Factors and strategies affecting motor imagery ability in people with multiple sclerosis: a systematic review.

BACKGROUND:Although growing evidence has shown beneficial effects of motor imagery (MI) training in different populations including people with multiple sclerosis (pwMS), not all patients with neurological diseases may benefit from MI. OBJECTIVES:To investigate factors and strategies affecting and enhancing MI ability in pwMS. DATA SOURCES:MEDLINE/PubMed, PsycINFO, Cochrane Library, Scopus, EMBASE, EBSCOhost, Web of Science and REHABDATA databases, clinical trials registries, dissertation repositories, study bibliographies and internet search engines were searched through August 2021. STUDY SELECTION:Any study type but single case studies investigating factors or strategies contributing to MI ability in pwMS. STUDY APPRAISAL AND SYNTHESIS METHODS:Risk of bias (RoB) was assessed using the Joanna Briggs Institute Checklist for Case-Control and Analytical Cross-Sectional Studies and Cochrane RoB-2.0 tool for randomised trials. A qualitative synthesis was performed summarising main results. RESULTS:Eight databases, 4 trial registries, 9 dissertation repositories, and 1 internet search engine were searched. Fourteen studies including 366 pwMS and 236 healthy controls were included. Most frequently, cognitive impairment was reported as a negative factor influencing MI ability in pwMS. Other negative factors were cognitive fatigue and disability. Inconsistent evidence was found on the contribution of MS phenotype, anxiety, and depression. Using a theory-based MI framework and familiarisation to MI and external cueing may enhance MI ability. LIMITATIONS:Eligible studies were highly heterogeneous. CONCLUSION AND IMPLICATIONS OF KEY FINDINGS:Cognitive impairment, cognitive fatigue and disability negatively influence MI ability in pwMS. Visual and/or auditory cueing of MI are strategies for facilitating MI ability. SYSTEMATIC REVIEW REGISTRATION NUMBER:PROSPERO CRD42020173081 CONTRIBUTION OF THE PAPER.