INDIVIDUALIZING
THE MAPPING
SESSION
WENDY B. POTTS, AU.D., CCC-A
DISCLOSURE STATEMENT
I am employed by the University of South Carolina.
Disclosure: I have no relevant financial or nonfinancial relationship(s)
within the products or services described, reviewed, evaluated or
compared in this presentation.
Pictures/graphics supplied by Cochlear Corporation, Advanced
Bionics, and Med El.
TOPICS COVERED
What is a cochlear implant and who is a candidate?
What should we expect from a cochlear implant?
What happens in an appointment?
How do we know the electrodes are working?
What are some objective measures for a map?
What are the map parameters that are adjusted?
How does a map stimulate the ear?
What are the subjective measures for a map?
How do we test patient performance with the map?
How often should a recipient return for a new map?
COCHLEAR
IMPLANT BASICS
WHAT IS A COCHLEAR IMPLANT?
COCHLEAR IMPLANT BASICS
Two components of a cochlear implant:
1
An internal implant
placed just under the
skin, behind the ear
Photos provided courtesy of Cochlear™ Americas, © 2009 Cochlear Americas
COCHLEAR IMPLANT BASICS
Two components of a cochlear implant:
1
2
An internal implant
placed just under the
skin, behind the ear
And an external
sound processor
HOW A COCHLEAR
IMPLANT WORKS:
Coil
The microphones collect sound
and sends it to the speech
processor
Microphones
The speech processor converts
the sound using a coding strategy
the electrodes understand
Processor
Coil Cable
The signal is then sent up the
cable to the coil
Photos provided courtesy of Cochlear™ Americas, © 2009 Cochlear Americas
The coil transmits the signal via
radio waves across the skin to
the internal component of the
implant
The internal component delivers
the signal to the electrode array
in the cochlea
The electrodes stimulate the
hearing nerve with electrical
impulses
Electrodes
Photos provided courtesy of Cochlear™ Americas, © 2009 Cochlear Americas
COCHLEAR
IMPLANT
CANDIDACY
WHO IS A CANDIDATE?
WHAT SHOULD WE EXPECT FROM A COCHLEAR
IMPLANT?
COCHLEAR IMPLANT CANDIDACY
Speech
Recognition Criteria:
Adults:
• ≤ 60% on sentence test
(best aided condition) for private
insurance
• ≤ 40% on sentence test
(best aided condition) for Medicare
Children:
• ≤ 30% MLNT or LNT
(best aided condition) if have spoken
language.
• Demonstrate lack of progress in
developing spoken language when
appropriately aided with intervention.
Adults
Adults/Children 2+
Adults/Children 1+
Photos provided courtesy of Cochlear™ Americas, © 2009 Cochlear Americas
Adapted from Hearing in Children. Northern J., Downs M., (1991) 4th
Edition. Ch 1, page 17. Lippincott Williams & Wilkins.
EVOLUTION OF CANDIDACY
1985
AGE
ONSET of
Adults
Postlinguistic
Hearing
Loss
DEGREE
Profound
1990
1998
2000
Current
Adults
Adults
Adults
Adults
Children (2yrs)
Children (18
mo)
Children (12 mo)
Children (12 mo)
Postlinguistic
Adults
Adults &
Children
Adults & Children
Adults & Children
Pre & Postlinguistic
Pre & Postlinguistic
Pre &
Postlinguistic
Children
Pre &
Postlinguistic
Profound
SevereSevere-Profound:
Profound Adults
2 yrs & older
Profound
Profound : < 2 yrs
Children
of SNHL
Adults Moderate-to-profound Infants
(12-23 mos) Profound
Children (2-17 yrs) Severe to
Profound
-bilateral sensorineural hearing loss
ADULT
0%
0%
40% or less
(CID)
Speech
Scores
< 60% sentence recognition (aided)
< 40% Medicare
Open-set
sentences
Pediatric
< 50% (HINT) in
implanted ear
< 60% contra ear/bin.
