Early Intervention of Children identified with Auditory Neuropathy

Early Intervention of Children identified with Auditory Neuropathy Karen M. Ditty, Au. D. 1, 2 Sharon M. Parham, M. S. 3 National Center for Hearing Assessment and Management Logan, UT 1 Texas ENT Specialists, PA Houston, TX 2 Northwest Harris County Cooperative for the Hearing Impaired Houston, TX 3

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

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 http: //www. medschool. lsuhsc. edu/Otorhinolaryngology/deafness_article 1. asp 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 Neuropathy / Dys-synchrony • Inner hair cells • Tectorial membrane • Synaptic juncture between the inner hair cells • Auditory neurons in the spiral ganglion, • VIIIth nerve fibers, or any combination above (Starr et al. , 1996; Berlin et al. , 1998) • Neural problems may be axonal or demyelination. http: //www. medschool. lsuhsc. edu/Otorhinolaryngology/deafness_article 1. asp • Afferent as well as efferent pathways may

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

What Causes Auditory Neuropathy / Dys-Synchrony?

Possible etiologies of Auditory Neuropathy / Dys-synchrony • Hyperbilirubinemia (Jaundice)12 -16 cc/dl, cc/dl (probably #1) • Neurodegenerative diseases, e. g. , Fried. Reich's ataxia • Neurometabolic diseases • Hereditary motor sensory neuropathies: e. g. : Charcot-Marie-Tooth syndrome • Demyelinating diseases • Inflammatory neuropathies

Possible Etiologies of Auditory Neuropathy / Dys-synchrony continued • • Ischemic/hypoxic neuropathy Hydrocephalus Abnormality with neurotransmitter release Cerebral palsy Infectious disease such as mumps Immune Disorders Severe developmental delay

What does auditory neuropathy / dys-synchrony (AN / AD) sound like?

Computer simulation of what Auditory Neuropathy / Dys. Synchrony may sound like Developed speech waveforms based on simulations of different degrees of Auditory Funding agency: National Institutes of Health (DC 02618) Neuropathy / Dys-synchrony PI: Arnold Starr; Co-investigator: Fan-Gang Zeng “Communication difficulties in individuals with auditory neuropathy / dys-synchrony, even with mild hearing loss are more severe than individuals with cochlear hearing loss of

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 Funding agency: National Institutes of Health (DC 02618) deficit that is disproportional to pure tone PI: Arnold Starr; Co-investigator: Fan-Gang Zeng 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 Funding agency: National Institutes of Health (DC 02618) PI: Arnold Starr; Co-investigator: Fan-Gang Zeng

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” Funding agency: National Institutes of Health (DC 02618) PI: Arnold Starr; Co-investigator: Fan-Gang Zeng

Are all Auditory Neuropathy / Dyssynchrony 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

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 (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

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

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 Neuropathy / Dys-Synchrony • • • Complete Medical / Case history Otoscopy: Outer Ear and Ear Canal Otoacoustic Emissions testing: Cochlea (outer hair cells) Brainstem Response testing: Auditory nervous system Behavioral Audiometry: Brain Tympanometry w/ acoustic reflexes: Middle ear and reflex 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/deskrefjournals/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.

Audiological Management of Auditory Neuropathy / Dys-Synchrony • • • Complete Medical / Case history Otoscopy: Outer Ear and Ear Canal Otoacoustic Emissions testing: Cochlea (outer hair cells) Brainstem Response testing: Auditory nervous system Behavioral Audiometry: Brain Tympanometry w/ acoustic reflexes: Middle ear and reflex arc

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

Transient OAE results

Distortion Product OAE

OAE Summary • OAEs are objective evidence of healthy cochlear function. Looks at ‘pre-neural’ response. • The majority of hearing loss in the low-risk population is a result of cochlear/outer hair cell system malfunction. This is the most sensitive part of the hearing mechanism tested by OAEs. • Auditory neuropathy / dys-synchrony is statistically rarer in the low-risk, well baby population than in the special care population,

Audiological Management of Auditory Neuropathy / Dys-Synchrony • Complete Medical / Case history • Otoscopy: Outer Ear and Ear Canal • Otoacoustic Emissions testing: Cochlea (outer hair cells) • Brainstem Response testing: Auditory nervous system • Behavioral Audiometry: Brain • Tympanometry w/ acoustic reflexes: Middle ear and reflex arc

