The Effectivity of Anodal Transcranial Direct Current Stimulation in Enhancing Wrist Extensor Muscle Activation After Stroke: A Randomized Trial

Abstract

Background: Disability in stroke patients is frequently due to upper limb motor dysfunction, in which wrist extension control plays a major role. Beneficial effects of anodal transcranial direct current stimulation (tDCS) on motor recovery after stroke have been previously reported, but data regarding its effect on wrist extensor muscle activity is limited. Objective: To investigate whether anodal tDCS has an effect on wrist extensor activation in post-stroke patients. Methods: Ten patients suffering from first ischemic stroke were randomized to either an experimental group (anodal tDCS + occupational therapy) or a control group (occupational therapy only). Anodal tDCS over ipsilesional primary motor cortex (M1) was delivered with 2 mA intensity for 20 minutes. Evaluations of wrist extensor muscle activation during isometric contraction using surface electromyography were performed before and after five days of intervention. Results: Within-group comparison in the experimental and control groups; and between-group comparison showed no significant difference in wrist extension control before and after intervention (p = 0.446, p = 0.764, and p = 0,917, respectively). Conclusions: Five sessions of anodal tDCS showed no significant effect on wrist extensor activation in post-stroke patients. Further studies with a larger sample size and a longer period of intervention are necessary to clarify the effects of tDCS on wrist extension control in stroke patients.