Efficacy of anodal transcranial direct current stimulation for upper extremity function after ischemic stroke: A systematic review of parallel randomized clinical trials

•A-tDCS could facilitate upper limb function rehabilitation in post-ischemic stroke patients.•A-tDCS could facilitate improve activity of daily living in post-ischemic stroke patients.•The most frequently used stimulation sites are the anode for the primary motor cortex.•A-tDCS is relatively safe for ischemic stroke patients. Although existing studies had shown therapeutic effects of transcranial direct current stimulation (tDCS) on upper limb dysfunction after stroke, previous systematic reviews had mostly provided general analyses on the polarity of tDCS and the type of stroke, with inconsistent results. We aimed to determine the efficacy of anodal transcranial direct current stimulation in enhancing upper extremity function following ischemic stroke. A comprehensive search was conducted across a variety of databases, spanning from their inception to March 15th, 2024.The focus was on parallel randomized clinical trials published that explored the impact of anodal transcranial direct current stimulation on upper extremity function in ischemic stroke patients. Data extraction and quality assessment were conducted independently by two reviewers. The Cochrane Risk of Bias Tool was utilized to assess the risk of bias in the included studies. A total of 19 studies involving 1032 participants were included in the analysis. The pooled results of these studies indicated that anodal transcranial direct current stimulation had a positive impact on the Fugl-Meyer Assessment Upper Extremity, Wolf Motor Function Test, Resting Motion Threshold, and Barthel Index Score in ischemic stroke patients with upper extremity dysfunction. Follow-up data suggested the potential long-term efficacy of anodal transcranial direct current stimulation in ischemic stroke. Reported adverse reactions indicated that anodal transcranial direct current stimulation was relatively safe for stroke patients. Anodal transcranial direct current stimulation is an effective intervention and relatively safe and effective intervention for improving upper extremity function in ischemic stroke patients.