Determining auditory brain stem response threshold using an adaptive stimulus selection procedure

Auditory brain stem response (ABR) measurements provide a method to determine the hearing threshold of laboratory animals and humans who are unable to provide behavioral responses to auditory stimuli. Determining hearing threshold using ABR typically requires a large number of pre-selected frequency and stimulus levels, which may not be the most efficient method to sample the stimulus space. The goal of the current study is to develop an adaptive procedure that determines in situ the stimulus that will provide the best estimate of the threshold, based on data collected earlier in the procedure. A Gaussian Process model is iteratively fitted after each testlevel, and the subsequent test level is chosen at the interim threshold estimate predicted by the current model fit. Simulations of the adaptive procedure were conducted using previously collected toneburst ABR measurements from mice presented at 5 dB increments from 0 to 80 dB at seven frequencies ranging from 4 to 32 kHz. The thresholds determined by this procedure were compared to those produced by human raters who viewed the response at all stimulus levels. Initial results indicate that the threshold may be accurately estimated utilizing fewer stimuli levels than current methods, thereby reducing the duration of the measurements.