Title: The Bodily Self in Pain: The Role of Interoceptive Processing

Abstract: Previous research suggests that the processing of internal body sensations (interoception) affects how we experience pain. Some evidence suggests that people with fibromyalgia syndrome (FMS) – a condition characterised by chronic pain and fatigue – may have altered interoceptive processing, but findings to date have been mixed, therefore we recently ran studies to explore this further.

In a first study, we examined interoception in adults with FMS (N = 154) and an age- and gender-matched pain free group (N = 94). We employed a relatively new heartbeat detection task (the Phase Adjustment Task; PAT), which participants completed at home via a smartphone application. We found that the FMS sample had significantly higher scores on the heartbeat detection task and had significantly higher self-reported interoception. Within the FMS sample, participants classified as ‘interoceptive’ on the heartbeat detection task (PAT) had significantly lower symptom impact than unclassified participants. Conversely, self-reported interoception was positively correlated with FMS symptom severity and impact.

The aim of our second (lab-based) study was to identify the optimal duration for an interoceptive (cardio-visual) full body illusion intervention (adapted from Aspell et al., 2013), that is balanced in terms of tolerability and benefit (reduction in pain). The illusion is created using virtual reality (VR) and we used a dose-finding protocol (e.g., Colluci et al., 2017) to determine the ideal duration of a single session. Twenty female adults with FMS were tested. Results showed a quadratic relationship between VR session duration and changes in self-reported pain-intensity, with 8–16-minute durations yielding the most significant improvements. After the 12-minute session, pain relief was sustained at a 24-hour follow-up, and this is the duration we recommend be used in future studies.

Our findings suggest that interoception and more broadly, the multisensory representation of the body, are important factors to consider in understanding chronic pain.

Reference: Todd, J., Plans, D., Lee, M.C., Bird, J.M., Morelli, D., Cunningham, A., Ponzo, S., Murphy, J., Bird, G. and Aspell, J.E. (2024) Heightened interoception in adults with fibromyalgia. Biological psychology, p.108761.

The studies were funded by a Versus Arthritis Pain Challenge Research Award to Jane Aspell (PI, ref 22461)