Investigating the nociceptive neural responses under focused hypnotic analgesia: local and remote effects

Details

Supervisors

Legrain, Valéry

Faculty

Faculté de pharmacie et des sciences biomédicales

Degree label

Master [120] en sciences biomédicales, à finalité approfondie

Abstract

Pain is a major healthcare issue and a better understanding of the physiological mechanisms underlying it and the psychological and cognitive factors that can modulate it is necessary to help diagnose and treat pain. There is evidence that focused hypnotic analgesia using the suggestion of a protective glove on one arm can reduce the perception of pain and its physiological responses. Nevertheless, experiences using focused hypnotic analgesia have not yet investigated the potential selective effect of this technique on pain processing by comparing the nociceptive brain response elicited by nociceptive stimuli applied on the two arms, the arm concerned by the focused hypnotic analgesia, the local arm, and the other arm considered as the control arm, the remote arm. Therefore, the aim of this study is to investigate the effect of focused hypnotic analgesia on pain perception and nociceptive ERPs using contact heat stimulation. For this, two experiments were conducted. In the first one, 40 healthy subjects participated. This consisted of collecting pain and unpleasantness evaluations after each nociceptive stimulation delivered either to the protected forearm or to the unprotected forearm. For the second one, ERPs were recorded for 15 healthy volunteers in response to nociceptive stimuli delivered either to the protected forearm or to the unprotected forearm. For the first experiment, repeated measures ANOVAs performed on the pain ratings showed a significant decrease in the ratings during the suggestion as compared to before. There is also a significant difference between the two arms, with lower ratings when the stimulations were applied on the suggested arm compared to the unprotected arm, confirming that the protective glove was efficient on the arm on which it was built. For the second one, there are no significant results, either for differences in amplitudes or latencies of the ERPs components when nociceptive stimuli have been applied on both arms and hypnotization was focused on one limb by the method of the protective glove, mainly because the experiment is still in progress and that more subjects have to be tested.