Auditory neuropathy/dyssynchrony: its diagnosis and management.

Patients with auditory neuropathy/dyssynchrony exhibit no auditory brain stem response (ABR), no middle ear muscle response, and both normal otoacoustic emissions or normal cochlear microphonics. An absent or grossly abnormal ABR is not always associated with deafness. In contrast, a hearing loss of 30 dB or more usually predicts absent otoacoustic emissions, but normal emissions can be seen in some patients whose behavioral audiograms imply total deafness. This article reviews the underlying physiology that makes these tests both useful and potentially misleading, and recommends steps to be considered by primary care physicians and other professionals to compensate for the vulnerabilities of each of the procedures.