Effect of click rate on the latency of auditory brain stem responses in humans

The effect of the click repetition rate on the latency of the auditory evoked brain stem response and its clinical use for a neurological diagnosis

The effects of click repetition rate on the latency of the auditory brain stem responses (BSR) and its possible use as a clinical diagnostic tool of the brain stem disorders were investigated. When the click rate was increased, the latency of the BSR waves was prolonged. The latency of the later response components increased more than that of the earlier response components. This method was applied to the clinical cases with brain stem disorders. A case with a IVth ventricle epidermoid tumor showed a marked latency prolongation and disappearance of the waves at higher repetition rates. An explanation of the latency shift in the normal subjects and the abnormal responses of the patient to repetition rate is attempted.

Influence of the stimulus repetition rate on brain-stem-evoked responses in man

In order to record brain-stem-evoked responses as fast as possible, the influence of the stimulus repetition rate was investigated. The repetition frequency was varied from 2.5 to 80 Hz. The amplitudes of N2-N4 diminish uniformly with increasing stimulus rate. The repetition rate has little or no influence on the amplitude of N5; however, increasing the repetition frequency about 10 Hz causes an increase in the latencies of N2-N5. It seems that the decrease in the amplitude of N2-N4 and the increase in the latencies of N2-N5 are of cochlear origin, since the amplitude and the latency of the cochlear responses are influenced in the same way by the repetition rate as the above-mentioned brain stem responses.