Bilateral simultaneous sudden deafness.

Although sudden deafness has many causes, it is often a sensorineural hearing loss with an abrupt onset and unknown origin. The majority of these latter cases are unilateral in their occurrences, while bilateral simultaneous involvement is rarely seen. During the past 13 years, we have treated 997 patients with sudden deafness. All patients were seen at our university hospital within 2 weeks after the onset of their hearing losses and were observed until the hearing level was fixed. Among them, 10 patients were found to have bilateral simultaneous onsets. The average age and the incidence of vestibular symptoms were similar to those with unilateral deafness. The hearing recovery was much better in the ear with the lesser deafness. No improvement was observed on the side with no sound perception. Those patients in whom common cold and fever seemed to trigger the onset of deafness were also noted to have high viral antibody titers, and were more commonly seen than were those cases with unilateral deafness.