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

Cochlear Microphonic Reverses Kraus et al, 2000

Latency does not shift with stimulus rate change Kraus et al, 2000

Latency does not shift with stimulus intensity Kraus et al, 2000

ABR in summary • Large CM appears to be an “ABR”, but reverses with stimulus polarity • Waves may be absent or severely abnormal

Audiological Management of Auditory Neuropathy / Dys-Synchrony • Complete Medical / Case history • Otoscopy: Outer Ear and Ear Canal • Otoacoustic Emissions testing: Cochlea (outer hair cells) • Brainstem Response testing: Auditory nervous system • Behavioral Audiometry: Brain • Tympanometry w/ acoustic reflexes: Middle ear and reflex arc

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

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

Audiological Management of Auditory Neuropathy / Dys-Synchrony • Complete Medical / Case history • Otoscopy: Outer Ear and Ear Canal • Otoacoustic Emissions testing: Cochlea (outer hair cells) • Brainstem Response testing: Auditory nervous system • Behavioral Audiometry: Brain • Tympanometry w/ acoustic reflexes: Middle 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 neuropathy / dys-synchrony • • • Otoacoustic Emissions : Tympanograms Middle-ear muscle reflexes: Cochlear microphonic: Normal Absent Present, invert with stimulus polarity reversal Auditory Brainstem Response: Absent, severely abnormal Masking level difference: No MLD OAE suppression: No suppression Speech recog. In noise: Generally poor Speech recog. In quiet Normal to severe Pure-tone thresholds: Variable (normal to profound ranges)

Infants with AN/AD require a Multidisciplinary Approach to Management • • Audiologist Neurodiagnostician Geneticist Early Interventionist / Deaf and Hard of Hearing Educator Speech Pathologist Occupational Therapists Physical Therapist Ophthalmologist

Patient Outcomes • • Some actually get better, start to hear and speak within a year or two. Some get worse, lose their emissions and cochlear microphonics. Some stay the same. Some develop peripheral neuropathies later in life. (This latter category more commonly describes adult onset AN. )

Ongoing Audiological / Educational Management Strategies for AN / AD • Provide up-to-date information regarding the present understanding of AN, this is important in making decisions. – Parents and Educators • Children with AN/AD should have access to appropriate early intervention and/or education programs. – Develop a personalized plan (Individualized Family Services Plan (IFSP) or Individual Education Plan (IEP) • .

Ongoing Audiological / Educational Management 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

Ongoing Audiological / Educational Management Strategies for AN / AD • 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)

Ongoing Audiological / Educational Management Strategies for AN / AD • Intervention should be competency-based where the interventionist identifies the strengths exhibited in the child’s developmental profile and identifies strategies to 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

Ongoing Audiological / Educational Management Strategies for AN / AD • Follow patients audiologically: Define hearing sensitivity with behavioral Audiometry There may be a change in auditory function over time • Consider hearing aid fitting if no progress is seen. Distinguish detection (sensitivity) from discrimination (especially in noise) when evaluating hearing aid benefit. • Consider FM system this technology has benefited many infants

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

Trends • 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

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

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

Case Study 1

Case Study 2

Case Study 3

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

Another Parent’s Comments What if: 1) I was expecting to much like the Dr. said 2) If maybe he didn't have AN & that I hadn't worked enough with him 3) If he did have AN but a CI wasn't going to work 4) That with enough AVT he would have been fine 5) If in addition to SNHL he had a processing disorder not AN 6) I was taking the easy way out 7) That I was trying to fix him 8) Should we have learned ASL and been happy with that 9) Was it all my fault because my other kids could hear and I had done something while pregnant to damage him 10) Does too much raspberry sherbet in the first

Final 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.

Resources • ELF Early Listening Function • Functional Auditory Performance Indicators: An Integrated Approach to Auditory Skill Development • Hood, L. April, 2002“Auditory Neuropathy/Auditory Dyssynchrony 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”

Resources • My Baby’s Hearing, Boystown National Research Hospital, http: //www. babyhearing. org/Hearing. Amplifica tion/Caus es/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/Specific. Disability-

Resources • 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

Resources • Zeng, F. G. , Oba, S. , Garde, S. , Sininger, Y. and Starr, A. (1999) Temporal and speech processing deficits in Auditory Neuropathy. Neuro. Report 10(16), 3429 -3435. • Zeng, F. G. (2000) Auditory Neuropathy: Why some hearing- impaired listeners can hear but do not understand how can DSP technology help them? spib. rice. edu/DSP 2000/submission/DSP/papers/ paper 117/paper 117. pdf