The two cerebral hemispheres find themselves in a state of balanced mutual inhibition. A
stroke with involvement of motor function leads to a reduced excitability in affected
hemisphere M1 and to an increased excitability of contralateral M1. Stroke therefore might
impair interhemispheric balance, leading to a decreased inhibition of contralesional
hemisphere by ipsilesional hemisphere and, in turn, to an increased inhibition of
ipsilesional hemisphere by contralesional hemisphere. Permanence of healthy hemisphere
hyperactivation in chronic phase after stroke is usually index of little functional recovery
and is correlated with a greater ipsilateral structural damage.
Robot-mediated physical therapy is an innovative rehabilitation technique that is effective
in stroke patients. In this study, the investigators will add a non-invasive brain
stimulation protocol with Transcranial stimulation with direct current (tDCS) to the robotic
treatment in chronic stroke patients. tDCS is a non-invasive brain stimulation technique that
is able to modulate cortical excitability. The hypothesis is that dual t-DCS (ipsilesional
excitation and concomitant contralesional inhibition) could restore interhemispheric balance
improving the benefits of robotic therapy with Armeo Power®.