The present pilot study is designed to assess the extent to which rasagiline may improve cognition in Parkinson's disease patients requiring dopaminergic therapy. The primary objective is to assess improvement in the Montreal Cognitive Assessment (MoCA) in patients who have been on rasagiline at 1mg daily for twelve weeks. The secondary objective is to assess changes in the SCOPA-COG, FAB, and UPDRS II & III at the end of week 14.

Inclusion Criteria:

• Men and women aged 40 or older with idiopathic Parkinson's disease on stable dopaminergic therapy for at least 1 month. The UK Brain Bank Criteria will be used to establish the diagnosis of Parkinson's disease. Women must be post menopausal or agree to avoid pregnancy. Modified Hoehn & Yahr staging < 3 and MoCA score must be greater than 21 but less than 28. Geriatric Depression Scale (GDS) is a sensitive and specific screen for depression in the Parkinson's disease population. GDS scores of < 5 will be included in the study.

Exclusion Criteria:

• Patients with secondary dementia, severe depression and atypical Parkinson's syndromes or Parkinson's plus will be excluded from the study. Patients on acetylcholine esterase or NMDA inhibitor medication will be excluded from the study. Patients with history of brain surgery for Parkinson's disease, stroke or significant head injury, active epilepsy will be excluded. Patients on Amantidine, neuroleptics, metoclopramide, alphamethyldopa within the last 6 months will be excluded. Individuals using meperidine, and tramadol will be excluded. Patients with congestive heart failure or myocardial infarction will also be excluded to avoid vascular dementia.