High frequency thresholds: variations with age and industrial noise exposure.

The effects of age and noise exposure were investigated. 97 normal subjects representing 6 age groups were tested with both conventional pure tone audiometry and high frequency audiometry (10-20 kHz) using a commercial high frequency audiometer. Thresholds were obtained by means of earphones as opposed to a quasi-free field technique. The results were discussed in terms of the age effect. In addition, conventional and high frequency thresholds were obtained for 64 subjects who had a history of industrial noise exposure representing 4 age groups. Significant differences were found between the noise exposed group and the normal subjects. The implications of the results are discussed.