Combining High-definition Transcranial Direct Current Stimulation with Conventional Coma Stimulation to Improve the Level of Consciousness Among Patients with Disorders of Consciousness: A Pilot Study

Disorders of consciousness (DOCs) are very common after cerebrovascular accidents or traumatic brain injuries. The absence of consciousness entirely prevents the standard rehabilitation process that aims to improve function and participation in life-related skills. This DOC makes the appropriate course of action unclear to the entire medical team and caregivers. Traditionally, rehabilitation has only involved coma stimulation (CS); however, it has not been very successful in many situations. This study aimed to evaluate combining traditional CS with high-definition transcranial direct current stimulation (HD-tDCS). Since CS aims to enhance sensory input to the brain, we aimed to reorganize the brain cellular connections through neuromodulation via HD-tDCS. A combination of physical sensory inputs to the neuro-modulated brain may offer an added advantage to patients with DOC, eliciting an improved response. This study enrolled nine patients with DOC (six males and three females aged 50-80 years) following a traumatic brain injury or cerebrovascular accident. All participants received a combination therapy comprising daily CS and HD-tDCS; no control group was included. HD-tDCS was delivered at 2 mA three times a week for 4 weeks (a total of 12 sessions), with each session lasting 20 min. Outcomes were assessed using the Coma Recovery Scale–Revised (CRS-R) and the Glasgow Coma Scale (GCS). The combination therapy significantly improved consciousness among participants. Their mean CRS-R score improved from 6.44 ± 3.50 to 13.33 ± 4.09, and their mean GCS score improved from 5.22 ± 1.86 to 8.33 ± 1.22. This pilot study suggests that combining CS with neuromodulation therapy, such as HD-tDCS applied to the left dorsolateral prefrontal cortex, may potentially enhance consciousness in patients with DOC. The findings from this small cohort suggest potential benefits of combining CS with HD-tDCS, which warrant further investigation in larger, controlled trials.