- 96 patients with clinically diagnosed PD. For the PD diagnosis, we will use the University of Kentucky PD brain bank diagnostic criteria implemented by a movement disorders trained neurologist. Only early stage PD within 5 years of diagnosis who have never taken rasagiline will be included. 5 years since diagnosis was chosen to focus on early stages of PD, where MAO-B inhibitors have shown the most promise. PD are eligible to participate if they are age 40-77, Hoehn and Yahr stage < or equal to 2 when on medication, and able and willing to sign informed consent to be randomized to the placebo or active drug arm.