Clinical and Audiological Features in Auditory Neuropathy

Abstract

AUDITORY neuropathy (AN) is a hearing disorder characterized by an absent or severely abnormal auditory brainstem response (ABR), with preservation of the cochlear microphonics (CM) and otoacoustic emissions (OAEs). Clinically, AN is defined as (1) hearing loss, usually bilateral, of any degree; (2) normal outer hair cell function as evidenced by the presence of OAEs and/or CM; (3) abnormal evoked potentials beginning with wave I of the ABR; (4) poor speech perception; and (5) absent acoustic reflexes to the ipsilateral and contralateral tones at a 110-dB hearing level. Starr et al1 described 10 patients, 5 adults and 5 children, who demonstrated these findings and no other auditory diagnosis on results of clinical, audiological, or radiographic studies. They coined the term auditory neuropathy.1 The prevalence of AN is not known. Davis and Hirsh2 reported 1 case of AN (0.5%) in 200 patients with sensorineural hearing loss (SNHL). Other investigators found a higher rate of prevalence, with Kraus et al3 reporting a rate of 15% and Rance et al4 of 11% of their population with permanent hearing loss.