The Long-Term Maintenance of Upper Limb Motor Improvements Following Transcranial Direct Current Stimulation Combined with Rehabilitation in People with Stroke: A Systematic Review of Randomized Sham-Controlled Trials.

Víctor Navarro-López,Alicia Cuesta-Gómez,María Carratalá-Tejada,Rubén Fernández-Matías,Francisco Molina-Rueda,Manuel Del Valle-Gratacós

doi:10.3390/s21155216

Abstract

Background: The effectiveness of transcranial direct current stimulation (tDCS) in the upper limb (UL) motor rehabilitation of stroke has been widely studied. However, the long-term maintenance of its improvements has not yet been proven. Methods: A systematic search was conducted in MEDLINE/Pubmed, Web of Science, PEDRo, and Scopus databases from inception to April 2021. Randomized controlled trials were included if they performed a tDCS intervention combined with UL rehabilitation in stroke patients, performed several sessions (five or more), and assessed long-term results (at least three-month follow-up). Risk of bias and methodological quality were evaluated with the Cochrane RoB-2 and the Oxford quality scoring system. Results: Nine studies were included, showing a high methodological quality. Findings regarding UL were categorized into (1) functionality, (2) strength, (3) spasticity. All the studies that showed significant improvements retained them in the long term. Baseline functionality may be a limiting factor in achieving motor improvements, but not in sustaining them over the long term. Conclusion: It seems that the improvements achieved during the application of tDCS combined with UL motor rehabilitation in stroke were preserved until the follow-up time (from 3 months to 1 year). Further studies are needed to clarify the long-term effects of tDCS.

Highlights

Cerebrovascular accident is defined by the World Health Organization as “the set of rapidly progressive clinical signs due to a focal, sometimes global, alteration of brain function that lasts more than 24 h or causes death without any other apparent cause than its vascular origin” [1]
The abnormal neurorepair factor that occurs after a stroke, as well as the limitations of functional recovery that arise after rehabilitation protocols, cause alternatives to be considered in order to increase the margin for improvement of the patient by increasing the modulation on cortical plasticity [2]
The study by Allman et al [20] showed significant improvements in the Action research arm test and Wolf Motor Function Test (WMFT) by applying 9 sessions of anodic transcranial direct current stimulation (tDCS) at a current intensity of 1 mA (35 cm2 electrodes, density—0.028 mA/cm2) before PT. These results were maintained at the 3-month follow-up, correlating with increased activity during movement of the affected hand and increases in gray matter volume in the ipsilesional motor and promoter cortex in the anodic tDCS stimulation group compared with the control group

Summary

Introduction

Cerebrovascular accident is defined by the World Health Organization as “the set of rapidly progressive clinical signs due to a focal, sometimes global, alteration of brain function that lasts more than 24 h or causes death without any other apparent cause than its vascular origin” [1]. The abnormal neurorepair factor that occurs after a stroke, as well as the limitations of functional recovery that arise after rehabilitation protocols, cause alternatives to be considered in order to increase the margin for improvement of the patient by increasing the modulation on cortical plasticity [2]. The effectiveness of transcranial direct current stimulation (tDCS) in the upper limb (UL) motor rehabilitation of stroke has been widely studied. Randomized controlled trials were included if they performed a tDCS intervention combined with UL rehabilitation in stroke patients, performed several sessions (five or more), and assessed long-term results (at least three-month follow-up). Baseline functionality may be a limiting factor in achieving motor improvements, but not in sustaining them over the long term. Conclusion: It seems that the improvements achieved during the application of tDCS combined with UL motor rehabilitation in stroke were preserved until the follow-up time (from 3 months to 1 year). Further studies are needed to clarify the long-term effects of tDCS

Objectives

Methods

Results

Conclusion