INCLUSION CRITERIA:

1. Diagnosis of PSP with bilateral symptoms based on medical history and neurologic examination in accordance with NINDS criteria. Those evidencing ratable limb dysfunction bilaterally as well as a past history levodopa responsivity will be especially sought.
2. PSP will be considered clinically to be at a moderate to moderately advanced stage (PSP Staging System grade BB - DD), associated with ratable parkinsonian signs in the limbs bilaterally and a Hoehn and Yahr grade of 3 - 5.
3. Men or nonpregnant women age 35 to 75 years. Women of childbearing potential must have a negative human chorionic gonadotropin (HCG) test result immediately before (within 48 hours) catheter and pump implantation and repeated again immediately before (within 48 hours) the start of drug infusion; men and women of childbearing potential must practice adequate contraception during the course of the study.
4. Before any study-specific procedures are performed, the subject and their designated representative must give signed informed consent for their participation. All patients must sign a Durable Power of Attorney (DPA). Device implantation must occur within 60 days after a subject consents to participate in the study.
5. The subject is medically able to undergo the surgical procedures required to implant bilateral pumps and intracranial catheters using stereotactic procedures.

EXCLUSION CRITERIA:

1. Treatment with levodopa, dopamine agonists or any other antiparkinsonian medications.
2. Presence of clinically significant psychosis or hallucinations.
3. Any disorder that precludes a surgical procedure (e.g., bleeding diathesis, signs of sepsis or inadequately treated infection) alters wound healing or renders bilateral catheter and infusion pump implants unsuitable.
4. Any history of clinically significant head trauma or cerebrovascular disease or recent history (within previous 2 years) of drug or alcohol abuse.
5. A computed tomography (CT) scan or magnetic resonance image (MRI) of the brain within 3 months before the implantation procedure that indicates the presence of a central nervous system abnormality that may interfere with the assessments of safety or biologic effect in this protocol, or represent a surgical risk to the subject.
6. The presence of an intracranial shunt or catheter system other than the one used in this protocol.
7. Any medical disability, condition or laboratory abnormality (e.g., severe degenerative arthritis, compromised nutritional state, body weight less than 15% of ideal, Na less than 130 (grade 3 or above), cardiovascular disease) that would be deemed likely to increase risk of participation in the protocol or interfere with assessment of the safety and biologic effect of study materials, the chronic implantation of catheters and infusion pumps, or would compromise the ability of the subject to give informed consent.
8. Known allergy to E coli-derived products or history of anaphylaxis.
9. Treatment with an investigational agent or used an investigational device within 60 days before the first dose of study material, other than those described in this protocol.