The Effects of Combined Action Observation and Motor Imagery practice on Upper-limb Recovery Following Stroke: A Systematic Review and Meta-Analysis

Introduction: Optimal upper-limb recovery requires high-dose physiotherapy, yet this basic need is frequently unmet. Mental practice represents an accessible and cost-effective adjunct to conventional therapy. We therefore evaluated the efficacy of an enhanced mental practice treatment (combined action observation and motor imagery, AO+MI) for promoting upper-limb recovery post stroke. Methods: Searching 10 databases, we identified 18 eligible studies (N=336), comprising nine randomised controlled trials (RCTs) and nine non-randomised controlled trials (non-RCTs). RCTs were meta-analysed using upper-limb function outcomes (Fugl-Meyer Assessment for upper extremity, FMA-UE; Action Research Arm Test, ARAT). Non-RCTs (not eligible for meta-analysis) were narratively synthesised using upper-limb and neuroimaging outcomes. Results: Seven RCTs reported FMA-UE scores (n=189), where the standardised mean difference (SMD) for AO+MI treatments was moderate (SMD=0.58, 95%CI: 0.13–1.04, p=0.02). Two additional RCTs reported ARAT scores. Meta-analysing the combined FMA-UE and ARAT scores (n=239) revealed SMD=0.70 (95%CI: 0.32–1.09, p=0.003). No significant correlations existed between the pooled effect size and several moderators (age, time since stroke, intervention duration, control condition, outcome measure and AO+MI arrangement), indicating consistent AO+MI practice effects. Overall, AO+MI significantly improved upper-limb function across all nine RCTs, and all nine narratively synthesised studies, including neuroimaging outcomes. Limitations included inconsistent terminology, intervention design, clarity of reporting, and modality.