Early Intervention of Children identified with Auditory Neuropathy Karen M. Ditty, Au.D. 1,2 Sharon...

Early Intervention of Children identified with Auditory Neuropathy

Karen M. Ditty, Au.D. Karen M. Ditty, Au.D. 1,21,2

Sharon M. Parham, M.S.Sharon M. Parham, M.S.33

National Center for Hearing Assessment and ManagementNational Center for Hearing Assessment and ManagementLogan, UTLogan, UT11

Texas ENT Specialists, PATexas ENT Specialists, PAHouston, TXHouston, TX22

Northwest Harris County Cooperative for the Hearing ImpairedNorthwest Harris County Cooperative for the Hearing ImpairedHouston, TXHouston, TX33

What is Auditory Neuropathy / Dys-Synchrony (AN / AD)?

Auditory Neuropathy / Dys-synchronyAuditory Neuropathy / Dys-synchrony

http://www.medschool.lsuhsc.edu/Otorhinolaryngology/deafness_article1.asphttp://www.medschool.lsuhsc.edu/Otorhinolaryngology/deafness_article1.asp

Auditory Neuropathy / Dys-synchrony is a term used to describe a condition found in some patients ranging in age from infants to adults.Characteristics are:

•Normal outer hair cell function (Normal Otoacoustic Emissions)•Abnormal neural function at the level of the VIIIth

nerve abnormal Auditory Brainstem Response test (ABR)

In other words….

• Is a hearing disorder in which sound comes in to the inner ear normally, but the conduction of the signals from the inner ear to the brain are impaired

• May involve damage to the inner hair cells or may be due to faulty links between the inner hair cells and the nerve leading from the inner ear to the brain

Possible sites of Auditory Possible sites of Auditory Neuropathy / Dys-synchronyNeuropathy / Dys-synchrony

http://www.medschool.lsuhsc.edu/Otorhinolaryngology/deafness_article1.asphttp://www.medschool.lsuhsc.edu/Otorhinolaryngology/deafness_article1.asp

•Inner hair cellsInner hair cells•Tectorial membraneTectorial membrane•Synaptic juncture between the inner hair cellsSynaptic juncture between the inner hair cells•Auditory neurons in the spiral ganglion, Auditory neurons in the spiral ganglion, •VIIIth nerve fibers, or any combination above VIIIth nerve fibers, or any combination above (Starr et al., 1996; Berlin et al., 1998)(Starr et al., 1996; Berlin et al., 1998)•Neural problems may be axonal or demyelination.Neural problems may be axonal or demyelination.•Afferent as well as efferent pathways may be Afferent as well as efferent pathways may be involved.involved.

Pathway for HearingPathway for Hearing

from "Promenade around the cochlea" EDU website www.cochlea.org by Rémy Pujol et al., INSERM and University

http://www.cochlea.org/

What Causes Auditory Neuropathy / Dys-Synchrony?

Possible etiologies of Auditory Possible etiologies of Auditory Neuropathy / Dys-synchronyNeuropathy / Dys-synchrony

• Hyperbilirubinemia (Jaundice)12-16 cc/dlHyperbilirubinemia (Jaundice)12-16 cc/dl, (probably #1)(probably #1)• Neurodegenerative diseases, e.g., Neurodegenerative diseases, e.g.,

FriedReich's ataxiaFriedReich's ataxia• Neurometabolic diseasesNeurometabolic diseases• Hereditary motor sensory neuropathies:Hereditary motor sensory neuropathies:

e.g.: Charcot-Marie-Tooth syndromee.g.: Charcot-Marie-Tooth syndrome• Demyelinating diseases Demyelinating diseases • Inflammatory neuropathiesInflammatory neuropathies

Possible Etiologies of Auditory Neuropathy / Dys-synchrony continued

• Ischemic/hypoxic neuropathyIschemic/hypoxic neuropathy • HydrocephalusHydrocephalus• Abnormality with neurotransmitter release• Cerebral palsyCerebral palsy• Infectious disease such as mumps• Immune Disorders• Severe developmental delaySevere developmental delay

What does auditory neuropathy /

dys-synchrony (AN / AD) sound like?

