Aural Rehabilitation 2

Hearing Aids and Assistive Listening Devices (part 1)

Purpose of Amplification

• Make speech and environmental sounds audible

• Optimize intelligibility and sound quality

• Ensure loud inputs are not uncomfortable or distorted

Responsibility of Fitting

• Cost effective and appropriate fitting

• Adjust to the specific type and degree of hearing loss

• Follow-up evaluations to verify fitting

• Facilitate other aspects of aural rehabilitation

Types of Hearing aids.

Custom hearing aid

In-The-Ear (ITE)

In-The- Canal (ITC)

Completely- In-Canal (CIC)

(Non custom hearing aids can be donated)

Hearing Aid Basic Components

• Microphone: sound waves enter here

Converts the acoustical signal (sound waves) into electrical signal

• Amplifier: increases the strength of the electrical signal (makes it louder)

• Receiver: converts the amplified electrical signal back into amplified acoustical signal

(sound waves)

Channels the sound directly into the ear canal

• Battery: provides electrical energy to power the hearing aid

HA Circuit Block Diagram

Controls and Features

• On/Off Switch

• M = microphone

• O = turns the hearing aid off

• T = if present, activates the telecoil

• Telecoil

• Enhances use of hearing aid on the telephone

• Picks up “leaked” electromagnetic signals and converts them into acoustic energy.

Controls and Features

-Volume Control

• Controls the loudness levels of the hearing aid

• Toggle switch, rotating wheel or a remote control

automatic adjustment

• Some patients may prefer a volume control, even if it is disabled due to what they are used to

Hearing Aid Overview

• Licensure laws used to allow HIS to tell people that their hearing aids would prevent hearing loss

• HAs will NOT restore hearing loss, but will improve their current (residual) hearing

Hearing Aid Overview

• All minors (18 years and younger) must have medical clearance (a physician) by obtaining a signed release

To rule out medical contraindication of fitting hearing aids

• Adults can waive medical clearance

• Parents are not allowed to waive medical clearance for children

Hearing Aid Overview

• Cannot use results older than 6 months for fitting someone

• Need to re-evaluate regularly

A SNHL needs to be monitored frequently in children due to absence of ear aches etc. (not as noticeable if a change occurs)
Age dependent

Maintenance Tips

• Hearing aids need a yearly electroacoustic analysis from the manufacturer

• Hearing aid companies provide warranties that vary in length of time

Renewal of warranty after expired for a fee

• Turning off the hearing aid prevents feedback for removal or insertion

• Never use alcohol or oil to clean aids

• During the first few weeks, use the hearing aids in a normal, quiet, everyday environment

Why? Because you need to get used to them. (could take up to 10 years to get used to them)

Hearing Aid Technology

• Regulated by the FDA and are medical prosthetic appliances

• Circuit design

Digital signal processing algorithms
Multiple channels of signal processing

• Digital/programmable hearing aids

All current technology is programmable
Use digital processing of the signal
Programmed by using a computer

Hearing Aid Technology

• Probe-microphone measures

Used to measure the reliability of the output of hearing aids at the level up to the

tympanic membrane

Allows for a precise, frequency specific fitting of the hearing aids
Provides a verifiable measurement for evaluation

• Computerization

Allows the hearing instrument to be programmed through specific fitting

software for patient verification

Allows the audiologist to see adjustments made to the hearing aid in real time
Frequency specific adjustment capabilities

Initial Hearing Aid Process

• Audiological examination

• Counsel regarding results

• Discuss the types of hearing aids

• Explain the pros and cons of styles/brand

Make and model are important, but it is more important to find a hearing aid that

fits their lifestyle needs

• Take an ear mold impression

Hearing Aid Fitting/HIO

• Discuss proper maintenance and care

How it works
Batteries
Cleaning
Check their dexterity

• There will always be an adjustment period for hearing aids

Warn them about loudness levels and environmental sounds they were missing

Hearing Aid Evaluation

• Program to the patient’s hearing loss

• Electroacoustic analysis and probe microphone measures

• “Aided” sound field testing

Recorded with an “A” on the audiogram

• Before and after view of their test results

• There is a 60 day refund policy required by federal law (varies from state to state)

• Allowed to return the hearing aids before 30 days for a full refund

Minus examination and fitting fees

09/11/2024

Hearing Aids and Assistive Listening Devices (part 2)

Purpose of Amplification

• To make speech and environmental sounds audible to the hearing impaired person

• Optimize intelligibility and sound quality

• Ensure loud inputs are not uncomfortable or distorted

Definitions

• Gain – the difference in dB between input and output of the hearing aid

Remember the input signal plus the aid gain equals the total output

• Frequency Response – the response or gain at the frequencies it amplifies

• Bandwidth – information about the frequency range of the frequencies the aid

effectively amplifies

Controls and Features

• Frequency Specific Gain

Control the amount of amplification in specific frequencies
Frequency band control

