Effect of Transcranial Direct Current Stimulation on Neurorehabilitation of Task-Specific Dystonia: A Double-Blind, Randomized Clinical Trial

Task-specific focal hand dystonia can disable affected individuals. Although neurorehabilitation techniques such as sensory motor retuning can result in complete recovery in some patients, it requires many months of treatment. Combining transcranial direct current stimulation (tDCS) with neurorehabilitation is a new and promising approach that can help these patients. However, the results in different studies are contradictory. OBJECTIVE: Analyze whether delivering tDCS (cathode over left and anode over right parietal region) during the neurorehabilitation process for musicians with dystonia can increase the effectiveness of therapy. METHOD: A parallel double-blind randomized design was used to study 30 musicians with right-hand primary focal dystonia. All patients underwent a 2-week course of neurorehabilitation based on sensory motor retuning therapy coupled with either real or sham tDCS for the first 30 minutes of each daily 1-hour therapy session (total 10 sessions). The therapist and patient were blind to the tDCS condition. A dystonia severity score was obtained before and after the 2-week protocol. The therapist also rated the evolution of each patient. RESULTS: Both groups significantly improved their dystonia severity score during the 2 weeks. Score differences were 88.23 (±40.51) and 63.36 (±30.57) for the active and sham groups, respectively. The active group showed a statistically significant greater improvement. CONCLUSIONS: Biparietal tDCS with left-sided cathode is a safe technique that does not interfere with the neurorehabilitation procedure and can increase therapy effectiveness in rehabilitation patients with right-hand task-specific focal dystonia.