Crossover Target Engagement Study of Cholinergic Mechanisms of Gait Dysfunction in Parkinson's Disease (Project #3 - Experiment 3 [UdallP3E3])

Exclusion Criteria

• •1. Other disorders which may resemble PD with or without dementia, such as vascular dementia, normal pressure hydrocephalus, progressive supranuclear palsy, multiple system atrophy, corticobasal ganglionic degeneration, or toxic causes of parkinsonism. Prototypical cases have distinctive clinical profiles, like vertical supranuclear gaze palsy, early and severe dysautonomia or appendicular apraxia, which may differentiate them from idiopathic PD. The use of the UKPDSBRC clinical diagnostic criteria for PD will mitigate the inclusion of subjects with atypical parkinsonism and all participants will undergo \[11-Carbon\]dihydrotetrabenazine PET to confirm striatal dopaminergic denervation.
• •2. Subjects on neuroleptic, anticholinergic (trihexphenidyl, benztropine), or cholinesterase inhibitor drugs.
• •3. Current or previous (within last 6 months) use of any product or medication containing nicotinic agents,including use of tobacco products such as cigarettes, cigars, pipes, chewing tobacco, etc., electronic cigarettes, over-the-counter nicotine patches, chewing gum containing nicotine, or varenicline.
• •4. Evidence of a stroke or mass lesion on structural brain imaging (MRI).
• •5. Participants in whom magnetic resonance imaging (MRI) is contraindicated including, but not limited to, those with a pacemaker, presence of metallic fragments near the eyes or spinal cord, or cochlear implant.
• •6. Severe claustrophobia precluding MR or PET imaging
• •7. Subjects limited by participation in research procedures involving ionizing radiation.
• •8. Pregnancy (test within 48 hours of each PET session) or breastfeeding.
• •9. Significant risk of cardiovascular event.
• •10. Active, significant mood disorder.