.27e-07 0.335
0.728
-0.510 6.11e-07 -0.294 0.939
-0.504 6.26e-07 -0.283 0.985
-0.502 8.31e-07 -0.237 0.958
-0.515 4.38e-07 -0.306 0.953
-0.535 9.86e-07 -0.205 0.925
.0.513 4.32e-07 -0.352 0.991
-0.513 4.90e-07 -0.453 0.969
-0.475 2.47e-07 0.227
0.960
-0.485 3.19e-07 -0.260 0.968
-0.466 5.72e-07 -0.317 0.999
-0.483 4.12e-07 0.007
0.991
-0.451 1.94e-07 0.044
1.000
-0.456 2.76e-07 -0.144 0.999
-0.477 3.40e-07 -0.157 1.000
-0.458 3.36e-07 -0.267 0.969
-0.449 2.85e-07 -0.175 0.999
-0.449 1.19e-06 -0.003 0.997
-0.497 4.30e-07 -0.255 0.985
-0.459 2.67e-07 0.129
0.979
-0.433 2.86e-07 0.318
0.979
-0.431 1.04e-07 0.147
0.996
-0.393 9.98e-08 0.220
0.997
-0.370 1.02e-07 0.096
1.000
-0.452 5.66e-08 0.063
0.972
P
1.000
0.999
0.911
0.988
0.988
0.994
0.983
0.976
0.932
0.939
0.941
0.978
0.942
0.987
0.940
0.965
0.996
0.986
0.981
0.996
0.997
0.998
0.996
0.992
0.993
0.994
0.832
0.842
0.992
0.999
1.000
0.974
0.874
0.961
0.964
0.385
0.602
0.781
0.628
0.751
0.778
0.635
0.996
0.995
0.837
0.859
0.999
0.986
0.999
0.999
0.601
0.935
0.993
0.999
0.991
0.923
0.896
0.973
0.989
0.998
0.850
OMIN Data
0.0201
0.0203
0.0018
0.0260
0.0260
0.0152
0.0139
0.0096
0.0093
0.0185
0.0210
0.0127
-0.0278
-0.0016
0.0078
0.0198
0.0283
0.0231
0.0335
0.0022
0.0029
0.0002
-0.0013
0.0023
-0.0010
-0.0001
0.0104
0.0104
0.0030
-0.0050
0.0025
0.0043
0.0067
0.0018
0.0045
0.0108
0.0137
-0.0083
-0.0099
-0.0092
0.0006
0.0067
-0.0085
-0.0028
0.0068
-0.0025
-0.0024
-0.0015
-0.0010
-0.0034
-0.0041
-0.0037
-0.0039
-0.0236
-0.0049
0.0034
0.0020
0.0005
0.0001
0.0007
0.0004
Table C.19: Linear model parameters calculated from 1000 Hz data.
205
MIN Model
0.0204
0.0204
0.0217
0.0187
0.0178
0.0162
0.0159
0.0120
0.0094
0.0170
0.0210
0.0098
-0.0258
-0.0006
0.0098
0.0193
0.0353
0.0252
0.0272
0.0036
0.0029
-0.0007
-0.0015
0.0013
0.0010
0.0009
0.0071
0.0015
0.0089
0.0050
0.0049
0.0067
0.0017
0.0066
0.0063
0.0060
0.0033
-0.0083
-0.0089
-0.0112
-0.0056
-0.0113
-0.0087
-0.0031
0.0022
-0.0035
-0.0077
-0.0005
-0.0015
-0.0034
-0.0036
-0.0040
-0.0033
-0.0041
-0.0058
0.0024
0.0030
0.0018
0.0011
-0.0007
0.0001
Data set
dB SPL
1000al.
