Amyloidopathy, Cholinopathy, Dopamine Responsiveness and Freezing of Gait in PD

Early stage Parkinson disease (PD) is characterized by a 'honeymoon' phase in terms of responsiveness of motor symptoms, including gait, to dopaminergic pharmacotherapy. Advancing PD is associated with disabling axial motor complications, such as freezing of gait (FoG), with decreased or even refractory dopamine responsiveness in over 50% of patients. The management of dopamine resistant gait problems represents the most important unmet need in PD. This study will related detailed motor testing to brain PET imaging to see if certain molecules (or lack thereof) involved with neurologic transmission in the brain are involved with FoG.