Neurotological studies on Meniere's disease and sudden deafness.

During the period from January 1973 to June 1975, 60 cases with definite Meniere's disease and 30 cases with sudden deafness were listed according to such criteria for the diagnosis of both diseases as determined by the Research Committee of Japan. A neurootological assessment for both diseases were performed in our series. In patients with definite Meniere's disease, hearing impairment was characterized by deficiency in detecting low- and middle-pitched tones and fluctuation of auditory threshold in low frequency range. In sudden deafness, highly impaired hearing loss, i.e., total deafness, was frequently observed (45%). However, recruitment occurred at the same incidence (80%) in both diseases tested. The incidence of spontaneous nystagmus was almost the same regardless of associated vertigo and the course of both diseases. Moreover, it was also recognized that a reduction of caloric responses was a better indication for assessment of the affected ear in both diseases.