Relationship between ABR Evoked by Clicks and Cochlear Function

Abstract

The auditory brain stem response (ABR) is a composite of several sequential fast wavelets and a positive slow wave. Relationships between both of each component and cochlear function are not completely clearified.
There have been two principal suggestions for specific origin of the click response. One view is that most parts of the cochlea are important for generation of the evoked response. The other view is that evoked response reflects mainly the activity of the most basal part of the cochlea. So, thresholds and waveforms of the ABRs evoked by clicks were examined in hearing-impaired subjects.
The results were as follows.
1) The threshold of the click evoked ABR reflected the cochlear function of the most sensitive area from 1kHz to 8kHz.
2) The fast waves were evoked only in the limited part of the cochlea covering high frequencies, whereas, the positive slow wave was evoked in the more expanded part of the cochlea covering both low and high frequencies.