Computer simulation of what Auditory Neuropathy / Dys-Synchrony may sound like

Funding agency: National Institutes of Health (DC02618)PI: Arnold Starr; Co-investigator: Fan-Gang Zeng

Developed speech waveforms based on simulations of different degrees of Auditory Neuropathy / Dys-synchrony

“Communication difficulties in individuals with auditory neuropathy / dys-synchrony, even with mild hearing loss are more severe than individuals with cochlear hearing loss of 60dB HL or more.” Kumar, et al

http://darwin.bio.uci.edu/neurobio/Faculty/Starr/starr.htm

Study Findings• Intensity processing is not significantly affected by

AN/AD• Frequency discrimination is significantly affected at

low frequencies but not high frequencies• Temporal processing deficits in AN/AD provide

direct evidence for an important role of neural synchrony in auditory perception

• Data accounts for the speech recognition deficit that is disproportional to pure tone hearing loss



Study Findings continued:

• Patients can perceive sound and usually have normal cortical potentials and negative brain imaging results

• New Hearing aids that accentuate the temporal envelope or cochlear implants that produce highly synchronous neural activity may be more effective than the conventional hearing aids in the clinical management of AN / AD



Study Findings continued:

• Real time DSP technology should be able to implement such an envelope expansion algorithm and may help solve the “I can hear but do not understand problem”



Are all Auditory Neuropathy / Dys-synchrony infants the same?

• Clearly NOT!There are large individual differences – Hearing may improve over time (most commonly

seen when the cause is hyperbilirubinemia)– Hearing may stay the same– Hearing may get worse and show signs that the outer

hair cells no longer function (OAE’s become absent)– Hearing loss may fluctuate over time (periods of

“good hearing” and other times function as deaf)

Patient Variation continued:

• Some have clear hereditary sensory-motor neuropathy.• Some have less apparent neuropathy that is only

evident on clinical exam.• Some demonstrate no signs of neuropathy other than

the auditory findings.• Some have unilateral auditory neuropathy• Some have temperature sensitive AN/AD• Some show a familial tendency which may suggest

genetic causes. Hood Hood

(2002)(2002)

Are there really that many kids with Auditory Neuropathy?

• 10% of children seen with severe-to-profound deafness may have a neural rather than a hair cell disorder (Kraus et al., 1984; Rance et al., 1999)

• 1 in 183 of persons with Sensory neural hearing loss (.005) have AN based on a retrospective review of cases in India (Kumar & Jayaram, 2006)

• There appears to be an equal distribution of male (55%) and female (45%) with AN (Sininger / Starr 2001)

• 27% of AN patients have no associated medical conditions or family history before age 2 (Sininger/Star 20001)

• 80% had either family or neonatal risk factors

How are individuals with Auditory Neuropathy / Dys-Synchrony

Distinguished from individuals with Auditory Processing ?

Characteristics are similar but:SIMILARITIES:

– Poor understanding, even simple sentences in competing noise-despite the fact that they can understand some words or sentences in quiet.

– Learning speech and language through the auditory channel exclusively is very difficult

BUT:– AN/AD refers to a disorder of peripheral portions of the

auditory pathway, between the outer hair cells and brainstem.– Peripheral measures such as Absent Acoustic Reflexes, ABR

abnormalities in the presence of Present OAEs helps to distinguish AN/AD from auditory processing.

Can we predict outcomes for individual infants?

• Until we can clinically distinguish what caused the infant’s AN/AD, it will be difficult to make any predictions on improvement or decline of auditory functioning

• Currently we can only determine changes in auditory ability through long-term follow up

• Research; however, is ongoing!

How do we Audiologically manage infants with Auditory Neuropathy /

Dys-Synchrony?

Audiological Management of Auditory Audiological Management of Auditory Neuropathy / Dys-SynchronyNeuropathy / Dys-Synchrony

• Complete Medical / Case historyComplete Medical / Case history• Otoscopy: Outer Ear and Ear CanalOtoscopy: Outer Ear and Ear Canal• Otoacoustic Emissions testing: Cochlea (outer hair Otoacoustic Emissions testing: Cochlea (outer hair

cells)cells)• Brainstem Response testing: Auditory nervous systemBrainstem Response testing: Auditory nervous system• Behavioral Audiometry: BrainBehavioral Audiometry: Brain• Tympanometry w/ acoustic reflexes: Middle ear and Tympanometry w/ acoustic reflexes: Middle ear and

reflex arcreflex arc

Medical Case History

• ASHA Guidelines for the Audiologic Assessment of children From Birth to 5 years of Age 2004 has a simple, but relatively comprehensive case history that can be obtained from families

• http://www.asha.org/members/deskref-journals/deskref/default

http://www.asha.org/members/deskref-journals/deskref/default

http://www.asha.org/members/deskref-journals/deskref/default

Why is Case History so important?

