Contralaterally evoked transient otoacoustic emissions

Abstract

Contralaterally evoked transient otoacoustic emissions (CETOAEs) were recorded from 10 normal-hearing young adults (20 ears) in response to monaural, 11/s, 65 dB pe SPL clicks to the ear contralateral to the microphone probe. A burst of CETOAEs was observed 12–22 ms (average peak at 18.5 ms) after the contralateral click, and its mean level was −7.3 dB pe SPL, 4 dB above the averaged noise level. The frequency content of CETOAEs included a prominence around 1 kHz. In 40% of the ears examined CETOAEs were 3 dB or more above noise level in both replications of records from the same ear. To explain these results CETOAEs are suggested to reflect mechanical events induced by the crossed efferent system in the cochlea that was contralateral to the stimulated ear. The latency of the contralateral responses suggests that they may be related to the contralateral suppression effect observed with binaural stimulation. The latency of the response, coupled with the anatomical origin of the crossed efferent system at the superior olivary complex, suggest its involvement in the contralateral CETOAEs reported here.