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Understanding ANSD

Learn about the diagnosis and difficulties in diagnosing ANSD, recommended support for children with ANSD, and the limitations of hearing aids, cochlear implants, and FM. Resources and support for families.

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Understanding ANSD

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  1. Understanding ANSD March 2018

  2. Topics • What is ANSD? • How we diagnose ANSD? • The difficulties diagnosing ANSD • The recommended support for children with ANSD • The use and limitations of hearing aids, cochlear implants, FM • Signposting to other useful resources and support for families

  3. Prevalence 10% of children seen with severe-to-profound deafness may have a neural rather than a hair cell disorder Kraus N, Ozdamar O, Stein L, Reed N. Absent auditory brain stem response: peripheral hearing loss or brain stem dysfunction. Laryngoscope 1984:94:400-6

  4. Prevalence Data from 3.5m NHSP England eSPrecords to Dec 2009 • 87% of bilateral ANSD come from SCBU/NICU populations. • The screen is NOT picking up babies from the well baby population. These enter the system via targeted surveillance (25% of all ANSD 0.03/1000) and other routes (0.1/1000) Presented by Graham Sutton at PAIG 2010

  5. History • Auditory Neuropathy (AN) (Starr et al, 1996) • Auditory Neuropathy / Auditory Dys-synchrony (AN/AD) (Berlin, 2003) • Auditory Neuropathy Spectrum Disorder (Global Consensus Conference, Lake Como, 2008) NOT Auditory Processing Disorder (APD)

  6. ANSD is caused by damaged inner hair cells, faulty connections between the inner hair cells and the auditory nerves, or a fault or malformation of the nerve itself Typical sensorineural deafness is caused by damage to, or a lack of working outer hair cells

  7. (APD - beyond the ear) The auditory pathways

  8. Causes ANSD encompasses a range of conditions which differ in site and pathology (Cone Wesson & Rance, 2000, Starr et al, 2000) • Delayed maturation / myelination of the auditory nerve (maturational or transient ANSD) • NICU/SCBU populations (e.g. prematurity, ventilator dependency, hyperbilirubinaemia, ototoxicity) • Genetics (e.g. Otoferlin) • Other neurological disorders (e.g. cerebral palsy) or hereditary neuropathies (e.g. Charcot Marie Tooth syndrome) • Absent or thin auditory nerve • None identified!

  9. Definition Auditory Neuropathy Spectrum Disorder is a term used to describe a hearing disorder characterised by: • normal outer hair cell function, AND • abnormal neural function at the level of the VIIIth nerve

  10. Diagnosis - infants • Achieve evidence of outer hair cell function using OAEs – used to routinely screen all babies. • Abnormal neural function detected using ABR – only used routinely for babies who have spent more than 48 hors in NICU. • “Well babies” therefore NOT diagnosed with newborn hearing screening protocols 

  11. Diagnosis – older children • Behavioural testing often gives very variable results as hearing may fluctuate • OAEs naturally disappear with age and may no longer be detected • ABR can only be done with sedation or anaesthetic or when the child is old enough to lie absolutely still with eyes closed for duration of testing • Presence of ANSD does not rule out the possibility of cochlear loss or of a conductive component (glue ear), and there can be several confounding factors that may make the diagnosis more difficult So practicalities of testing makes diagnosis trickier, although not impossible

  12. OAE ABR Thanks to GOSH via http://www.ssc.education.ed.ac.uk/courses/deaf/dnov09i.html

  13. Dys-synchrony Perceptual consequences of disrupted auditory nerve activity. Zeng, F.G., Kong, Y.Y., Michalewski, H.J., Starr, A. J Neurophysiology 3:2005

  14. Impact of dys-synchrony Difficulties in detecting timing differences and gaps between sounds (‘temporal processing’) affects: • ability to hear speech clearly and discriminate between different letter sounds e.g. ‘sh’‘ch’‘f’‘th’ • ability to pick out speech from background noise • ability to tell the direction of sounds (localise) Psychoacoustics and Speech Perception in Auditory Neuropathy, Zeng, F-G., Oba, S., Garde, S., Sininger, Y., Starr, A. in Auditory Neuropathy: A New Perspective on Hearing Disorders, edsSininger, Y., & Starr, A. 2001

  15. Explaining ANSD Parent’s explanation: “Imagine a speaker. Everybody’s had a broken speaker at some stage where the wire doesn’t quite connect properly… that’s the one I use and everyone says ‘I get what you mean’” Audiologist’s explanation: Speech perception and discrimination difficulties over and above what we would expect from the level of hearing loss alone.

