1. 1 MedStar Health Research Institute, Hyattsville, Maryland
2. 2 MedStar National Rehabilitation 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 Georgetown University Hospital Department of Rehabilitation Medicine, Washington, DC
6. 6 Georgetown University School of Medicine, Washington, DC