Dose–response effects of robot-assisted training on poststroke functional recovery

Background: Robot-assisted training (RAT) is widely used in poststroke rehabilitation, but the relationship between training dose and functional recovery remains unclear. This review evaluated the effectiveness of RAT and examined dose–effect relationships. Methods: PubMed, Web of Science, the Cochrane Library, and Embase were searched from inception to October 2025. Randomized controlled trials of adults with stroke comparing RAT or RAT combined with conventional rehabilitation (CR) were included. Study quality was assessed using the Cochrane risk-of-bias tool, and analyses were performed using Review Manager 5.4 and Stata 16.0. Pooled effects were expressed as mean differences (MDs) or standardized MDs with 95% confidence intervals (CIs). Exploratory subgroup analyses and random-effects meta-regression were conducted across 5 training-dose parameters, and restricted cubic spline analyses assessed nonlinear dose–effect relationships. Evidence certainty was evaluated using the Grading of Recommendations Assessment, Development and Evaluation. The review was registered with International Prospective Register of Systematic Reviews (CRD420251267710). Results: Thirty-six randomized controlled trials involving 1941 patients were included. Compared with CR, RAT significantly improved upper limb motor function (MD = 2.89, 95% CI: 1.49–4.28) and activities of daily living (ADLs; standardized mean difference = 0.28, 95% CI: 0.13–0.43), but not balance function (MD = 1.27, 95% CI: −0.92 to 3.47). Exploratory subgroup analyses showed numerical differences across dose levels, but no between-subgroup differences were significant. None of the 5 training-dose parameters showed significant linear associations with Fugl–Meyer Assessment–Upper Extremity, Berg Balance Scale, or ADL, and restricted cubic spline analyses showed no significant nonlinear associations (all P > .05). Evidence certainty was moderate for Fugl–Meyer Assessment–Upper Extremity and ADL and low for Berg Balance Scale. Dose-related findings should be interpreted cautiously because some subgroups included few studies and actual training dose was incompletely reported. Conclusion: RAT may improve upper limb motor function and ADL after stroke, but has not shown a significant advantage for balance. Current evidence does not demonstrate a clear linear or nonlinear relationship between training dose and rehabilitation outcomes.