The therapeutic efficacy of transcranial direct current stimulation in managing Alzheimer’s disease: a systematic review and meta-analysis

Objective: The present study aimed to investigate the therapeutic efficacy of transcranial direct current stimulation (tDCS) for Alzheimer's disease (AD) and identify potential influential factors. Methods: A comprehensive literature search was conducted in PubMed, Embase, Web of Science, and the Cochrane Library up to April 2025. Eligible studies were randomized controlled trials (RCTs) in which tDCS was the sole differential intervention between study arms. The pooled effects of tDCS on patients' global cognition, language, memory, executive function, and emotion were evaluated. Subgroup analyses were also performed to identify potential influential factors. Results: < 0.01), but had no significant effects on language or emotion. Subgroup analyses further revealed that significant memory improvement was observed in patients who received ≤ 10 sessions of tDCS and those with >6 years of education. Additionally, executive function was improved in patients who received stimulation on the left dorsolateral prefrontal cortex and in tDCS groups with ≤ 10 sessions. Moreover, improved executive function was observed in patients with 6-10 years of education, but not in other subgroups. Conclusion: tDCS treatment leads to improvements in global cognition, memory, and executive function in AD patients, but not in language or psychomotor symptoms. However, due to the relatively high heterogeneity of the included data, further well-designed studies are warranted before tDCS can be established as a standard therapeutic approach for AD.