Manipulating the Perceived Shape and Color of a Virtual Limb Can Modulate Pain Responses

Abstract

Changes in body representation may affect pain perception. The effect of a distorted body image, such as the telescoping effect in amputee patients, on pain perception, is unclear. This study aimed to investigate whether distorting an embodied virtual arm in virtual reality (simulating the telescoping effect in amputees) modulated pain perception and anticipatory responses to pain in healthy participants. Twenty-seven right-handed participants were immersed in virtual reality and the virtual arm was shown with three different levels of distortion with a virtual threatening stimulus either approaching or contacting the virtual hand. We evaluated pain/discomfort ratings, ownership, and skin conductance responses (SCRs) after each condition. Viewing a distorted virtual arm enhances the SCR to a threatening event with respect to viewing a normal control arm, but when viewing a reddened-distorted virtual arm, SCR was comparatively reduced in response to the threat. There was a positive relationship between the level of ownership over the distorted and reddened-distorted virtual arms with the level of pain/discomfort, but not in the normal control arm. Contact with the threatening stimulus significantly enhances SCR and pain/discomfort, while reduced SCR and pain/discomfort were seen in the simulated-contact condition. These results provide further evidence of a bi-directional link between body image and pain perception.

The Rocketbox Library and the Utility of Freely Available Rigged Avatars

“…Several studies have demonstrated that virtual embodiment can modulate pain (Lenggenhager et al, 2010;Martini et al, 2014). In particular, it has been shown that pain perception is modulated by the visual appearance of the virtual body, including its color (Martini et al, 2013), shape (Matamala-Gomez et al, 2020), or level of transparency (Martini et al, 2015), as well as by the degree of spatial overlap between the real and the virtual bodies (Nierula et al, 2017). This is a relevant area regarding chronic pain-therapeutical applications (Matamala-Gomez et al, 2019b), although pain of different origins may require different manipulations of the embodied-avatars (Matamala-Gomez et al, 2019a).…”

“…Several studies have demonstrated that virtual embodiment can modulate it (Lenggenhager et al, 2010;Martini et al, 2014) with important implication for pain treatment applications (Matamala-Gomez et al, 2019a,b). In particular, it was shown that pain perception is modulated by the visual appearance of the virtual body, including its color (Martini et al, 2013), shape (Matamala-Gomez et al, 2020), and level of transparency (Martini et al, 2015), as well as by the degree of spatial overlap between the real and the virtual bodies (Nierula et al, 2017).…”

Body illusions for mental health: a systematic review

“…Over the last ten years, the development of the technology introduces the use of VR systems to reproduce the RHI in VR but allowing researchers to modify the morphological characteristics of the virtual limb. This specific characteristic could help deal with the link between pain and body image distortions in patients with chronic pain (Matamala-gomez et al, 2019;Matamala-Gomez et al, 2020). In this regard, in this systematic review, some studies used BOI toward body parts through virtual limbs, or virtual FBOI to manage pain perception in patients with chronic pain (Alphonso et al, 2012;Matamala-gomez et al, 2018;Ortiz-Catalan et al, 2016;Osumi et al, 2019;Pamment & Aspell, 2017).…”

User Experience and usability of a new virtual reality set-up to treat eating disorders: a pilot study

“…VR is an advanced form of human-computer interface that enables participants to interact with an immersive virtual environment which has naturalistic characteristics that the experimenter may manipulate for neuroscientific research or clinical applications (Riva et al, 2016;Spanlang et al, 2014). Through VR systems we can induce the feeling of being embodied in another body (Kilteni et al, 2012a), and modify the morphological characteristic of a virtual body (Kilteni et al, 2012b;Matamala-Gomez et al, 2020b). Following this line, full virtual body illusions through VR has been used to improve body representation in clinical populations with eating disorder patients, specifically in patients with AN (Corno et al, 2018;Keizer et al, 2016;Mölbert et al, 2018;Serino et al, 2019).…”

“…Particularly, today there is an increasing interest in the use of VR to modulate the mental body representation of healthy and clinical populations by means of body-illusions, that is the illusion of perceiving a fake body as if this was the real one (Matamala-Gomez et al, 2018, 2020bSerino et al, 2019). For instance, body illusions have been targeted towards specific body parts, such as in the case of the rubber hand illusion (RHI) (Botvinick and Cohen, 1998).…”