101
10Ob1
100
1000a..2 101;99
1000b..2 110;108
1000c_2 111;108
1000la_3 110
1000b3
110
1000c_3 111
1000d.3
111
00OOe..3 111
00OOff3 111
1000g_3
112
1000h.3
111
1000i.3
111
1000j_3
112
1000k.3
112
10001_3 109;113
1000m-3 113
1000n.3
102
1000a_4 106
1000b_4 98
1000c4
106
1000d_4 106
1000e_4 106
1000f_4 98
1000g_4 106
1000a_5
103
1000b5
102.5;102.5
1OOOc5 103.2;101.9
1000d_5 103.7;101.2
1000e.5
104.4;100.5
1000f_5
103.0;102.3
1000g_5 105
10OOh.5 110
10005
115
1000j_5
100
1000k_5 95
10001_5 110
1OOOm_5 105
10OOn5 100
10OOpS 95
lO000q5
90
10OOr-5 115
1OOO5
120
1000a_6 104
10OOb_6 114
10OOc_6 104
100OOd6 113
10OOe_6 98
10OOf.6 98
lO1000g6 110
10OOh_6 100
1000i-6
90
1000j_6
80
10OOk_6 120
1000laJ
119
10OOb_7 99
10OOc_7 109
10OOd_7 99
10OOe_7 89
1000f_7
119
CMRR
18.02
18.16
16.77
13.01
13.16
16.53
16.27
20.62
20.47
18.32
17.19
21.15
15.46
43.54
23.45
17.13
12.66
15.25
14.07
32.12
33.29
33.45
28.99
44.22
45.13
47.31
26.09
33.55
26.21
27.42
30.56
22.88
27.53
26.59
24.69
23.68
21.44
25.51
23.41
22.14
39.82
16.83
27.58
24.92
30.34
38.00
28.91
34.35
36.94
33.56
32.48
32.74
33.40
20.69
30.11
32.10
30.77
35.50
37.79
35.29
43.93
Logarithmic model parameters: 1000 Hz
IDI
D
ICI
C
PMAG
2.98e,06 -0.499 3.74e-07 0.263
1.000
3.06e-06 0.499
3.79e-07 0.271
0.999
4.54e-06 -0.381 6.58e-07 0.155
0.968
5.48e-06 -0.381 1.23e-06 0.207
0.996
5.15e-06 -0.382 1.13e-06 0.209
0.992
5.20e-06 -0.385 7.75e-07 -0.488 0.997
5.04e-06 -0.390 7.73e-07 -0.489 0.998
4.70e-06 -0.380 4.38e-07 -0.497 0.998
4.49e-06 -0.378 4.25e-07 -0.485 0.998
4.64e-06 -0.377 5.63e-07 0.350
0.997
4.37e-06 -0.379 6.04e-07 0.312
0.997
4.10e-06 -0.378 3.59e-07 0.275
0.995
4.25e-06 -0.353 7.16e-07 -0.128 0.997
4.42e-06 -0.364 2.94e-08 0.125
0.995
4.12e-06 -0.360 2.77e-07 0.295
0.997
4.07e-06 -0.379 5.66e-07 0.302
0.998
3.45e-06 -0.400 8.03e-07 0.280
0.997
3.56e-06 -0.382 6.16e-07 0.298
0.997
3.65e-06 -0.373 7.22e-07 0.312
0.996
8.11e-06 -0.416 2.01e-07 0.241
1.000
8.48e-06 -0.407 1.84e-07 0.280
0.999
7.55e-06 -0.418 1.61e-07 0.060
1.000
7.49e-06 -0.412 2.66e-07 0.105
0.999
7.10e-06 -0.408 4.37e-08 0.319
1.000
7.21e-06 -0.400 3.99e-08 0.432
0.999
6.90e-06 -0.406 2.97e-08 0.188
1.000
1.54e-05 0.462
7.65e-07 0.208
0.991
1.48e-05 0.479
3.10e-07 0.478
0.958
1.75e-05 -0.474 8.57e-07 0.274
0.994
1.76e-05 -0.431 7.47e-07 0.335
0.996
1.78e-05 -0.427 5.27e-07 0.366
0.999
1.72e-05 -0.461 1.23e-06 0.273
0.978
1.36e-05 0.495
5.73e-07 0.267
0.982
1.67e-05 -0.479 7.82e-07 0.364
0.986
1.67e-05 -0.458 9.71e-07 0.399
0.948
1.46e-05 0.400
9.55e-07 0.100
0.984
1.40e-05 0.348
1.19e-06 -0.476 0.584
1.38e-05 0.455
7.34e-07 -0.290 0.995
1.37e-05 0.433
9.26e-07 -0.279 0.995
1.42e-05 0.427
1.lle-06
-0.284 0.993
1.44e-05 0.368
1.47e-07 0.469
0.949
1.07e-05 0.428
1.54e-06 -0.229 0.942
1.08e-05 0.479
4.53e-07 -0.345 0.995
8.60e-06 0.490
4.88e-07 -0.407 0.982
1.25e-05 -0.491 3.82e-07 0.192
0.983
1.26e-05 -0.472 1.59e-07 -0.184 0.981
1.44e-05 -0.451 5.16e-07 -0.292 1.000
1.44e-05 -0.463 2.75e-07 -0.016 1.000
1.35e-05 -0.447 1.91e-07 0.043
1.000
1.31e-05 -0.452 2.75e-07 -0.137 1.000
1.14e-05 -0.375 2.72e-07 -0.166 0.993
1.55e-05 -0.464 3.58e-07 -0.308 0.999
1.37e-05 -0.451 2.93e-07 -0.182 0.999
1.34e-05 -0.452 1.24e-06 -0.021 0.998
