Transcript South Carolina - National Center for Hearing Assessment and

Diagnostic Pediatric Audiology
from Birth to Intervention
Karen M. Ditty, M.S.
NCHAM
Antonia Brancia Maxon, Ph.D.
NECHEAR
NCHAM
Timely and Appropriate Diagnosis of
Hearing Loss

Newborns screened by 1 month

Infants with hearing loss diagnosed by 3
months

Amplification use begins within 1 month
of diagnosis
Benchmarks (JCIH, 2000)
Timely and Appropriate Diagnosis of
Hearing Loss

Infants enrolled in family-centered early
intervention by 6 months

Ongoing audiological management - not
to exceed 3 month intervals

Professionals working with these infants
are knowledgeable about all aspects
Benchmarks (JCIH, 2000)
Newborns screened by 1 month

Approximately 90% of
all newborns in the
United States have
their hearing screened
at birth

The number of infants
referred for diagnostic
audiological evaluations
has dramatically
increased .
Infants with hearing loss
diagnosed by 3 months

Progress has been made however it is affected
by
» Testing site may influence age of diagnosis
– Goal is often met in hospital clinics
– Less likely in non-hospital centers

Geographic access to services may influence
age of diagnosis
» Rural communities are less likely to meet the goal
Impediments to Lowering
Diagnostic Age

Audiologists lack experience with very young
infants
» uncomfortable making the final diagnosis.
» Defer to and refer for second opinion

Facilities do not have the equipment needed to
assess very young infants.
» Frequency specific ABR
» AC and BC ABR
» High frequency tympanometry
Impediments to Lowering
Diagnostic Age

Audiologists are not familiar with clinical
protocols necessary for making accurate
diagnosis with very young infants.
» Do not have “norms”
» Cannot “read” ABR for this population

Inadequate number of audiologists with pediatric
expertise
» No academic training to work with very young
infants
» No clinical training to work with very young infants
Aids to Lowering the Age of
Diagnosis

Although there are no national protocols or
standards many states have guidelines for their
audiologists.
» These guidelines can be obtained via the
following link on the NCHAM website
http://www.infanthearing.org/states/table.html
Aids to Lowering the Age of
Diagnosis

Audiologists can get training through continuing
education provided by national associations

NCHAM audiology training
» Pediatric Diagnostics
–Covers the initial diagnostic procedure
» Pediatric Amplification Fitting
–Covers behavioral assessment, hearing aid
selection, fitting and validation and cochlear implants
Pediatric Audiologist

Have the appropriate audiological equipment and
protocols for testing newborns and young infants.

Can evaluate a child’s hearing within a short period
of time after being contacted for an appointment.

Specializes in working with infants and young
children.

Wants to work with infants and young children.

Has worked with Part C program in their state
Pediatric Audiologist

Is familiar with the procedures of the Part C system,
including IFSP development and procedures for
acquiring hearing aids or assistive technology.

If dispenses hearing aids:
» can make earmolds,
» has loaner hearing aids available
» provides hearing aids on a trial basis
» has resources to repair hearing aids quickly
Pediatric Audiologist

Is willing to review the test results of the audiological
evaluation face to face with the family, respecting
the Cultural Differences of family units.

Is willing to provide a comprehensive written report
with a copy of the test findings in a timely manner.

Is willing to continue to explain results at follow-up
evaluations
Pediatric Diagnostic Test Battery

Comprehensive Case History

Frequency-Specific Auditory Brainstem Response

High Frequency Probe Tone Tympanometry

Transient and/or Distortion Product Otoacoustic
Emissions

Hearing aid Fitting with Real Ear Measurements

Behavioral Audiometry

Referrals
Comprehensive Case History
Frequency Specific Auditory
Brainstem Response

Air Conduction Clicks
» Abrupt or rapid onset of a broad frequency
bandwidth .
» Greatest agreement in the 2000-4000Hz
frequency range.
» Not enough information across the frequency
range
– Low frequencies absent
Frequency Specific Auditory
Brainstem Response

Tonebursts
» Provides information for narrower frequency
regions
» Better relates to pure tone audiogram

