Effect of high stimulation rates and paired stimuli on the electrically evoked brain‐stem response

Abstract

Temporal cues are a primary source of information for the single‐channel cochlear implant subject. Two temporal features of the electrical auditory brain‐stem response (EABR) in patients implanted with single‐channel devices are being investigated. In the first of these studies the stimulus rate is varied from 10 to 150/s and changes in wave V amplitude and latency are recorded. Increasing the stimulus repetition rate causes a prolongation of wave V latency and a decrease in amplitude. These changes are particularly prominent for stimulation rates exceeding 70/s. In the second experiment the EABR response to the second stimulus of a stimulus pair is computed as the time interval between the two stimuli is varied from 0.5 to 10 ms. Initial data indicate a significant interaction only for interstimulus intervals less than 4 ms. In these two studies, variations across patients have been found and an attempt is being made to correlate these variations with other measures of the subjects' implant performance. Findings and clinical implications will be reported.