Motor tDCS in patients with Disorders of Consciousness

Objectives: To evaluate the effects of 20 minutes of tDCS applied on the affected primary motor cortex in patients with disorders of consciousness (DOC).

Methods: We enrolled 11 patients with a disorder of consciousness or a Locked-in Syndrome: five in unresponsive wakefulness syndrome/vegetative state, five in minimally conscious state and one in Locked-in Syndrome (mean age: 48±19 years; 5 traumatic etiologies). Five were in the acute/subacute stage (< 3 months post injury) and six were in the chronic state (> 3 months post injury). In this randomized double-blind controlled study, patients received anodal tDCS (2mA for 20 minutes) over the motor cortex (F3) and sham stimulation. Patients’ consciousness was evaluated before and after the stimulation with the Coma Recovery Scale Revised (CRS-R). Effects were evaluated using the Wilcoxon signed-rank test.

Results: CRS-R score obtained after anodal tDCS is not significantly higher (p=0.0607) than CRS-R score obtained after sham tDCS. Regarding the motor subscale, there was no significant difference either after the real stimulation (p=0.081).

Conclusion: tDCS doesn’t seem to improve the motor status of patients with DOC neither their state of consciousness. Patient’s tailored stimulation should be further investigated to improve the rate of response.