1.32e-05 -0.464 4.13e-07 -0.250 1.000
1.19e-05 -0.451 2.96e-07 0.211
0.999
9.48e-06 -0.431 2.74e-07 0.278
0.981
5.77e-06 -0.399 9.68e-08 0.128
1.000
5.68e-06 -0.374 7.33e-08 0.187
1.000
5.77e-06 -0.367 9.94e-08 0.090
1.000
5.13e-06 -0.406 3.27e-08 0.378
0.998
P
1.000
1.000
0.889
0.997
0.997
0.999
0.996
0.999
0.999
0.998
0.995
0.989
0.988
0.994
0.977
0.980
0.997
0.993
0.991
0.998
0.998
0.999
0.999
0.996
0.994
0.996
0.943
0.673
0.992
1.000
1.000
0.995
0.959
0.982
0.990
0.702
0.530
0.979
0.957
0.921
0.851
0.876
0.997
0.999
0.925
0.946
0.999
0.995
0.999
1.000
0.985
0.999
0.996
1.000
0.999
0.994
0.976
0.985
0.997
0.998
0.979
MIN Data
0.0201
0.0203
0.0018
0.0260
0.0260
0.0152
0.0139
0.0096
0.0093
0.0185
0.0210
0.0127
-0.0278
-0.0016
0.0078
0.0198
0.0283
0.0231
0.0335
0.0022
0.0029
0.0002
-0.0013
0.0023
-0.0010
-0.0001
0.0104
0.0104
0.0030
-0.0050
0.0025
0.0043
0.0067
0.0018
0.0045
0.0108
0.0137
-0.0083
-0.0099
-0.0092
0.0006
0.0067
-0.0085
-0.0028
0.0068
-0.0025
-0.0024
-0.0015
-0.0010
-0.0034
-0.0041
-0.0037
-0.0039
-0.0236
-0.0049
0.0034
0.0020
0.0005
0.0001
0.0007
0.0004
PMIN Model
0.0194
0.0192
0.0046
0.0187
0.0188
0.0143
0.0138
0.0096
0.0089
0.0187
0.0210
0.0117
-0.0268
-0.0006
0.0088
0.0203
0.0333
0.0252
0.0292
0.0036
0.0029
-0.0007
-0.0015
0.0013
0.0007
0.0001
0.0084
-0.0004
0.0076
0.0065
0.0049
0.0118
0.0066
0.0066
0.0063
0.0098
-0.0123
-0.0081
-0.0109
-0.0120
-0.0012
-0.0196
-0.0046
-0.0031
0.0042
-0.0020
-0.0028
-0.0012
-0.0015
-0.0034
-0.0041
-0.0032
-0.0033
-0.0061
-0.0051
0.0033
0.0040
0.0002
0.0010
-0.0007
0.0001
Table C.20: Logarithmic model parameters calculated from 1000 Hz data.
206
ZVcp (cycles)
IVcpl (dB re 1V)
IVcpl (dB re 1V)
0.5
-80 _-
-80 -
-100
o Data points
o Noisy data points
-100
-
Linearfit
---
Logarithmic fit
0
-120
-140
no1000b 1L
..--------------noisefloor |100
dB SPL
.............
I
-
-.
-0.5
-
-
-
I
-
-
-
0
-
-120
-140
a
lI
0.5
-0.02
·
II
·
0
II
-0.5
-0.5
0.02
0
0.5
0.5
-80
-80
-100
-100
-120
-120
-140
-140
m
-
O
i f'
I.
i
-0.5
0
v (cycles)
0.5
-0.02
-0.5
.
I
0
0.02
'v(cycles)
-- -- -- -- -- A
I
I
-0.5
0
-
-
-
I
0.5
v (cycles)
Figure C-27: Simultaneous-stimuli measurement sets and model fits at 1000 Hz on Cat
#1.
207
ZVCP (cycles)
IVcpl (dB re 1V)
lVcpl (dB re 1V)
_
U.O r--
-80
_ o Data points
* Noisy data points
Linear fit
-80
_-
-100
--- Logarithmicfit
-100
I!II
0
-120
II
II
-120
-140
-
noisefloor
'
1000a_2
OW 101 dB SPL
RW 99 dB SPL
'
-0.5
I
·
0
I
-140
I
.
·
I
0.5
-80 I.
-0.02
I
i
.
.
0
I
0.02
...
.
B.-
.
-0.5
0.5
-
--
0
I
0.5
-80 _
-100
I.
-100
-120
I.
-120
0
1000b_2
-140
OW 110 dB SPL
RW 108 dB SPL
--
-140
1-.
II
-0.5
0
0.5
·.
-0.02
I
iI
I.
0
-0.5
0.02
r
.
-0.5
.
.
.
.
.1
.
.
.
.
.
.
I
I.
.
0
.
T.
|
0. 5
0.5
-80 _
-80
-100
-100
0
-120
-140
-120
I
'I
.
.
.
-0.5
.
I
1000c_2
OW 111 dB SPL
RW 108
dB
SPL
.
.
.
.
0
iV
-140
-0.5
.
(cycles)
0.5
i
.
-0.02
0
.I
0.02
,q (cycles)
· ........!:::., !
-0.5
0
0.5
Vr (cycles)
Figure C-28: Simultaneous-stimuli measurement sets and model fits at 1000 Hz on Cat
#2.
208
lvCl (dB re 1V)
Zvcp (cycles)
IVcpl (dB re 1V)
0.5
-80
-80
_
-100
-100
-120
-120
-
o Datapoints
_°"~n
- Linear fit
--- Logarithmic fit
0
)L
-140
-140
~;;;;~;;·.............................
