Bodily resonance: Exploring the effects of virtual embodiment on pain modulation and the fostering of empathy toward pain sufferers

Globally, around 20% of people suffer from chronic pain, an illness that cannot be cured and has been linked to numerous physical and mental conditions. According to the BioPsychoSocial model of pain, chronic pain presents patients with biological, psychological, and social challenges and difficulties. Immersive virtual reality (VR) has shown great promise in helping people manage acute and chronic pain, and facilitating empathy of vulnerable populations. Therefore, the first research trajectory of this dissertation targets chronic pain patients’ biological and psychological sufferings to provide VR analgesia, and the second research trajectory targets healthy people to build empathy and reduce patients’ social stigma. Researchers have taken the attention distraction approach to study how acute pain patients can manage their condition in VR, while the virtual embodiment approach has mostly been studied with healthy people exposed to pain stimulus. My first research trajectory aimed to understand how embodied characteristics affect users’ sense of embodiment and pain. Three studies have been carried out with healthy people under heat pain, complex regional pain syndrome patients, and phantom limb pain patients. My findings indicate that for all three studies, when users see a healthy or intact virtual body or body parts, they experience significant reductions in their self-reported pain ratings. Additionally, I found that the appearance of a virtual body has a significant impact on pain, whereas the virtual body’s motions do not. Despite the prevalence of chronic pain, public awareness of it is remarkably low, and pain patients commonly experience social stigma. Thus, having an embodied perspective of chronic pain patients is critical to understand their social stigma. Although there is a growing interest in using embodied VR to foster empathy towards gender or racial bias, few studies have focused on people with chronic pain. My second trajectory explored how researchers can foster empathy towards pain patients in embodied VR. To conclude, this dissertation uncovers the role of VR embodiment and dissects embodied characteristics in pain modulation and empathy generation. Finally, I summarized a novel conceptual design framework for embodied VR applications with design recommendations and future research directions

Seeing pain and pleasure on self and others: behavioural and psychophysiological reactivity in immersive virtual reality

Studies have explored behavioral and neural responses to the observation of pain in others. However, much less is known about how taking a physical perspective influences reactivity to the observation of others' pain and pleasure. To explore this issue we devised a novel paradigm in which 24 healthy participants immersed in a virtual reality scenario observed a virtual: needle penetrating (pain), caress (pleasure), or ball touching (neutral) the hand of an avatar seen from a first (1PP)- or a third (3PP)-person perspective. Subjective ratings and physiological responses [skin conductance responses (SCR) and heart rate (HR)] were collected in each trial. All participants reported strong feelings of ownership of the virtual hand only in 1PP. Subjective measures also showed that pain and pleasure were experienced as more salient than neutral. SCR analysis demonstrated higher reactivity in 1PP than in 3PP. Importantly, vicarious pain induced stronger responses with respect to the other conditions in both perspectives. HR analysis revealed equally lower activity during pain and pleasure with respect to neutral. SCR may reflect egocentric perspective, and HR may merely index general arousal. The results suggest that behavioral and physiological indexes of reactivity to seeing others' pain and pleasure were qualitatively similar in 1PP and 3PP. Our paradigm indicates that virtual reality can be used to study vicarious sensation of pain and pleasure without actually delivering any stimulus to participants' real body and to explore behavioral and physiological reactivity when they observe pain and pleasure from ego- and allocentric perspectives

Presence and rehabilitation: toward second-generation virtual reality applications in neuropsychology

Virtual Reality (VR) offers a blend of attractive attributes for rehabilitation. The most exploited is its ability to create a 3D simulation of reality that can be explored by patients under the supervision of a therapist. In fact, VR can be defined as an advanced communication interface based on interactive 3D visualization, able to collect and integrate different inputs and data sets in a single real-like experience. However, "treatment is not just fixing what is broken; it is nurturing what is best" (Seligman & Csikszentmihalyi). For rehabilitators, this statement supports the growing interest in the influence of positive psychological state on objective health care outcomes. This paper introduces a bio-cultural theory of presence linking the state of optimal experience defined as "flow" to a virtual reality experience. This suggests the possibility of using VR for a new breed of rehabilitative applications focused on a strategy defined as transformation of flow. In this view, VR can be used to trigger a broad empowerment process within the flow experience induced by a high sense of presence. The link between its experiential and simulative capabilities may transform VR into the ultimate rehabilitative device. Nevertheless, further research is required to explore more in depth the link between cognitive processes, motor activities, presence and flow

Interactive Gaming Reduces Experimental Pain With or Without a Head Mounted Display

While virtual reality environments have been shown to reduce pain, the precise mechanism that produces the pain attenuating effect has not been established. It has been suggested that it may be the ability to command attentional resources with the use of head mounted displays (HMDs) or the interactivity of the environment. Two experiments compared participants’ pain ratings to high and low levels of electrical stimulation while engaging in interactive gaming with an HMD. In the first, gaming with the HMD was compared to a positive emotion induction condition; and in the second experiment the HMD was compared to a condition in which the game was projected onto a wall. Interactive gaming significantly reduced numerical ratings of painful stimuli when compared to the baseline and affect condition. However, when the two gaming conditions were directly compared, they equally reduced participants’ pain ratings. These data are consistent with past research showing that interactive gaming can attenuate experimentally induced pain and its effects are comparable whether presented in a head mounted display or projected on a wall

