Towards effective assessment of normal hearing function from ABR using time-variant sweep-tone stimulus approach.

The auditory brainstem response (ABR) audiometry is a means of assessing the functional status of the auditory neural pathway in clinic. The conventional click ABR lacks good neural synchrony and it mainly evaluates high-frequency hearing. Also, the common tone-burst ABR only detects hearing loss of a certain frequency per time. Besides, the existing chirp stimuli are designed based on average data of cochlear characteristics, ignoring individual differences amongst subjects. Therefore, this study designed a new stimulus approach based on a sweep-tone concept with a time-variant and spectrum characteristics that could be customized based on an individual's cochlear characteristics. To validate the efficiency of the proposed method, we compared its performances with the click and tone-bursts using ABR recordings from eleven normal-hearing adults. Experimental results showed that the proposed sweep-tone ABR achieved a higher amplitude compared with those elicited by the click and tone-bursts. When the stimulus level or rate was varied, the sweep-tone ABR consistently elicited a larger response than the corresponding click ABR. Moreover, the sweep-tone ABR appeared earlier than the click ABR under the same conditions. Specifically, the mean wave V peak-peak amplitude of the sweep-tone ABR was 1.3 times that of the click ABR at 70 dB nHL and 20/s, in which the former saved 40% of test time. In summary, the proposed sweep-tone approach is found to be more efficient than the traditional click and tone-burst in eliciting ABR.