Explicit Motor Imaging Abilities Are Similar in Complex Regional Pain Syndrome, Chronic Limb Pain and Healthy Individuals: A Cross-Sectional Study.

Abstract

Background: Complex regional pain syndrome (CRPS) is a chronic pain condition characterized by peripheral, central sensory and motor dysfunction. Implicit motor imagery is known to be impaired in CRPS patients, but evidence for explicit motor imagery is still lacking. Using a self-rated questionnaire, this study aims to compare explicit motor imagery abilities between individuals with CRPS, with chronic limb pain (CLP), and healthy controls, and to also examine differences between affected and unaffected limbs. We hypothesize that both CRPS and CLP patients will show a decrease in motor imagery abilities compared to healthy controls and in their affected limb compared to their own contralateral, unaffected side.

Patients and methods: In this single-center observational study, 123 participants were recruited (CRPS = 40, chronic limb pain, CLP = 40, and healthy individuals = 43). Participants completed the Movement Imagery Questionnaire-Revised Second (MIQ-RS) once for each side of the body. The total MIQ-RS score, and the kinesthetic and visual subscores were compared between groups and between the affected and unaffected sides.

Results: A high degree of heterogeneity was observed in the explicit motor imagery scores and subscores, regardless of whether the participants were healthy or individuals with chronic pain. The MIQ-RS did not reveal any significant differences in explicit motor imagery abilities, neither between groups nor between the affected and unaffected side. Bayesian testing of the null hypothesis for kinesthetic motor imagery abilities indicated a sevenfold likelihood of no differences between groups and a more than a fivefold likelihood of no differences between sides.

Conclusion: Individuals with CRPS and chronic limb pain displayed preserved explicit motor imagery abilities, notably on the pain side. The preservation of these abilities supports the recommendation of mental imagery therapy to improve motor function and relieve pain in chronic pain patients.