RecruitingDietary supplementPilot Study of Open Label Homocysteine Management Therapy in Levodopa-treated Parkinson's DiseaseThis is a research study investigating elevated homocysteine in the blood of patients with Parkinson's disease who are currently receiving treatment with levodopa. We are evaluating if elevated homocysteine can be corrected using open label B vitamin therapy, as well as the impact of homocysteine levels on cognitive function.