Visual illusions modulate body perception disturbance and pain in Complex Regional Pain Syndrome: a randomized trial

BackgroundEffective treatment of longstanding Complex Regional Pain Syndrome (CRPS) is a challenge, as causal mechanisms remain elusive. People with CRPS frequently report distorted subjective perceptions of their affected limb. Evidence of pain reduction when the affected limb is visually altered in size, suggests that visual illusions used to target central processing could restore coherence of this disrupted limb representation. We hypothesised that using virtual reality that alters hand image to match the patient’s desired hand appearance, would improve body perception disturbance and pain. Also, repeated exposure would maintain any therapeutic effect.MethodsA blinded randomised controlled trial of 45 participants with refractory upper‐limb CRPS and body perception disturbance (BPD) viewed a digital image of their affected hand for one minute. The image was digitally altered according to the patient’s description of how they desired their hand to look in the experimental group and unaltered in the control group. BPD and pain were measured pre and post‐intervention. A subgroup was followed up two weeks after a course of repeated interventions.ResultsBPD (mean‐6, ±SD 7.9, p=0.036, effect size (ES)=0.6) and pain intensity (mean‐0.43, ±SD 1.3, p=0.047, ES=0.5) reduced in 23 participants after single exposure compared to controls (n=22). At follow‐up, the subgroup (experimental n=21; control n=18) showed sustained pain reduction only (p=0.037, ±SD 1.9, ES=0.7), with an overall 1.2 decrease on an 11‐point scale.ConclusionsVisually changing the CRPS hand to a desired appearance modulates BPD and pain suggesting therapeutic potential for those with refractory CRPS. Further research to optimise this therapeutic effect is required.</div

Additional file 3: of A community-based physical activity intervention to prevent mobility-related disability for retired older people (REtirement in ACTion (REACT)): study protocol for a randomised controlled trial

REACT process evaluation protocol and Logic model. (DOCX 128 kb

Additional file 4: of A community-based physical activity intervention to prevent mobility-related disability for retired older people (REtirement in ACTion (REACT)): study protocol for a randomised controlled trial

REACT Telephone Screening Form used to collect demographic data and undergo and initial eligibility assessment with potential participants. (DOCX 149 kb

Additional file 6: of A community-based physical activity intervention to prevent mobility-related disability for retired older people (REtirement in ACTion (REACT)): study protocol for a randomised controlled trial

REACT Case Report Form including all measures and items used to collect outcome data as described in Table 2. (DOC 1427 kb

Additional file 1: of A community-based physical activity intervention to prevent mobility-related disability for retired older people (REtirement in ACTion (REACT)): study protocol for a randomised controlled trial

Completed SPIRIT (2013) Checklist detailing on which page of the protocol manuscript each of the relevant recommended items is addressed. (DOC 123 kb

Additional file 2: of A community-based physical activity intervention to prevent mobility-related disability for retired older people (REtirement in ACTion (REACT)): study protocol for a randomised controlled trial

Additional detail from the REACT Trial Protocol relating to the SPIRIT 2013 Checklist (Additional file 1). (DOC 117 kb

Additional file 5: of A community-based physical activity intervention to prevent mobility-related disability for retired older people (REtirement in ACTion (REACT)): study protocol for a randomised controlled trial

REACT Participant Consent Form. (DOCX 135 kb