Speech Audiometry
Thresholds,
Recognition Tests,
MCL &UCL
Testing with Recorded Speech
 1000
Hz Calibration tone provided on
recording
 Balance calibration tone on VU meter at 0
Live Voice Testing:
 Controlled Vocal
 Adjust
Effort,
microphone sensitivity
 to have the speech balanced at 0 dB on VU
meter
Thresholds for Speech:
 Speech
Detection Threshold: lowest level
at which the listener can tell that something
is there (when the signal happens to be
speech).
 Speech Recognition Threshold: lowest
level at which the listener can actual
identify what the speech stimulus is.
SRT Stimuli: Spondees
 2-syllable
 can
words with equal stress
be divided into two monosyllables
 e.g.,
hotdog, baseball, whitewash,
mousetrap, birthday, eardrum...
Why spondees?
 because
their intelligibility curves rise from
near chance to 100% performance within a
few decibels.
 This
provides a much more accurate
threshold.
SRT Methods
ASHA:
 Instruct
 Familiarize (16 words)
 Find Starting Level
 Begin Descending
procedure
 Thresh = Start Level # C + Corr. Factor
Adaptive
 Instruct
 Familiarize
 Bracket (2-4 wds/level)
 Thresh = lowest level
where you get at least
50% correctly repeated.
The SRT should agree with the
PTA
 (-8
to +6 dB of best threshold at these
frequencies).
 This way we have a double-check on
results.
Exception for steeply-sloped high
frequency losses.

SRT will be better than PTA
 In this case use Fletcher average: 500 Hz +
1000 Hz / 2.
Masking for SRT's:
 IF
SRT - IA > best BC THRESH in NTE.
 WHITE
or PINK NOISE
 STARTING LEVEL=SRTTE –35 +ABGNTE
Long Term Spectrum of Speech
And the variance around it.
Bone Conduction SRT's:
 useful
in children
 useful in malingerers.
Masking for SRT
 If
SRT - IA > best BC Thresh NTE
 Put in at least:
STARTING LEVEL=SRTTE –35 +ABGNTE
But no more than:
OVERMASK = EMNTE-IA> Best BC Thresh TE
Most Comfortable Loudness Level

Instructions important: you can strongly influence
how a person responds.
 "I am going to continue talking to you as I make
my voice louder and softer. I will keep asking you
to tell me whether my voice is too soft, too loud or
comfortably loud."
 Do a number of sweeps in level.
 normally between 40 and 55 dB above SRT
Uncomfortable Loudness Level

Begin at MCL, raise level as you continue to talk.
 "I am now going to ask you to tell me how my
voice sounds to you as I make it louder. Please
tell me if the level is comfortable, a little loud, or
uncomfortably loud.”
 Uncomfortable = loud enough so you would not
want to listen to my voice for a long time.
Range of Comfortable Loudness
 (Or
the Dynamic Range for Speech)
 = UCL – SRT
 Normally 100 dB or greater
 Unchanged in conductive losses
 Can be much smaller in sensorineural
hearing loss
Word Recognition Testing

Open set-client can respond with any word he/she
can think of.
 Closed set-response options are provided for the
client (multiple choice test).

Free response-client is free to respond or not.
 Forced Response-client must say something.


[Forced choice = closed set forced response.]
Phonetically Balanced Word Lists
 selection
of a group of words so that each
phoneme appears with the same frequency
it has in the normal lexicon. Based on
Thorndike-Lorge lists of words and word
frequencies.
 So-called
PB word lists-- CID W-22 Lists
 Four lists of 50 words each.
CNC Word Lists
 Consonant-Nucleus-Consonant words
 Phonemically balanced
 Four
50-item lists: the NU-6 Word Lists
Alternative Speech Choices

High Frequency Word Lists
• Gardner’s Hi Frequency Word Lists
• California Consonant Test

Nonsense Syllable Lists
• The Nonsense Syllable Test (NST)

Sentence Tests
•
•
•
•
The Synthetic Sentence Identification (SSI) test
Speech Perception in Noise (SPIN) test
Connected Speech Test (CST)
The Hearing In Noise Test (HINT)
Children’s Tests

Word Intelligibility by Picture Identification
(WIPI) test – six pictures to choose from.
 Northwestern University Children’s Perception of
Speech (NUCHIPS) test – four pictures to choose
from
 Monosyllable-Spondee-Trochee test –
distinguishing word shapes, not identifying
particular words; used in cochlear implant cases.
WIPI Sample Item
NU-CHIPS Sample Item
Administration: once you've
chosen materials
 transducer: AC,
BC, or sound field.
 level: at some SL (40)--may be specified by
test.
 response: repeat, write, or mark on list.
 competing noise: what, how loud.
 masking: calculate (Test Level - IA) - BC nte
Adaptive Testing
 Finding
a threshold, not a % score
 Typically in presence of competing noise
 Measure has low variance
 Not yet common in clinical practice
• (although we will talk about the HINT soon)
Performance-Intensity Functions
 PI
function: word recognition scores
obtained at a range of stimulus levels.
 Curve reaches a peak (Pbmax), and then
 Either remains high (normal), or
 Drops at higher levels (Rollover)
 Rollover
Index = (PBmax – Pbmin)/PBmax
100
90
80
% Correct
70
60
NORMAL
ROLLOVER
COCHLEAR
50
40
30
20
10
0
20
40
60
70
dB HL
80
90
100
Rollover Indices for the
preceding examples

Normal: (100 - 100) / 100 = 0.0

Rollover: (44 - 20) / 44 = 0.54

Cochlear: (80 - 70)/80 = 0.125

Rollover Indices of 0.45 or greater indicate a neural
(VIIIth nerve) problem.
Cross Hearing & the Need to Mask

If Word level (HL)TE – IA > Best BCNTE

Use Pink (Speech) Noise, or white noise
 Suggested Levels:
EM = PBHL TE – IA + ABGNTE + 20 dB
PB Test Level
40 dB HL
60 dB HL
80 dB HL
Masker Level
--40 dB EM
60 dB EM
Reliability of Word Recognition Scores

Range of possible scores upon retest
Thornton & Raffin (1978)
# of Items
Initial
Score
90
100
50
25
10
81-96
76-98
72-100
50-100
50
37-63
32-68
28-76
10-90
20
11-32
8-36
4-44
0-60
NU-6 Words Ordered by Difficulty
 Present
10 words- stop if 0 or 1 error
 If >1 error, present next 15 words
 If < 3 errors (out of 25), stop
 If > 3 errors administer all 50 words
Hurley & Sells, 2003
Interpreting Word Recognition Scores
Score:
General Word Recognition Ability:
90 to 100
Within Normal Limits
75 to 90
Slight Difficulty
60 to 75
Moderate Difficulty
50 to 60
Poor
< 50
Very poor
Expected PB max by Hearing Loss
Dubno, J. et al. JSHR 1995
Abnormally Low Word
Recognition for HL
1st % Correct Score
2nd % Score
PTA (dB HL)
SPRINT: Speech Recognition Interpretation Chart
© by Linda M. Thibodeau, 1999
SPRINT: Speech Recognition Interpretation Chart
PTA (dB HL)
2nd % Score
1st % Correct Score
© by Linda M. Thibodeau, 1999
Predicting WRS from the audiogram:
The AI
 The Articulation Index
 Audibility
Index
 “Count the dot” audiogram
 If
word recognition is poorer than prediction:
neural hearing loss or central disorder.
Counting Dots: (Mueller & Killion)
 Each
dot = 1%
 # of dots below HL
line on audiogram
= % correct
identification for
speech.