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

Abstract

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.

<p>The Hypnotic Analgesia Suggestion Mitigated the Effect of the Transcranial Direct Current Stimulation on the Descending Pain Modulatory System: A Proof of Concept Study</p>

“…Through the 8 final minutes of the induction, suggestions were used to reduce the pain of the participants and increase control over their own sensations. 39 We used the protocol of HS previously published by Jansen, 28 which follows standardized steps (see the hypnotic analgesia suggestion protocol in the Supplemental material ( Appendix I )). The duration of experimental manipulation (induction + suggestions) is 20 min.…”

“…And, they give us new insight into the mechanism involved in hypnotic suggestion analgesia, which likely changes the cortical pain processing, whereas a-tDCS induced either downregulation of the pain-facilitating pathways or upregulation of the inhibitory function of the DPMS. 28 And, its effect was modulated positively by the serum brain-derived-neurotropic factor (BDNF). 28 Hypnotic analgesia is a social interaction in which one person (the subject) responds to suggestions given by another person (the hypnotist) to produce creative experiences that involve changes in perception, memory, and voluntary control.…”

“…28 And, its effect was modulated positively by the serum brain-derived-neurotropic factor (BDNF). 28 Hypnotic analgesia is a social interaction in which one person (the subject) responds to suggestions given by another person (the hypnotist) to produce creative experiences that involve changes in perception, memory, and voluntary control. 29,30 According to a meta-analysis, which included both laboratory and clinical studies, the effect size (ES) of hypnotic analgesia was moderate (ES = 0.71).…”

“…And, they give us new insight into the mechanism involved in hypnotic suggestion analgesia, which likely changes the cortical pain processing, whereas a-tDCS induced either downregulation of the pain-facilitating pathways or upregulation of the inhibitory function of the DPMS. 28 And, its effect was modulated positively by the serum brain-derived-neurotropic factor (BDNF). 28 …”

“… 28 And, its effect was modulated positively by the serum brain-derived-neurotropic factor (BDNF). 28 …”