  16. Explaining ANSD http://youtu.be/IY5YIiu_4t4

  17. Spectrum disorder • Ranges from normal hearing levels on behavioural testing to profound deafness • Unilateral or bilateral • Behavioural testing and responses to everyday sounds variable • Variable speech delay

  18. But in common… • Distortion of sound • Difficulty perceiving and discriminating speech over and above what would be expected from the hearing loss alone • Both the level of distortion and difficulty discriminating speech very variable between individuals

  19. Conclusion… Regardless of the audiological test results, in newborns and pre-verbal children, we cannot predict which children will have access to enough linguistically useful input to learn language spontaneously.

  20. Recommendation 1/3 • Provide specialist early years support (even if hearing aids aren't used) • Family and multi-disciplinary team must work closely to determine the functional auditory profile for each child and evaluate ongoing development of their speech and language skills

  21. Recommendation 2/3 A child with a diagnosis of ANSD should receive visual communication support in addition to spoken language until such time as it is known what level this support is needed at • SSE • Cued speech

  22. Recommendation 3/3 Improve listening conditions as much as possible: • Acoustic improvements • Background noise reduction • Use of personal FM / Soundfield

  23. A child on your caseload? Existing hearing aid wearers, children with other neurological disorders… • Not progressing in speech development or listening skills as expected in relation to any aiding and/or support received? • Language disorders? • More difficulty with background noise than expected? • Fluctuating hearing levels without glue ear? • "Difficult to test" children / unreliable results?

  24. Management – hearing aids • fit to behavioural thresholds • conservative fitting early on - age of audiological certainty higher than SNHL • parental and team observations vital • more frequent f/u • some children show threshold improvement over time • How may children benefit from them?

  25. Management – cochlear implants Outcomes may be related to site of lesion: • children with inner hair cell or inner hair cell-cochlear nerve junction pathology appear to perform as well as those with a typical SNHL • children with cochlear nerve deficiencies do not tend to reach the same levels of performance as those with typical SNHL or auditory dys-synchrony Cochlear implants in Auditory Neuropathy Spectrum Disorder, Simmonds, J.L. ASHA Access Audiology Vol. 8, No. 3, May/June 2009

  26. Use other technologies and strategies Everything you’d recommend for any other deaf child! • Use other assistive listening devices, such as loop systems, FM systems including radio aids, soundfieldetc • Environmental adaptations • Deaf awareness training

  27. Monitor and act on observations MDT assessment to measure skills in variety of developmental domains: • Communication development • Language skills • Functional auditory skills & observing auditory behaviours • Speech discrimination & production • Cognition Repeat testing at regular intervals to monitor achievement of identified goals

  28. Early Support Materials http://www.ndcs.org.uk/professional_support/other_academic_and_professional_resources/education_resources.html#contentblock4

  29. How do we know management is working? "Insofar as the child makes more than three months progress every quarter, then the therapeutic choices made by the family are salutary. If the child does not make such progress, changes in treatment, management and habilitation programs should be considered." (Berlin, Morlet & Hood, 2008)

  30. Parents perspective http://www.ndcs.org.uk/professional_support/external_research/index.html

  31. Useful resources • http://www.ndcs.org.uk/family_support/childhood_deafness/causes_of_deafness/index.html#contentblock1 • https://www.facebook.com/groups/ANSD777/ • https://www.facebook.com/groups/ANSDParents/

  32. Thank you for listening! vicki.kirwin@ndcs.org.uk

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