Effect of Transcranial Direct Current Stimulation on Patients With Disorders of Consciousness

Abstract Objective The aim of this study was to evaluate the efficacy of transcranial direct current stimulation (tDCS) for improving disorders of consciousness (DOCs), and to compare efficacy of the different etiologies of DOCs. Design Randomized controlled trials or crossover trials examining effects of tDCS in patients with DOCs were searched in PubMed, EMBASE, Cochrane Library and Web of Science. The sample characteristics, etiology, tDCS treatment characteristics and outcomes were extracted. Meta-analysis was performed using the RevMan software. Results We included nine trials providing data with 331 participants and found that tDCS improved the Coma Recovery Scale- Revised (CRS-R) score of DOCs patients. We found a significant improvement of CRS-R score in the minimally conscious state (MCS) group (WMD = 0.77, 95%CI [0.30, 1.23], P = 0.001), but not in the VS/UWS group. The effects of tDCS are related to etiology, as the CRS-R score was improved in the traumatic brain injury (TBI) group (WMD = 1.18, 95%CI [0.60, 1.75], P < 0.001), but not in vascular accident and anoxia groups. Conclusions This meta-analysis revealed the evidence for positive effects of tDCS on DOCs without side-effects observed in MCS patients. In particular, tDCS may be an effective treatment in rehabilitating cognitive functions in people with TBI.