• Purpose - to validate a combination of biological and clinical markers in the rapid-eye-movement (REM) sleep behavior disorder (RBD) population as indicative of the pre-symptomatic stage of Parkinson's disease (PD).
• Procedures - All subjects (RBD diagnosis and controls) will have 1) a medical and neuro history and physical including videotape of movements, 2) neuropsychological testing, 3) a sleep study, 4) olfactory testing, 5) blood draw for serum testing , 6) functional MRI. All of these procedures are often performed clinically in the diagnosis of PD. Enrollment of subjects with PD is complete. Any testing performed prior to enrollment as part of the clinical evaluation may be used in place of repeating the procedure for the study. Subjects will be followed for 5 years. It is hypothesized that a 5 year follow up may capture a significant number of pre-Parkinson's subjects who will be diagnosed. Subjects may be offered a repeat enrollment after 5 years.

Enrollment of PD and PS cohorts is complete. Currently enrolling only confirmed RBD and Controls.

Inclusion Criteria:

1. 35-70 year old men & women
2. (1) Diagnosis of idiopathic RBD (see AASM criteria), 2) Normal control or control with a non-neurodegenerative disorder, age and gender-matched to (1)
3. Gives written informed consent
4. Pregnant women are not excluded, but will be identified by HCG.

Exclusion Criteria:

a A diagnosis of any non-Parkinsonian Neurodegenerative Disease.

b. Any unstable or uncontrolled medical or psychiatric condition.

c. Parasomnia or RBD not idiopathic, eg., secondary to metabolic derangement or medicine effect.

d. Renal (creatinine over 1.6) or hepatic insufficiency (LFT significantly out of range), or a history of significant uncontrolled cardiac disease.

e. Significant dementia (MMSE<25 of 30 or MOCA<25/30) that would interfere with study procedures or informed consent.

f. Any reason which, in the opinion of the PI, would increase the risk or decrease the value of any study procedure.

g. fMRI will not be performed for anyone for whom the screening questionnaire indicates is ineligible for MRI imaging.

Patients with polysomnographically-documented RBD, non-neurodegenerative diagnosis Age and gender matched non-RBD diagnosis, non-neurodegenerative diagnosis idiopathic PD diagnosis atypical PD diagnosis