Transcranial direct current stimulation (tDCS) effects on upper limb motor function in stroke: an overview review of the systematic reviews

Stroke is the prime cause of disability in the elderly population. Transcranial direct current stimulation (tDCS) is an emerging noninvasive brain stimulation in rehabilitating upper limb function post-stroke. However, mixed evidence exists in the literature and ambiguous conclusions regarding the effect of tDCS on upper limb function.This study aimed to assess the current evidence on the effect of (tDCS) on upper limb motor function and activities of daily living in patients after stroke by conducting an overview of systematic reviews.We performed electronic database searches and gray literature searches for the articles.Two distinct literature searches gathered a total of 203 studies. Out of them, six systematic reviews and meta-analyses were included for methodological quality assessment and data extraction. All included studies were determined to be of good to high quality based on a methodological appraisal using the Assessment of Multiple Systematic Reviews checklist.Identified evidence suggests that tDCS has superior effects to control interventions in improving functions of the upper limb and activities of daily living in patients who have had a stroke. Moreover, cathodal stimulation over the non-affected brain region was more effective than anodal and dual tDCS stimulation.