Download Behavioral Testing

Behavioral Testing;
Hearing Aid Selection
and Fitting
AG Bell/MUSC OTO-HNS Conference
October 18, 2013
Kimberly Astrid Orr, Au.D., CCC-A
Director of Audiology
Medical University of South Carolina
Department of Otolaryngology, Head and Neck Surgery
Charleston, S.C.
What is a Behavioral Test?
 A test requiring the participant to reliably demonstrate a
change in behavior when a sound is heard. Goal is to
determine the lowest (softest) intensity level (threshold)
at which a child can detect a sound at specific frequencies.
 Techniques utilized in behavioral testing are selected
based upon the child’s developmental level.
Behavioral Test Techniques
 Behavioral Observation Audiometry (BOA)
 Used when testing infants ≤ 5 months of age or for those
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functioning at a developmental age of ≤ 5 months.
Not used for diagnosis of hearing loss.
Unconditioned responses consist of startle, eye widening,
sucking or cessation of sucking, etc.
Results can be examiner biased.
Levels reported are “minimum response levels”.
Visual Reinforcement Audiometry
(VRA)
 Technique used to obtain behavioral audiometric
thresholds from children who function at at 6 month
through 30 month old developmental level.
 Operant conditioning task in which the child is trained to
look for an auditory stimulus and is reinforced with flashing
lights/animated toy.
 Can be used in sound field, under headphones, with insert
earphones or bone oscillator.
 Results should correlate with ABR predicted thresholds.
VRA Demo
Conditioned Play Audiometry (CPA)
 Used to obtain behavioral thresholds from children who
function at the 2.5 through 5 year old developmental level.
 Child is engaged in a play-oriented activity and trained to perform a
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task such as stacking rings, dropping blocks, placing pegs etc, in
response to an auditory stimuli.
Testing performed under headphones, insert earphones, in sound
field or through bone oscillator.
Speech awareness testing may also be completed using this
method.
Language is never a barrier, as there are no verbal directions.
Degree of hearing loss should not be an issue. If child does not
respond, attempt conditioning using vibrotactile stimulation.
Conventional Hand Raising
 Method used to establish pure-tone thresholds from
children who have a developmental age of ≥ 5 years of age.
 Can be less engaging to those < 7 years, so if fatigue or
reliability is an issue, try implementing CPA techniques.
 Remember….just because a child can raise their hand in
response to a stimulus like an adult, they are NOT adults.
 Children require consistent and positive
feedback during testing.
Speech Audiometry
 For infants ≤ developmental age of 2 years, speech
awareness thresholds (SAT) can be obtained via air and
bone conduction stimuli.
 SAT is often obtained at slightly lower thresholds
(5- 10 dB) than frequency specific pure tone thresholds, as
speech stimuli can be more interesting and meaningful to
a child.
Speech Audiometry Continued
 Speech reception thresholds (SRT) can be obtained from
young children by having them point to body parts or
spondees on a picture board, after they have been
familiarized to the test stimuli. SRT can be obtained via
air or bone conduction transducers.
 Word recognition scores (WRS) is not usually attempted
until at least a developmental age of 3 years. If pictures
are used, child must know the vocabulary. If task is to
repeat words orally, articulation must be good.
 It is far more important to obtain accurate pure tone
thresholds prior to attempting word recognition testing.
Physiological Test Components
Acoustic Immitance
 Tympanometry and acoustic reflex thresholds are most
common.
 Used to assess middle ear function.
 Used to evaluate acoustic reflex pathways, which include
cranial nerves VII and VIII and the auditory brainstem.
 Is the measurement of energy or air pressure flow, which
involves the ear canal, eardrum, ossicular chain, tensor
tympani, stapedius muscle, cochlea, CNs VII and VIII and the
brainstem.
Physiological Test Components
 Otoacoustic Emissions (OAEs)
 OAEs are low-level sounds generated by the outer hair cells of
the cochlea in response to auditory stimuli.
 Present in nearly all normal hearing ears.
 Absent in ears with hearing loss and/or middle ear pathology.
 OAEs are often PRESENT in infants with auditory
neuropathy/dyssynchrony.
Auditory Brainstem Response
 Neurologic test of auditory function in response to auditory
stimuli.
 It is an evoked potential generated by a brief click or tone
transmitted from an acoustic transducer.
 It is measured via surface electrodes (one on forehead and one
on each mastoid).
 Produces identifiable waveforms plotted in amplitude
(microvolts) versus time (milliseconds)
 Waveform components include waves I, II, III, IV and V. V is
most commonly analyzed in clinical applications of ABR.
 Used to provide information regarding auditory function and
hearing sensitivity. Should be used in conjunction with
behavioral audiometry, if possible.
Types of Hearing Loss
 Conductive (CHL)
 Occurs when sound is not conducted efficiently through the
outer ear canal to the tympanic membrane and the ossicles
of the middle ear.
 Hearing loss can often be medically or surgically corrected.