Definitions

• Maximum Pressure/Power Output (MPO)

The maximum output that the hearing aid will amplify up to its “upper limit”
SSPL 90 curve – volume control full on and a 90 dB SPL input level
High Frequency Average SSPL 90 – average of 1000, 1600 and 2500 Hz values of SSPL 90

Controls and Features

• Compression

Also known as “Automatic Gain Control” (AGC)
Limits the amount of maximum power output (MPO)

• AGCo – limit MPO of hearing aid; happens after the amplifier

• AGCi – monitor input (the signal) before it’s amplified

Compression Cont’d

• Peak Clipping: an old form of compressing the signal by essentially cutting off the

peaks of the signal

Introduced distortion to the sound quality of the output signal

• Distortion is still present even with AGC

even the most expensive aids do not reproduce an exact amplified reproduction

of the original signal

Controls and Features

• Directional Microphones

Allows for better signal-to-noise ratio (SNR)
Can be single directional or omnidirectional
May have a button to change between directional/omnidirectional or the aid may

do this automatically

Circuitry is dependent on the degree of loss and size of hearing aid

HA Components (BTE) (HA-Hearing aid) “Behind the ear”

HA Components (RITE) “Receiver in the ear”

HA Components (ITE/ITC) “in the ear” “in the ear canal” (costume ear device)

HA Components (CIC) ”Completely in canal” (Custom ear device)

Ear Impressions

• Perform otoscopy

• Use an otolight to place an eardrum just beyond the second bend of the ear canal

• Ear impression material is mixed together which contains a base and a catalyst

• A type of syringe is used and the material is injected into the ear canal until the concha and helix are filled

• Lift the pinna up and back and remove hardened impression material

Ear Molds

• Impressions are sent in to a company and the ear molds are made

• Couples the hearing aid to the patient’s ear using a specific type of tubing

• Provides support and stability for BTEs, OTEs and CIs.

For CIs it is used for retention purposes only

• Directs and modifies the sound depending on the style and features that are chosen

(Ear impressions are taken by the audiologist and sent to the manufacturer. Ear mold that we received from the manufacturer.)

Ear Molds

How might Erikson's stages be impacted by a hearing loss?

How Might acquired hearing loss affect these stages?

Psychologically, because you lose something that you had before

09/23/2024

Hearing Aids and Assistive Listening Devices (part 3)

Earmolds/Hearing Aid Shells

• A tight fit of the earmold/shell may be the most important aspect of successful use of hearing aids

• What are some negative effects of a loose shell/earmold?

Feedback from patients.

Earmolds/Shells

• The Vent: a small hole drilled into the canal portion of the shell/earmold.

Types of Vents

Vents cont’d

• 3 primary reasons for a vent

• Allows low frequencies (up to 1500Hz) to escape from the ear canal

Larger vent = more low frequency attenuatio

• Release pressure to decrease a “plugged up” feeling

• Allows for normal input of unamplified sounds

Hearing Aid Dampers

• Mesh screens, cotton, lamb’s wool

• Placed within the tubing or earhook for a BTE

• Placed in the receiver of a custom instrument

• Used to dampen the peaks at around 1500 Hz

Hearing Aid Acoustic Horns

• Produced by progressively increasing the internal diameter of the earmold tubing or custom shell sound bore

• Enhances high frequency gain especially in the 3000 to 4000 Hz range

• Size of horn is limited to the size of the earmold/shell

Batteries

• 5 common sizes

675, 13, 312, 10 and 5

• Current batteries are zinc-air

Removing the tab on a battery “activates” it for use

• Length of battery life varies.

Electroacoustic Properties

• Regulated by American National Standards Institute (ANSI) S3.22

All hearing aids must operate under this standard

• Audioscan Verifit for electroacoustic analysis

Selecting the HA Candidate

• Degree of Loss

Dependent on the severity of the hearing loss and their pure-tone thresholds

• Degree of Communication Disability

How the patent perceives their communication difficulties

• Motivation

Is the patient willing to wear aids and accept aural rehab process

Preselection Measurements

• Pure-tone thresholds

Used to predict how much gain is needed in the prescriptive fitting formula

• Loudness discomfort levels (LDL)

Use of pure-tones or Narrow Band Noise (NBN) to obtain how loud of a sound can be tolerated by the patient at various frequencies

• Speech-In-Noise

Ability to understand speech in the presence of background noise

Hearing Aid Selection

• Hearing Aid Style

Dependent on patient’s dexterity, canal size, medical conditions, cosmetic appeal, degrees and configuration of hearing loss

Hearing Aid Selection

• Gain and Frequency Response

Power of hearing aid
Gain and output are manipulated by prescriptive formulas

NAL-NL1 (adults)
DSL (kids)

