Parkinson''s Disease

- Idiopathic Parkinson's disease (PD). As defined by:
 -- presence of bradykinesia and either rest tremor or rigidity
 -- history of asymmetry of PD signs
 -- history of progression of PD signs, and
 -- no other suspected cause of PD signs
- Patient is between 40 and 70 years of age, inclusive
- Patient is L-dopa-sensitive and has unequivocal clinical "off" periods as documented by home diary, completed on 4 consecutive days with an average of 1.5 hours/day in the clinically "off" state
- Patient is Hoehn & Yahr stage III or higher in the practically defined "off" phase
- All other medical problems are stable or under control and are not contraindications to general anesthesia or stereotactic neurosurgery
- Patient's brain magnetic imaging resonance (MRI) shows no abnormality that would contraindicate Spheramine implantation
- Patient does not have a major psychiatric problem or dementia
- Patient must give written informed consent to participate in this study
- Patient must be on a stable dose of antiparkinsonian medication for at least 1 month prior to completion of the home diary assessment and the baseline UPDRS assessments
- If the patient is a woman of childbearing potential, she must not be nursing or pregnant and must use an adequate form of birth control for the duration of the study deemed appropriate by the investigator such as oral contraceptives, IUD, or condoms
- Patient must be living with or in close constant contact with a person who can contribute information as to the patient's condition before and after implant and provide assistance, if necessary

- Patients with atypical Parkinson's disease (e.g. parkinsonian "plus" syndrome, secondary Parkinsonian syndrome)
- Patients exhibiting only a tremor-based symptomatology
- Patients exhibiting very severe dyskinesias (lasting more than 2 hour/day) exacerbated by L-dopa, evaluated as 4/4 on the dyskinesia scale (violent dyskinesias, incompatible with any normal motor task)
- Women of childbearing potential without contraception
- Patients who are non-cooperative or incapable of completing self-evaluation scales or diaries
- Patients presenting with known pharmacologic immunosuppression related to chemotherapeutic treatment for malignancy, autoimmune disease, allografts or other medical conditions associated with immunosuppression
- Patient's cardiovascular, pulmonary, renal and hematological state contraindicates use of general anesthesia
- Evidence of abnormal coagulation including PT > 13 sec, PT > 35 sec or platelets < 5 ml
- Patients having had previous stereotactic brain surgery
- Patients treated by apomorphine pump
- Patients with significant cognitive impairment, untreated or treatment resistant depression, psychosis, hallucinations or delusions that would prevent their effective participation in the study
- Patients who have participated in another experimental drug or device trial in the past 30 days