Auditory Neuropathy

Auditory neuropathy, also called auditory neuropathy spectrum disorder (ANSD), is a hearing condition in which the outer hair cells of the cochlea function normally but the transmission of signals from the cochlea to the brain along the auditory nerve is disrupted or unreliable. This disrupted neural transmission results in poor speech understanding that is often disproportionately worse than the degree of hearing loss suggested by threshold testing alone.

The key distinguishing feature of auditory neuropathy is the combination of present otoacoustic emissions (OAE) or cochlear microphonic (indicating functional outer hair cells) with absent or severely abnormal auditory brainstem response (ABR). Behavioral hearing thresholds can range from normal to profound. The condition can affect newborns, children, and adults and may be associated with premature birth, hyperbilirubinemia, genetic factors, or neurological conditions.

Management is complex because conventional hearing aids may provide limited benefit. Cochlear implants have shown good outcomes for many individuals with ANSD, particularly children identified early. In Canada, assessment of ANSD typically occurs through diagnostic audiology programs and cochlear implant centres.