Safety and Efficacy of Anodal transcranial direct-current stimulation over the Dorsolateral Prefrontal Cortex in Post-Stroke Cognitive Impairment: A Systematic Review and Meta-Analysis.

INTRODUCTION: This meta-analysis evaluated the safety and efficacy of anodal transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) for post-stroke cognitive impairment (PSCI). METHODS: Eight databases were searched from inception to June 7, 2026 for randomized controlled trials (RCTs). Two reviewers independently performed study selection, data extraction, and risk of bias assessment using the revised Cochrane risk-of-bias tool. Meta-analyses were conducted using Stata version 18, with subgroups stratified by control type and stimulation site. RESULTS: Twenty-three RCTs involving 1326 participants were included. Anodal tDCS over the DLPFC significantly improved global cognitive screening performance: Clinical Efficacy (odds ratio [OR] = 1.37, 95% confidence interval [CI]: 1.01-1.85, P =0.043), Montreal Cognitive Assessment (MoCA) score (weighted mean difference [WMD] = 3.17, 95% CI: 2.53-3.80, P = 0.000), and Mini-Mental State Examination (MMSE) score (WMD = 2.52, 95% CI: 1.81-3.22, P = 0.001). Subgroup analyses demonstrated superiority of active tDCS regardless of control condition: rehabilitation therapy (RT) plus sham tDCS (MoCA: WMD = 2.45, 95% CI: 1.60-3.30; MMSE: WMD = 2.40, 95% CI: 0.97-3.83) and RT alone (MoCA: WMD = 3.47, 95% CI: 2.81-4.12; MMSE: WMD = 2.72, 95% CI: 2.12-3.32). Benefits were also consistent across stimulation of the affected hemisphere (MoCA: WMD = 2.88, 95% CI: 2.05-3.71; MMSE: WMD = 2.59, 95% CI: 1.50-3.68) and the left hemisphere (MoCA: WMD = 3.42, 95% CI: 2.47-4.38; MMSE: WMD = 2.48, 95% CI: 1.45-3.51). Activities of daily living (ADL) measured by the Modified Barthel Index (MBI) also improved significantly (WMD = 10.75, 95% CI: 8.67-12.84, P = 0.000), with benefits maintained across all subgroups: RT plus sham tDCS (WMD = 11.18, 95% CI: 8.76-13.60), RT alone (WMD = 10.49, 95% CI: 7.67-13.32), affected hemisphere (WMD = 11.37, 95% CI: 7.83-14.91), and left hemisphere (WMD = 10.06, 95% CI: 8.00-12.13). Safety outcomes were infrequently reported. CONCLUSIONS: Anodal tDCS over the DLPFC may improve global cognitive screening performance and ADL in PSCI patients, yet low methodological quality and inadequate safety reporting limit the current evidence. Further high-quality RCTs with rigorous adverse event monitoring are warranted.