Classification of Hearing Losses Induced by Noises in Workmen's Accidents, and Counter Measures againt Noise Induced Hearing Loss

Abstract

While working under noise ranging from the safety noise level up to the harmful, workers are liable to suffer from chronic occupational deafness or sudden hearing loss due to industrial noise. The latter case has been made a subject of the Workmen's Compensation Insurance in Japan since April, 1959. Mention was also made of Aptitude Test in the field (by Kawamura) as a counter measure against hearing losses and Temporary Threshold Shift as criteria of treatment of occupational deafness. On the other hand, a wide range revision of grades of the hearing losses was effected in September, 1975, and the lowest compensation criteria was raised from 60dB to 30dB. Since this kind of revision is related not only to compensation for, but also prevention of hearing losses and arresting their further progress, it is considered that it will pose a serious problem.