Effects of repetitive transcranial magnetic stimulation on upper limb motor recovery after stroke: an overview of systematic reviews

Background Well-conducted meta-analyses and systematic reviews (MAs/SRs) provide high-level evidence to inform clinical decision-making. However, the overall methodological rigor and reporting quality of MAs/SRs evaluating the effects of repetitive transcranial magnetic stimulation (rTMS) on upper limb motor recovery after stroke have not yet been comprehensively assessed. Therefore, this study aimed to critically appraise the methodological and reporting quality of existing systematic reviews and meta-analyses addressing this topic. Methods A systematic search was conducted across nine electronic databases (CNKI, Wanfang, VIP, CBM, PubMed, Embase, Web of Science, Cochrane Library, and ClinicalTrials.gov ) and gray literature from inception to April 1, 2024. Two reviewers independently performed literature screening and data extraction. Methodological quality and risk of bias were assessed across six dimensions—including publication year, homogeneity, study type, publication bias, AMSTAR-2 score, and PRISMA 2020 score—using AMSTAR-2 and PRISMA 2020 criteria, visualized via radar plots. Finally, the certainty of evidence for outcomes was graded using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Results A total of 17 MAs/SRs were included, with an average multivariate rank score of 11.82. GRADE assessment revealed that the certainty of evidence was high for 13 outcome indicators, moderate for 47, low for 91, and very low for 71. Overall, the methodological and reporting quality was suboptimal. Insufficient methodological rigor and incomplete reporting were identified as the primary drivers of downgraded evidence, while publication year and potential bias played secondary roles. Conclusion Although current systematic reviews suggest that rTMS may enhance upper limb motor function post-stroke, the overall quality of evidence remains limited, and its impact on muscle spasticity warrants further investigation. Future research must adopt rigorous methodological standards and transparent reporting practices. Crucially, integrating MRI-derived biomarkers is needed to address current evidence heterogeneity, ultimately facilitating the transition toward personalized, biomarker-driven neuromodulation in stroke rehabilitation. Systematic review registration www.crd.york.ac.uk/prospero/ , identifier, CRD42024523846.