I
1
....
.
-0.5
11.
.
.
I,''1
0
.-
0.5
We.e.......
·...........·.....·
.....
l
I
-0.02
I
I
0.02
I
-0.02
0
-0.5
-0.5
0.02
0
0.5
0.5
-80
-80
-100
-100
-120
10001_3
OW 109 dB SPL
RW 113 dB SPL
-
-140
I
:-
-
-
-0.5
-
II
I
-
-
-
0
-
.....
I
. ...........................
l
l
I
-0.02
-80
-80
-100
-100
-120
-120
1000a 3
-
-120
II
I
0.5
O
0
-140
..........................................
0'.~
0.
O
V
I
.
-0.5
0.02
0
0.02
i
I
I
..
' .
-0.5
0.5
.
.
.
.
1.1
.
.,!
!
0
0.5
0.5
0
0.5
0
0.5
0
110 dBSPL
-140 111,,,,,,,,,,,,,,,,,,,,,,,,,,, -140
-0.5
0
0.5
-0.5
-0.02
0
0.02
-0.5
0.5
-80 -
-80
-100
-100
-120
-120
-140
-140
0
.0.....
l
-0.5
0
vi
(cycles)
0.5
§
-0.02
I
I
0
0.02
v (cycles)
-0.5
-0.5
NV(cycles)
Figure C-29: Simultaneous-stimuli measurement sets and model fits at 1000 Hz on Cat
#3.
209
ZVcp (cycles)
IVcpl (dB re 1V)
lVcpI (dB re 1V)
I,_
-80
-80
-100
-100
o Data points
o Noisy data points
-Linear fit
--- Logarithmic fit
U.b
0
-120
m
-le
-120
!
111 a ISrL
noisefloor
..............................................
-140
,
.
-0.5
.
.
L
I
-
-
-
0
-
-140
!
!
0.5
-0.02
I
0
0
0.02
I
-0.5
-.
.
-0.5
0.5
-80
-80
-100
-100
-120
-120
-140
-140
.
.
I.
0
!
.
.
II
.
.
.
0.5
o
0
-0.5
-0.5
0
0.5
-0.02
0
0.02
-0.5
.
.
.
0
0.5
0
0.5
0
0.5
0.5
-80
-80
-100
-100
-120
-120
0
1000CL3
1 11 dB SPL
-140
-140
I
!
!
-0.5
0
0.5
.......
-0.02
-80
-80
-100
-100
-120
-120
-140
-140
0
-0.5
0.02
-0.5
0.5
0
-0.5
-0.5
0
xv(cycles)
0.5
-0.02
0
yV(cycles)
0.02
-0.5
v (cycles)
Figure C-30: Simultaneous-stimuli measurement sets and model fits at 1000 Hz on Cat
#3.
2i0
LVcp (cycles)
IVcpl (dB re 1V)
IVcpI (dB re 1V)
n rU.D
o Data points
Linear fit
Logarithmic fit
-80
-80
---
-100
-100
-120
-120
-140
1000h_3
111 dB SPL
noisefloor
.w ....................
*
.........................
0
-140
9I
1
-0.5
0
0.5
I
I
-
-0.02
-80
-80 --
-100
-100 i-
I
I
'
0
0.02
-0.5 I .
-0.5
0.5
.T-
..
.
. .
I
.
.
1
. . . '
0
0.5
0
-120
-120
1000i 3
111 dB SPL
-140
-140
,...............................................
1
.
.
.I..
-0.5
I
I
0
0.5
-80
-100
-100
~~_
~
B
~~112dB SPL3
112 dB SPL
I
-140
-140
1..
.I
-0.5
-120
,
0
r (cycles)
.
0
0
0.02
"ap
.........
·..
II
0.5
I
.
I
0
-0.5
-0.5
0.5
I
I
0
0.5
-
e
-120
'
-0.02
-80
L........ "
,...................................
.
.. · · · ·
I
I
.
-0.02
0
v
.
0
....
.. · ·........
-0.5 T
-0.5
II
-
0.02
(cycles)
.
..
.
.. .
..
I.
II
.
.
..
.
0
.
.*
I
0.5
v (cycles)
Figure C-31: Simultaneous-stimuli measurement sets and model fits at 1000 Hz on Cat
#3.
211
ZVcp (cycles)
IVcplI (dB re 1V)
lVcpl (dB re 1V)
0.5
-80
-80
-100
-100
120
-120
o Data points
Linear fit
--- Logarithmic
fit
0
1000j3
noisefloor
m
-140
112 dB SPL
T
I
-140
I
I
-0.5
0
0.5
-0.02
I
I
·'
'
0
0.02
T
-0.5
.
-0.5
0.5
-
.
.
.
I
.
.
.
.
I
I
0
0.5
0
0.5
0
0.5
-80 _
-80
-100
-100
-
0
I
-120
-120
1000k_3
-140
I
I
112 dB SPL
T
-~
-140
. .............................................
,
I
.
!
I
!
!
0.5
-0.02
.
.
