Inclusion Criteria:

• 1. Participants must meet the Movement Disorders Society (MDS) diagnostic criteria for clinically established Parkinson disease.
• 2. Able to provide signed informed consent (in English or Spanish)
• 3. Mild, moderate, or severe Parkinson disease, able to ambulate (Hoehn and Yahr stages I-IV)
• 4. Taking instant release oral carbidopa/levodopa therapy
• 5. Either not taking, or on stable doses of any of the following antiparkinsonian medications: dopamine agonists, monoamine oxidase B (MAO-B) inhibitors or catecholamine O-methyl transferase (COMT) inhibitors

Exclusion Criteria:

• 1. Other neurological conditions including but not limited to stroke, dementia (including Parkinson disease dementia), or traumatic brain injury
• 2. Co-existent major psychiatric disease
• 3. Uncontrolled, active medical conditions (e.g., heart, kidney, or liver failure, diabetes, etc.)
• 4. Status post deep brain stimulation (DBS) device placement
• 5. Any other condition, that in the opinion of the investigators, would place the participant at risk.