1. Department of Neurology, National Parkinson’s Foundation Center for Excellence, Translational Neurotherapeutics Program. Movement Disorders Program. MedStar Georgetown Hospital Washington, DC, USA
2. Department of Neurology, Laboratory for Dementia and Parkinsonism, National Parkinson’s Foundation Center for Excellence, Translational Neurotherapeutics Program. Georgetown University Medical Center, Washington, DC, USA
3. Department of Biostatistics, Georgetown University Medical Center, Washington, DC, USA