Not candidates 0% open-set
Lack of auditory Lack of auditory
progress
progress
< 20%
(MLNT/LNT)
< 30% (MLNT/LNT)
Infants: No progress in auditory skill
development with hearing aids and
intervention
Children: < 30% open set speech
recognition
TEAM APPROACH
All evaluations are completed and the
team discusses each candidate to see
if they are within FDA and/or
Medicare/Medicaid guidelines
Teacher of
The Deaf
Surgeon &
Pediatrician
Psychologist
We look at the whole patient, the
whole family, the total environment
the patient is in
Child
SLP
Care Givers
Audiologist
FACTORS FOR SUCCESS WITH THE IMPLANT:
Support and motivation
•
•
•
Family support and commitment
Motivation to create and utilize opportunities to communicate and use audition
at home, at school, at work
Active participation in rehabilitation: both recipient and family
Previous Auditory Stimulation and success with speech and language
•
•
•
•
•
Short duration of deafness and/or…
Early Identification with Early Intervention and Early Implantation
Auditory memory of spoken language
The ability to benefit to some degree from a hearing aid
Auditory-verbal/oral mode of communication
Consistent use of the device and care for the sound processor
•
•
Attends regular mappings
Maintains equipment
At least average cognitive skills for age and good attention skills
Absence of medical contraindications and full insertion of internal electrodes
APPROPRIATE
EXPECTATIONS
One of the criteria for successful cochlear implant recipients
is listed as “appropriate expectations.”
What does that mean?
It means that the recipient and family fully understands what
can and cannot be achieved through the implant and they
commit to putting the work in to achieve their goals.
APPROPRIATE
EXPECTATIONS
Expected outcomes for adults who lost their hearing after learning speech
and language:
• Awareness of environmental sounds
• Reduction in speech reading effort
• Reduction in communication stress/fatigue level
• Range from limited to considerable understanding of speech without visual
cues
• Potential ability to use telephone
• Some appreciation of music
• Adjustment period - increased ‘noise’ from environmental sound awareness
requires time to adjust to. As with any major life change, it takes time to feel
comfortable. Expecting the adjustment period for the CI will make it easier.
APPROPRIATE
EXPECTATIONS
For the child and family:
• Children vary significantly in their hearing performance and
in how much time it takes them to achieve hearing
functions that result in using spoken language.
• Sometimes benefit is more limited due to factors such as
late age of implantation, use of sign language,
inappropriate educational setting and multiple disabilities.
• The CI does not provide normal hearing functions. The
cochlear implant provides sound stimulation and the child
learns to interpret the sound stimulation. The child needs
the support of the family and assistance by hearing and
speech and educational professionals to achieve the most
from the CI.
POST IMPLANT FOLLOWUP –
SPEECH THERAPY
Adult Aural Rehabilitation
Aural Habilitation
Auditory-Verbal or Oral Therapy
POST IMPLANT FOLLOWUP MAPPINGS
Initial Hookup:
• 4 weeks post surgery
• Need time for the incision to heal and
swelling to go down
• The first, basic listening program/map is
created
• Just to give access to sound, to acclimate
new recipient to CI stimulation, not to
optimize for speech on the first day
• Sound is different than a hearing aid
• Also complete an equipment orientation
Photos provided courtesy of Cochlear™ Americas, © 2009 Cochlear Americas
POST IMPLANT FOLLOWUP MAPPINGS
Subsequent Mappings:
• Goal is to optimize for speech
understanding in quiet and in
noise. Need to have appropriate
expectations with CI
• Also want to provide other quality
of life benefits
• Provide referrals and
recommendations for other
services or equipment that will
provide more speech
understanding benefit
COCHLEAR
IMPLANT
MAPPING
WHAT HAPPENS IN AN APPOINTMENT?
MAPPING
APPOINTMENT
Time to assess:
• Subjectively, how the patient is doing with sound and speech
discrimination
• If the equipment is working properly
• If the site of the magnet and behind the ear look normal vs.
irritated
• Re-measure electrode current levels and fine-tune the Map or
listening program
• Objectively measure the performance of the patient in the sound
booth
MAPPING
PROCEDURES
Check ALL equipment
•
•
•
•
Listening check
Look at condition of speech processor
Replace/Order new equipment, if needed
Upgrade counseling, if appropriate
MAPPING
PROCEDURES
Get patient history
• Ex….
•
•
•
•
•
•
•
•
•
•
•
Decrease in auditory reaction or alertness to sound
Decrease in vocalizations and/or vocal play
"Slushy" production of previously mastered speech sounds
Any sign of physical discomfort, such as eye or facial twitches
Refusal to wear sound processor
Complaints of difficulty of hearing
SLP tx results – particular problem sounds
Volume comfort
Sound/Voice quality, naturalness, bass/treble
Difficulty operating external equipment
Irritation to the skin under the transmitting coil/magnet
MAPPING
PROCEDURES
Hook the processor up to the mapping computer
Photos provided courtesy of Advanced Bionics
Photos provided courtesy of Cochlear™ Americas, © 2009 Cochlear Americas
COCHLEAR
IMPLANT
MAPPING
HOW DO WE KNOW THE ELECTRODES ARE WORKING?
WHAT ARE SOME OBJECTIVE MEASURES FOR A MAP?