Attenuation of capsaicin-induced ongoing pain and secondary hyperalgesia during exposure to an immersive virtual reality environment

Introduction: There is growing evidence that virtual reality (VR) can be used in the treatment of chronic pain conditions. However, further research is required in order to better understand the analgesic mechanisms during sensitised pain states. Objectives: We examined the effects of an immersive polar VR environment on capsaicin-induced ongoing pain and secondary hyperalgesia. We also investigated whether the degree of analgesia was related to baseline conditioned pain modulation (CPM) responses. Methods: Nineteen subjects had baseline CPM and electrical pain perception (EPP) thresholds measured prior to the topical application of capsaicin cream. Visual analogue scale (VAS) ratings were measured to track the development of an ongoing pain state and EPP thresholds were used to measure secondary hyperalgesia. The effects of a passive polar VR environment on ongoing pain and secondary hyperalgesia were compared to sham VR (i.e. 2D monitor screen) in responders to capsaicin (n=15). Results: VR was associated with a transient reduction in ongoing pain and an increase in EPP thresholds in an area of secondary hyperalgesia. Baseline CPM measurements showed a significant correlation with VR-induced changes in secondary hyperalgesia, but not with VR-induced changes in ongoing pain perception. There was no correlation between VR-induced changes in pain perception and VR-induced changes in secondary hyperalgesia. Conclusions: Virtual reality can reduce the perception of capsaicin-induced ongoing pain perception and secondary hyperalgesia. We also show that CPM may provide a means by which to identify individuals likely to respond to VR therapy

Virtual Body Ownership Illusions for Mental Health: A Narrative Review.

Over the last 20 years, virtual reality (VR) has been widely used to promote mental health in populations presenting different clinical conditions. Mental health does not refer only to the absence of psychiatric disorders but to the absence of a wide range of clinical conditions that influence people\u2019s general and social well-being such as chronic pain, neurological disorders that lead to motor o perceptual impairments, psychological disorders that alter behaviour and social cognition, or physical conditions like eating disorders or present in amputees. It is known that an accurate perception of oneself and of the surrounding environment are both key elements to enjoy mental health and well-being, and that both can be distorted in patients suffering from the clinical conditions mentioned above. In the past few years, multiple studies have shown the effectiveness of VR to modulate such perceptual distortions of oneself and of the surrounding environment through virtual body ownership illusions. This narrative review aims to review clinical studies that have explored the manipulation of embodied virtual bodies in VR for improving mental health, and to discuss the current state of the art and the challenges for future research in the context of clinical care

Virtual reality in the treatment of pain

Many medical procedures produce acute pain that in most cases is quite disturbing for the individual. Medication is the treatment of choice for acute pain. However, given the involvement of psychological aspects in the experience of pain, psychological techniques are being used as an effective adjunct to alleviate pain related to medical procedures. In the last years a new technology is demonstrating an enormous potential in this field: Virtual Reality (VR) distraction. In this article we review studies that explore the efficacy of immersive VR distraction in reducing pain related to different medical procedures. We include clinical studies and analogue studies with healthy participants. We discuss the results achieved by these studies and recommend future directions of VR pain control research

Visuo-tactile stimulation, but not type of movement, modulates pain during the vision of a moving virtual limb

Aims: Evidence has revealed a relationship between pain and the observation of limb movement, but it is unknown whether different types of movements have diverse modulating effects. In this immersive virtual reality study we explored the effect of the vision of different virtual arm movements (arm vs. wrist) on pain threshold from heat applied to the wrist. Patients & Methods: Forty healthy participants underwent four conditions in virtual reality while heat pain thresholds were measured. Visuo-tactile stimulation was used to attempt to modulate the feeling of virtual limb ownership. Results: Effects on pain threshold were present for type of stimulation but not type of movement. Conclusions: The type of observed movement does not appear to influence pain modulation, at least not during acute pain states

Altered bodily perceptions in chronic neuropathic pain conditions and implications for treatment using immersive virtual reality

Chronic neuropathic pain is highly disabling and difficult to treat and manage. Patients with such conditions often report altered bodily perceptions that are thought to be associated with maladaptive structural and functional alterations in the somatosensory cortex. Manipulating these altered perceptions using body illusions in virtual reality is being investigated and may have positive clinical implications for the treatment of these conditions. Here, we have conducted a narrative review of the evidence for the types of bodily distortions associated with a variety of peripheral and central neuropathic pain conditions. In addition, we summarize the experimental and clinical studies that have explored embodiment and body transformation illusions in immersive virtual reality for neuropathic pain relief, which are thought to target these maladaptive changes, as well as suggesting directions for future research

Manipulating the perceived shape and color of a virtual limb can modulate pain responses

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