. --
.
-0.5
-
-
0
l..................................
·
II.
,
0
I
0.02
-0.5
-0.5
0.5
-80
-80
-100
-100
-120
-120
_
0
'4"%,
'L.
-140
-140
..............................................
.
.
-0.5
.
.
.
.
I
.
0
Nf (cycles)
.
.
.
I
0.5
,i ·
-0.02
-0.5
,
0
yf (cycles)
0.02
-0.5
v (cycles)
Figure C-32: Simultaneous-stimuli measurement sets and model fits at 1000 Hz on Cat
#3.
212
LVcp (cycles)
IVcpI (dB re 1 V)
IVcpI (dB re 1 V)
0.5
-80
-80
-100
-100
-120
-120
-140
-140
Data points
Linear fit
--- Logarithmic fit
o
0
,Q_11·9__
ms.$
l~~~~~
l-
...............................
i
I
0
-0.5
_
-80
0.5
-0.01
-80
i---
0
0.01
-0.5
-0.5
0.5
0
0.5
_
1~~~~~~
..I
-100
-100 I-
0
-120
10Of_4
98 dB SPL
-- ----------140 A.....................
0.5
I
-0.5
0.5
0
-120
'CI
-140
I
-0.01
.
.
-0.01
0I
0
0.01
-0.5
0.01
-0.5
0
0.5
0
0.5
0.5
-80
-80
_
-100
-100
_
0
-120
-120
1000a.4
106 dB SPL
-140
.
·
. _
_
.
.
. .
-
I
.
-
0
-0.5
-140
..................................
I
.
-
0.5
.
-0.01
.
I
0
-0.5
0.01
-0.5
0.5
-80
-80
_
-100
I
-100 _
1OOOc_4
-120
............................................
-140
-120
106 dB SPL
-140
.
.
-0.5
-0.5
.
.
.
.
.
.
.
I
I0
.
.
0
M (cycles)
.
.
.I .
.
I
0. 5
-0.01
0.5
-0.01
(
·
I
0
0
Nr(cycles)
.
I
0.01
0.01
-0.! i
r
-0.5
....
I
..
0
I
0.5
v (cycles)
Figure C-33: Simultaneous-stimuli measurement sets and model fits at 1000 Hz on Cat
#4.
213
IVcpl (dB re 1 V)
ZVcp (cycles)
lVcpl (dB re 1 V)
0.5
-80
o Data points
-80
Linear fit
-
--- Logarithmicfit
-100
-100
-120
-120
-140
-140
0
..............................- 0.5
.....
0
-0.5
0.5
I
-0.01
I
!
.
.
.
!
0
0.01
-0.5
-0.5
0.5
0
0.5
0
0.5
0
0.5
-80 _
-80
-100
_
-100
0
-120
-120
1000e_4
t106 dB SPL
-140
,.......................................
I
0.5
.
.
.
.
I
I-.
-
.
.
0
-
-140
.
I
-0.01
0
.
0. 5
.
,
0.01
-0.5
-0.5
0.5
-80 l
-80
-
-100
-100 --
-120
-120
0
-140
i
L
L ..... .......... I... ...... ....
. . ...
*
-0.5
0.5
0
v (cycles)
-140
"-8"
..................................
iI
-0.01
.
'
I
I.
I
I
0
0.01
r (cycles)
-0.5
-0.5
v (cycles)
Figure C-34: Simultaneous-stimuli measurement sets and model fits at 1000 Hz on Cat
#4.
214
IVcpl (dB re 1 V)
(dB re 1 V)
IvCl
/Vcp
(cycles)
0.5
-80
-80
o Data points
Linear fit
--- Logarithmic fit
-
-100
-100
0
_-
-120
U 1000b 5
OW 102.5 dB SPL
RW 102.5 dB SPL
noisefloor
-120
c~<CqlF
-140
-140
.
..
.
.
-0.5
.
0
.
.
.
I
I
II
0.5
-0.01
0
.
0
,
I
.
-0.5
0.01
-0.5
0
0.5
0
0.5
0.5
_
-80
-80
-100
-100
-120
-120 _
oo-ooooo
.
.
.
.................................................
-140
.
.
.
-0.5
.
0
1000c_5
OW 103.2 dB SPL
RW 101.9 dB SPL
O
t0awo
0
-140
.
1
.
.
.
0
:
I
I
0.5
-0.01
,I
.
,
.
I
0
1
I
-0.5
0.01
-0.5
0.5
-80
-80
-1 00
-100
-120
1000d_5
OW 103.7 dB SPL
--
................................................
.
-0.5
-
r
-.
0
_
Ii
RW101.2 dB SPL
-
-140
-120
--
.
7
T '
1I
I
.
.
0
V (cycles)
'
1
'
.
-140
I1
1
0.5
1
I
-0.01
'
1
I
I
'.
0
yr (cycles)
1
I
0.01
-0.5
1- .
I
l
l
l
l
!
-0.5
-0.5
0
0.5
V (cycles)
Figure C-35: Simultaneous-stimuli measurement sets and model fits at 1000 Hz on
Cat #5.