WHAT IS TELEMETRY?
Bi-directional communication of data using radio-frequency
code between programming hardware and the implant
Programming
Hardware
Processor,
Programming
Interface, & Mapping
Software
Skin Flap
Telemetry is not measured if the coil is not over the implant,
or the implant is not functional
Implant
IMPEDANCE TELEMETRY
Check electrode impedances / Impedance Telemetry
• Electrode impedance is a measure of the opposition to
electrical current flow
• Allows for a quick check of individual electrode function
• Impedance = voltage/current
Programming
Hardware
Processor,
Programming
Interface, & Mapping
Software
Skin Flap
• Values are listed and pattern of impedances is important
Photos provided courtesy of Cochlear™ Americas, © 2009 Cochlear Americas
ELECTRODE IMPEDANCES
• High Impedance
• Short Circuit
• Electrode open circuited
• Electrode not in contact
with body fluids
• Electrode or lead wire in
contact with another
electrode
Deactivate electrodes that are either open or short
Current
source
Short circuit
Open circuit
Photos provided courtesy of Cochlear™ Americas, © 2009 Cochlear Americas
ECAP TELEMETRY
Neural Response Telemetry (Cochlear)
Neural Response Imaging (AB)
Auditory-Nerve Response Telemetry (Med-El)
Programming
Hardware
Processor,
Programming
Interface, & Mapping
Software
Skin Flap
• Quick, non-invasive, objective measure of peripheral neural
function (Electrically Evoked Compound Action Potentials)
Photos provided courtesy of Cochlear™ Americas, © 2009 Cochlear Americas
OVERVIEW OF
NRT/NRI/ART
Electrical pulses of varying intensity are delivered to the
stimulating electrode
Neural activity, the Electrically Evoked Compound Action Potential
(ECAP), is obtained by recording electrode and the waveform is
displayed in the programming software
The threshold of the ECAP is found and can be marked in the map
We can see the electrophysiological responsiveness of neural
populations at different sites on the electrode array
ECAP
CHARACTERISTICS
P2
Amplitude
N1
Photos provided courtesy of Cochlear™ Americas, © 2009 Cochlear Americas
Photos provided courtesy of Cochlear™ Americas, © 2009 Cochlear Americas
Photos provided courtesy of Advanced Bionics
NRT/NRI/ART APPLICATION
AND BENEFITS
Supplements behavioral measures
Provides assurance of auditory nerve function
Provides objective information to improve clinical management
• To create entire MAPs
• To monitor peripheral responsiveness over time when
behavioural responses are inconsistent or questionable
• Potential for improved speech understanding through a MAP
which is optimally adapted without extensive feedback from the
recipient
Reduced programming time in young children
COCHLEAR
IMPLANT
MAPPING
WHAT ARE THE MAP PARAMETERS THAT ARE
ADJUSTED?
HOW DOES A MAP STIMULATE THE EAR?
WHAT IS A MAP?
Set of parameters for any given speech coding strategy
The individualized listening program stored in the memory of
the speech processor
Based on responses to differences in loudness and pitch
MAP PARAMETERS
Number of channels
and/ or maxima
• How many sites of
stimulation
Speech coding
strategy
• Does the map use
spectral or temporal
information or a
combination of both
Stimulation mode
• How the electrodes are
coupled together to form
a channel
Pulse width
• How long the stimulation
stays on when a pulse is
presented
Stimulation rate
• How fast each channel
or the whole array is
pulsing/sec
WHAT IS AN
ELECTRODE?
Electrodes are the physical contacts in the cochlea
The number of electrodes equals the number of electrical
contacts on the electrode array
WHAT IS A CHANNEL?
An electrical circuit is formed by pairing an active electrode
and an indifferent electrode (ground)
An active site together with a ground site makes a channel
There can be a different number of channels than electrodes
on the array
CHARGE-BALANCED, BIPHASIC
CURRENT PULSE
The electrical stimulus
delivered to the nerve
The negative and positive
phases are equal so that no
net charge remains. This
form of stimulation is safe
for biological systems.
Photos provided courtesy of Cochlear™ Americas, © 2009 Cochlear Americas
REPRESENTING
SPEECH IN A MAP
Amplitude = amount of stimulus current
• Loudness
Frequency/Spectral Info = place/site of stimulus
• Pitch
Temporal Info = rate and pattern of stimulation
• Timing cues
COCHLEAR
IMPLANT
MAPPING
WHAT ARE THE SUBJECTIVE MEASURES FOR A
MAP?
