Virtual social touch on embodied avatars in patients with fibromyalgia

Introduction: Fibromyalgia (FM) is a syndrome characterized by chronic widespread pain. Among all the aspects of quality of life impaired by FM, social functioning is one of the most affected. Considering that social touch represents one of the preferred channels to establish and maintain personal relationships, we investigated how ‘vicarious’ social touch is perceived in FM, using Virtual Reality (VR), combined with physiological recordings. Methods: Two groups of women were recruited (FM and age-matched healthy controls). Participants were lying on a deckchair and were presented with a VR scenario showing a female avatar in underwear matching their real position. 24 virtual pleasant touches (3cm/sec) were delivered by another female avatar on 6 different body parts, categorized in previous studies as neutral (knee and foot), social (head and hands), and intimate (breast and pelvis). Participants were asked to rate the perceived appropriateness, pleasantness, erogeneity, and ownership for the touched body part evoked by each virtual stimulus, using 0-100 Visual Analogue Scales (VAS). Skin Conductance Response and Heart Rate were recorded during teach trial. Results: The analysis showed that the virtual touch on the intimate area was perceived as less appropriate, less pleasant but more erogenous as compared to the social and neutral ones in both groups. Furthermore, FM reported higher ratings of appropriateness, pleasantness, and erogeneity as compared to HC. No differences emerged between the groups in ownership ratings, mood, and affective dimensions. Discussion: Our results seem to suggest that although the qualitative evaluation of touch and the ownership over the virtual body parts did not vary between the two groups, FM patients’ ratings were higher than controls. A generalized increased response to touch is suggested, while the hypothesis of anhedonia to gentle touch is not confirmed, at least for virtual touches. These results might be relevant when considering touch as a therapeutic practice for FM.