• Provides information about medical complications prior to birth, during birth and after birth.

• Provides invaluable information regarding risk indicators for progressive or late onset hearing loss .(i.e.: family history of hearing loss)

• Also tells you what type of screen was performed in the hospital and whether a similar re-screen should also be performed.


• Complete Medical / Case historyComplete Medical / Case history• Otoscopy: Outer Ear and Ear CanalOtoscopy: Outer Ear and Ear Canal• Otoacoustic Emissions testing: Cochlea (outer hair Otoacoustic Emissions testing: Cochlea (outer hair

cells)cells)• Brainstem Response testing: Auditory nervous systemBrainstem Response testing: Auditory nervous system• Behavioral Audiometry: BrainBehavioral Audiometry: Brain• Tympanometry w/ acoustic reflexes: Middle ear and Tympanometry w/ acoustic reflexes: Middle ear and

reflex arcreflex arc

Otoacoustic EmissionsOtoacoustic Emissions

• Auditory Neuropathy / Dys-Synchrony (AN/AD) : is Auditory Neuropathy / Dys-Synchrony (AN/AD) : is characterized by robust, or present OAEscharacterized by robust, or present OAEs

Transient OAE resultsTransient OAE results

Distortion Product OAEDistortion Product OAE

•OAEs are objective evidence of healthy cochlear OAEs are objective evidence of healthy cochlear functionfunction . Looks at ‘pre-neural’ response. . Looks at ‘pre-neural’ response.

•The majority of hearing loss in the low-risk The majority of hearing loss in the low-risk population is a result of cochlear/outer hair cell population is a result of cochlear/outer hair cell system malfunction. This is the most sensitive part of system malfunction. This is the most sensitive part of the hearing mechanism tested by OAEs.the hearing mechanism tested by OAEs.

•Auditory neuropathy / dys-synchrony is statistically Auditory neuropathy / dys-synchrony is statistically rarer in the low-risk, well baby population than in the rarer in the low-risk, well baby population than in the special care population,special care population,

OAE SummaryOAE Summary


• Complete Medical / Case historyComplete Medical / Case history• Otoscopy: Outer Ear and Ear CanalOtoscopy: Outer Ear and Ear Canal• Otoacoustic Emissions testing: Cochlea (outer Otoacoustic Emissions testing: Cochlea (outer

hair cells)hair cells)

• Brainstem Response testing: Auditory Brainstem Response testing: Auditory nervous systemnervous system

• Behavioral Audiometry: BrainBehavioral Audiometry: Brain• Tympanometry w/ acoustic reflexes: Middle ear Tympanometry w/ acoustic reflexes: Middle ear

and reflex arcand reflex arc

Auditory Brainstem Response (ABR)Auditory Brainstem Response (ABR)

•An electrophysiological test is An electrophysiological test is used to assess auditory function in used to assess auditory function in infants and young children using infants and young children using electrodes on the head to record electrodes on the head to record electrical activity from the hearing electrical activity from the hearing nerve. nerve. • Looks at ‘neural’ response.Looks at ‘neural’ response.

Cochlear Microphonic Reverses

Kraus et al,2000Kraus et al,2000

Latency does not shift with stimulus Latency does not shift with stimulus rate changerate change


Latency does not shift with stimulus Latency does not shift with stimulus intensityintensity


ABR in summary

• Large CM appears to be an “ABR”, but reverses with stimulus polarity

• Waves may be absent or severely abnormal



hair cells)hair cells)• Brainstem Response testing: Auditory nervous Brainstem Response testing: Auditory nervous

systemsystem

• Behavioral Audiometry: BrainBehavioral Audiometry: Brain• Tympanometry w/ acoustic reflexes: Middle ear Tympanometry w/ acoustic reflexes: Middle ear

and reflex arcand reflex arc

Behavioral AudiometryBehavioral Audiometry

• VRA: a pediatric hearing test VRA: a pediatric hearing test procedure in which the child's procedure in which the child's responses to sound are responses to sound are reinforced with a visual event reinforced with a visual event (e.g., a moving toy). This (e.g., a moving toy). This procedure is most appropriate procedure is most appropriate for children in the 6 month to 3 for children in the 6 month to 3 year age range. year age range.

