Effect of transcranial magnetic stimulation on perioperative neurocognitive dysfunction: study protocol for a systematic review and meta-analysis of randomised controlled trials.

introductionPerioperative neurocognitive disorders (PNDs), a common postoperative complication associated with anaesthesia and surgical procedures, are characterised by impairments in memory, attention, language comprehension and social functioning. Accumulating evidence from clinical studies indicates that transcranial magnetic stimulation (TMS)-a non-invasive neuromodulatory modality capable of targeted cortical stimulation-may offer therapeutic promise for PND management. To comprehensively assess the intervention efficacy and safety parameters of TMS in mitigating postoperative cognitive decline, we propose conducting a systematic review and meta-analysis of randomised controlled trials adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Our findings aim to provide evidence-based insights into the neuroprotective potential of TMS for mitigating cognitive decline in surgical populations. METHODS AND ANALYSIS: The investigation will implement a multifaceted search protocol encompassing international and Chinese scholarly resources. The search will be conducted in major databases, including Web of Science, Embase, PubMed, Cochrane Library, China Biology Medicine, China National Knowledge Infrastructure, Wan Fang Database and Chinese Scientific Journal Database from inception to 31 March 2025. To capture the latest research trends, ongoing trials will be simultaneously searched in the WHO International Clinical Trial Registry Platform, ClinicalTrials.gov and the China Clinical Trial Registry. Grey literature will be supplemented through resources such as GreyNet International, OpenGrey and Google Scholar. The inclusion criteria for this review are restricted to randomised controlled trials investigating the application of TMS as an intervention for PND. Primary endpoints comprise clinically confirmed incidence rates of postoperative delirium and delayed neurocognitive recovery. Two researchers will independently perform literature screening, data extraction and risk of bias assessment. The risk of bias in included studies will be evaluated using the Cochrane Risk of Bias Tool 2.0. Evidence certainty will be appraised through the GRADE framework with explicit justification for downgrading decisions. Meta-analysis will be conducted using STATA V.15.1 statistical software. The data synthesis process will incorporate standardised methodologies, including heterogeneity testing, sensitivity analysis and assessment of publication bias. ETHICS AND DISSEMINATION: This study will not involve the collection of biometric information or medical privacy data throughout the research process, thus complying with the exemption criteria outlined in the 'Measures for Ethical Review of Biomedical Research Involving Human Subjects.' The findings will adhere to academic standards and be submitted for publication in reputable international medical journals following a rigorous double-blind peer-review process. SYSTEMATIC REVIEW REGISTRATION: The research protocol has been prospectively registered on the PROSPERO international prospective systematic review registration platform (registration number: CRD42025636978).