Helps guide amount/time of compression
Don’t trust the manufacturers fitting formulas because that are not validated by NAL or DSL research

Hearing Aid Selection

• Multiple Channels

Allows the signal to be broken down into separate categories by frequency range for processing

Provides a more appropriate adjustment of gain and compression

Hearing Aid Selection

• Multiple Memories

Specific “programs” that can be fine tuned with different fitting parameters for varying environmental situations

Ex: restaurant, music, crowd noise etc

Hearing Aid Selection

• Dynamic Range

The difference between the patient's LDL and threshold for that signal (pure-tone or speech
Provides a guide to fitting range
Helps determine limiting of MPO

Hearing Aid Selection

• Directional Technology

Most effective in improving SNR based on spatial location

Works best when the desired sound input is directly in front of the patient

Directional provides better SNR than omnidirectional

Hearing Aid Selection

• Directional Technology (cont’d)

Automatic digital noise reduction

Hearing aid channels analyze the sound input and when it’s determined to be noise, the aid automatically decreases the gain to that channel

Hearing Aid Selection

• Directional Technology (cont’d)

• Adaptive Feedback Reduction

Possibly the leading cause of hearing aid rejection besides proper fit. (Why????)
Hearing aid identifies the frequency of feedback and applies gain reduction

Provides the patient ability to increase the gain to make soft sounds more audible

Allows for a more open fitting (decreased occlusion effect)

Hearing Aid Selection

• Directional Technology (cont’d)

Directional Mic Control

Automatic or adaptive

Automatic switches automatically
Adaptive allows the aid to change the strength and pattern dependent on the noise source

Hearing Aid Selection

• Binaural Fitting Advantages

Two is better than one
Increased gain, improved localization, sound quality and better speech understanding in the presence of background noise

Hearing Aid Selection

• Binaural Hearing Advantages

Binaural Summation – when listening with 2 ears we are able to hear sound at a lower level compared to 1 ear

Advantages for low level sounds is 3 dB better
Suprathreshold advantage is as much as 10- 12 dB better

2. Intensity/Frequency – can hear smaller changes in the intensity and frequency of sounds

Hearing Aid Selection

• Binaural Hearing Advantages (cont’d)

3. Sound localization – improved ability to localize sounds with 2 ears (localization- where the sound is coming from)

4. Time differences – an increased acoustic signal provides for timing in localization

5. Speech discrimination – provides greater speech discrimination capabilities in the presence of background noise

Verification

• Informal Patient Rating

Asking for their input
Does their self verification provide the best fitting parameters
Reevaluate and possibly re-counsel

•Loudness Scaling

Aided measurement to see where adjustments are needed for gain, compression and MPO settings

Speech

• Provides a measurable comparison of real world usage for aided and unaided testing

HINT
Quick SIN

Probe Mic Measures

• Most reliable method in assessing real time hearing aid adjustments and performance.

Post Fitting

• HIO/HAO

HIO BASICS

H = Hearing expectations
I = Instrument operation
O = Occlusion effect
B = Batteries
A = Acoustic feedback
S = System troubleshooting
I = Insertion and removal
C = Cleaning and maintenance
S = Service, warranty and repairs

HIO BASICS

• Hearing expectations

Adjustment periods and realistic expectations

• Instrument operations

Ability to turn the aid on/off, change programs, adjust volume, activate telecoil and use telephone

Occlusion effect

• Plugged up feeling/head in barrel

• Batteries

types, sizes, where to buy, battery life
Ability to insert/remove battery

• Acoustic feedback

Demonstrate when feedback is appropriate

System troubleshooting

review hearing aid manual

•Insertion and removal

properly insert and remove the hearing aid

• Cleaning and maintenance

Cleaning tools, wax removal, no fluids allowed, not to drop the aid

Service, warranty and repairs

• Warranty explanation of coverage, repair policies, when to service the aid and the process of repairs

Should patients ever “fix” their hearing aids themselves?

Depend on the issue
If they pull it apart and cant get it back to work the warranty won’t work.

Follow-Up/Outcome Measures

• Measure functional gain

• Measure LDL with patient’s normal settings

• Repeat self assessment questionnaires

• Check general care and maintenance of hearing aid

• Check data logging

Acclimatization

• Remind the patient that it takes several weeks to months for the brain to adjust to

new sounds

• Unaided ear effect

• Monaural to binaural fitting will have a possible degradation of sound quality, but allow them to acclimate during the trial period

Pediatric Patients

• Prefitting

Infants: use ABR results to plot audiogram for fitting

RECD very important
Re-evaluate often
Obtain behavioral measurements as soon as possible

Aided and unaided

Fitting Considerations

• Use Real Ear measurements to verify appropriate fitting and changing ear canal

resonance

• RECD still important for older children

Helps with setting proper MPO levels

• Use DSL formula to approximate appropriate high frequency information

Verification of fitting

Infants and young children can’t self report!
Consult parents on child’s performance
Again, use Real Ear measurements to obtain proper fitting

Output is often 10-15 dB higher than an electroacoustic measurement in the test box alone!!!!!!!

