Introduction
The obvious relationship between noise in industry and occupational deafness has resulted in considerable research being concentrated on the deafening effects of noise as measured by temporary threshold shift. As a result of this approach, the greater emphasis has fallen on the measurement of auditory fatigue resulting from exposure to intense sounds. The crucial question of the critical intensity level in effecting pathological damage to the ear has been answered only vaguely. Estimates of maximum noise levels to which the hearing organ may be exposed before suffering pathological trauma range between 80 and 100 db.1-5However, threshold shift has also been demonstrated for exposure to stimuli at low intensities in studies of auditory fatigue resulting from stimulation by pure tones. In recent experimental work on poststimulatory auditory fatigue, a differentiation between deafness due to traumatic stimulation by extremely loud sounds and a decrease in sensitivity due to stimulation