Examining the Optimal Duration of a Virtual Reality Body Illusion for Managing Pain in Fibromyalgia

Background: Fibromyalgia is a chronic condition characterised by widespread pain, as well as sleep disturbances, fatigue, and memory and concentration difficulties. Research suggests that an alteration in how the brain represents multisensory inputs from the body may cause or maintain chronic pain conditions, including fibromyalgia. Virtual reality (VR) setups that generate multisensory conflicts have been shown to alleviate pain, however, the optimal duration for such interventions remains unexplored. Here, we aimed to determine an optimal duration for the VR cardio-visual full body illusion (FBI) in fibromyalgia, considering both tolerability and changes in pain. Methods: Participants wore VR headsets to view a video of their own body, filmed from behind, and their self-image flashed in synchrony with their own heartbeat. We used an established dose-finding protocol to determine the ideal duration. Seven cohorts of participants (N = 20) were exposed to different durations of the FBI, with adjustments to duration made according to predefined criteria. Measures included a numeric rating scale for pain intensity, pressure pain thresholds, and scales measuring fibromyalgia symptom severity and impact. Results: We found a quadratic relationship between session duration and changes in self-reported pain-intensity, with 8–16-minute durations yielding the most significant improvements. Notably, in the 12-minute cohorts pain relief was sustained at 24-hour follow-up, and this is the recommended duration for future research. Conclusions: The present research represents a key step towards developing an effective non-pharmacological intervention for fibromyalgia. Future dose-optimisation research should explore the optimum number of VR sessions and spacing between sessions.