Postfitting

• Extensive parent counseling/monitoring

• Frequent hearing re-evaluations

• Frequent monitoring of earmold fit

Infants may require new earmolds weekly

• Regular electroacoustic checks

Children are more active and hearing aids need maintenance and frequent checks

09/25/2024

Hearing Aids and ALDs (part 4)

Exposure leads to learning – kids need to hear words!

• Psychology study: counted the number of words that children were exposed to in families with professional, working class, and welfare parents.

• By 4 years: children of professional parents were exposed to 46 million words, working class was exposed to 28 million, welfare class was exposed to 13 million

• Researchers concluded that by age 4 the difference between exposure to 46M and 13M words cannot be made up

• Auditory access = language learning

Children cannot listen like adults!

• Children are not as able to compensate for the acoustic smearing effects of reverberation

• They need a better signal to noise ratio (SNR) to perceive speech clearly

• Noise and reverberation work together to create an adverse listening and learning environment

Classroom Acoustics Effects:

SUMMARY for normal hearing

• The newer or more difficult the task, the greater the chance for noise interference

• Slower reading acquisition – phonemic perception and reading comprehension

• Learned helplessness – lack of perseverance for difficult tasks

• Attention and distractibility affects

• Children with hearing loss are affected more by noise and reverberation than children with normal hearing

Processing Abilities

• At 3-5 years of age, a child’s central auditory system can process the phonemic/linguistic codes of spoken speech at a rate of approx. 120- 124 WPM

Mr. Rogers spoke at approx. 124 WPM

• Age 5-7, the normal CNS can process phonemic/linguistic codes well at the rate of approximately 128-130 WPM

Only if little to no background noise, visual distractions etc.

- Ray Hull, Ph.D. Wichita State University (AAA Conference 2013)

•Children w/normally maturing CNS in 5th and 6th grade can process speech at approx. 135 WPM

• Middle school thru high school should be able to interpret in the 140 WPM range.

- Optimum listening environment

• The average adult speaking WPM is 160-180! Some reach 190 WPM (you know who you are...)

• Dora the Explorer: 124 WPM (words per minute)

• SpongeBob: 160-180 WPM (words per minute)

• Cartoon Network shows were timed to be OVER 180-190 WPM at times!!!!

They have actually been found to be detrimental to the ability of young children to attend to spoken language at home and in the classroom

• News broadcasters have been timed in upwards of 200 WPM

How might this affect the elderly population? They can’t communicate, their brains have deteriorated.
Additional situations may occur??? School, Grandparents watching TV at home, outdoor events, phone calls.
How might this affect your therapy? Parenting? Dealing with the elderly? Harder for them to understand what we are saying, harder for them to learn.

Classroom Disadvantages

• dB references for speech

Shout: 85 dB SPL
Conversational Speech: 65-75 dB SPL
Soft Speech: 45 dB SPL

Loudness range of some quieter and louder speech sounds in relation to loudness of background noise

30 dB speech signal range (45-75 dB) from quiet sounds (s, f) to loudest (oo, ay)

Classroom Disadvantages

• Boundaries to Overcome

Signal: the ratio of signal to noise
Distance: speaker to the mic of their aids
Reverberation: poor acoustics
Background noise

• Typical SNR in class is +6 dB

Adequate for kids WNL
H.O.H child needs at least +25 dB SNR

- They need a +33 dB SNR to hear ALL consonants

• Distance - (The physics of it)

▫ As distance doubles you lose -6 dB SPL

Ex: 1 ft = 60 dB SPL; 2ft=53.98 dB SPL

▫ Decreasing the distance by half equals a gain of +6 dB SPL

▫ Conversational level speech spoken within a few inches of a H.O.H. individuals ear reaches their ear canal at about 117-123 dB SPL

•Intensity

When you decrease the intensity of the sound by -10 dB, perceptually you decrease the LOUDNESS of the sound by ½.
Increasing intensity of the sound by +10 dB makes it perceptually sound twice (2Xs) as loud
Each 10 dB increase/decrease will make the perception of loudness increase/decrease by ½ or 2Xs

Head Shadow Effect

▫ Shows how much intensity is lost in the opposite ear

▫ Low frequencies aren’t affected as much

4 Types of ALD/HATS (Assistive Listening Devices, Hearing assistance technology system)

• Hardwire

• Induction Loop

• Infrared

• Frequency Modulation (FM) systems

A review of research supporting FM use

• Hearing aids amplify background sounds as well as the teacher’s voice. Nabelek, Donahue, & Letowski, (1986).

