Comparison of Impact noise and continuous noise on cochlear function

Abstract

Acute guinea pig preparations have been exposed to noise produced by a mechanical impact noise generator. Impacts were at a rate of 1/s and produced a peak sound pressure level of 130 dB at the preparation. Exposure periods of 20 min were used. Cochlear potentials in response to 6‐kHz tone bursts were recorded from differential electrodes in the basal cochlear turn. The extent of suppression and the time courses of decline and recovery associated with exposure to impact noise were measured. These results were compared with those occurring after exposure to continuous broad band white noise at an intensity such that the same total energy was delivered to the preparation over a similar 20 min period. Tone induced responses were found to be suppressed to a greater extent by impact noise although the recovery from this exposure was more rapid. The dependence of response suppression on the rate of impacts or peak intensity has also been investigated.