Graded motor imagery is effective for long-standing complex regional pain syndrome: a randomised controlled trial

Abstract

Complex regional pain syndrome type 1 (CRPS1) involves cortical abnormalities similar to those observed in phantom pain and after stroke. In those groups, treatment is aimed at activation of cortical networks that subserve the affected limb, for example mirror therapy. However, mirror therapy is not effective for chronic CRPS1, possibly because movement of the limb evokes intolerable pain. It was hypothesised that preceding mirror therapy with activation of cortical networks without limb movement would reduce pain and swelling in patients with chronic CRPS1. Thirteen chronic CRPS1 patients were randomly allocated to a motor imagery program (MIP) or to ongoing management. The MIP consisted of two weeks each of a hand laterality recognition task, imagined hand movements and mirror therapy. After 12 weeks, the control group was crossed-over to MIP. There was a main effect of treatment group (F(1, 11) = 57, P < 0.01) and an effect size of approximately 25 points on the Neuropathic pain scale. The number needed to treat for a 50% reduction in NPS score was approximately 2. The effect of treatment was replicated in the crossed-over control subjects. The results uphold the hypothesis that a MIP initially not involving limb movement is effective for CRPS1 and support the involvement of cortical abnormalities in the development of this disorder. Although the mechanisms of effect of the MIP are not clear, possible explanations are sequential activation of cortical pre-motor and motor networks, or sustained and focussed attention on the affected limb, or both.

The Effects of Graded Motor Imagery and Its Components on Chronic Pain: A Systematic Review and Meta-Analysis

“…Four authors were contacted to gain additional information required to calculate the effect size of their intervention 2,3,23,25,26,28 . One author could not be contacted, thus the effect size for this study could not be calculated 2 .…”

“…The two studies comparing GMI to usual physiotherapy care both found large effect sizes (1.70 (0.36, 3.04) 26 and 0.89 (0.31, 1.47) 25 ). In the study which compared a course of GMI to an unordered course of GMI 28 , moderate to large effects in favour of the ordered GMI were found (0.73 (-0.41, 1.87) and 0.99 (-0.19, 2.17)).…”

“…Three studies evaluated the effects of GMI on chronic pain 25,26,28 . Two of these studies compared a six week programme of GMI to usual physiotherapy care 25,26 .…”

“…Two of these studies compared a six week programme of GMI to usual physiotherapy care 25,26 . The third study compared an ordered programme of GMI to an unordered programme of GMI 28 .…”

“…Participants were instructed to spend ten minutes of each waking hour on the intervention. All studies collected follow-up data: one at six weeks post-intervention 26 , one at twelve weeks post-intervention 28 , and one at six months postintervention 25 . These studies used varying methods of collecting participant pain scores.…”