[Hearing impairment in operators of motor saws]

An otolaryngological and audiometric examination was performed among 901 motor-sawers occupationally exposed to motor-saw noise, and among 177 persons in a non-exposed control group. Hearing impairment of various degrees was found in 83.7% of motor-sawers examined. In 63.5% of motor sawers hearing impairment was due to noise exposure. The hearing impairment found, was in 88% a reciprocal receptive loss, more intensified in the left ear. It was positively correlated with motor-savers' age, duration of employment in exposure to motor-saw noise, and the amount of wood cut. The average hearing impairment in both ears was significantly higher among motor-sawers with hearing damage due to various causes, than among those with damage due to the motor-saw noise only, which proves a simultaneous overlapping of different factors inducing impairment, including motor-saw noise.