This report is a clinical statistical observation of tinnitus gathered from the 9 main otolaryngological departments in Japan. A total of 34, 717 patients visiting these 9 departments were analyzed. The incidence of tinnitus was 7.3%. Bilateral tinnitus cases were seen 2. 4 times as much as unilateral tinnitus cases. In Iwate Medical University 5, 271 patients were analyzed and the results are as follows. The incidence of tinnitus was 10. 1 % and cases with bilateral tinnitus were seen 3 times as much as unilateral tinnitus cases. The chief complaint in 39.7% of the 532 cases was tinnitus. The others were all complaints concerned with other otological symptoms. In the case with hearing disturbances, tinnitus was usually accompanied with sensorineural hearing loss and was found to a high degree in cases of sudden deafness, Meniere's disease and cochlear neuronitis. A lot of the cases complained of hearing a sound they called kee-n, therefore we thought the foundamental sound of tinnitus was this sound.
