Investigating the impact of focused hypnotic analgesia on the nociceptive neural response: an electrophysiological study

Details

Supervisors

Legrain, Valéry

Faculty

Faculté de psychologie, logopédie, sexologie et des sciences de la famille

Degree label

Master [120] en sciences psychologiques, à finalité spécialisée

Abstract

Abstract Pain is a multidimensional experience essential for human survival, shaped by the complex interplay of sensory inputs, emotions, cognitions, and behavior. Factors such as stress, attention, and hypnosis can significantly modulate pain perception (Acapo et al., 2017; Legrain & Torta, 2015; Zachariae et al.,1991). Hypnosis has consistently and efficiently been shown to alter pain perception, making it a promising therapeutic option in pain management (Arendt-Nielsen et al., 1990; De Pascalis et al., 2001; De Pascalis et al., 2007; Friederich et al., 2001; Zachariae & Bjerring, 1994). However, the neurophysiological mechanisms underlying this effect may produce inconsistent results (Valentini et al., 2013) and remain underexplored, particularly regarding the selective effect of hypnosis (Benhaiem et al., 2001; Paqueron et al., 2019; Sharav and Tal, 2006). This study investigates the psychophysiological mechanisms of focused hypnotic analgesia. Thirty healthy participants underwent nociceptive thermal stimulations on both forearms, during which they reported the perceived intensity of the stimulation. Concurrently, contact heat-evoked potentials (CHEPs) were recorded using electroencephalography (EEG) across three stages: Before, During, and After the induction of focused hypnotic analgesia. The intervention involved a hypnotic suggestion of a protective glove applied to one arm (i.e, Protected arm), while the other arm served as a control (i.e, Unprotected). The results showed that perceived pain intensity decreased in both arms during focused hypnotic analgesia, indicating no selective effect of the protective glove. Early nociceptive processing was unaffected by hypnosis. However, the later stages of nociceptive processing were significantly impacted, with a reduction in the amplitudes of the P2 component and the N2-P2 complex during hypnosis with a persistent post-hypnosis effect. Latencies for all components remained consistent throughout the experiment, suggesting no significant change in conduction velocity.