Stimulus duration and waves of auditory brainstem response.

This study was conducted to investigate the effects of stimulus duration on auditory brainstem response (ABR) waveform. Stimuli were 3-kHz tone bursts with 1 ms rise/fall times and durations of 5, 10, 20 and 30 ms. They were delivered at interstimuli intervals ranging from 80 to 140 ms. Latency and amplitude increases were observed in waves V and VI as the stimulus duration increased, whereas wave III showed no increase in latency, but decreased in amplitude. Animal experiments showed that the slowly rising curve of the response with increasing stimulus duration results in an increase in the peak latency and in the amplitude of the slow component of the ABR. Thus the change in ABR waveform observed when the duration of the stimulus was increased is not explained by a recovery process of the nervous system, but is possibly mediated by the slow component of the ABR.