Hearing aids for auditory neuropathy patients

Auditory Neuropathy (AN) is a hearing disorder characterized by disruption of temporal coding of acoustic signals in auditory nerve fibers resulting from lesions involving the nerve fibers themselves, the inner hair cells or their synapses with auditory nerve terminals. In contrast, outer hair cell activities are preserved (cochlear microphonic and otoacoustic emissions, OAEs). AN may be underlain by genetic disorders or result from a wide range of other etiologies. The disruption of auditory nerve discharge underlies both the absence of auditory brainstem responses (ABRs) and the impairment of speech perception. These alterations show high variability depending on etiology, site of lesion and stage of the disease. Cochlear implantation constitutes the only rehabilitative tool able to restore speech perception in patients with genetic AN. Nevertheless, some patients benefit from the use of auditory input delivered by hearing aids before cochlear implantation. Differently from subjects affected by genetic AN, hearing-impaired children discharged from Neonatal Intensive Care Units (NICUs) with absent ABRs and presence of OAEs may be successful hearing aid users. In this presentation I shall report the outcome of hearing aid use in patients with genetic AN and in a group of children discharged from NICUs with the clinical picture of AN.