Behaviour of High-Frequency Hearing in Noise

Abstract

Because of an improved coupling and of special loudspeakers high-frequency (HF) audiometry may now be used for routine audiometry. Examinations of 200 weaving-mill workers showed hearing threshold levels with a broad dip at about 4 or 6 kHz but with relatively good hearing at about 11 and 12 kHz. The greatest hearing threshold shifts were observed at 15 kHz and above. The course of the curves clearly showed a dependence on the noise level. With most cases of acute acoustic traumata there was a total loss in the HF range reaching far into the frequency range of normal hearing. This pattern is correlated with the area of destruction of the hair cells in the cytocochleogram. Another characteristic course of the curves was marked by an extreme hearing loss in the HF range showing, however, a horizontal course. A similar cytohistogram could not be found in the literature.

Key Words:

• High-frequency audiometry
• Acute and chronic acoustic trauma
• Cytocochleogram