Deep Anterior Cerebellar Stimulation in Treatment of Poststroke Spasticity and Motor Function Impairment.

The aim of this clinical trial is to determine whether deep brain stimulation (DBS) interventions improve rehabilitation and functional recovery in patients with post-stroke spasticity who meet the other inclusion criteria listed below. Primary question(s) to be answered: Is DBS stimulation effective in treating post-stroke spasticity? What stimulation frequency is most effective in treating post-stroke spasticity? Study participants will: * Undergo surgery to implant a DBS electrode targeting the DRTt (dentate-rubro-thalamic tract ) in close proximity of the dentate nucleus of the cerebellum ipsilateral to the spastic side of the body. * Each patient will then receive an initial stimulation frequency of 130 Hz (arm 1) and will be assigned to a 4- to 6-week rehabilitation program. After this period, the participant will return for a follow-up visit for a clinical evaluation. * The frequency will then be changed to 70Hz (arm 2). Patients who have undergone this change will also undergo a rehabilitation period of 4 to 6 weeks. After this period, they will return to the Clinic for a follow-up evaluation. * The frequency will then be changed to 30Hz (arm 3). Patients who have undergone this change will also undergo a rehabilitation period of 4 to 6 weeks. Researchers will compare the results obtained from patients in each arm to determine the clinical effects of stimulation and whether they are dependent on the stimulation frequency.