[Acoustic trauma from firearms: study of auditory function]

This article deals with the shift in audiometric tracings brought about by the discharge of firearms (acute acoustic trauma). The study included 60 subjects with normal hearing, between 18 and 20 years of age. Each individual shot 25 bullets in about 5 minutes, at an intensity level calculated at 163 dB. None of them related antecedents of sensorineural deafness. The audiometric examinations were performed as follows: the first one prior to the experiment, the second immediately after the series of shots, and others 8 and 40 hours later. These are the conclusions drawn out by the AA.: the most important and lasting deafness was verified in the left ear. The 6000 c/s frequency was the most affected. Recovery of the previous hearing level was total in 80.5% of the cases within 40 hours. Two subjects having otosclerotic relatives showed certain difficulties in recovering.