Sudden deafness is not a clinical entity but a symptom complex of acute hearing impairment, tinnitus, and, in some patients, vertigo. This alarming syndrome attacks healthy adults like a bolt from the blue without any cause. Hallberg1 described several conceivable etiological factors: (1) vascular changes such as thrombosis, spasm, or hemorrhage of the auditory apparatus; (2) toxic involvement of the cochlea or the cranial VIII nerve; (3) neuritis of the cranial VIII nerve; (4) systemic diseases such as blood dyscrasias; (5) acute rise of pressure in the labyrinth; (6) an anaphylactic phenomenon; (7) emotional factors; (8) pressure as from a tumor, and (9) trauma to the head. In practice, it is difficult to establish the etiology, and the pathogenic process in individual patients is most often speculative. We have recently observed a patient whose sudden deafness is likely to be associated with vascular change due to thromboangiitis obliterans cerebri