The Effect of Transcranial Direct Current Stimulation on Neglect Syndrome in Stroke Patients

Objective To examine whether transcranial direct current stimulation (tDCS) applied over the posterior parietal cortex (PPC) improves visuospatial attention in stroke patients with left visuospatial neglect. Methods Patients were randomly assigned to 1 of 3 treatment groups: anodal tDCS over the right PPC, cathodal tDCS over the left PPC, or sham tDCS. Each patient underwent 15 sessions of tDCS (5 sessions per week for 3 weeks; 2 mA for 30 minutes in each session). Outcome measures were assessed before treatment and 1 week after completing the treatment. Results From pre- to post-treatment, there was an improvement in the motor-free visual perception test (MVPT), line bisection test (LBT), star cancellation test (SCT), Catherine Bergego Scale (CBS), Korean version of Modified Barthel Index (K-MBI), and Functional Ambulation Classification in all 3 groups. Improvements in the MVPT, SCT, and LBT were greater in the anodal and cathodal groups than in the sham group. However, improvements in other outcomes were not significantly different between the 3 groups, although there was a tendency for improved CBS or K-MBI scores in the anodal and cathodal groups, as compared with the sham group. Conclusion The study results indicated that the facilitatory effect of anodal tDCS applied over the right PPC, and the inhibitory effect of cathodal tDCS applied over the left PPC, improved symptoms of visuospatial neglect. Thus, tDCS could be a successful adjuvant therapeutic modality to recover neglect symptom, but this recovery might not lead to improvements in activities of daily living function and gait function.