 20 Parkinsonian patients will be enrolled. After implantation of a bilateral strip electrode Resume, Medtronic over the motor cortex, after setting of optimal stimulation parameters, and after implantation of a neurostimulator, Medtronic, the patient will be randomly assigned to group A Motor cortex stimulation on or to group B sham stimulation for 6 months. Randomization will be based on the output of a program based on a random number generation function that will output a 0 or 1 with a 50 chance of having a 1. 