Objective tinnitus: a case report.

Objective tinnitus is a rather rare condition that may be due to myoclonus of certain muscles, such as the palate, or to arteriovenous communications, either congenital or acquired. In cases of palatal myoclonus the diagnosis of the causative factor is not always easy, but the use of tympanometry, EMG, and EEG may help in establishing the diagnosis. In cases of arteriovenous communications a pulse synchronous tinnitus is present. It may be temporarily obliterated by applying pressure over the mastoid area or over the carotid artery on the affected side. Audiometric and tympanometric studies are not diagnostic, and very careful angiographic studies are necessary because routine tests may not show the lesion. The case presented suggests another etiologic possibility for vascular objective tinnitus: a stenosis of certain branches of the external carotid artery. The treatment for myoclonic causes of objective tinnitus has been for the most part unsatisfactory, whether it be medical or surgical. On the other hand, surgical treatment of arteriovenous communications results in complete amelioration of signs and symptoms--hence the necessity for an accurate diagnosis.