Do People With Chronic Musculoskeletal Pain Have Impaired Motor Imagery? A Meta-analytical Systematic Review of the Left/Right Judgment Task

The left/right judgment task (LRJT) is the most commonly used method of assessing motor imagery performance. Abnormally long response times are thought to reflect delayed processing of body/spatial representations, and poor accuracy is thought to reflect disrupted cortical proprioceptive representations or body schema. Slower and less accurate responses on the LRJT have been reported in a variety of chronic musculoskeletal pain conditions. To date, no systematic review of the literature has been conducted to assess if altered motor imagery performance as measured by the LRJT is characteristic of all chronic musculoskeletal pain conditions. Therefore, the aim of this study was to conduct a comprehensive systematic review and meta-analysis of the literature to answer the following question: Do people with chronic musculoskeletal pain have impaired left/right body part judgment? Twenty-five studies (2,266 participants) including a range of chronic pain populations who undertook an LRJT were identified from searches of 8 electronic databases from inception to March 2017. Results indicate that chronic musculoskeletal pain conditions affecting the limbs and face (P ≤.01) are associated with altered motor imagery performance as measured by the LRJT. Perspectives: This review synthesizes evidence of altered motor imagery performance using the LRJT across chronic musculoskeletal pain conditions. Consistent evidence was found for altered motor imagery performance in peripheral pain conditions, but evidence was less consistent for axial conditions. Treatment to restore a normal body schema may be beneficial in chronic limb and facial pain.