Transcranial Direct Current Stimulation Improves Swallowing Function in Stroke Patients

Abstract

Background. Poststroke dysphagia can persist, leading to many complications. Objective. We investigated whether noninvasive brain stimulation to the pharyngeal motor cortex combined with intensive swallowing therapy can improve dysphagia. Methods. A total of 20 patients who had dysphagia for at least 1 month after stroke were randomly assigned to receive 10 sessions lasting 20 minutes each of either 1-mA anodal transcranial direct current stimulation (tDCS) or a sham procedure to the ipsilesional pharyngeal motor cortex, along with simultaneous conventional swallowing therapies. We evaluated swallowing function with the Dysphagia Outcome and Severity Scale (DOSS) before, immediately after, and 1 month after the last session. Results. Anodal tDCS resulted in an improvement of 1.4 points in DOSS ( P = .006) immediately after the last session and 2.8 points ( P = .004) 1 month after the last session. The sham tDCS group improved 0.5 points ( P = .059) after the last session and 1.2 points ( P = .026) 1 month after the final session. The improvements in the anodal tDCS group were significantly greater than those in the sham tDCS group ( P = .029 after the last session, and P = .007 1 month after the last session). Conclusions. Anodal tDCS to the ipsilesional hemisphere and simultaneous peripheral sensorimotor activities significantly improved swallowing function as assessed by the DOSS.