Inclusion criteria:
1. Aged ≥18 years to ≤85 years of age.
2. Body mass index (BMI) ≥18 to 40 kg/m2.
3. In adequate health based on medical history and physical examination (other than PD) undertaken following standard care procedures and presenting minimal risk for taking part in the study, per investigator assessment.
4. Participant or caregiver has demonstrated ability to perform satisfactory in-clinic and remote procedures during the screening period.
5. Clinically established PD, consistent with Postuma et al (Mov Disord; 2015).
6. H\&Y stage 1 or 2.
Exclusion criteria:
1. Unable to commit to 12 months of data collection.
2. Planning to enroll in a clinical trial for disease modifying therapy that will overlap with the duration of this study.
3. Parkinsonism due to drugs(s) and or toxin(s).
4. Increased risk of falling, defined as \>6 falls within the 12 months prior to screening.
5. Urine drug screen positive for opiates, phencyclidine (PCP), cocaine, or amphetamines.
6. Regular binge drinking, defined as ≥4 alcoholic drinks for women or ≥5 alcoholic drinks for men, per investigator assessment.
7. Current or recent (within 6 months prior to screening) diagnosis of a moderate or severe substance use disorder (excluding caffeine) according to Diagnostic and Statistical Manual of Mental Disorders-5 criteria. Note that nicotine use disorder is an exclusion criterion only if it has an effect on sleep (i.e., a participant who routinely awakens at night to smoke), and medical or recreational marijuana is not included in this exclusion criterion.
8. Severe cardiopulmonary, hepatic, renal, or musculoskeletal disease such that activities of daily living are adversely impacted.
9. History of neoplastic disease, with the exception of (1) an adequately treated basal cell carcinoma or carcinoma in situ of the cervix; (2) other malignancies which have been successfully treated \>5 years prior to screening without evidence of recurrence.
10. Currently participating in another clinical trial, or previous participation in a clinical trial in which an investigational product was received within 30 days prior to screening or within at least 5 half-lives of the investigational product.
11. Current or planned pregnancy.
12. History of seizures, epilepsy, stroke, multiple sclerosis, or traumatic brain injury (other than mild traumatic brain injury).
13. Intracranial metallic or magnetic devices, such as a cochlear implant or deep brain stimulator.
14. Implanted active device, such as a pacemaker or defibrillator.
15. History of gene therapy, intracranial antisense oligonucleotide treatment, cell transplantation, or experimental brain surgery.
16. Current untreated or unstable depressive disorder or a serious mood disorder requiring hospitalization.
17. Other primary degenerative dementia or neurodegenerative conditions outside of the specific basket in which the participant is enrolled, where applicable.
18. Other uncontrolled infectious, metabolic, or systemic diseases affecting the central nervous system, such as syphilis, hypothyroidism, vitamin B12 or folate deficiency, and other laboratory values.
19. Any other medical, psychiatric, or social condition that, in the opinion of the investigator, is likely to unfavorably alter the risk-benefit of participation, to interfere with protocol compliance, or to confound safety or efficacy assessments.
Additional exclusion criterion for the subset of treatment-naive participants only:
1\. No prior treatment to manage motor symptoms of PD; note that brief periods of dopaminergic therapy administered to establish diagnosis are not grounds for exclusion.
