Study on the distribution of hearing levels in idiopathic bilateral sensorineural hearing loss

The pattern of aggravation in hearing was investigated in 105 patients who were diagnosed as having idiopathic bilateral sensorineural hearing loss at the Hearing Loss Clinic, Department of Otolaryngology, Kitasato University Hospital. Audiograms were taken 1,069 times from the 105 cases over more than 3 years, and were used to obtain the distribution of hearing levels at each test frequency. The clinical course of idiopathic bilateral sensorineural hearing loss was divided into three stages: Stages I, II and III, based on the pattern of aggravation. The pattern of distribution of hearing levels at different stages was compared with each other with reference to peaks or clustering points. Similar peaks were noted at Stage II and Stage III as aggravation proceeded from Stage I. Another peak was noted in the zone of scale-out.