Striatal and Extra-striatal Mechanisms of Falling in Parkinson's Disease

This research study will evaluate functions of memory, thinking, eye movements and walking and how these relate to the measurement of certain chemicals (acetylcholine and dopamine) in the brain using an imaging procedure called positron emission tomography (PET). You may know that the brain chemical dopamine, a "neurotransmitter" substance (a chemical messenger that nerve cells need to communicate with each other), is important for the brain to control movements and that the brain chemical acetylcholine may have functions related to mental concentration and attention. At the present time, the investigators have no clear information how these two chemicals in the brain of patients with Parkinson's disease are related to the risk of falling.

Although most research in PD has a focus on presynaptic dopaminergic denervation, new lessons may be learned by exploring to what extent alterations in non-motor and non-dopaminergic systems may play a role in the balance impairment in this disorder. This project is designed to evaluate striatal pre-synaptic dopaminergic, cortical, thalamic, and brainstem cholinergic, cognitive, and oculomotor mechanisms underlying the risk of falling and imbalance in PD. The proposed study will exploit advances in our center in the development of dynamic biomathematical modeling of electronic platform data, application of specialized cognitive and oculomotor assessments, and positron emission tomography (PET). This novel multi-system approach holds promise for understanding mechanisms of falling in PD beyond pre-synaptic dopaminergic nigrostriatal denervation.