# XR body illusion for managing pain in fibromyalgia: examining optimal duration

## TL;DR

This study explores how long a virtual reality illusion should last to best reduce pain in fibromyalgia patients.

## Contribution

The study identifies an optimal 12-minute duration for pain relief using a cardio-visual full body illusion in fibromyalgia.

## Key findings

- An 8–16-minute session duration provided the most significant pain relief.
- Pain relief was sustained at 24-hour follow-up in the 12-minute session group.
- A quadratic relationship was found between session duration and pain intensity changes.

## Abstract

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. Extended reality (XR) and virtual reality setups generating 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 cardio-visual full body illusion (FBI) in fibromyalgia, considering both tolerability and changes in pain.

Participants wore headsets to view a video of their own body, filmed from behind, and their virtual body flashed in synchrony with their heartbeat. We used an established dose-finding protocol to determine the ideal duration (balancing benefit and tolerability). 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.

We found a quadratic relationship between session duration and changes in self-reported pain-intensity, with 8–16-min durations yielding the most significant improvements. Notably, in the 12-min cohorts pain relief was sustained at 24-h follow-up, and this is the recommended duration for future research.

These findings represent a key step towards developing an effective non-pharmacological intervention for fibromyalgia. Future dose-optimisation research should explore the optimum number of sessions and spacing between sessions.