Clinical Research Directory

Inclusion Criteria: * Clinical diagnosis of Parkinson's disease according to Movement Disorder Society clinical diagnostic criteria (59), Hoehn and Yahr stages I-III at enrollment (ON medication state when applicable) (60). * Age ≥55 years at enrollment. * Adequate hearing and visual acuity to participate in the examinations * Ability to provide written informed consent in English. * Ability to complete study procedures, including seated tasks and walking tasks (with or without an assistive device, if needed for safety). * Stable antiparkinsonian medication regimen for ≥4 weeks prior to baseline (or drug-naive). Exclusion Criteria: * Not able to communicate or follow instructions due to aphasia or severe cognitive impairment. * Active CNS disease including multiple sclerosis, uncontrolled seizures, active cancer. * Cerebrovascular accident other than TIA within 60 days prior to Visit 0. * Major psychiatric disease, including major depression not currently controlled on medications, alcohol or drug abuse. * Abnormal kidney function (creatinine \>2mg/dL or EGFR \<30mL/min) by most recent labs within 6 months prior to Visit 0. * Elevated liver enzymes (AST and/or ALT above x2 upper limit of normal) by most recent labs within 6 months prior to Visit 0. * Treatment with other NAD enhancers (Nicotinamide riboside or nicotinamide mononucleotide) within 4 weeks prior to randomization. * Any other medical condition and/or unstable or severe medical illness which, in the opinion of investigator, would render the patient inappropriate or too unstable to complete the study protocol.