Recovering Arm Function in Chronic Post-stroke Patients Using Combined HD-tDCS and Virtual Reality Therapy

Stroke remains the leading cause of acquired disability in France. Moreover, even after the first 3 months of intense arm rehabilitation, 80% of chronic stroke patients don't use their paretic arm in activities of daily living. To this day, despite notable developments, techniques of rehabilitation of the arm for chronic stroke patients are still insufficient. In this context, two promising stroke rehabilitation techniques are to be considered: * Virtual reality-based systems provide specific, intensive, repetitive and motivational therapy with real-time feedback of movement and performance which can promote activity-dependent brain neuroplasticity, and therefore functional arm recovery. Thus, virtual reality therapy (VRT), in addition to usual rehabilitation, would improve the function of the arm more effectively as well as daily activities. * Non-invasive transcranial direct current stimulation (tDCS) uses constant low intensity (2 mA) continuous electrical currents to modulate the excitability of cortical neurons. Because of its greater focality of neuromodulatory effect that promotes brain neuroplasticity, anodal HD-tDCS to the lesioned hemisphere can improve functional arm recovery after a stroke. In addition, the combined use of the HD-tDCS with a rehabilitation modality, such as constraint induced movement therapy, would potentiate the combined effects of both techniques. Therefore, the investigators hypothesize that the combination of HD-tDCS in a rehabilitation program based on VRT would potentiate the effects on neuroplasticity and would further improve functional recovery of the paretic arm in chronic stroke patients