Finneran James J
U.S. Navy Marine Mammal Program, Space and Naval Warfare Systems Center Pacific Code 71510, 53560 Hull Street, San Diego, California 92152, USA.
J Acoust Soc Am. 2017 Aug;142(2):1034. doi: 10.1121/1.4999072.
Auditory brainstem response (ABR) measurements using conventional averaging (i.e., constant interstimulus interval, ISI) are limited to stimulus rates low enough to prevent overlapping of the ABRs to successive stimuli. To overcome this limitation, stimuli may be presented at high rates using pseudorandom sequences (e.g., maximum length sequences) or quasi-periodic sequences; however, these methods restrict the available stimulus sequences and require deconvolution to recover the ABR from the overlapping responses. Randomized stimulation and averaging (RSA) is an alternate method where evoked responses at high rates are obtained by averaging responses to stimuli with ISIs drawn from a random distribution. The RSA method enables precise control over stimulus jitter, is flexible with respect to stimulus sequence parameters, and does not require deconvolution to extract the ABR waveform. In this study, ABRs were measured in three normal-hearing dolphins using conventional averaging and RSA. Results show the RSA method to be effective in dolphins if the ISI jitter ≥ ∼1.5 ms and that the influence of stimulus artifacts in the averaged ABR can be substantially reduced by alternating stimulus polarity on successive presentations rather than employing digital blanking or iterative processes.
使用传统平均法（即恒定刺激间隔，ISI）进行听觉脑干反应（ABR）测量，其刺激率必须足够低，以防止ABR与连续刺激重叠。为克服这一限制，可使用伪随机序列（如最大长度序列）或准周期序列以高刺激率呈现刺激；然而，这些方法限制了可用的刺激序列，并且需要进行去卷积以从重叠反应中恢复ABR。随机刺激与平均法（RSA）是另一种方法，通过对来自随机分布的ISI的刺激反应进行平均，以获得高刺激率下的诱发反应。RSA方法能够精确控制刺激抖动，在刺激序列参数方面具有灵活性，并且不需要去卷积来提取ABR波形。在本研究中，使用传统平均法和RSA对三只听力正常的海豚进行了ABR测量。结果表明，如果ISI抖动≥约1.5毫秒，RSA方法在海豚中是有效的，并且通过在连续呈现时交替刺激极性，而不是采用数字消隐或迭代过程，可以显著降低平均ABR中刺激伪迹的影响。
