Introduction Optimal upper limb recovery requires high-dose physiotherapy; however, this essential component of rehabilitation is under-delivered. 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 randomized controlled trials (RCTs) and nine non-randomized controlled trials (non-RCTs). RCTs were meta-analyzed 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 synthesized using upper limb and neuroimaging outcomes. Results Seven RCTs reported FMA-UE scores ( n = 189), where the standardized 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-analyzing 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 synthesized studies, including neuroimaging outcomes. Limitations included inconsistent terminology, intervention design, clarity of reporting, and modality. Discussion AO + MI practice can promote upper limb recovery following stroke. AO + MI can therefore be used as a bridge between AO therapy (requiring little effort in early recovery), and the more cognitively demanding MI. Researchers must adopt standardized reporting protocols to further establish AO + MI practice efficacy. Systematic review registration The review was registered with PROSPERO under the registration number CRD42023418370. The registration is publicly accessible at the following URL: https://www.crd.york.ac.uk/PROSPERO/view/CRD42023418370 .
Lin et al. (Wed,) studied this question.