 Examples: fluid/infection in the middle ear, poor eustachian
tube function, perforation of the TM, tumor in outer or
middle ear (cholesteatoma), impacted cerumen, presence of
foreign body, microtia or atresia, ossicular fixation or
malformation.
Types of Hearing Loss Continued
 Sensorineural (SNHL)
 Occurs when there is damage to the cochlea or to the VIII
nerve pathways or from the inner ear (retrocochlear) to
the brain.
 Cannot be medically or surgically corrected.
 Permanent, but not necessarily stable.
 In addition to making sounds appear soft, SNHL also affects
both speech understanding or the ability to hear clearly.
 Can be caused by: birth injury, ototoxic drugs, genetic
syndromes, diseases, noise exposure, viruses, head trauma,
aging, tumors and congenital malformations.
Types of Hearing Loss Continued
 Mixed
 Combination of CHL and SNHL.
 Transient CHL issues are treated more aggressively in
children with underlying SNHL.
Types of Hearing Loss Continued
 Auditory Neuropathy Spectrum Disorder (ANSD)
 Disorder characterized by evidence of normal cochlear
outer hair cell function and abnormal auditory nerve
function
 Children should be fit with amplification when reliable,
stable hearing thresholds are determined.
 Children should be considered for cochlear implantation if
not making progress in language development regardless
of behavioral pure-tone thresholds.
Degrees of Hearing Loss
Diagnosis of Hearing Loss
 Referral to ENT for Otologic workup
 Offer referal for genetics
 Offer referral for opthalmology
 Referral to speech pathology
 Possible referral for developmental evaluation
 Referral to Babynet for Early Intervention services for
those from 0 months to 30 months
 Referral to public schools for 31 months to 5 years
Habilitation/Rehabilitation
 Hearing aids
 Fit only after comprehensive medical evaluation and workup.
 Medical clearance is required by FDA for those less than 18.
 Behind-The-Ear
 Bone conduction, including BAHA
 Early intervention
 Babynet
 SCSDB
 Beginnings
 Speech therapy
 AVT
Candidacy for Amplification
 Children with aidable unilateral hearing loss , including good WRS in
affected ear.
 Children with severe/profound unilateral hearing loss (CROS or bone
conduction devices can be considered, not traditional HA).
 Children with minimal or mild sensorineural hearing loss.
 Children with ANSD who have reliable, behavioral audiograms
consistent with hearing loss.
 Children with permanent conductive hearing loss.
 Children considered for cochlear implantation should have a trial with
amplification prior to CI surgery.
Hearing Aid Considerations
 Good quality amplification which when programmed
appropriately allows for maximized audition while keeping
amplified sounds comfortable and safe for the user.
 Flexible in programming to accommodate fluctuating or
progressive hearing loss.
 Compatible with direct audio input.
 Durable units with moisture protection and locking
mechanisms.
Signal Processing and Features
 Compression: input levels should be compressed sufficiently to
accommodate sensitivity to loud sounds while allowing low
level speech audibility.
 Channels: number of software channels/bands that can be
manipulated for sufficient frequency shaping to meet the needs
of the audiometric configuration.
 Frequency compression: compresses selected high frequency
sounds into a lower frequency range where both hearing
sensitivity and discrimination ability are better.
 Feedback suppression
 Directional microphones
 Digital noise reduction circuitry
Verification Measures
 Use of evidence based prescriptive methods: typically DSL
(Desired Sensation Level) for children.
 For children, there are two options
1. Real-ear aided probe microphone measurements: output of
the hearing aid is measured in the child’s ear at a variety of
input levels, including speech-like stimuli and maximum
power output.
2. Simulated real-ear aided response measurements in the
coupler using measured or age-appropriate real-ear to
coupler difference (RECD) using a variety of input levels,
including speech-like stimuli and maximum power output.
Functional Gain
 Aided thresholds determined in the sound field while the child is
wearing the hearing aids, compared to the unaided thresholds.
 Word recognition testing in the presence of speech noise is
often utilized.
 Provides helpful information regarding frequency transposition
/compression hearing aids.
 Potential errors secondary to interaction with input stimulus
and hearing aid signal processing.
 Parents, teachers and therapists value the aided audiogram.
Audiologists should use these in addition to verification
measures.
Management and Follow-up
 Hearing impaired children require on-going audiologic
evaluation and management/adjustment of amplification to
ensure consistent audibility over time.
 Managing audiologist should ensure proper medical referrals.
 Managing audiologist should ensure proper referrals to early
intervention and schools.
 Managing audiologist should provide resources for financial
support and funding to aid in offset of amplification fees.
 Managing audiologist should offer parent-to-parent support for
families and caregivers with hearing impaired children.
Team Approach
 The diagnosis and management of hearing loss in children
in an ongoing and collaborative effort among the
otolaryngologist, audiologist, primary care physician,
educational personnel/early interventionist, speechlanguage pathologist and the family.
The End