In this study researchers will apply transcranial direct current stimulation (tDCS) for 5 consecutive days in chronic patients in minimally conscious state (MCS).

2 sessions of 5 days of stimulation will be realized, one anodal and one sham. After each stimulation, behavioral improvement will be assessed with the Coma Recovery Scale Revised (CRS-R). A final assessment will be done one week after the end of the sessions to assess the long term effect of the tDCS.

Positive effects of tDCS in patients in MCS was showed in a recent study published in Neurology. But the effects went down after 1 or 2 hours. To increase the lasting of the effects, a new study will evaluate the effects of tDCS on the left prefrontal dorsolateral cortex for 5 consecutive days in chronic patients in MCS.

2 sessions of 5 days of stimulation will be realized, one session will be real (anodal stimulation) and one placebo (sham stimulation). After each stimulation, behavioral improvement will be assessed with the Coma Recovery Scale Revised (CRS-R). A final assessment will be done one week after the end of the sessions to assess the long term effect of the tDCS.

Researchers expected to see an improvement of the CRS-r total score at the end of the anodal session and that this improvement persists for a week.

Inclusion Criteria:

• post comatose patients
• patients in minimally conscious state
• patients with stable condition
• patients free of sedative drugs and Na+ or Ca++ blockers (e.g., carbamazepine) or NMDA receptor antagonist (e.g., dextromethorphan)

Exclusion Criteria:

• premorbid neurology antecedent
• patients in coma or vegetative state
• patients < 3 months after the acute brain injury
• patients with a metallic cerebral implant or a pacemaker (in line with the safety criteria for tDCS in humans)