ABSTRACT
OBJECTIVES: Changes in hearing thresholds were determined by standard and high-frequency audiometry in subjects exposed to occupational noise for long durations. PATIENTS AND METHODS: Hearing thresholds were measured between 250 and 16000 Hz frequencies by standard and high-frequency audiometry in 64 male workers (mean age 42 years; range 31 to 55 years) of a hydroelectric power plant and in 30 age- and sex-matched controls with no hearing problems. The workers were divided into three groups according to the noise level and into four groups according to the duration of exposure. RESULTS: The mean hearing thresholds of workers showed significant increases in all frequencies from 4000 to 16000 Hz (p<0.005), the most affected frequencies being 4000, 6000, 14000, and 16000 Hz (p<0.0005). Increases in hearing thresholds were significantly correlated with the noise level and duration of exposure to noise (p<0.05). CONCLUSION: The results suggest that high-frequency audiometry should be used together with standard audiometry in the detection and follow-up of individuals who are at potential risks for hearing losses.