• Looks at response of ‘brain’Looks at response of ‘brain’

Observing Auditory Behaviors

• Regardless of outcome of electrophysiologic / acoustic tests, it is recommended that audiologists:– Examine auditory behaviors– Query family regarding their observations– Describe auditory function in relationship to

electrophysiologic & acoustic test results– Comment if findings are not in accord

Gravel et al., 1989



hair cells)hair cells)• Brainstem Response testing: Auditory nervous Brainstem Response testing: Auditory nervous

systemsystem• Behavioral Audiometry: BrainBehavioral Audiometry: Brain

• Tympanometry w/ acoustic reflexes: Tympanometry w/ acoustic reflexes: Middle ear and reflex arcMiddle ear and reflex arc

Tympanometry

• a measure of tympanic membrane (eardrum) mobility. Tympanometric are typically normal

Tympanometry

• Acoustic reflexes: Absent or severely elevated ipsilaterally and contralaterally despite normal tympanometry

Test Results with Bilateral Auditory Test Results with Bilateral Auditory neuropathy / dys-synchronyneuropathy / dys-synchrony

• Otoacoustic Emissions : Otoacoustic Emissions : NormalNormal• TympanogramsTympanograms NormalNormal• Middle-ear muscle reflexes: Middle-ear muscle reflexes: AbsentAbsent• Cochlear microphonic:Cochlear microphonic: Present, invert with Present, invert with

stimulus polarity reversalstimulus polarity reversal• Auditory Brainstem Response:Auditory Brainstem Response: Absent, severely abnormalAbsent, severely abnormal• Masking level difference:Masking level difference: No MLDNo MLD• OAE suppression:OAE suppression: No suppressionNo suppression• Speech recog. In noise:Speech recog. In noise: Generally poorGenerally poor• Speech recog. In quietSpeech recog. In quiet Normal to severeNormal to severe• Pure-tone thresholds:Pure-tone thresholds: Variable (normal to Variable (normal to

profound ranges)profound ranges)

Infants with AN/AD require a Infants with AN/AD require a Multidisciplinary Approach to Multidisciplinary Approach to

ManagementManagement• AudiologistAudiologist• Neurodiagnostician Neurodiagnostician • GeneticistGeneticist• Early Interventionist / Deaf and Hard of Hearing Early Interventionist / Deaf and Hard of Hearing

EducatorEducator• Speech PathologistSpeech Pathologist• Occupational TherapistsOccupational Therapists• Physical TherapistPhysical Therapist• OphthalmologistOphthalmologist

Patient OutcomesPatient Outcomes

• Some actually get better, start to hear and speak Some actually get better, start to hear and speak within a year or two. within a year or two.

• Some get worse, lose their emissions and Some get worse, lose their emissions and cochlear microphonics. cochlear microphonics.

• Some stay the same. Some stay the same. • Some develop peripheral neuropathies later in Some develop peripheral neuropathies later in

life. (This latter category more commonly life. (This latter category more commonly describes adult onset AN. )describes adult onset AN. )

Ongoing Audiological / Educational Management Strategies for AN / AD

• Provide up-to-date information regarding the present Provide up-to-date information regarding the present understanding of AN, this is important in making understanding of AN, this is important in making decisions.decisions. – Parents and EducatorsParents and Educators

• Children with AN/AD should have access to Children with AN/AD should have access to appropriate early intervention and/or education appropriate early intervention and/or education programsprograms..– Develop a personalized plan (Individualized Family Develop a personalized plan (Individualized Family

Services Plan (IFSP) or Individual Education Plan (IEP)Services Plan (IFSP) or Individual Education Plan (IEP)• ..