• A hearing aid will not provide benefit to speech perception in environments with noise levels in excess of 60dBA. Duquesnoy, Plomp, (1983).

• Noise levels in public school classrooms average 60 dB SPL and range from 53-74 dB SPL (Finitzo- Hieber, (1981).

• Even in acoustically treated classrooms, noise from young children can be so high that listening is affected. Blair, (1977)

Advantages of ALD/HATS

• Better SNR

• Decreases distance

• Decreases background noise

• Decreases reverberation for wearer

• Decreases intensity/loudness problems

Components of ALDs

• Mics can be directional or omnidirectional

• Tabletop or speaker

• Lapel mics

The location of the mic is vital to the amplified signal

Listening Devices

• Headphones

• Earbuds

• Neck loops

• Direct Audio Input (DAI)

• FM Boots/receivers

ALD/HATS

• Infrared Systems (cheap option)

▫ Mic placed near speaker (acoustic to electrical)

▫ Electrical signal converted to infrared

▫ Infrared signal directed to receiver

Must be a clear line of sight to receive signal

▫ Receiver converts light signal back into electrical signal

▫ Converted again back into acoustic signal

Infrared Systems

• Advantages

Inexpensive
Wireless
Stays within a specified perimeter

• Disadvantages

Requires direct line of sight
Won’t work in direct sunlight
Confined to specific area

ALD/HATS

• Hardwire System

▫ Direct wire from mic to amp and receiver

▫ Mic near speaker

▫ Signal routed to a Direct Audio Input (DAI) to allow the signal to reach the listener

Primarily for personal use only
Ex: Pocket Talker

ALD/HATS: Hardwire Systems

• Advantages:

Inexpensive
Lightweight and portable

• Disadvantages

Limited by length of component wires
Reduced sound quality
Can’t hear their own voice amplified
No peer interaction (can only hear teacher)
Everyone receives the same strength of signal

ALD/HATS: Induction Loop

▫ Wiring is looped around the perimeter of a room

▫ Mic is placed near speaker

▫ Sound source sent via wired connection or FM signal to a receiver (electrical energy)

▫ Electrical current transferred via wire loop

The current creates a magnetic field (telecoil)

▫ Telecoil converts electrical to acoustic

▫ Can be used by anyone in room using a telecoil receiver unit

Induction Loop

• Advantages

Wireless connection to listener
Works with listener’s existing telecoil
Easy to operate

• Disadvantages

Must install loop in room
Not portable
Dependent on strength of telecoil
Increased distance = decreased signal
Multiple units in area can cause interference

ALD/HATS FM/ROGER Systems (most expensive)

▫ Operate under Federal Communications Commission (FCC)

▫ Essentially uses radio wave signals

ROGER uses a different frequency allocation

▫ Bandwidths are allocated specifically for the hearing impaired

Short distances

ALD/HATS

• FM/ROGER Systems

▫ Speaker wears transmitter

▫ Receiver is worn or placed by listener

▫ FM signal is transmitted to receiving device

Signal is sent via a specific frequency

FM System (best option, more expensive)

• Advantages

Portable
Wireless
Easy operation
Indoors and outdoors
No electromagnetic interference
Good sound quality

• Disadvantages

Radio interference possible

May not be cost effective
Each listener requires a receiver

ALD/HATS: Successful Use

▫ Speak clearly

▫ Do not cover the mic

▫ Must place mic within approx. 6 inches of mouth

▫ Try to keep background noise to a minimum

▫ Frequently complete system checks

▫ Repeat questions from speakers not wearing transmitters

▫ Face audience to provide facial cues when speaking

ALD/HATS

• Television

ALD connects to audio output
Wired, induction loop, FM and infrared
Infrared is most common
Transmitter placed near TV
Closed captioning also an option

ALD/HATS: Telephones

▫ Requires a better SNR due to an auditory only signal

▫ HA users can use telecoil

▫ Can use an amp connected to telephone and a headset

▫ May have a volume control to increase output

▫ May also use lights to provide a visual cue

ALD/HATS: Telephones (cont’d)

▫ Severe to profound hearing losses

May not be able to use amplified telephone
A t-coil may not provide enough amplification
Use of a teletype device may be implemented
Referred to as a text telephone (TT)
Can only text other users of TT
Must use a relay system when calling individuals without a TT phone

ALD/HATS

• Alerting/Signaling Devices

▫ Use vibration, lights or an increased amplified sound

▫ Alarm clocks: vibration device in pillow, lights connected to device to provide a visual

▫ Smoke Alarms: include a strobe light etc. for visual cues

10/02/2024

Cochlear Implants (part 1)

3 Companies approved by the FDA to manufacture and sell CIs

• Cochlear

• Advanced Bionics

• MED-EL

Cochlear Implants: History

• Cochlear was first implant in 1985 used in America (Nucleus 22)

