• Forceplate Measurement of Dyskinesia [ Time Frame: 2 weeks, 5 weeks, 8 weeks ] [ Designated as safety issue: No ]
  

• Inertial Sensor Signal [ Time Frame: 2 weeks, 5 weeks, 8 weeks ] [ Designated as safety issue: No ]
  

Nearly all Parkinson's disease (PD) patients eventually develop abnormal and unwanted movements (dyskinesias) caused by the gold standard treatment, Levodopa. The severity of these movements can range from subtle to extremely debilitating and may or may not interfere with normal activities such as putting on a coat or brushing ones teeth. Currently, one of the very few treatments for these unwanted and involuntary movements is Amantadine. In a previous study, we developed an objective measuring device to quantify dyskinesia.

All PD participants will receive all three of the drug treatment intervention (placebo, Amantadine 200 mg, Amantadine 300 mg). After 2 weeks of one drug treatment, the participants will complete an overnight visit at the OCTRI Inpatient unit. During the next day, participants will complete a mental task while standing on a force plate for one minute every half hour until the end of the study. A levodopa IV infusion will occur from 0900 to 1100.. The subjects will be split into 'high' and 'low' dose groups. Those who take <50 mg/hour of oral levodopa or levodopa equivalents will be considered 'low' dose subjects and will receive 1 mg/kg/hr of IV Levodopa during the study visits (1, 2, and 3). Those who administer > 50 mg/hr of oral levodopa to themselves normally will be considered 'high' dose subjects and will received 1.5 mg/kg/hr levodopa. Both groups will receive the infusion for two hours from 0900 - 1100. The study drug will be taken orally at 0800.