Ongoing Audiological / Educational Ongoing Audiological / Educational Management Strategies for AN / ADManagement Strategies for AN / AD

• Determine the functional profile of each child. • Assessment needs to measure skills in a variety of

developmental domains– Communication– Language– Functional auditory skills– Speech– Cognition

• Repeat testing at regular intervals to monitor achievement of identified goals


• Suggested Assessment Procedures – Family Assessment of Multi-disciplinary Interactional

Learning for the Young Child (Stredler-Brown & Yoshinaga-Itano)

– Functional Auditory Performance Indicators: an integrated Approach to Auditory Development (Stredler-Brown & Johnson C)

– Auditory-verbal ages & stages of development (Estabrooks)

– The Development of Listening Function (Razack)

– The Developmental Approach to Successful Listing II (DASL) (Stout & Windle)


• Intervention should be competency-based where the Intervention should be competency-based where the interventionist identifies the strengths exhibited in the interventionist identifies the strengths exhibited in the child’s developmental profile and identifies strategies to child’s developmental profile and identifies strategies to address delays.address delays.

• Language development is critical– Visual Communication methods (cued speech, sign

language, signed English) are necessary for language development. (Auditory verbal in these cases are not recommended)

• Functional auditory skills should be evaluated on a regular basis

• Provide comprehensive neurological evaluationsProvide comprehensive neurological evaluations

Ongoing Audiological / Educational Management Strategies for AN / AD

•Follow patients audiologically:Follow patients audiologically: Define hearing sensitivity with behavioral AudiometryDefine hearing sensitivity with behavioral AudiometryThere may be a change in auditory function over timeThere may be a change in auditory function over time

•Consider hearing aid fitting if no progress is seen.Consider hearing aid fitting if no progress is seen.Distinguish detection (sensitivity) from discrimination Distinguish detection (sensitivity) from discrimination (especially in noise) when evaluating hearing aid benefit.(especially in noise) when evaluating hearing aid benefit.

•Consider FM systemConsider FM systemthis technology has benefited many infantsthis technology has benefited many infants

•Consider cochlear implantation if:Consider cochlear implantation if: Progress is not indicated and cochlear implant team Progress is not indicated and cochlear implant team considers the infant a good candidate for the procedureconsiders the infant a good candidate for the procedure

Goal of Treatment• Ongoing diagnostic testing by individuals capable of

providing such services• Development of language

– Develop a profile of child’s skills in all developmental domains

• Recognize that identification takes time in these cases and re-assure the family

• Inform the family of resources available to not only educate but to provide emotional support

• Educate the educators working with these infants

TrendsTrends• Amplification

– is controversial, but if managed by a knowledgeable audiologist, may be beneficial

• Cochlear Implants– A very difficult decision for families, some consider it and

even are considering binaural CIs• Use of visual communication

– Does not rule out sign language, and should be continued even after implants are performed

“The dependence of a child on visual communication is related to the child’s ability to benefit from auditory input. If the child can process auditory information, there will be less dependence on visual information.” (Stredler - Brown)

How can the professional be more supportive of parents?

• Parents know their children better than anyone does. Listen to them! If they feel there is a problem, there usually is.

• Never discount odd occurrences as denial of the diagnosis. If the parent of an AN / AD child tells you that the child seems to hear sometimes, believe them, it happens.

• Provide:– Emotional support– Follow up calls (which show you care)– Easy to understand information about the diagnosis with

sources of information

Tips for Professionals as summarized from: http://auditoryneuropathy.com

http://auditoryneuropathy.com/

How can the professional be more supportive of parents?

• Provide sources of information on all communication choices and available intervention services in your area

• Direct them to other families, support groups, internet email loops and websites dealing with the diagnosis, conferences, seminars, etc.

• Be honest if a question is outside your knowledge base. It is ok to say “I don’t know, but I will find out”, and then find out! Stay current in your field.

• Be a team player! Effective working relationships between all members of the educational team and the family is imperative to the child’s future.

Case Study 1

Case Study 2

Case Study 3

Actual comments on a list-serve!Actual comments on a list-serve!

