Sudden sensorineural hearing loss.

Approximately 4000 new cases of sudden hearing loss (SHL) occur annually in the United States, and 15,000 annually worldwide, accounting for approximately 1% of all cases of SHL. Although prevalence studies do not necessarily distinguish between idiopathic and acquired SHL, most cases of spontaneous SHL have no identifiable cause. In this article, the authors assess the cause, history, diagnosis, and treatment of SHL.