Hearing loss among miners claiming compensation.

Otological and audiological evaluations were performed on 278 miners claiming compensation for noise-induced hearing loss (NIHL). Of the total sample, 28.7% had to be excluded as cases of nonmining NIHL. Of the cases of diagnosed as NIHL, approximately 50% showed an actual hearing impairment as based on a low fence of 25 dB for the average hearing levels at 0.5, 1, and 2 kHz, and 63% as based on the average hearing levels at 0.5, 1, 2, and 3 kHz for exposures of 15 to 49 years. No significant difference in NIHL was apparent except at 2 kHz between subjects exposed to intermittent vs intermittent-continuous noise. It was difficult to differentiate NIHL from sensorineural losses of other causes and impossible to apply an adequate correction factor for presbycusis.