Effect of long-lasting repeated high-definition transcranial direct current stimulation on consciousness recovery in minimally conscious state patients

Abstract

Objective To assess the efficacy of long-lasting repeated high-definition transcranial direct current stimulation (HD-tDCS) over the precuneus on consciousness recovery in patients with minimally conscious state (MCS). Methods A prospective case-control study was carried out on 40 MCS patients admitted in the Fifth Affiliated Hospital of Zhengzhou University from June 2018 to January 2021. They were randomly divided into HD-tDCS group (n=20) and control group (n=20). The patients in the control group received routine treatment, while those in the HD-tDCS group were treated with HD-tDCS protocol over the precuneus (at 2 mA, for 20 min per time, twice per day for 14 d, with totally 28 sessions) on the basis of routine treatment. Gender, age, duration of consciousness, Coma Recovery Scale-Revised (CRS-R) scores before (T0), and at a single session (T1), 7 d (T2), and 14 d (T3) were recorded and analyzed. Results The CRS-R score at T3 was significantly higher in the HD-tDCS group than the control group (P < 0.05). In the control group, 2 MCS patients demonstrated a new sign of consciousness at T3, and the CRS-R scores at T1, T2 and T3 were not significantly changed than those at T0. While in the HD-tDCS group, 17 patients showed a new sign of consciousness, and the CRS-R scores at T1, T2, and T3 were obviously increased when compared with those at T0 (P < 0.05). And the scores of visual, auditory and motor subscales at T3 were also statistically elevated than the scores at baseline (P < 0.01). Conclusion Long-lasting repeated HD-tDCS over the precuneus improves the recovery of consciousness in MCS patients at the 14th day of neuromodulation, especially in the visual, auditory and motor aspects of conscious behaviors.

Keywords

• transcranial direct current stimulation
• minimally conscious state
• precuneus
• neuromodulation