Comparison of click and CE-chirp-evoked human auditory brainstem responses: a preliminary study

摘要

Background and Aim: CE-Chirp stimulus has been developed for stimulating more apical regions of the cochlea. Inadequacy of clinical information on the latency and amplitude characteristics of ABR evoked by CE-chirp at different levels in addition to discrepancy in identifying earlier ABR waveforms using CE-chirp stimulus are the reasons of this study.Methods: This study was done by recoding ABR to click and broad-band CE-chirp stimuli in the right ear of 15 non-randomly selected normal-hearing individuals with age range of 20-30 years old. Frequency of recordable waves I and III, as well as threshold, amplitude, and latency of wave V were compared in response to click and CE-Chirp at 20-80 dB nHL.Results: At 80 dB nHL, click stimulus evokes waves I and III more frequently than chirp stimulus (p=0.012 and p=0.016 respectively). At 20 and 40 dB nHL, wave V latency evoked by CE-Chirp is significantly longer than wave V latency evoked by click (p=0.012 and p=0.0001 respectively); however, at 80 dB nHL wave V latency evoked by CE-Chirp is shorter than click (p=0.0001). Wave V amplitude for CE-Chirp is significantly larger than for click at levels of 20, 40 and 60 dB nHL (p=0.0001, p=0.0001 and p=0.013 respectively). Wave V threshold is approximately 5 dB lower with CE-chirp compared to click (p=0.014).Conclusion: Except at high levels, CE-Chirp evokes wave V with larger amplitude and lower threshold than click. Possibility of recording earlier ABR waves is reduced with CE-chirp stimulus.