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[Findings of standard and high-frequency audiometry in workers exposed to occupational noise for long durations].

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.