Efficacy of transcranial direct current stimulation on cognitive function in post stroke cognitive impairment: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND: Post-stroke cognitive impairment (PSCI) significantly hinders recovery. Transcranial direct current stimulation (tDCS) is a promising intervention, yet its efficacy varies, and the optimal therapeutic window remains debated. OBJECTIVES: To evaluate the efficacy of tDCS on global cognition, memory, and executive function in PSCI and determine if stroke onset duration influences treatment outcomes. METHODS: We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) searched from databases including PubMed, Embase, and Cochrane Library up to January 2026. Outcomes included Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE), memory, and executive function. Subgroup analyses stratified patients by stroke chronicity (<6 months vs. >6 months). RESULTS: = 0.38). Significant improvements were also observed in memory and executive function. CONCLUSIONS: tDCS effectively enhances cognition in PSCI. However, efficacy is time-dependent, suggesting a "critical window" for intervention within the first 6 months post-stroke. Early application is recommended. REGISTRATION NUMBER: CRD42024543596.