Bone-Conducted Clicks
» Should get when either the click or 500-Hz
tonebursts responses are not present at
expected normal levels.
Frequency-Specific ABR
Accuracy of pure tone threshold estimates with tone
burst ABR

High correlation (>.94) for infants and older
children (Stapells, et al, 1995)

90% of ABR thresholds within 20 dB of PT
thresholds with most within 10 dB

audiometric configuration does not affect
accuracy of match (Oates and Stapells, 1998)
Frequency Specific Auditory
Brainstem Response

Auditory Steady State Response (ASSR)
» An electrophysiologic response, similar to
ABR
» Generated by rapid modulation of “carrier”
pure tone amplitude or frequency.
» Signal intensity can be as high as 120 dB
Frequency Specific Auditory
Brainstem Response

Auditory Steady State Response (ASSR)
» Done in conjunction with ABR Clicks, or
on a separate occasions
» Major advantage is it estimates severe-toprofound HL
» Best used in conjunction with ABR and
tone burst testing.
ABR (Click and Tone Burst) versus
ASSR: Clinical Application
ABR
ASSR
Advantages
Disadvantages
•Estimates normal hearing
•Can’t estimate profound HL
•Skilled analysis required
•Limited BC intensity levels
thresholds
•Ear-specific BC findings
•Diagnosis of AN
•Estimates severe to
profound HL
•No ear-specific BC findings
•Requires sleep or sedation
R. Ruth, 2003
Pediatric Sedation for ABR



Who and When
» 4 months to 5 years
Options
» conscious sedative
» mild general anesthesia
Monitoring
» administered and managed by nurse
– monitor O2, HR and BP
– crash cart and suction available
(J. Hall, 2001)
Pediatric Sedation for ABR

Negative outcomes associated with
» overdoses, drug interactions
» non-trained personnel
» injuries on the way to facility (administered at
home)
» drugs with long half-lives (chloral hydrate,
pentobarbital)
(J. Hall, 2001)
Pediatric ABR summary

Air conduction measures should be done with
insert earphones
» Headphones can affect latency of waveform

Bone conduction measures are needed to rule
out conductive loss or find conductive
component.
» Use B-70 bone vibrator
» Use mastoid placement
Pediatric ABR summary

Use earlobe inverting electrodes

Use alternating tone burst to minimize artifact

A slower rate (e.g., 11.1/sec) enhances Wave I

Begin testing near maximum intensity (50 dB
nHL)
» Allows good waveform to be seen

Identify Wave I in ipsilateral ear to verify test ear

Plot I-L function of Wave V
Pediatric ABR summary

Air conduction measures should include
frequency specific tone bursts and/or ASSR as
part of a battery of electrophysiological tests.

Of the audiological test battery, only an ABR can
help determine an auditory neuropathy case;
therefore, ASSR should not be performed alone,
but as part of a battery of electrophysiological
tests.
High Frequency Probe Tone
Tympanometry

Tympanometry provides information about middle
ear status
» add information to BC results

May be affected by conditions in very young
infant’s ears
» Ear canal and eardrum are very compliant

Use of high frequency probe tone (800 Hz or
greater) increases reliability and accuracy in
young infants.
Transient & Distortion Product
Otoacoustic Emissions

Infants and young children with normal hearing
have robust
» transient evoked otoacoustic emissions
(TEOAE)
» distortion product otoacoustic emissions
(DPOAE)

TEOAEs and DPOAEs are easily measured in
infants and children.
Middle Ear Effects on OAEs

Middle ear effusion may
» obliterate emission
» eliminate low frequency component

Negative middle ear pressure may
» reduce amplitude, particularly in high
frequencies
OAE Summary
● OAEs are objective evidence of healthy cochlear
function
● The vast majority of hearing impairment in the low-risk
population is a result of malfunction of the outer hair
cells
- the most sensitive and vulnerable part of the
hearing mechanism tested by OAEs.
● OAEs provide meaningful information when
retrocochlear lesions and/or auditory neuropathy
are a concern.
Amplification Assessment
and Fitting

Initiate amplification process immediately
after diagnosis.

