All patients will receive a stereotactic placement of bilateral stereotactic insertion of two quadripolar electrodes into the Globus pallidus, two contacts reaching the GPE, two the GPI within both hemispheres. Surgery will be done under general anesthesia, The implantation of the stimulator (Kintera®) will take place in the same procedure. Postoperatively patients will be monitored at three and six months and regularly up to 60 months with a battery of clinical, neuropsychological, psychiatric, neurophysiological and neuroimaging tests.