Recovery of auditory threshold following exposures to a pure tone and white noise.

Recovery from temporary threshold shift (TTS) was measured for a subject with normal hearing following exposures to a continuous pure tone 1000 Hz and white noise. The intensity of the exposure tone was 123, 117, and 110 dB SPL and the exposure duration was 21, 10, and 10 min, respectively. The intensity and duration of exposure to white noise were 123 dB SPL and 30 min. Automatic audiometer was used to obtain TTS and recovery at a frequency 1500 Hz measured from 1 min to 51 days, 6 days, and 23 h after exposures to 1000 Hz. For white noise, TTS and recovery were measured from 1 to 25 min. Results indicated that, (1) there was steady progression of recovery to pre‐exposure threshold, and (2) recovery was neither a simple linear nor monotonic process. These results were compared with our previous study of TTS and recovery obtained at various frequencies following exposures to pure tones 250 and 1000 Hz.