Can Transcranial Direct-Current Stimulation Alone or Combined With Cognitive Training Be Used as a Clinical Intervention to Improve Cognitive Functioning in Persons With Mild Cognitive Impairment and Dementia? A Systematic Review and Meta-Analysis

Frontiers in Human Neuroscience

Ted Brown¹  Raymond C. K. Chung²  Pablo Cruz Gonzalez²  Lawla L. F. Law³  Kin-Hung Ting⁴  Kenneth N. K. Fong⁴ 

[1] Department of Occupational Therapy, Monash University, Melbourne, VIC, Australia;Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong;School of Medical and Health Sciences, Tung Wah College, Kowloon, Hong Kong;University Research Facility in Behavioral and Systems Neuroscience, The Hong Kong Polytechnic University, Kowloon, Hong Kong;

关键词: tDCS (transcranial direct-current stimulation);    neuromodulation;    MCI (mild cognitive impairment);    dementia;    cognitive rehabilitation;    cognitive training;   

DOI  :  10.3389/fnhum.2018.00416

来源: DOAJ

【 摘 要 】

Background: Transcranial direct-current stimulation (tDCS) facilitates cognitive improvement in healthy and pathological populations. It has been increasingly used in cases of mild cognitive impairment (MCI) and dementia. Our research question is: Can tDCS serve as a clinical intervention for improving the cognitive functions of persons with MCI (PwMCI) and dementia (PwD)?Objective: This systematic review evaluated the evidence to determine the efficacy of tDCS in improving cognitive outcomes in PwD and PwMCI.Methods: A systematic review was conducted of studies published up to November 2017 involving tDCS in cases of MCI and dementia. Studies were ranked according to the level of evidence (Oxford Center for Evidence-Based Medicine) and assessed for methodological quality (Risk of Bias Tool in the Cochrane Handbook for Systematic Reviews of Interventions). Data was extracted on all protocol variables to establish a reference framework for clinical interventions. Different modalities, tDCS alone or combined with cognitive training, compared with sham tDCS were examined in both short and long-term effects. Four randomized control trials (RCTs) with memory outcomes were pooled using the fixed-effect model for the meta-analysis.Results: Twelve studies with 195 PwD and four with 53 PwMCI met the inclusion criteria. Eleven articles were ranked as Level 1b. The results on the meta-analysis on pooled effects of memory indicated a statistically significant medium effect size of 0.39 (p = 0.04) for immediate effects. This improvement was not maintained in the long term 0.15 (p = 0.44).Conclusion: tDCS improves memory in PwD in the short term, it also seems to have a mild positive effect on memory and language in PwMCI. However, there is no conclusive advantage in coupling tDCS with cognitive training. More rigorous evidence is needed to establish whether tDCS can serve as an evidence-based intervention for both populations.

【 授权许可】

Unknown