1990: for children (2-17 yrs..)
1998: Nucleus 24 for 18 month children
1998: Nucleus 24 Contour for 12 month old kids

• Adv. Bionics was 2nd in 1996 (Clarion)

1997: children 2-17 yrs. old

2003: HiRes 90K for 12 month olds

• Med-El in 2001 for 12 months to adult

1. external speech processor captures sound and converts to digital signal

2. processor sends signals to internal implant

3. internal implant converts signals into electrical energy and sends it to electrode array

4. electrodes stimulate 8th nerve and the brain perceives it as sound

How it works: BTE

• microphone, receiver and transmitter coil

Transmitter coil adheres to the head via a magnet
Microphone picks up sound waves and converts to electrical signal; sends it to the external speech processor
Speech processor codes it and send it to the transmitter coil

How it works (cont’d)

Coil sends info through the skin via FM radio waves to internal receiver
Internal receiver sends the information to the implanted electrodes
Electrodes stimulate Auditory nerve (8th)
8th nerve sends info to the brain

- The entire process happens within microseconds

Cochlear “N5” Body Worn

• Implant team

Parent/Patient
ORL/ENT: medical decisions and surgery
Audiologist: determines audiologic candidacy and programs the speech processor
SLP: performs rehabilitation process
Psychologist: mental assessment
Teachers: classroom management/IEP
Social workers: ensure follow-up and proper care

CIs: Pre-Operative Assessment

• Medical evaluation

• CT scan/MRI

• Vestibular testing (optional)

• Counseling

Set realistic expectations
Device counseling

CIs: Pre-Operative Assessment

Meets the candidacy criteria
Non-audiologic candidacy factors
Ear(s) to implant
Assess patient expectations and counsel on potential benefits
Build a positive rapport with the patient and family

Pre-Operative Assessment (Adults)

Audiologic Assessments

• Unaided and aided testing

Assessment of hearing aid function

Is patient using an optimal hearing aid?
Rear ear probe microphone measures

• ABR/ECoG/OAEs (optional)

• Aided speech perception testing

CI detection thresholds are typically between 20-35 dB HL.
If hearing aid thresholds are poorer than 35 dB HL, it is very likely that detection can be improved with a cochlear implant.

Cochlear Implants: Candidacy (Adults)

• Moderate to Profound, Bilateral Sensorineural Hearing Loss

PTA > 70 dB in both ears

• Limited benefit from hearing aids : Sentence score < 50% in the ear to be implanted

• Healthy adult over 18 years of age

• Postlingual onset of deafness (after age 6 yrs..)

Candidacy: Adults

• Moderate-Profound, Bilateral Sensorineural Hearing Loss

• Limited benefit from hearing aids : Sentence score < 50% in the ear to be implanted (< 60% in best-aided condition)

• Healthy adult over 18 years of age

• Pre- or Postlingual onset of deafness (after age 6 yrs.)

CI Candidacy (Pediatric)

•Goal: appropriate candidacy for implantation

Improve of child’s speech perception/production?
Improved quality of life?

• There are specific pediatric candidacy criteria as outlined by the FDA, most centers use these as guidelines

• Plasticity of the auditory system appears to decline rapidly after about 6 years of life

CI Candidacy (Pediatric)

• Words like “benefit” and “success” are hard to quantify and mean different things to different people. Here are some examples of success as defined by parents of potential implantees:

Environmental sound awareness: ability to hear warning sirens
Talking on the phone
Being mainstreamed in school
Ability to hear parent say ”I love you”
High speech perception scores
Increased independence
Able to order a burger in McDonalds
Ability to speak intelligibly

CI Candidacy (Pediatric)

Assessment:

• Detailed case history: medical and otological history, communication, educational and psycho- social factors

Important factors include age @ onset of HL, duration of deafness, etiology, health history, family support, etc.

• Audiological assessment: to determine degree and type of hearing loss and amount of functional benefit from acoustic amplification

• Medical, otological and radiological examination

CT Scan is standard, but MRI is becoming more common.

Audiological Assessment

•Auditory Brainstem Response

•ECochG/Otoacoustic Emissions

•Tympanometry

• Hearing Aid Assessment

• Behavioral Audiometry

Unaided (left and right)
Aided (binaural and if

possible left and right)

• Speech Perception Testing

Appropriate materials selected according to child’s level of listening and linguistic development

CI Candidacy (Pediatric)

• 12 months – 2 years of age

• Profound bilateral SNHL (> 90 dB HL)

• Trial with hearing aids (at least 3 months)

Trial waved if x-rays indicate ossification of the cochlea

• Little/no benefit from hearing aids

Children < 4 years of age: failure to reach developmentally appropriate milestones (NR to name or environmental sounds)
Children > 4 years of age: score of < 12% on a difficult open- set word recognition test or < 30% on an open- set sentence test.

