[Deafness and tinnitus in flare-ups in 10 cases of multiple sclerosis].

Deafness in multiple sclerosis is rare, being reported in less than 1 p. 100 of the cases. Ten cases of deafness associated with tinnitus during acute episodes of multiple sclerosis are presented, the diagnosis being definite in 9 patients and probable, according to McAlpine's criteria, in the tenth case. These were not cases where routine examinations demonstrated a latent hearing defect, but were all patients with sudden, often unilateral, incapacitating deafness during an acute episode of the disease, with regression usually after less than 3 months. Deafness recurred in 3 patients and was the initial symptom in 5 cases. Serial audiometric examinations were performed in most cases together with recordings of various evoked potentials, including early auditory evoked potentials during or after the onset of deafness in all 10 patients. BAEPs abnormalities were noted in 8 and appeared to be correlated more with brain stem demyelinization, as it has been established for a few years, than with the deafness itself. Severe anomalies of auditory evoked potentials regressed after the acute episode in only 1 patient. Lesions of the auditory pathways within the brain stem appear to be the cause of the deafness, as shown by results of auditory tests, which pointed to a central origin. The onset of deafness did not indicate a particular progression of multiple sclerosis.