Auditory Neuropathy

Auditory neuropathy (AN) is a disorder in which the amplification function of the inner ear is preserved, but the timing (or synchrony) of action potentials in the auditory nerve are disrupted. This has led some individuals to suggest that auditory dys-synchrony would be a better name for this disorder.
Testing - Individuals with auditory neuropathy have normal otoacoustic emissions (OAE) and absent or severely abnormal auditory brainstem responses (ABR).
Results of testing of pure-tone thresholds are quite variable in AN patients and can range from normal to profound hearing loss. Word recognition by individuals with AN is generally poorer than one would predict from pure-tone thresholds. This underscores the importance of neural synchrony in speech perception and may explain why individuals with AN commonly complain that "I can hear you but I cannot understand you."
Intervention - Development of language in children with AN can be facilitated by use of a visual communication system. Some children with AN show improvement with verbal auditory function over time. It may be therefore be wise to choose a visual communication system that follows the grammatical structure of English, such as signed English or cued speech, rather than American Sign Language. This would allow such patients to assimilate spoken language into a language system that already follows English language structure.
Although hearing aids are typically of little benefit to individuals with AN, FM auditory systems may be helpful in situations where enhancement of signal-to-noise ratios would allow use of residual hearing for speech understanding. Several studies suggest that cochlear implantation is a potentially successful habilitation method for AN. It appears that the supraphysiologic electrical stimulation provided by cochlear implantations can reintroduce synchronous neural activity in the auditory nerve in at least a subset of AN patients.
Associated disorders - Although some patients with AN have only an auditory abnormality, many have either overt or subtle neuropathies outside the auditory system. Auditory neuropathy has been seen in patients with: Charcot-Marie-Tooth syndrome, Friedreich ataxia, gait ataxia, loss of deep tendon reflexes, and motor system disturbances. If clinical findings suggest any co-existing neurological abnormalities, children with AN should be referred to a pediatric neurologist for evaluation and management.


Author: Karl White, Ph D - 3/2010
Content Last Updated: 3/2010

Page Bibliography

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