•2 years – 17 years of age

•Severe to Profound bilateral SNHL

• Trial with hearing aids (at least 3 months)

Trial waived if x-rays indicate ossification of the cochlea

• Little/no benefit from hearing aids

Children < 4 years of age: failure to reach developmentally appropriate milestones (NR to name or environmental sounds)

Children > 4 years of age: score of < 12% on a difficult open- set word recognition test or < 30% on an open- set sentence test.

Candidacy (Pediatric)

Assessment:

• Speech, language and listening development

Most important variable

• Cognitive and general development

PET Scan

• Psycho-social assessment/child’s motivation

• Parental expectations and motivation

CI Candidacy (Pediatric)

• 0 – 24 months of age:

Parent Questionnaires: IT-MAIS, Agnes Ling Schedule of development in audition, speech, language

• 2 – 4 years of age: (Live Voice presentation)

Questionnaire: IT-MAIS/MAIS
Closed set: ESP, TAC, Ling 6, Mr Potato Head, PSI
Open set: MLNT, LNT, PB-K, GASP, HINT-C

• 5+ years of age: (Taped presentation)

Questionnaire: MAIS
Closed set: ESP, TAC, Ling 6, PSI
Open set: MLNT, LNT, PB-K, GASP, HINT-C

Cochlear Implants

•Deaf Culture and CIs

May resent CIs due to trying to “fix” the child

-Foot binding in China

Decided parents have the right to choose
Want all communication options presented to families
Stated that young prelingually deaf kids don’t have the auditory foundation to learn spoken language ****Not research based****

Treatment Plans

• Surgery

Incision behind the ear
Drills a small hole in the mastoid

- Insertion of receiver stimulator and electrode array

Array is threaded through mastoid area and middle ear cavity
Array is inserted into the round window of the cochlea

- Around 30mm insertion depth

- Surgery takes around 1-3 hours on outpatient basis

- Patient must wait 3-6 weeks to allow for incision to heal and let the swelling subside for better impedances

Treatment Plans

• “Hook Up” (aka initial fitting)

Lasts 1 ½ to 2 hours
Audiologist program the speech processor
Telemetry: aids in testing the integrity of the internal device

- Sends signal from processor to internal device

- Internal device resends info to external processor and to the computer for analysis

•Hook Up (cont’d)

Telemetry

- Provides impedance measures

-Diagnostic assessment of internal device

-When electrodes are found to be out of compliance, they are deactivated and will not be programmed

Telemetry

• Electrode Impedance: is a measure of the opposition of electrical current flow across the electrode.

This test is performed at the start of each programming session.
A small amount of current is delivered to each electrode and a measurement is made of how much current returns to the indifferent electrode.
Normal: 1 to 20-30 kOhms
Electrodes with abnormal impedance values are disabled

10/09/2024

Cochlear Implants (part 2)

Cochlear Implants

• MAP: a cochlear implant program that encodes the acoustic signal and

translates it into electrical stimulation levels based on the measured T and C levels

Hearing aid “programs”

Cochlear Implants: Mapping

• T-level: Minimal amount of electrical stimulation a patient can detect. Similar to the audiometric threshold.

• C or M level (MCL): Maximum amount of electrical stimulation that is comfortable (or most comfortable) or loud but comfortable.

These measures are obtained for stimulation of channels across the electrode array.

• Interpolation: Predicting programming levels for unmeasured channels based on measures made on adjacent channels.

C Levels

• Obtaining C levels in kids is a difficult task due to obvious reporting issues

• Neural Response Telemetry (NRT): provides a general estimation of “upper” levels by using evoked potentials to sample and record nerve responses generated by

electrical stimulation

Great for estimating thresholds for younger kids and difficult to test patients

Allows us to avoid over stimulating the patient with loud sounds

(T level- is the minimum sound that the cochlea can hear)

(M level- is the maximum sound.)

(C level- most comfortable sound.)

(6 is the most comfortable to listen for a long time)

Cochlear Implant: Mapping

• After T and C levels are established and the MAP is created, the mic is

turned on to provide acoustical stimulation to the patient

• During mapping the mic is turned off to allow the patient to focus on the

presented tones to obtain T and C levels

Also allows us to avoid making speech and loud sounds sound distorted or overwhelming

•After the mic is turned on

Voices may sound robotic, cartoon like, hollow, mechanical, etc.
Initially only 1 program
Parents shown how to check the system and troubleshoot
Remind them about acclimatization periods
Electrostatic Discharge (ESD): not as much of a problem in current units due to increased shielding of the implant/processor

10/14/2024:

nvisible link to batter heating

• Cochlear Baha 4 Attract system offers:

No skin penetration.
A leap in hearing performance.
Unique Baha softwear pad for wearing comfort and reliable retention.
Straightforward surgical procedure.
Options for a lifetime of better hearing.

