Two Intensities of Transcranial Direct Current Stimulation to Improve Consciousness in Severely Brain Injured Patients

Limited treatments are available to improve consciousness in severely brain injured patients. Transcranial Direct Current stimulation (tDCS) is one of the few therapeutics that showed evidence of efficacy to increase level of consciousness and functional communication in some minimally conscious state (MCS) patients, and in some vegetative state (VS) patients. However the optimal intensity of electrical current stimulation remains unknown.

This study will test the effects of two intensities of tDCS stimulation (either 0.2mA or 2mA) applied on left dorso-lateral prefrontal cortex on both behavior, - assessed by the Coma Recovery Scale-Revised (CRS-R) scores -, as well as quantified EEG recorded during resting state (using algorithms previously designed and published by the investigators) and event-related potentials (using auditory paradigms we previously published) in severely brain damaged patients with disorders of consciousness (MCS, VS, and conscious but cognitively disabled patients) of various etiologies.

This study will use a cross-over double-blind design with each patient receiving both current intensities in a randomized order during 4 weeks (2 weeks for each tDCS intensity, totalizing a number of 10X2 stimulation sessions of 20 minutes each).

Inclusion Criteria:

• Non communicative patients (including conscious patients but presenting with major fluctuations of vigilance and/or of cognitive abilities)
• Patients with stable clinical examination
• Age between 18 and 80 years
• Brain injury confirmed by cerebral imaging (MRI or TDM)
• Disorder of consciousness diagnosed by CRS-R (VS, MCS, exitMCS)

Exclusion Criteria:

• Status epilepticus
• Severely neurodegenerative illnesses (Alzheimer disease, Lewy Body Dementia)
• Pregnancy
• Patients underage