Human Auditory-Nerve Action Potentials and Cochlear Microphonics Recorded Nonsurgically

Abstract

Auditory‐nerve action potentials (APs) and cochlear microphonics were recorded from human subjects by placing a needle electrode in the external auditory canal and averaging the responses. A series of control experiments demonstrated that valid records of human auditory‐nerve APs and cochlear microphonics were obtained. However, human click APs differ from those of animals in that the second peak (N 2) is usually less prominent in humans. An attempt to correlate click loudness with click AP amplitude showed that AP amplitude reaches a peak at about 60 dB SL, whereas loudness continues to increase as click intensity is increased well beyond this level. However, there was a much better correlation between recovery of click loudness following masking (“auditory adaptation”) and recovery of click AP amplitude.