Subthalamic Nucleus Versus Globus Pallidal Internus Deep Brain Stimulation for Parkinson Disease

Inclusion Criteria: 1. Age at the time of enrollment: 22-75 years. 2. Diagnosis of bilateral idiopathic PD with the presence of at least 2 of the following: resting tremor, rigidity, or bradykinesia 3. Duration of idiopathic PD: ≥ 5 years. 4. Severity of PD in the meds off condition: Hoehn-Yahr stages 2.5\~ 4.0. 5. Despite optimal medication treatment, there are still persistent symptoms or drug side effects of disabling Parkinson's 6. Must have tried a form of carbidopa/levodopa and/or one of the dopamine agonists as part of medication therapy. 7. Anti-parkinsonian medications must improve PD symptoms by ≥33%, as measured by UPDRS-III score. 8. UPDRS-III score of ≥ 30 in the meds off condition. 9. The MMSE assessment was higher than the demarcation score of the corresponding educational level, and the cognitive function was normal. 10. HAMD score≤24. 11. No change in antidepressant medications utilized for treatment of depression for at least 8 weeks prior to informed consent. 12. Stable on anti-parkinsonian medication for 28 days prior to informed consent. 13. Could tolerate bilateral STN DBS and bilateral GPi DBS. 14. Be willing and able to comply with all visits and study related procedures (e.g., using the remote control, charging system and completing the PD Diary 15. Able to understand the study requirements and the treatment procedures and provides written informed consent before any studyspecific tests or procedures are performed. Exclusion Criteria: 1. Any intracranial abnormalities or medical conditions that Lead to the prohibition of DBS surgery. 2. Have any significant psychiatric condition likely to compromise the subject's ability to comply with requirements of the study protocol (e.g. bipolar, schizophrenia, mood disorder with psychotic features, cluster B personality disorders). 3. HAMD score\>24. 4. Any current drug or alcohol abuse, per DSM-IV criteria 5. Any history of recurrent or unprovoked seizures. 6. Any history of hemorrhagic stroke. 7. Any previous treatment for movement disorders involving intracranial surgery or device implantation. 8. Any other active implanted devices including neurostimulators (e.g., cochlear implant, pacemaker) and /or drug delivery pumps, whether turned on or off. Passive implants (e.g., knee prostheses) would be allowed provided that they do not interfere with the functioning of the DBS system 9. Any previous thalamotomy, pallidotomy or subjects who have undergone a DBS procedure. 10. Any previously implanted Vagus Nerve Stimulation (VNS) patients. 11. Any previous brain surgery that would interfere with the placement of the leads or the functioning of the device. 12. A condition requiring or likely to require the use of Magnetic Resonance Imaging (MRI), diathermy or electroconvulsive therapy (ECT) 13. Likely to require the use of monopolar cau Likely to require the use of monopolar cautery, radiofrequency (RF) procedures, external defibrillation, lithotripsy, radiation therapy or transcranial stimulation.tery, radiofrequency (RF) procedures, external defibrillation, lithotripsy, radiation therapy or transcranial stimulation. 14. Currently on any anticoagulant medications that cannot be discontinued during perioperative period. 15. Currently exhibiting secondary Parkinsonism due to prescribed medications. 16. Have any significant medical condition that is likely to interfere with study procedures or likely to confound evaluation of study endpoints. 17. Any terminal illness with life expectancy of \< 1 year. 18. Any unresolved infection, a coagulopathy or significant cardiac or other medical risk factor for surgery 19. Current or future risk of being immunocompromised that might significantly increase risk of infection. 20. Participation in any other clinical trial (e.g. drug, device, or biologics) concurrently or within the preceding 30 days. Participation in any other study will be allowed per investigator/sponsor discretion only. 21. A female who is breastfeeding or of child-bearing potential with a positive urine pregnancy test or not using adequate contraception. 22. Preoperative DBS plan failed to implant STN and GPi. nuclei.(Usually limited by individual anatomical differences) 23. Preoperative CT scan of the head revealed calcification of the GPI.