Includes medical clearance
» Federal regulation - ENT

Includes earmolds
» overnight mailing to get within 1 week
» continue to remake to avoid fitting problems
Pediatric amplification fitting

Does not require exhaustive audiological
data
» Target audiogram
» Individual ear information

Ability to conduct real-ear measures

Scheduling flexibility and immediacy

Experience with functional measures of
benefit
Real Ear to Coupler Difference
Procedure (RECD)

The infant ear is smaller than an adult ear
» More SPL for same input compared to adult
» Differences can be as large as 15-20 dB
» Many hearing-aid fitting algorithms do not take these
differences into account.

RECD affects estimates of
» Threshold
» Real-ear gain and output
Real ear measurement
•The insert phone is coupled to the earmold
•The probe microphone is placed into the ear canal
•The earmold is inserted into the ear
•Test stimulus is presented
•Total test time 5-10 minutes per ear
RECD

After the RECD is obtained, all hearing aid
testing can be done in the test box

RECD values are entered into the hearing
aid fitting program to provide a more
accurate estimate of real-ear aided gain
and output

The RECD will change as the child grows.
A good rule of thumb is to obtain a new
RECD when a new earmold is needed
Basic Audiological Information
Used to Fit Amplification

Hearing Sensitivity
» ABR frequency specific information low, mid and high frequency
» Individual ear measures: insert phones

Middle Ear Status
» Tympanometry - high frequency
» BC to rule out conductive loss
Basic Audiological Information
Used to Fit Amplification

Cochlear status
» ABR intensity-latency function
» OAEs

Behavioral Responses
» target audiogram
» speech awareness
Behavioral Response
Audiometry

Provides information about how an infant or
young child uses hearing

Behavioral observation techniques can be used
to give functional information
» Sometimes only suprathreshold information
is obtained
» will get better responses to speech than
tones

Can look at amplification benefit
Behavioral Response
Audiometry

Look at amplification benefit

Need to provide speech at greater than detection
level
» Cannot learn language with threshold-only
information
» All of normal conversational level speech needs to
reach child through amplification
Speech Sounds

Range from softest to loudest speech sound =
30 dB
» “th” – “ah”

Low frequencies carry suprasegmental, vowel,
and voicing information.

High frequencies carry consonant, perceptual,
and syntactic cues.
Referral to and Enrollment in
Early Intervention

Know established Part C guidelines in state

Know child eligibility criteria
» automatic enrollment - diagnosed condition
» significant developmental delay

Know state guidelines for selecting a program
Enrollment in Early Intervention

Develop Individualized Family Service Plan
(IFSP)
» All services
– speech and language development
– auditory development
– assistive technology
» Goals and objectives
» Timelines
Components of IFSP for I/T with
Hearing Loss





Amplification provision
Parent education
Audiological monitoring
Development of auditory skills
Communication development
» listening skills - speech perception
» speech production
» language development

Monitoring middle ear status
Status of EHDI Programs
Early Intervention

Many of the programs in the current system
designed to serve infants with bilateral
severe-profound losses

BUT, majority of those identified have mild,
moderate, and unilateral losses
» Programs and professionals not appropriate for
children and families
» Therefore, Part C of IDEA is severely under
utilized
Status of EHDI Programs
Early Intervention

State Coordinators estimate
» Only 53% of infants with hearing loss are enrolled in
EI programs before 6 months of age
» Only 31% of states have adequate range of
choices for EI programs
Barriers to Early Intervention
● 30-40% of children with hearing loss demonstrate
additional disabilities that may affect communication
and related development.
● Families who live in under-served areas may have
less accessibility, fewer professional resources, deaf or
hard of hearing role models, or sign language
interpreters available to assist them.
● A growing number of children with hearing loss in the
United States are from families that are non-native
English Speaking.
JCIH, 2000
Pediatric Audiology
• Pediatric Audiology
with newborns and
young infants can
be challenging!
Pediatric Audiology

But also rewarding!
Some babies are born listeners..
•If we
•use the elements of an
effective EHDI program
•use the JCIH 2000
Benchmarks
•use appropriate
diagnostic protocols and
procedures
•refer to early intervention
•are active participants in
early intervention