Neurol Disord Stroke Int | Volume 1, Issue 1 | Research Article | Open Access

Transcranial Direct Current Stimulation and Its Effects on Upper Extremity Neurorehabilitative Training in Stroke: A Meta-Analysis

Winifried Backhaus1,2,4, Marco Anziano1,2 and Friedhelm C. Hummel1,2,3*

1Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Swiss Federal Institute of Technology (ETH Lausanne), Switzerland
2Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Clinique Romande de Réadaptation, Swiss Federal Institute of Technology (ETH Valais), Switzerland
3Department of Clinical Neuroscience, University of Geneva Medical School, Switzerland
4Department of Neurology, UKE, 20246 Hamburg, Germany

*Correspondance to: Friedhelm Hummel 

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Abstract

Objectives: To evaluate the efficacy of tDCS as an adjuvant to neuro-rehabilitative training in stroke patients with motor deficits by a meta-analysis and discuss the results critically in the view of the current literature.
Methods: In the current analyses, we included randomized controlled trials applying tDCS to primary motor areas (anodal, cathodal, bihemispheric) combined with motor training to improve upper extremity deficits in stroke patients. Two pooled effect size meta-analyses were performed to address immediate and longer-lasting effects of tDCS. A meta-regression model was performed to evaluate tDCS dose-response relationships and the influence of various moderator factors.
Results: A total of 35 studies were included. For both, the immediate and longer-lasting analyses, tDCS respectively demonstrated a significant impact on rehabilitative training with a moderate effect size of +0.52 (p <0.001) and +0.69 (p < 0.001). A negative direct linear relationship was found between tDCS efficacy and the number of stimulation sessions. No significant relationships were found between tDCS efficacy and other moderator factors such as charge density, stimulation type, phase after stroke, time point of assessment, training type. Conclusions: The current results support the therapeutic potential of tDCS as an adjuvant treatment strategy to enhance neurorehabilitative training in stroke patients with upper extremity deficits. Treatment effects are mixed between studies, which might be explained by a considerable amount of heterogeneity due to moderator factors that have to be identified in more detail. Understanding such moderator factors and their impact on the treatment effect will pave the way to precision medicine approaches for motor recovery based on tDCS to maximize the magnitude of neuro-rehabilitation in patients suffering from stroke.

Citation:

Backhaus W, Anziano M, Hummel FC. Transcranial Direct Current Stimulation and Its Effects on Upper Extremity Neurorehabilitative Training in Stroke: A Meta-Analysis. Neurol Disord Stroke Int. 2018; 1(1): 1003.

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