用一次性非痛刺激记录痛觉诱发电位的研究

STUDY ON PAIN RELATIVE EVOKED POTENTIALS ELICITED BY SINGLE NON - PAIN STIMULATION

目的:探讨引导痛觉相关诱发电位(PREPs)的无创性电刺激方法。方法:右拇指 (食指)、Erb氏点表面电刺激,头皮Cz-A1A2导联记录,刺激方波脉宽0.5ms,强度5-70mA可 调,在不事先预告的情况下一次性给予。结果:各种刺激强度下,均在刺激后200ms前后出现N2- P3-N3三相波,主波P3即P240(P250)波幅最高也最稳定,波幅数+微伏,远大于SSEP;一次性刺 激与10次刺激平均波形相似;刺激强度改变不影响潜时,仅影响波幅;30mA刺激强度基本无痛或 仅有微痛,能够耐受,且此强度下的末梢上行传导速度为18.0±8.6m/s,比其他强度更符合Aδ纤 维传导特性,P3潜时比体感P300短50-60ms,一次性刺激也不存在引导P300那样的认知过程,故 PREP并非体感P300。结论:本研究发展了一种研究痛觉相关诱发电位的新方法--无痛无创性一 次性30mA非预告性电刺激,用此法所获末梢传入传导速度在Aδ纤维范围,且与P300无关。

Objective: To explore the non - pain electrical stimulation method to elicit pain relative evoked potentials (PREPs). Method: The evoked potentials were elicited by surface electrical stimuli on right thumb (fore finger) and Erb's point in 24 healthy volunteers and were recorded at scalp Cz - A1A2. Pulse width of stimulate square wave was 0. 5ms, and intensity range was from 5mA to 70mA. Single stimulation was applied without informing in advance. Results: In different stimulate intensity, the evoked potentials were always N2 - P3 - N3 triphasic waves about 200ms after stimulation. The amplitudies of the main waves P3, namely P240 ( P250) were steady and highest than SSEPs. The PREPs wave shape by single stimulus was similar to the average results of 10 stimuli. Variety of stimulate intensity affected only on the amplitudes, but not the latencies. The stimulate intensity of 30mA could be felt no pain or slight endurable pain. Under the intensity, the ascending condution velocity of terminal nerve was 18. 0±8.0ms, which was more corresponding to conduct character of A fibre. The latency of P3 shortened 50 - 60ms than that of P300 with somatosensory stimulus. And single stimulus didn't possess the congnitive process as well as P300. Conclusion: A new method is developed in the study. In this method, single 30mA electrical stimulus can elicit PREPs without producing pain and wound. Also, in this method, the conduction velocity is proved to be corresponding to conduct character of A fiber, and PREPs hasn't relation with P300.