• “On Monday I woke up so angry. I feel like a child stamping their foot saying it's not fair. I can't seem to shake this. I'm mad that Julie was born deaf, that they didn't do newborn hearing screening. I'm mad that it took almost a year to find out she couldn't hear. I'm mad at myself for believing the DRs .I'm so angry that I had to diagnose her with AN. I'm the one that brought it to her ENT's attention. I'm angry that not one person who I was in contact with believed me that she could hear at times. I'm so angry that she wore HA's with little benefit for so long. I'm also upset that through out all of this I was made to feel like I was the crazy one. She had speech therapy twice a week and not one of her therapists wondered why she wasn't progressing “

Another Parent’s CommentsWhat if:

1) I was expecting to much like the Dr. said2) If maybe he didn't have AN & that I hadn't worked enough with

him3) If he did have AN but a CI wasn't going to work4) That with enough AVT he would have been fine5) If in addition to SNHL he had a processing disorder not AN6) I was taking the easy way out7) That I was trying to fix him8) Should we have learned ASL and been happy with that9) Was it all my fault because my other kids could hear and I had

done something while pregnant to damage him10) Does too much raspberry sherbet in the first trimester cause

hearing loss- (I seriously wondered this at one time)

Final ThoughtsFinal Thoughts

• AN / AD is not simple• Still much research is needed• Parents need the professionals to be educated.• Professionals need to be understanding of the mixed

signals parents are given.• We need to listen to the parents.• AN / AD kids need help too! But that help may be different

from what audiologists are used to! Stay current on the research, and if you do not know what to do, get the parents the help they need.

ResourcesResources• ELF Early Listening Function• Functional Auditory Performance Indicators: An Integrated

Approach to Auditory Skill Development• Hood, L. April, 2002“Auditory Neuropathy/Auditory Dys-

synchrony in infants and children: Issues in Assessment and Management”. www.kresgelab.org,

• Kraus,N., Bradlow, A.R., Cheatham, M.A., Cunningham, J., King, C.D., Koch, D.B., Nicol, T.G., Mcgee, T.J., Stein, L.K., and Wright, B.A. “Consequences of Neural Asynchrony: (2000) A Case of Auditory Neuropathy”JARO 01:033-045

• Kumar, U.A., Jayaram,M.M. (2006) “Prevalence and audiological characteristic in individuals with auditory neuropathy/auditory dys-synchrony” International Journal of Audiology; 45:360-366

ResourcesResources• My Baby’s Hearing, Boystown National Research Hospital,

http://www.babyhearing.org/HearingAmplification/Causes/Neuropathy.asp

• Rance G, Beer D. cone-Wesson B, et al. Clinical findings for a group of infants and young children with auditory

neuropathy. Ear Hear 1999; 20: 238-252• Stredler-Brown,A. “Developing a Treatment Program for

children with Auditory Neuropathy”, http://www.csdb.org/chip/m_audnueropathy.html

• Stredler-Brown A, Johnson C. Functional Auditory Performance Indicators: An Integrated Approach to Auditory

Development {on line}, Colorado Department of Education, Special Education Services Unit. 2001: www.cde.state.co.us/cdesped/SpecificDisability-Hearing.html





http://www.csdb.org/chip/m_audnueropathy.html

http://www.cde.state.co.us/cdesped/SpecificDisability-Hearing.html

ResourcesResources• Stredler-Brown A & Yoshinaga-Itano C. Family assessment: A

multidisciplinary evaluation tool. In: Roush J & Matkin N, eds. Infants and Toddlers with Hearing Loss. Timonium, MD: York Press, Inc: 1994: 133-161

• Estabrooks W. Auditory-Verbal ages & stages of development. In Estabrooks, W. ed. Cochlear Implants for Kids.

Washington, DC: Alexander Graham Bell Associat for the Deaf, Inc; 1998: 387-399

• Razack Z. The Development of Listening Function. Ontario, Canada: The Waterloo county Board of Education; 1994: 26-30

• Stout G, Windle J. The developmental Approach to Successful Listening II (DASL) Englewood, CO: Resource Point,

Inc; 1992

ResourcesResources

• Zeng, F.G., Oba, S., Garde, S., Sininger, Y. and Starr, A. (1999) Temporal and speech processing deficits in Auditory

Neuropathy. NeuroReport 10(16), 3429-3435.• Zeng, F.G.(2000) Auditory Neuropathy: Why some hearing-

impaired listeners can hear but do not understand and how can DSP technology help them? spib.rice.edu/DSP2000/submission/DSP/papers/paper117/paper117.pdf

Early Intervention of Children identified with Auditory Neuropathy Karen M. Ditty, Au.D. 1,2 Sharon...

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