This study evaluates metabolic and functional parameters in the skeletal muscle of Parkinson's disease patients for comparison to a set of healthy age-matched controls.

The goal of this study is to identify the unique signature of bioenergetic markers and mitochondrial (dys)function in muscle of individuals with PD, who are 65-85 of age, read and speak English, have a Hoehn & Yahr score between 2 and 3 (bilateral disease, not severely disabled) and have a clinical diagnosis of PD. Bioenergetic markers and muscle functional properties will be compared to a control dataset collected over the last few years from healthy elderly subjects in the same age range to provide a foundation for future intervention studies.

Inclusion Criteria:

• Age 65-85 years.
• Ability to attend a 3-hour study visit in Seattle, WA.
• Ability to read and speak English.
• Hoehn & Yahr Stage 2-3. (bilateral disease, not severely disabled.)

Exclusion Criteria:

• Any contra-indication to magnetic resonance imaging
• A history of epilepsy, stroke, brain surgery, or structural brain disease.
• The presence of other serious illnesses
• Current or recent enrollment in a clinical trial involving an investigational product or device.
• Supplementation with NAD, nicotinamide mononucleotide (NMN), nicotinamide riboside (NR), and other nutraceuticals designed to target NAD for 30 days prior to baseline study visit.
• Current drug or alcohol use or dependence.
• Inability/unwillingness to provide informed consent. (e.g. diagnosis of dementia, confusion about study goals or participation.)
• Acute infection (e.g. upper respiratory, dermal) in the previous 30 days.
• Right limb tremor or dyskinesia that cannot be comfortably controlled for 90 minutes.

Patients diagnosed with Parkinson's disease