1. 1 MedStar National Rehabilitation Hospital, Washington, DC
2. 2 Department of Rehabilitation Medicine, MedStar Georgetown University Hospital, Washington, DC
3. 3 Collaborative for Research on Outcomes and Metrics, Silver Spring, Maryland
4. 4 Departments of Neurology, Rehabilitation Medicine, and Biostatistics, Bioinformatics & Biomathematics, Georgetown University, Washington, DC
5. 5 MedStar Health Research Institute, Hyattsville, Maryland