(Compared to existing magnetic bone conduction implant system)

No skin penetration.

Discreet and cosmetically appealing.
No daily wound care.
Reduced the risk for infections and trauma.

Baha system candidacy criteria

•Types of hearing loss treated with the Baha system

Conductive hearing loss.
Mixed hearing loss.
Single-sided deafness.

• Indication for use

< 5 Years of age: Softband only.
≥ 5 Years of age: Implantation or Softband.
≤ 65 dB HL BC PTA
mixed/conductive hearing loss, single-sided deafness.

Single-sided deafness (SSD)

•Key indications

One ear: Sensorineural deafness
Other ear: normal (PTA AC threshold ≤ 20 dB HL across .5,1,2, and 3 KhZ)

•Overview

The purpose of the Baha system for SSD is to provide sufficient amplification force to overcome the head transfer function.

•Additional force may be required to:

Overcome large head transfer function
Compensate for SNHL (if loss develops due to aging or some other natural process later in life)

•Impact of SSD

•Common difficulties adults with SSD experience:

Hearing in background noise
Localization
Understanding a person situated on the deaf side

•Common experience of children with unilateral hearing loss:

Speech and language delay
Difficulty paying attention in school
Difficulty hearing in noisy environments
Difficulty localization sounds.

10/16/2024

Cochlear Implants: Mapping

•Follow-up Programming Within one week of the initial activation

Review of patient experiences

•New maps are added into designated programs

•review:

Programs -Questions

Controls

Accessories

Initial booth testing

•Microphone Sensitivity

Determines the gain applied to the input signal, which then determines the C-level.
Increasing: improve detection of low-level sounds, but will also increase delivery of ambient noise levels.
Decreasing: decreases intrusiveness of ambient noise, but also decreases access to soft sounds.

•Volume setting

Adjustment of the volume control adjusts the upper level of stimulation.
Actually adjusting the M-level/C-level
Goal: to set VC to provide comfortable, consistent stimulation

•Frequency Allocation

Determines which frequencies are allocated to what channels.
When electrodes are disabled, frequencies are not lost. The input is just re- allocated to the active electrodes.

•Pediatrics: Initial Stimulation

Prepare the parents for what to expect, pre-empting many of the parents’

questions which arise during programming.

Minimize distractions
Prepare the parent for child’s initial stimulation reactions

Pediatric Set-Up

• The programming room should be child friendly with:

Appropriate pictures at child height
Large selection of appropriate games BUT not so many that they distract the child
Child sized furniture
Hazard limitation e.g. corner covers, plugs
Room for several adults often the entire extended family will turn up for an initial stimulation (some clinics put extra adults in a neighboring observation room to reduce distractions)

• If possible, two persons are needed with small children

one at the computer (audiologist), one engaging the child (another audiologist, therapist, teacher, parent), both watching the child’s face

• To maintain child on task, the second person keeps all the game pieces, handing them one by one to the child as needed

• Child’s chair should be positioned so they cannot see the computer, or it’s reflection

Deaf children are highly tuned to visual cues

• All other people should be kept out of child’s sight-line if possible, since they may distract or give inadvertent clues when stimuli are presented

Pediatric Mapping

• Attempt Sound Awareness Response: to establish the lowest level of electrical stimulation a child can detect.

Initial response is typically supra-threshold

• Initial responses develop a solid conditioned response to electrical stimulation

• Check responses to Live Speech

• Initial Responses

Stilling (pacifier)
Looking up or at parent, audiologist, computer
Seeking reassurance
Touching CI/implant site
Slight body reflexes
Change in play activity
Surprise, pleasure, bewilderment, concern

Conditioning

• Condition response training is crucial for the response you need for programming

Loudness range training
Quality judgments

• Training should begin immediately

Therapists, parent and teacher involvement
Can begin even prior to initial stimulation in some cases

SOUNDS ARE TOO LOUD WHEN:

More active/aggressive play
Tension behaviors - twisting clothes, toys, fingers Body tensing, shoulder stiffening
Getting hot/red face, bothered, reddening
Eye blinking in response to stimuli /ba/ba/= blink/blink/
Distress, tears, lip wobbling
Seek comfort from parents

Verifying Audibility

• Is child responsive to environmental

sounds?

• Is a child responsive to speech sounds?

Ask parents to keep a log/diary
Advise parents to point out all sounds in the child’s environment
Keep in touch with child’s teachers and providers

Pediatrics: Verifying Audibility

• Parent Report

Is the child compliant/resistant to the implant?
Do they try to put the CI back on when it’s off?
How much do they wear it?
React to some sounds more than others, and if so, what sounds?

Do they persistently turn volume up or down?