Transcranial Direct Current Stimulation in Poststroke Hemianopia

Introduction. Development of the new approaches to the rehabilitation of patients with poststroke hemianopia is of great importance, given the high prevalence of that disorder and its negative impact on patients’ quality of life. This study aimed to investigate the effect of transcranial direct current stimulation (tDCS) on the quality of life and the quality of visual perception in patients with poststroke hemianopia, as well as to study the safety and tolerability of this technique. Materials and methods. The study included ten patients with poststroke hemianopia. Patients underwent ten tDCS sessions (2 mA, 20 min with anode placed over Oz, cathode — over Cz for a unilateral lesion, and anode — over O1 and O2, cathode — over Fp1 and Fp2 for bilateral lesions). The tolerability of tDCS was evaluated after each session using a standardized questionnaire. Clinical assessment before and after tDCS was performed using the Visual Function Questionnaire (VFQ-25) and the 36-item Short Form Survey (SF-36). Functional MRI using a visual paradigm was performed in 5 patients before and after the course of tDCS. Results. Adverse effects were recorded during 9.9% of the sessions and had low severity in most cases. There was one withdrawal from the study because of increased pain in the hand and leg, in a patient with central post-stroke pain syndrome, which was likely unrelated to the biological effects of stimulation. Data of 9 patients were included in the analysis. There was a statistically significant increase in the overall score on the VFQ-25 (p = 0.02) after tDCS with improvements in the social activity (p = 0.02), mental health (p = 0.02), dependence on others (p = 0.04), and peripheral vision (p = 0.04) sections. A statistically significant improvement was also found in the psychological component of quality of life (p = 0.04), vitality (p = 0.03), social functioning (p = 0.02), role functioning due to physical health (p = 0.04), and general health (p = 0.008). In 3 cases, increased activation of the occipital cortex after tDCS was identified using functional MRI with a visual paradigm. Conclusion. tDCS is a safe, well-tolerated, and potentially effective method in patients with poststroke hemianopia. Larger, controlled, and randomized studies are needed to clarify the efficacy of this method in hemianopia.