The effects of reversing the polarity of frequency-limited single-cycle stimuli on the human auditory brain stem response.

This study was conducted to investigate morphologic differences in the ABR as a result of reversing the stimulus polarity of frequency-limited single-cycle stimuli in normal-hearing subjects. The results clearly demonstrate that large latency differences occur between condensation and rarefaction stimuli for low-frequency stimuli. It is believed that polarity-specific latencies are a result of the highly phase-sensitive neural elements tuned to low-frequency stimuli. In the majority of test subjects the rarefaction stimulus produced shorter absolute wave latencies; however, in a small number of subjects, significantly shorter latencies were elicited with the condensation stimulus. It is believed that differences may occur from varying summation patterns of inner hair cell depolarization between subjects which would be consistent over time within the same subject.