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.