Cochlear Microphonics Recorded From The Ear Canal In Man

Abstract

By using average technique, cochlear micrc-phonics were recorded from an electrode in the ear canal, in response to 1 kHz-tone bursts, delivered via a μ-metal, magnetically shielded TDH 39 earphone in a closed acoustic system. No measurable artifacts could be recognized, either in normal ears or in deaf ears. The amplitude function is described from 65 dB to 120 dB p.e. SPL and appears to be similar to the established pattern in animals. The phase of the cochlear microphonic was compared with the phase of the stimuli in the ear canal, and the influence of the stapedius muscle contraction on amplitude and phase of the cochlear microphonic is briefly described. Besides the cochlear microphonics and the action potentials, a summating potential in response to 4 kHz-tone bursts was recorded. Cochlear microphonics in a few pathological ears are outlined. Approximately at a latency of 14 msec a multiphasic component was often present. The results are discussed.