经皮神经电刺激对实验性冷痛和热痛的对侧调制

The contralateral modulatory effects of transcutaneous electrical nerve stimulation on tonic heat and cold pain

目的本实验研究经皮神经电刺激(transcutaneous electrical nerve stimulation,TENS)对实验性冷痛试验(coldp ressor test,CPT)和热痛试验(tonic heat pain test,THPT)诱发的疼痛的对侧调制作用。方法20名右利手的健康男性大学生,参加基线阶段和调制阶段的实验。基线阶段包括CPT和THPT,要求被试以随机顺序把左手放入冷水(1℃)和热水(47℃)中各3min。调制阶段为左手诱发疼痛,右手接受TENS调制。用口头评分量表测量疼痛过程中的疼痛强度和不适度,用简易麦-吉量表(SF-MPQ)来评价被试对疼痛的主观感受。结果当被试左手诱发疼痛,TENS应用于右手正中神经位置时,显著降低了被试在THPT的疼痛强度和不适度以及SF-MPQ各项指标的评分。但是在CPT里,TENS没有明显的调制效果。结论TENS有调制对侧疼痛的作用,这种对侧镇痛作用证实了中枢机制的参与。对冷痛和热痛的不同调制作用提示TENS的镇痛效果部分受疼痛模型性质的影响。

Objective To investigate the modulation effect of transcutaneous electrical nerve stimulation（TENS）when applied contro- latarally to the hand of pain induced by two types of thermal tonic noxious stimulations. Methods Twenty healthy male subjects par- ticipated in a baseline（only tonic thermal pain）condition and pain modulation conditions（pain and TENS）. Subject put the non-domi- nant left hand into a thermal bath while the right hand received modulation. The ratings of pain intensity and distress were measured ev- ery 15 s during two separate tonic heat（47 ~C ,3 min）and tonic cold（ 1 ℃ ,3 min）pain tests. Additionally, subjective perception scored on the short-form McGill pain questionnaire（SF-MPQ）was analyzed. Results TENS exhibited significant pain modulation effects of intensity and distress measures in the heat, but not cold test. Likewise, the SF-MPQ results showed significant reduction in the heat, but not cold test. Conclusion The results suggest that clinicians can use TENS contralaterally to the site of pain where injury area may be difficult to achieve. A central inhibitory mechanism is induced by contralateral TENS. The differential modulation effects on cold pain and heat pain suggest that the analgesia of TENS may be partly dependent on the quality of pain modality.