Nearly all Parkinson's disease (PD) patients eventually develop abnormal and unwanted movements (dyskinesias; LID) 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. Current estimates of the prevalence of LID widely range from 12 % to 100% affected after one year. The purpose of this study is to estimate the median onset time of levodopa induced dyskinesia in newly treated Parkinson's disease patients. All participants will complete seven overnight visits at the OCTRI Inpatient unit over 5 years. 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.
