Neurophysiological Correlates of Dissociation Induced by Virtual Reality Hypnosis.

Neurophysiological Correlates of Dissociation Induced by Virtual Reality Hypnosis (VRH) and Hypnosis (HYP) in a Healthy Participants.

Hypnosis and virtual reality are potential tools in treating acute pain. Nevertheless, the neurophysiological correlates of such tools used together, i.e. 'virtual reality hypnosis' (VRH) (Patterson et al., 2004) remain mostly understudied. This study aims to improve our knowledge and understanding of the dissociation (i.e., a mental separation of components of behaviours that normally would be processed together) occurring during VRH. This is a randomized controlled study that will be conducted on healthy participants. As the final goal is to propose such a tool in the clinical context, a clinical application will also be carried out subsequently. Thus the principal outcome is to study dissociation in the context of VRH from a behavioral and neurophysiological point of view. Secondary objectives aim at identifying factors that influence the dissociative effect seen in VRH, as well as measuring traits of hypnotisability, absorption, immersive abilities, dissociation trait and state, pain, and anxiety levels that might impact the effectiveness of such a tool.

The protocol will follow the following steps: Before the experiment: A medical screening of the medical history and of any concomitant medications will be performed to eligibility. The 6-item Elkins Hypnotisability Scale (EHS) will be used to assess participant hypnotisability. Questionnaire sur la Propension à l'Immersion (QPI) will be used to assess participant immersion tendency. Experimental session: Cross-over and within-participant control design i. Visual Analogue Scale (VAS) : Anxiety. Pain. ii. EEG Resting-state (5-Min.). iii. EEG VRH or EEG Hypnosis alone (HYP) (15-Min.). iv. Adverse Events (AE) during the protocol will be recorded. v. Narrative recording. vi. VAS : Dissociation Absorption Pain Anxiety Arousal/wakefulness Automaticity vii. Time perception (open question) viii. CyberSickness (CSQ) (only if VRH) ix. Presence Questionnaire x. Satisfaction questionnaire xi. Washout Phase (30-Min.) during which we will administer : Six-item State-Trait Anxiety Inventory (STAI-6) . Tellegen Absorption Scale . Dissociative Experience Scales (DES) . xii. VAS: Anxiety Pain xiv. Adverse Events during the protocol will be recorded. xv. Narrative recording. xvi. EEG HYP or EEG VRH Phase (15-Min.). xvii. VAS: Dissociation Absorption Pain Anxiety Arousal/wakefulness Time perception xviii. CSQ (only if VRH) xix. Presence Questionnaire. xx. Satisfaction Questionnaire .

Cross-over and within-participant control design: Participants will receive recorded hypnosis without VR.

HYP will last for 15 minutes including an induction phase of 5 minutes. The hypnotic audio script "Heaven of Peace" developped/recorded by Pr. M-E. Faymonville will be used.

Corresponds to a dissociation between the bodily sensations and the actual environment that one feels in a particular situation. will be assessed with a numerical rating scale (0= no dissociation; 10 = dissociation from environment).

The amount of dissociation one experiences in one's daily life. Will be assessed with the Dissociative Experience Scale, the higher the score, the more one experiences dissociation in one's daily life.

The susceptibility one has concerning hypnosis. Will be assessed with the Elkins Hypnotizability Scale. A score : 0-3 : low hypnotizability 4-7: medium hypnotizability 8-11 : high hypnotizability 12 : very high hypnotizability

The tendency to become fully involved in a perceptual, imaginative or ideational experience. Will be assessed with the Tellegen Absorption Scale, the higher the score the higher the absorption in the daily life.

Level of anxiety one experiences in one's daily life. Will be assessed with the STAI-6 questionnaire. The higher the score, the higher the anxiety one feels in one's daily life.

Immersion propensity is the amount of sensory input the virtual reality system creates. Will be assessed with the Immersion Propensity questionnaire. The higher the score, the more one is immersed in the virtual environments.

The amount of anxiety one experiences in a particular situation. Will be assessed with a visual analogy scale. a score = 0 means no anxiety at all, while a score = 10 means most anxiety ever felt.

The amount of absroption one experiences in a particular situation. Will be assessed with a numercial rating scale, 0 = no absorption; 10 = fully absorption by the experience.

The amount of pain one experiences in a particular situation. Will be assessed with a visual analogy scale, 0= no pain at all; 10= worst pain imaginable.

A non-voluntary response related to the content of a communication that is intended to be a suggestion. Will be assessed with a numerical rating scale : 0= perfect control; 10 = passive witness.

The amount of arousal one experiences in a particular situation. Will be assessed with a visual analogy scale, 0=not aroused, awaked; 10 = completely aroused, awake.

Assesses the sickness one might experience after the VRH. Will be assessed with the Cybersickness questionnaire. The higher the score, the more one has experience sickness during the VRH.

Refers to the degree to which the subject experiences being in the virtual environment. Will be assessed with the presence questionnaire, the higher the score the higher one has the feeling of really being in the virtual environment.

Assesses the overall satisfaction one has had with the VRH and HYP session. Will be assessed by a self-made satisfaction questionnaire, the higher the score, the more one is satisfied with the experience.

Inclusion Criteria: Subject more than 18 years old and equal or less than 65 years old. Exclusion Criteria: Low auditory and/or visual acuity precludes the use of the device. Head or face wounds precluding the use of the device. Schizophrenia, dissociative disorder or any other psychiatric disorder. Non-proficiency in French (Research language). Patient under 18 years old. Phobia of deep water. Allergy to cutaneous electrodes. Chronic pain and/or chronic analgesics consumption. Medication affecting the autonomic nervous system. Dizziness.