The Effects of Transcranial Direct Current Stimulation on Dysarthria in Stroke Patients

ABSTRACT

OBJECTIVE: To investigate whether transcranial direct current stimulation (tDCS) can improve dysarthria in stroke patients. METHOD: Twelve patients who developed dysarthria after acute middle cerebral artery (MCA) infarction were included in this study. In a prospective, double blinded, randomized case control study performed between January 2007 and December 2008, six patients were randomized to anodal tDCS application and conventional speech therapy, and six patients were randomized to the sham group which received only conventional speech therapy. tDCS was delivered for 30 minutes at 2 mA with 25cm2, five times/week, for a total two weeks. The effects were assessed in maximal phonation time (MPT), alternative motion rates (AMR)-Pa, AMR-Ta, AMR-Ka, and sequential motion rates (SMR)-PaTaKa using the Multi-Media Dimension Voice Program. RESULTS: Pre-treatment patient evaluation showed no significant difference between the two groups for all parameters. The MPT, AMR-Pa, AMR-Ta, AMR-Ka, and SMR-PaTaKa were improved pre- and post-treatment in the stimulation group, while MPT, SMR-PaTaKa were improved in the sham group (p<0.05). The AMR-Pa significantly improved in the stimulation group compared to the sham group (p<0.05). CONCLUSION: As these results demonstrated the beneficial effects of anodal tDCS on dysarthria, tDCS can successfully be used as a treatment modality for patients suffering from dysarthria after stroke.