Towards a Better Understanding of Temporary Threshold Shift of Hearing.

It was thought that Temporary Threshold Shift of hearing due to exposure to noise might be more easily understood if the shifts were considered in terms of the rms pressure rather than in dB. Therefore, the forms to be expected if the rate of shift of the pressure threshold were proportional to the difference between itself and the ultimate threshold were calculated, and compared with a limited selection of published data. Good agreement with data for the growth of TTS in individuals was found, and moderately good agreement with recovery. Agreement with data on intermittent exposures was poor, but this may be due in part to the fact that only averaged data have been found, and averaging the widely disparate figures obtained for individuals may mask the true effects. It is also shown that the maximum ultimate TTS due exposure to noise may be simply related to the mean square pressure of that noise. Further consideration of the mass of published work is needed, but this study suggests that at least some facets of TTS can be simply described in terms of exponential pressure shifts. Author