Effectiveness and Safety of Directional Deep Brain Stimulation for Parkinson's Disease

Inclusion Criteria: Age at the time of enrollment: 18 ~ 75; Idiopathic Parkinson's disease; Patient whose symptoms are not adequately controlled by best medical therapy; Hoehn and Yahr stage≥2.5; Patient whose symptoms are improved by at least 30% with levodopa challenge test; Must be an appropriate candidate for the surgical procedures required for bilateral DBS; Is willing and able to comply with all visits and study related procedures; Patient understands the study requirements and the treatment procedures and provides written informed consent before any study-specific tests or procedures are performed. Exclusion Criteria: Had received lesioning surgical treatment; A female who is breastfeeding or of child-bearing potential with a positive urine pregnancy test or not using adequate contraception; Any current drug or alcohol abuse; Cognitive impairment (MMSE≦17 for primary school education or MMSE≦24 for middle school education and above); Any significant psychiatric problems, including unrelated clinically significant depression; Any history of craniocerebral injury, tumor, or severe cerebrovascular disease; Severe brain atrophy (confirmed by CT or MRI); A condition requiring or likely to require the use of diathermy; Abnormal blood routine or biochemical test, coagulation dysfunction, serious abnormal liver or kidney function; Uncontrolled high blood pressure, serious heart disease or serious medical or respiratory diseases; Long-term of immunosuppressive or hormone therapy; Other diseases requiring the stimulators; A condition requiring or likely to require the use of MRI; Participated in any other clinical trials within the preceding 3 months; Unwilling or unable to cooperate with the implantation of DBS system; Unwilling or unable to cooperate with postoperative follow-up; Not considered to be applicable by the investigator.