TINNITUS IN NOISE-EXPOSED WORKERS

Tinnitus is said to be a common complaint of workers who are exposed to noise. We studied the prevalence and characteristics of tinnitus in 647 noise-exposed workers who had been notified as cases of noise-induced deafness. One hundred and fifty-one had tinnitus, giving a prevalence of 23.3 percent. The tinnitus was bilateral in 42.4 per cent of cases, and of high frequency in 44.4 per cent. In 23.8 per cent it was associated with other symptoms. About 30 per cent of those with tinnitus complained that it interfered with daily activities like telephone conversation and sleep. The workers with tinnitus had consistently higher hearing thresholds at both high and low frequencies than those with no tinnitus. This finding remained even after adjusting for differences in sex, age and ethnic group composition and in the noise exposure duration. Workers are often told that noise exposure causes deafness, but little is mentioned about tinnitus. Awareness of the possible occurrence of tinnitus may encourage workers to cooperate more actively in a company hearing conservation programme.