ABSTRACT

The mechanisms underlying pain modulation by hypnosis and the contribution of hypnotic induction to the efficacy of suggestions being still under debate, our study aimed, (1) to assess the effects of identical hypoalgesia suggestions given with and without hypnotic induction, (2) to compare hypnotic hypoalgesia to distraction hypoalgesia and (3) to evaluate whether hypnotic suggestions of increased and decreased pain share common psychophysiological mechanisms. To this end, pain ratings, nociceptive flexion reflex amplitude, autonomic responses and electroencephalographic activity were measured in response to noxious electrical stimulation of the sural nerve in 20 healthy participants, who were subjected to four conditions: suggestions of hypoalgesia delivered with and without hypnosis induction (i.e. hypnotic-hypoalgesia and suggested-hypoalgesia), distraction by a mental calculation task and hypnotic suggestions of hyperalgesia. As a result, pain ratings decreased in distraction, suggested-hypoalgesia and hypnotic-hypoalgesia, while it increased in hypnotic-hyperalgesia. Nociceptive flexion reflex amplitude and autonomic activity decreased during suggested-hypoalgesia and hypnotic-hypoalgesia but increased during distraction and hypnotic-hyperalgesia. Hypnosis did not enhance the effects of suggestions significantly in any measurement. No somatosensory-evoked potential was modulated by the four conditions according to strict statistical criteria. The absence of a significant difference between the hypnotic hypoalgesia and hyperalgesia conditions suggests that brain processes as evidenced by evoked potentials are not invariably related to pain modulation. Time-frequency analysis of electroencephalographic activity showed a significant differentiation between distraction and hypnotic hypoalgesia in the theta domain. These results highlight the diversity of neurophysiological processes underlying pain modulation through different psychological interventions.

摘要

催眠调节疼痛的机制以及催眠诱导对建议有效性的贡献仍在争论中，我们的研究旨在（1）评估在有和没有催眠诱导的情况下给出的相同痛觉减退建议的影响，（2）比较催眠性痛觉减退到分散性痛觉减退和（3）评估增加和减少疼痛的催眠暗示是否具有共同的心理生理机制。为此，在 20 名健康参与者的腓肠神经受到有害电刺激时，测量了疼痛等级、伤害性屈曲反射幅度、自主神经反应和脑电图活动，这些参与者经历了四种情况：在有和没有催眠诱导的情况下提供的痛觉减退建议（IE 催眠 - 痛觉过敏和建议 - 痛觉过敏），心算任务分散注意力和痛觉过敏的催眠建议。结果，在分散注意力、建议性痛觉减退和催眠性痛觉过敏中疼痛评分降低，而在催眠性痛觉过敏中增加。伤害性屈曲反射幅度和自主神经活动在建议的痛觉减退和催眠-痛觉减退期间减少，但在分心和催眠-痛觉过敏期间增加。在任何测量中，催眠都没有显着增强建议的效果。根据严格的统计标准，四种条件均未调节体感诱发电位。催眠性痛觉减退和痛觉过敏状况之间没有显着差异表明诱发电位所证明的大脑过程并不总是与疼痛调制相关。脑电图活动的时频分析表明在θ域中分心和催眠性痛觉减退之间存在显着差异。这些结果突出了通过不同心理干预进行疼痛调节的神经生理过程的多样性。