The sum of the magnitudes of IPowi and IPRwl was held constant:
IPowl + IPRWI = 5.3 Pascals.
215
ZVcp (cycles)
IVcpl (dB re 1 V)
IVcpl (dB re 1 V)
0.5
o Data points
-80
-80
-100
-100
Linear fit
--- Logarithmic fit
o
4
---
0
1000e_5
OW 104.4dB SPL
RW 100.5 dB SPL
-120
-140
.
.
.
.
. .
.I
..
..
0
-0.5
.....................................
-140
noisefloor
'
-120
0
..
..
I...
,-- .--
·
0.5
-0.01
0.5
-0.01
0
,
-0.5
0.01
-
-(
.
*
.
.
-
.
-
I
I
-
-
-
-
0
0.5
0
0.5
0.5
-80
-80
-100
-100
-120
-120
0
OW 103.0 dB SPL
RW 102.3 dB SPL
-140
-140
I
-0.5
0
0.5
v (cycles)
-0.01
I
I
I
0
-V (cycles)
I
0.01
-0.5
-0.5
V (cycles)
Figure C-36: Simultaneous-stimuli measurement sets and model fits at 1000 Hz on
Cat #5. The sum of the magnitudes of IPowI and IPRwI was held constant:
IPowl + IPRwl = 5.3 Pascals.
216
IVcpl (dB re 1 V)
LVcp (cycles)
IVcpl (dB re 1 V)
0.5
-80
_
o Datapoints
-80
-100
-100
-120
-120
* Noisy data points
Linear fit
--- - Logarithmic fit
0
noisefloor
90 dB SPL
.....---------..-------.......................-
-140
r0
.,
.
.
.
-0.5
.
.
0.
-140
-l
I
I
-0.01
0
0.01
I
1
*
0
0.5
-0.5
0
-0.5
0.5
0.5
-80 _
-80
-100
-100
-120
-120
-140
-140
m
.
.
*
I
_
0
0
..
0
0.5
....I
.
.
-0.5
w-
............
I
.I
-0.01
0
-0.5
0.01
-
-
.
-
.
;Zi
.
-0.5
i0.!5
0
0.5
-80
-80
_-
-100
-100 I-
-120
-120
0
1000k_5
§
|95
-~
-
dB SPL
-140
-140
....
.
-0.5
.
-
-
-
.
....
-
I
_D,_ORM--
-
0
..
I
-
-
'
' . '
_
I
0
5
I ,
'
I
I
I
-0.01
0
!
1
1
-
I
-
-
-, "
-0.5
-0.5
0
0.5
-0.5
0
0.5
0.01
0.5
-80
-80
-100
-100
-120
-120
-140
-
0
''
-140
.
-0.5
-
.
.
I
.
0
Mf (cycles)
.
1
4_
0.5
-0.01
,
I
0
x (cycles)
-0.5
0.01
Mf (cycles)
Figure C-37: Simultaneous-stimuli measurement sets and model fits at 1000 Hz on Cat
#5.
217
IVcplI (dB re 1 V)
IVcpl (dB re 1 V)
ZVcp (cycles)
-
0.5
-80
-80
-100
-100
-120
-120
-
0
L
-140
-140
.
l
I
.
.
.
0
-0.5
0.5
05
-0.5
I
-0.01
0
0
. . .
I . .
0
. .
I
0.5.
0
0.5
-0.5
0.01
0
0.5
0.5
-80 K
-80
-100
-100
-120
-120
0
-d0t--'
-140
-140
I
0
-0.5
0.5
III
I.
-0.01
',
I
.
0
III
-0.5
-0.5
0.01
-0.5
0.5
-80
-80
_
-100
-100
_
-120
-120
-140
1000m 5
105 dB SPL
...........
...
,
.....
, ...
I....
0
0.5
4
I
-140
1I . . . .. II .. .. .. .. II
-0.5
0
'1
.
I
I
-0.5
.
I
-0.01
0
-0.5
0.01
0
.
.
.
.
0
0.5
0.5
-80
-80
-100
-100
-120
-120
-140
-140
_
_~
0
00
6,,o
o ,,
<5"'
.
:.
-0.5
0
f (cycles)
0.5
-0.01
.
0
f (cycles)
i
0.01
-0.5
-0.5
0
y (cycles)
0.5
Figure C-38: Simultaneous-stimuli measurement sets and model fits at 1000 Hz on Cat
#5.
218
IVcpl (dB re 1 V)
ZVcp (cycles)
IVcpl (dB re 1 V)
0.5
I
-8( 3
-80
-10(0
-100
0
.
-12(0
-
Data points
Linearfit
--- Logarithmic fit
o
1000h_5
110 dB SPL
noisefloor
-14( )
.......
'I .
.
.
-0.5
-140
.
.
-120
I
1 1 1 1 1 I
0
0. 5
.
