A map of Parkinson's (IMAGE) WashU Medicine Caption Researchers at Washington University School of Medicine in St. Louis have conducted the largest epidemiological study of Parkinson's disease. Red areas on the map indicate a prevalence of 13,800 or more Parkinson's patients per 100,000 Medicare recipients. Credit Neuroepidemiology/S. Karger AG Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.