Effectiveness of transcranial electrical stimulation combined with dual-task training in Stroke, Mild Cognitive Impairment and Parkinson's Disease: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Yutong Fu^1,2*Li Wen Wang²Qianxi Yan²Chang Zhu²Chai Siaw Chui¹Ponnusamy Subramaniam¹Yao Liqing²Devinder Kaur Ajit Singh^1*

• ¹Universiti Kebangsaan Malaysia Fakulti Sains Kesihatan, Federal Territory of Kuala Lumpur, Malaysia
• ²The Second Affiliated Hospital of Kunming Medical University, Kunming, China

Aim: In this systematic review and meta-analysis, we evaluated the effectiveness of transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS) or transcranial random noise stimulation(tRNS) combined with dual task training (DTT) on physical and cognitive functions in adults with mild cognitive impairment (MCI), Parkinson’s disease (PD) and stroke disorders. Method: We conducted a systematic search of the Web of Science, MEDLINE, Cochrane Library, PubMed, and CINAHL databases for English-language literature on randomized clinical trials (RCTs) investigating the effects of tDCS, tACS, or tRNS combined with DTT in adults with MCI, PD and stroke. The search covered studies from the inception of each database up to November 21, 2025. The initial screening of selected articles was performed by independent screening by two researchers (YLQ and WLW). Results: A total of twelve studies met the inclusion criteria, comprising individuals with stroke (n=4), MCI (n=3), and PD (n=5). Meta analysis revealed active tDCS+DTT yielded no significant overall improvement in global cognition (Montreal Cognitive Assessment(MoCA): SMD=0.09, 95% CI [−0.49, 0.66], P = 0.77, I² = 72%). A large, highly homogeneous benefit was observed for executive function (TMT-B: SMD=−1.33, 95% CI [−2.39 , −0.27], P = 0.01), driven exclusively by the MCI subgroup (SMD=−2.35, 95% CI [−3.20, −1.51], I² = 0%). Timed Up and Go cognitive motor dual task (TUG CMDT) cadence improved overall (SMD=0.58, 95% CI [0.09 , 1.08], P = 0.02, I² = 39%) in both MCI and stroke subgroups. TUG motor dual task(MDT) speed improved modestly (SMD=0.42, 95% CI [0.02 , 0.83], P = 0.04, I² = 34%) and CMDT speed showed a strong trend (SMD= −0.49, P = 0.09) ,only significant in stroke (SMD=−1.42, P = 0.002). In individual PD studies, which reported significant gains in force-tremor decoupling, postual stability and CMDT accuracy. Conclusion: tDCS combined with DTT yields robust but highly condition- and domain-specific benefits, with strongest evidence in MCI and stroke . Standard protocols appear ineffective in PD, underscoring the need for specific montages and exploration of tACS/tRNS in future trials.