Selective impairment of hearing and vestibular function in a brain stem lesion.

A case of sudden bilateral hearing loss in a diabetic patient is reported. Acoustic-vestibular examination indicated a lesion localized in the brain stem although no other neurological abnormality was found. Postmortem examination demonstrated severe vascular changes of the brain stem. Areas of fresh infarction and necrosis were found localized to the cochlear and vestibular nuclei. The case demonstrates that central vascular disorders may be the cause of sudden severe hearing loss even without other neurological symptoms or signs.