MAPPING
PROCEDURES
Take measurements of individual electrodes
• The CI recipient will only hear “beeps”, no speech
• Threshold (T) Level:
• Threshold for detection of sound through electrical stimulation of
each channel
• The lowest current level that elicits a very soft, but consistent
hearing sensation
• Comfortable (C) Level / Most Comfortable (M) level:
• The loudest level of electrical stimulation that is tolerable/most
comfortable for each channel
• The maximum current level for loudness
• Dynamic Range:
• The difference in current level between T and C/M level
MEASUREMENT TECHNIQUES
T-levels
• Standard Audiometry
C/M-levels
• Live speech overall comfort level
(flat map or contour of T’s)
• Count the beeps method
• Loudness scaling
• Play Audiometry
• Loudness balancing
• VRA/BOA Techniques
• Neural Response
• Neural Response
• Acoustic Reflexes
• Based on pre-map audiogram
• Based on pre-map audiogram
• Estimated Levels/Clinical
Judgment
• Set an equal percentage below
C/M’s
• Live speech threshold
• Based on input from speech
therapy
• Estimated Levels/Clinical
Judgment
Low frequency
High frequency
C-Levels
Dynamic Range
T-Levels
Photos provided courtesy of Cochlear™ Americas, © 2009 Cochlear Americas
Photos provided courtesy of Advanced Bionics
Photos provided courtesy of Med El
WHY T- AND C/MLEVELS MATTER
T – level
• Smallest amplitude of pulse that is audible
• Soft sounds in speech or other desired sound must be
provided at an audible level to patient
C/M – level
• Largest amplitude of pulse that is allowed
• Stimulation that is perceived as loud but not uncomfortable
• Allows patient’s full electrical dynamic range to be used for
range of loudness relationships in sound
NEED APPROPRIATE
T- AND C/M-LEVELS
T-LEVELS
C/M-LEVELS
T-Levels too low (not
enough electrical current)
C/M-Levels too low (not
enough electrical current)
• Recipient will not perceive
quiet sounds & lower-level
information
T-Levels too high (too
much electrical current)
• Recipient may perceive
persistent background
noise
• Stimulation does not take
full advantage of limited
dynamic range
• Recipient may perceive
overall sounds as too quiet
• Stimulation does not take full
advantage of limited dynamic
range
C/M-Levels too high (too
much electrical current)
• Increased risk of overstimulation
• Sounds will be uncomfortably
loud
• Reduced battery life
T’S AND C/M’S CAN
CHANGE
Growing awareness of sounds and adaptation to CI
stimulation
Physiological changes
Health / Sickness
Medication
Stress
TEST THE MAP IN
LIVE SPEECH
“Go Live” by turning on the microphone
• To assess how the patient perceives environmental sounds and
speech with the new map
• Ling 6 Sound Test/Words/Conversation
Fine-tune the Map to the best listening experience for that person
• Change Gains for sound emphasis, C/M-levels for volume, T-levels
for soft sound perception, etc……
Based on performance or other factors, may change some map
parameters such as rate, pulse width, or electrode coupling, etc.
For those types of changes, need to start over (re-measure) with
subjective measurements of T’s and C’s/M’s
MAKE PROGRAMS
MAP vs Program terminology
 Save the Map and add or change settings to create different
listening Programs

The term MAP has mostly been used to describe a recipient’s
“listening program”
 Important to differentiate between a MAP and a Program
MAP
• MAP parameters
- rate
- pulse width
- maxima
- coding strategy
• T and C levels
+
Environment Settings
=
PROGRAM
•SmartSound environments
•Program Position 1
•Volume and sensitivity
settings
•Program Position 2
•IDR
•ClearVoice
•Mixing Ratios
•Etc.
•Program Position 3
•Program Position 4
COCHLEAR
IMPLANT
MAPPING
HOW DO WE TEST PATIENT PERFORMANCE WITH
THE MAP?
TEST PERFORMANCE
IN BOOTH
Perform aided audiogram pre- or post-mapping session
Use results to confirm detection of soft sounds (tones), the
quietest dB they can understand speech (SRT), and how
much speech do they understand at a normal conversational
level (%)
Perform standardized speech tests as done pre-implant to
determine benefit
Can use aided thresholds to modify T- and C-levels as well
COCHLEAR
IMPLANT
MAPPING
HOW OFTEN SHOULD A RECIPIENT RETURN FOR
A NEW MAP?
GENERAL MAPPING
SCHEDULE
Initial stimulation 2-4 weeks post surgery
Once per week for 1 month
Once per month until map and recipient are stabilized
Every 3 months
Keep the 3 month schedule for young children
Every 6 months
Keep the 6 month schedule for older children
Every year
For teens and adults
As Needed for problems, equipment issues, or family/recipient
support