We studied on long-term outcome of patients with sudden deafness between 1972 and 1999. We investigated specific cases that have been followed longer than five years at Kitasato University Hospital. Twentyeight cases (18.3%) out of 153 showed some changes in hearing level during the observation period. All of the changes noted to be deterioration. We then divided these 153 cases into two groups: the one with the hearing deterioration and the one without. There appeared to be no significant difference in terms of sex, age, balance disorder, the grade of hearing level at the onset, the degree of recovery in initial presentation, and Jerger type in Bekesy audiogram between these two groups. The affected side of the ear tended to show more deterioration of hearing than non-affected side. We speculate that there may be a progressive nature in sudden deafness in a long-term period.
