接触性热痛诱发电位检测方法的建立及在腕管综合征中的应用

Establishment of a method of contact heat evoked potential and its application in carpal tunnel syndrome

目的建立接触性热痛诱发电位(CHEP)的检测方法,估测此诱发电位的外周神经传导速度,探讨其在腕管综合征中的应用。方法应用接触性热痛诱发电位刺激器,于两个强度水平应用可调节脉冲,刺激部位为鱼际肌、手背、前臂的掌侧面。受试者在每次刺激后,对刺激强度分级。以Keypoint.net 仪器记录,记录点为 Cz 和 Pz。测定刺激强度和疼痛分级的关系、诱发电位的主要成分及外周神经传导速度。结果刺激强度和疼痛分级的关系为:49.5℃和54.5℃刺激鱼际肌皮肤,疼痛分级分别为3.2±0.3,4.4±0.5;54.5℃刺激手背和前臂掌侧面皮肤,疼痛分级分别为6.3±0.8,7.2±0.5。记录到三个主要成分:Cz/N550、Cz/P750和 Pz/P1000,各波潜伏期与臂长有关。此诱发电位的外周神经传导速度分别为12.9 m/s±7.5 m/s,1.70 m/s±0.40 m/s,分别与 Aδ纤维和 C 纤维的传导速度相对应。腕管综合征患者中 Aδ纤维和 C 纤维的传导速度分别为12.0 m/s±5.6 m/s 和0.60 m/s±0.10 m/s。结论接触性热痛诱发电位能稳定、可靠引出;此诱发电位的外周神经为 Aδ纤维和 C 纤维。腕管综合征患者 C 纤维传导速度减慢。

Objective To establish a method to evoke cerebral potentials by stimulating nocieeptive fibers, estimate the conduction velocities of nerve fibers mediating these responses, and assess the value of the potentials in carpal tunnel syndrome. Methods One hundred patients with carpal tunnel syndrome and 20 sex-, and aged-matched healthy persons underwent stimulation of contact heat delivered via a circular thermode to excite selectively nociceptors with a rapid rising time at 70℃/s to elicit pain and contact heat evoked potential（CHEP）. Thermal stimuli were sent at two intensity levels （49.5℃ and 54.5℃ ） to three body sites： thenar eminence, dorsum of hand, and proximal volar forearm The CHEPs were recorded from Cz and Pz. The relation between the stimulus intensity and pain rating was observed, and the main components of the evoked potential were recorded. The nerve conduction velocity was calculated from the latency difference of the CHEP and center to center distance of distal and proximal stimulus arrays. Results The pain intensity ratings were 3.2 ± 0. 3 and 4. 4± 0. 5 when the thenar eminence was stimulated at the temperature Of 49.5℃ and 54. 5~C respectively; and the ratings were 6.3 ±0. 8 and 7.2 ±0.5 on the dorsum of hand and proximal volar forearm at the temperature of 54.5℃ respectively. Thtee components, Cz/N550, Cz/P750, and Pz/P1000, were found in the evoked potentials. The latency of the CHEP was significantly correlated with the ann length, and not significantly correlated with sex, age, and side difference of the arm. The conduction velocities of the A8 and C fibers of the carpal tunnel syndrome patients were 12.0 m/s ± 5.6 m/s and 0.6 m/s ± 0. 1 m/s respectively, both lowered, being 93.8% and 99.5% of those of the healthy persons （12. 9 m/s ±7.5m/s and 1.7 m/s ±0. 4m/s respectively）. Conduslon Elicited reliably, CHEP is mediated by A8 and C fibers. The conduction velocity of C fibers in the patients with carpal tunnel syndrome is decreased.