-0.01
. A
0
-0.5
0.01
0
-0.5
0.5
~
n=
U.O
-8C
-80
-10(
-100
-12(
-120
Bm
0
10001_5
110 dB SPL
-14( ) . .... ...-- . . .....
-
. .
I
-~~~~~~~~~~~~~~~~~
-140
i::::1
-VU.
0
-0.5
0.5
-0.01
0
0.01
'
-0.5
·
.·
I
.
·
0
I
I
0.5
0.5
-80
-80
-100
-100
Vr
-120
-140
1000i_5
115 dB SPL
3__............................................
.
-0.5
.
.
.
I
xV (cycles)
0
-
-140
.
, . I ' . .
0
.
-120
-7-""OF
.
.
I
0.5
I
I
-0.01
I
I
0
I
yr (cycles)
1
0.01
. .. :."'.!.
." . a
-0.5
-0.5
0
N (cycles)
0.5
Figure C-39: Simultaneous-stimuli measurement sets and model fits at 1000 Hz on Cat
#5.
219
-80
I
e
o Data points
Linear fit
--- Logarithmic fit
-80
-100
-100
-f
-120
-120
_-
10OOr_5
115 dB SPL
noisefloor
-140 - - --.-0.5. . . . 0. . . . .
0.5
-0.5
0
ZVcp (cycles)
IVcpl (dB re 1 V)
IVcpl (dB re 1 V)
0oot
V.0 EI
0
ee-0-
-140
a
lI
-0.01
0
1I
-0o5
_._
1
0
-0.5
0.01
0.i5
0.5
-80 _
-80
-100
0L
-100
·F-iP·9"Q
0
-120
-120
-140
-140
.....................................
1
-0.5
0
N' (cycles)
0.5
-0.01
·
I
I
0
0.01
V (cycles)
-0.5
i
-0.5
'
'
'
'
I
a
0
'
'
+-
I
0.5
Nf (cycles)
Figure C-40: Simultaneous-stimuli measurement sets and model fits at 1000 Hz on Cat
#5.
220
IVcpI (dB re 1 V)
IVcpl (dB re 1 V)
Z Vcp (cycles)
0.5
-80
-80
-100
-100
00
o Data points
- Linear fit
--- Logarithmicfit
0
-120
-120
b 1000a6
I
-~
1U
. noisefloor
-140
-140
I .· . .! . I
-0.5
3·b
ODL OrL
.
.
.
.
0
........
I
0.5
I
·
-0.01
h1
,
I
1
0
0.01
I·
,
-0.5
.
.
- 0.5
.
.
.
0
.
0. 5
0.5
-80 _
-80
---
-100
-100
-120
-120
IOO0bL6
114 dB SPL
~~~~~~~~~i~
0
i
-140
-140
.
.
.
.
-0.5
.
.
!
.
.
0
v (cycles)
.
.
I
0.5
_
-0.01
0
Ni (cycles)
"
"
111
-0.5
I
I
0.01
-0.5
0
0.5
v (cycles)
Figure C-41: Pre-TTX simultaneous-stimuli measurement sets and model fits at 1000
Hz on Cat #6.
221
IVcpI (dB re 1 V)
Z Vcp (cycles)
IVcPl (dB re 1 V)
V.0c_
_
-80
-80
-100
-100
-120
-120 _
1000j_6
~~8OdB
SPL
80dBSL
-
noisefloor
.............
-140 .......................
'
.
-
-
.
-
.
-
.
.
-0.5
I
-
-
0
0.5
-- - Logarithmicfit
0
/L,
-140
-0.5
is:2~;
I
-.
I
o Data points
o Noisy data points
Linear fit
-0.01
0
.
.
·
.r
.
.
.
..
-0.5
0.01
.
.
.
.
.
.
.
.
.
.
0
0.5
0.5F
-80
-80 _
-100
-100 _
-120
-120 _
-140
-140 ........v e ...................
0-
0
I
-0.01
-0.5
0
0.5
-0.01
I
I
0
0.01
0
0.01
L
--0.5
I
l
l
-l
-0.5
l
I
l
l
0
0.5
0.5
-80
-80 _-
-100
-1 00 _0
-120
d
-120
98 dB SPL
-140 .....................
'I
-0.5
.
.
.
-140
I......................
.
.
.
.
0
v (cycles)
.
I
I
I.
1.I0.01
-0.01
0
0.01
I
0.5
v (cycles)
-0.5
l
l
0.5
l
l
l
II
lII
l
l
0
l
l
I
l
I
0.5
' (cycles)
Figure C-42: Post-TTX simultaneous-stimuli measurement sets and model fits at 1000
Hz on Cat #6.
222
IVcpl (dB re 1 V)
IVcpl (dB re 1 V)
Vcp (cycles)
L
0.5
-80
o Data points
-80
i
---
Linear fit
Logarithmic fit
-100
100
120
1000t_6
98 dB SPL
-140 _ noisefloor
l
l
I-0.5
l
l
l
l
l
l
I
l
0
-0.5
l
0
-120
-140
l
I
0.5
-0.01
·
I
-0.5
i
I
-80 _
.
