Auditory‐Threshold Recovery after Exposures to Pure Tones

A modified Bekesy‐type audiometer was used to obtain a continuous recording of the auditory threshold before and after monaural exposures to different durations and intensities of pure tones. Preliminary studies confirmed the observations of Reger that the amount of temporary hearing loss at 1 kc following a 1‐min exposure to a 1‐kc tone is greater when the stimulating tone is 20 db above threshold than when it is 80 db above threshold. Temporary hearing loss at higher frequencies, however, increases with exposure level. These preliminary results led to an investigation of the dependence of temporary hearing loss on the duration and the intensity of exposure tones.Recovery curves for the threshold at 1 kc following exposure by 1 kc indicate that exposure tones at or above 60 db sensation level yield a rapid recovery followed by either a slowing down of the recovery process or a second rise in the threshold. Following exposure to a 20‐db tone, however, this rapid recovery is not so apparent, and therefore,...