Effect of temperature on cochlear responses during and after exposure to noise

Abstract

Anesthetized chinchillas were maintained in the quiet for 24–48 h with virtually no loss of maximum voltage or sensitivity of cochlear microphonics (CM). Changes in body temperature and cochlear temperature from 29° to 39 °C had little effect on normal CM. With presentation of steady octave‐band noise with center frequency of 1 kHz at 90 dB SPL overall, CM decreased and approached an asymptote at a rate dependent on the temperature of the preparation. The rate of reduction was less at low temperatures than at high temperatures. With termination of the noise, an initial rapid recovery of CM preceded a slow recovery toward normal CM values. The slow recovery was inhibited at low temperatures, and could be enhanced by raising the temperature. These studies indicate that noise‐induced reduction of CM may be linked to processes of energy metabolism and/or may involve temperature‐dependent structural changes that do not affect normal cochlear response. Subject Classification: [43]65.66, [43]65.40, [43]65.35.