0
0.01
_
-100
-120
-120
.
-0.5
0.5
- ..
-80
-100
I
II
.
II
.
.
.
0
0.5
dI
0
1000h_6
100 dB SPL
e4a
-140
-140
-
-0.5
-
-
-
I
-
-
-
-
0
-0.5
I
0.5
-0.01
-80
-80
-100
-100
-120
-120
1000q.-6
104 dB SPL
-140
-140
-
-!
-0.5
0
-
-
Mv(cycles)
-
-
II
!
0.5
0
0.01
I . . .e . . 4
..
-0.5
0.5
I
I
-
.
.
.
0
0.5
0
0.5
0
ft%000
.....................................
I.
0
II
-0.01
I !
vl (cycles)
II
0.01
-0.5
-0.5
s (cycles)
Figure C-43: Post-TTX simultaneous-stimuli measurement sets and model fits at 1000
Hz on Cat #6.
223
1vcI
n I:
U.::
_-
-80
-80
_;
-100
-100
-120
-120
-140
Z Vcp (cycles)
IVcpI (dB re 1 V)
(dB re 1 V)
10009g_6
110 dB SPL
T
noisefloor
-
......l
l
I .5
-0.5
o Data points
f~~~'
---
-140
l
I
l
l
0
A
_
#S# dc,1
_
Linear fit
Logarithmic fit
0
It
_~~~~~~~~~~~~~~~~~I
10
.....................................
I
I
I
0.5
-0.01
0
, ,
I
0.01
-0.5
a
_.
-0.5
0.5
.
-. .
a
- - - -
I
0
0.5
0
0.5
0
0.5
-80 _
-80
-100
-100
-120
-120
-140
140
0
-
I .*
-0.01
.
-0.5
0
0.5
'I
0
, I
0.01
-0.5
-0.5
0.5
-80 I-
-80
-100 19&I
-100
-120
1000k_6
120 dB SPL
0
-120 i_
-140
-140
..............
I
-0.5
.
.
.
.
I
............
0
N'(cycles)
I
0.5
I
I
I
-0.01
0
-0.5
·
0.01
v (cycles)
-0.5
Nr(cycles)
Figure C-44: Post-TTX simultaneous-stimuli measurement sets and model fits at 1000
Hz on Cat #6.
224
(dB re 1V)
IVCPI
IVcpI (dB re 1V)
ZVCP (cycles)
0.5
-80 _
-80
-100
-100
-120
-120
o Data points
_
---
Linear fit
Logaithmicfit
0
'L
-140
.......................
'I.
.;
..
..
-0.5
;.
.
·..............
.
;
I
X
I
.
-140
·........
.
.
.
1
0
.
1.1
.
I
I
0.5
.
I
*
I
-0.01
0
I
*
I
0.01
-0.5
-0.5
0.5
0
0.5
-80 _'
-80
---
-100
-100
-120
-120 _-
-140
-140
A
0
JAA
I
-0.5
0
v (cycles)
0.5
.
-0.01
I
0
Mi (cycles)
I
0.01
-0.5 -- -- --. -- -- -- -- -- - -0.5
I
I
0
0.5
-i (cycles)
Figure C-45: Pre-TTX simultaneous-stimuli measurement sets and model fits at 1000
Hz on Cat #7.
225
II"-U"V··"-~"~"~1~1"^--111`-"11-
IVcpl (dB re 1V)
ZVcp (cycles)
IVcpl (dB re 1V)
.
U.
-80
-80
-100
-100
-120
I
-140
I
-
o Data points
Noisy data points
Linear fit
- -- Logarithmic fit
140
II
I1
·
*
I
-0.5
0. 5
0
r
0
-120 _
I
,
-0.01
I
I
'
I
0
0.01
-"t-
-0.5 -rr .
-0.5
.
·
.
.
.
I
I
I
0.5
0
0.5
-80 I-
-8(
3
-10(0
-100 I-
-12(
-120
0
-14(0
-0 .............
-140
...........................
-0.5
°-5
0
1
-0.01
1
1
0
1~
0.01
-0.5
.
I
.
.
.
I
.
..
__"
.
I
I
-0.5
0.5
0
0.5
0
0.5
0
0.5
-80 _-
-81 O _
-10(
.....................................
1
O
-100 _0
-120
-12(
"110
4O
-14(
jF__;:··1
.
'
-0.5
I ·
.
L
.
0
-140
0.5
.....................................
EI .
I
I
-0.01
0
I
I
,
.
I
0.01
-0.5
-0.5
0.5
-80
-80 _
-100
-100 _
-120
-120
-140
1000f 7
119 dB SPL
................................................
-
-
-0.5
-
-
-
-II
l
-
-
-
0
v (cycles)
-
II
I
0.5
-140
0
l · I·,
-0.5
.....................................
I
.!
-0.01
0
0.01
v (cycles)
-0.5
Nf (cycles)
Figure C-46: Post-TTX simultaneous-stimuli measurement sets and model fits at 1000
Hz on Cat #7.
226
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228