Auditory neuropathy

Auditory neuropathy (AN) is a hearing disorder in which the outer hair cells of the cochlea are present and working, but sound information is not passed well enough along the auditory nerve to the brain. The cause may lie in the inner hair cells of the cochlea, the synapse between those cells and the auditory nerve, or the ascending auditory nerve itself. Hearing loss ranges from normal sensitivity to profound deafness, and most people have very poor hearing in background noise. The condition can be congenital or acquired, roughly 40 percent of cases are estimated to have a genetic cause, and it can occur alone or alongside diseases such as Charcot-Marie-Tooth disease and Friedreich ataxia. Risk factors in newborns include low oxygen, low birth weight, premature birth, jaundice and some antibiotic treatments. Diagnosis needs a battery of tests that includes auditory brainstem response and otoacoustic emissions, and newborn hearing screening can detect it early. Hearing aids are sometimes prescribed with mixed success, and some people receive cochlear implants, also with mixed success. The true prevalence in the general population is relatively unknown.