Analysis of auditory brain stem response sources along the basilar membrane to low-frequency filtered clicks

In order to complement the high-frequency auditory brain stem responses obtained in response to click acoustic stimuli, attempts have been made to elicit low-frequency responses by using low-frequency filtered clicks. The adequacy of these low-frequency stimuli was tested in patients with low-frequency hearing loss, and it was found that the electric response threshold was much better than the audiometric threshold to the center frequency of the filtered clicks. In addition, the responses to the low-frequency filtered clicks in normal subjects were very short in latency. However, when high-frequency noise was presented together with the low-frequency clicks, longer latency responses were obtained. These findings indicate that the high-frequency masking noise exposes low-frequency responses that were not otherwise apparent. Possible mechanisms and implications are discussed.