Davids Taryn, Valero Jerome, Papsin Blake C, Harrison Robert V, Gordon Karen A
Hospital for Sick Children Department of Otolaryngology-Head and Neck Surgery, 6th Floor, Elm Wing, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8.
Hear Res. 2008 Oct;244(1-2):7-14. doi: 10.1016/j.heares.2008.06.011. Epub 2008 Jul 25.
Discrepancies between electrophysiological and behavioral thresholds in cochlear implant users might be due to differences in stimuli such as the duration and rate of the electrical pulse train. In the present study, we asked: Is there an effect of stimulus duration on electrophysiological responses of the auditory brainstem, thalamo-cortex, and behavioral thresholds? In 5 pediatric cochlear implant users, behavioral thresholds in response to electrical pulse trains at 500 pulses per second (pps) were significantly lower for 40ms than 2ms duration pulse trains. Clear electrically evoked auditory brainstem responses (EABR) and electrically evoked middle latency responses (EMLR) were generated by single electrical pulses and 2, 6, and 10ms pulse trains (500pps) in 5 children. There was a linear decrease in the inter-wave latency between the eV of the EABR and the Na of the EMLR as duration increased. No significant effect of duration was found on eV latency relative to the last pulse in the train or Na latency relative to the onset of the stimuli. Behavioral threshold data is consistent with temporal integration of auditory activity. Electrophysiological data indicates that: (a) recognizable EABR and EMLR waveforms can be recorded in response to electrical pulse trains of up to 10ms; and (b) pulse train stimuli have unique effects on the auditory brainstem compared to thalamo-cortical areas.
人工耳蜗使用者的电生理阈值与行为阈值之间的差异可能是由于电脉冲序列等刺激因素的不同，如持续时间和频率。在本研究中，我们提出问题：刺激持续时间对听觉脑干、丘脑 - 皮层的电生理反应以及行为阈值是否有影响？在5名儿科人工耳蜗使用者中，对于每秒500次脉冲（pps）的电脉冲序列，40毫秒持续时间的脉冲序列所对应的行为阈值显著低于2毫秒持续时间的脉冲序列。在5名儿童中，单个电脉冲以及2、6和10毫秒脉冲序列（500pps）均可产生清晰的电诱发听觉脑干反应（EABR）和电诱发中潜伏期反应（EMLR）。随着持续时间增加，EABR的eV波与EMLR的Na波之间的波间潜伏期呈线性下降。未发现持续时间对相对于脉冲序列中最后一个脉冲的eV潜伏期或相对于刺激起始的Na潜伏期有显著影响。行为阈值数据与听觉活动的时间整合一致。电生理数据表明：（a）对于长达10毫秒的电脉冲序列可记录到可识别的EABR和EMLR波形；（b）与丘脑 - 皮层区域相比，脉冲序列刺激对听觉脑干有独特影响。
