This is an open-label study to investigate the effects of the rivastigmine patch on attention and behavior in Parkinson's disease when associated with memory and/or thinking problems. Rivastigmine (also sold under the name Exelon) is an FDA approved medication used for the treatment of mild to moderate Alzheimer's Disease (AD) and memory or thinking problems due to Parkinson's disease. Recently a rivastigmine patch was developed, which has shown similar effectiveness with fewer side effects and increased caregiver preference when compared to capsules. This is an open-label 12 week study where 15 subjects diagnosed with Parkinson's Disease who have mild to moderate memory and/or thinking complaints will be treated with the rivastigmine patch at UCSF. This study also analyzes the mechanism by which the rivastigmine patch works in people with Parkinson's disease and memory and/or thinking problems.

Participation in this study requires four visits: a screening visit to ensure eligibility, an initial/baseline visit where the medication is distributed at a dosage lower than the optimal recommended dosage, a four week follow-up visit where the dosage of the medication is increased to the optimal amount, and a final twelve week follow up visit.

• In the screening visit the patient will undergo a neurological exam (including a review of their medical history and short physical exam), electrocardiogram ( a painless procedure that measures electrical activity of your heart), cognitive testing (such as memory and thinking tests), and a blood draw.
• At the Baseline/Initial visit the patient will receive a brief physical exam, additional cognitive testing, and an MRI scan. Afterwards, the study drug will be distributed.
• At the four week follow up visit the patient will be asked to do some abbreviated cognitive and neurological testing and the study drug will be re-distributed at the target dosage.
• At the final twelve week visit the patient will receive additional cognitive and neurological testing, and an MRI scan.
• Study compliance and adverse events will be reviewed every two weeks throughout the study, whether in person or over the phone.

Inclusion Criteria:

• Must meet research criteria for Parkinson's Disease with Dementia (PDD)
• Males and females, ages between 55 and 100
• Able to undergo psychometric testing
• Mini-Mental State Examination ≥ 21 and Clinical Dementia Rating < 2
• Reliable informant with frequent contact with patient

Exclusion Criteria:

• Non-English speaking, as cognitive tests will be in English
• Evidence of other neurological or psychiatric disorders which preclude diagnosis of PDD (including, but not limited to, stroke, any psychotic disorder, severe bipolar or unipolar depression, seizure disorder, or head injury with loss of consciousness) within the past year
• Concurrent treatment with any acetylcholinesterase inhibitors (including rivastigmine in pill or patch form), antipsychotic agents (excluding quetiapine in dosages of 150 mg and lower, abilify and geodon as these medications are commonly used in treatment of Parkinson's Disease (PD) psychosis and should not affect results of study), mood stabilizers (valproate or lithium) or benzodiazepines (other than temazepam or zolpidem)
• Positive urine drug screen or suspected alcohol or substance abuse within last 1 year
• Current malignancy, or any clinically significant hematological, endocrine, cardiovascular, renal, hepatic, gastrointestinal or neurological disease. If the condition has been stable for at least the past year and is judged by the investigator not to interfere with the patient's participation in the study, the patient may be included
• Systolic blood pressure over 180 or less than 90 mm Hg. Diastolic blood pressure not greater than 105 or less than 50 mm Hg
• ECG is abnormal and judged to be clinically significant by the investigator
• Use of investigational drugs or participation in investigational drug studies within 30 days of screening
• Geriatric Depression Score score > 15/30
• Hachinski score > 4