Table_1_Comparison of Hypnotic Suggestion and Transcranial Direct-Current Stimulation Effects on Pain Perception and the Descending Pain Modulating System: A Crossover Randomized Clinical Trial.DOCX

Objectives: This paper aims to determine if hypnotic analgesia suggestion and transcranial direct-current stimulation (tDCS) have a differential effect on pain perception. We hypothesized that transcranial direct-current stimulation would be more effective than hypnotic analgesia suggestion at changing the descending pain modulating system, whereas the hypnotic suggestion would have a greater effect in quantitative sensory testing.Design: This is a randomized, double blind and crossover trial.Settings: All stages of this clinical trial were performed at the Laboratory of Pain and Neuromodulation of the Hospital de Clínicas de Porto Alegre.Subjects: Were included 24 healthy females aged from 18 to 45 years old, with a high susceptibility to hypnosis, according to the Waterloo-Stanford Group Scale of Hypnotic Susceptibility, Form C (15).Methods: The subjects received a random and crossover transcranial direct-current stimulation over the dorsolateral prefrontal cortex (2 mA for 20 min) and hypnotic analgesia (20 min).Results: Only hypnotic suggestion produced changes that are statistically significant from pre- to post-intervention in the following outcomes measures: heat pain threshold, heat pain tolerance, cold pressure test, and serum brain-derivate-neurotrophic-factor. The analysis showed a significant main effect for treatment (F = 4.32; P = 0.04) when we compared the delta-(Δ) of conditioned pain modulation task between the transcranial direct-current stimulation and hypnotic suggestion groups. Also, the change in the brain-derivate-neurotrophic-factor was positively correlated with the conditioned pain modulation task.Conclusion: The results confirm a differential effect between hypnotic suggestion and transcranial direct-current stimulation on the pain measures. They suggest that the impact of the interventions has differential neural mechanisms, since the hypnotic suggestion improved pain perception, whereas the transcranial direct-current stimulation increased inhibition of the descending pain modulating system.Clinical Trial Registration:www.ClinicalTrials.gov, identifier NCT03744897.Perspective: These findings highlight the effect of hypnotic suggestion on contra-regulating mechanisms involved in pain perception, while the transcranial direct-current stimulation increased inhibition of the descending pain modulating system. They could help clinicians comprehend the mechanisms involved in hypnotic analgesia and transcranial direct-current stimulation and thus may contribute to pain and disability management.

本论文旨在探究催眠镇痛暗示与经颅直流电刺激（tDCS）对疼痛感知是否具有差异性影响。本研究假设，经颅直流电刺激在改变下行疼痛调节系统方面可能比催眠镇痛暗示更为有效，而催眠暗示在定量感觉测试中可能产生更大的影响。研究设计：本研究为一项随机、双盲和交叉试验。试验环境：本临床试验的所有阶段均在波尔图阿雷格里斯临床医院的疼痛与神经调节实验室进行。研究对象：纳入了24名年龄介于18至45岁之间、根据沃特卢-斯坦福催眠易感量表C型（15）具有高度催眠易感性的健康女性。研究方法：受试者接受了随机交叉的经颅直流电刺激（在背外侧前额叶皮层进行，电流强度为2mA，持续20分钟）和催眠镇痛治疗（持续20分钟）。研究结果：仅在催眠暗示下，以下结果指标从干预前到干预后产生了具有统计学意义的改变：热痛阈、热痛耐受度、冷压测试和血清脑源性神经营养因子。分析显示，当比较经颅直流电刺激组和催眠暗示组条件性疼痛调节任务的delta-(Δ)值时，治疗因素具有显著的主效应（F = 4.32；P = 0.04）。此外，脑源性神经营养因子的变化与条件性疼痛调节任务呈正相关。研究结论：结果表明，催眠暗示与经颅直流电刺激对疼痛测量指标具有差异性影响。这表明，干预措施的影响具有不同的神经机制，因为催眠暗示改善了疼痛感知，而经颅直流电刺激增加了下行疼痛调节系统的抑制。临床试验注册：www.ClinicalTrials.gov，注册号为NCT03744897。研究展望：这些发现突出了催眠暗示对参与疼痛感知的逆调节机制的影响，同时经颅直流电刺激增加了下行疼痛调节系统的抑制。这些发现有助于临床医生理解催眠镇痛和经颅直流电刺激的机制，从而可能有助于疼痛和残疾管理。