Effect of Repeated tDCS Sessions on Cognitive Improvement in Patients With Disorders of Consciousness

A single session of tDCS showed positive effects on patients in MCS (study published in Neurology, 2014). Nevertheless, the effects went down after 1 or 2 hours. In a second study (Protocol ID: 2009/201/B) we have found that 5 days of tDCS increase the lasting of the effects up to one week. To know if tDCS could be use in clinical daily practice, a new study will evaluate the effects of 20 minutes of tDCS over the left prefrontal dorsolateral cortex for 4 weeks, 5 days per week, in chronic patients in MCS. 2 sessions of 4 weeks of stimulation (total=20 stimulations per session) will be performed, one session will be real (anodal stimulation) and one placebo (sham stimulation). Firstly, the patient will be seen at the hospital for a behavioral assessment (CRS-R) with one of his/her caregiver. The investigator will explain to the caregiver how to perform the stimulation. In addition, he/she will receive a folder and a video. The caregiver will take an exam to be sure he/she performs the tDCS properly. Before and after each stimulation session, behavioral improvement will be assessed with the CRS-R by a trained neuropsychologist, at the hospital. A final assessment will be done 8 weeks after the end of the session to assess the long term effect of tDCS. The compliance will be recorded by the deice to be sure that the caregiver performs the stimulation every day as expected. Researchers expect to see (a) an improvement of the CRS-R total score at the end of the anodal session and (b) this improvement persists for 8 weeks.