1. Department of Health Administration and Policy, George Mason University, Fairfax, VA, USA
2. Medicine Service Line, Inova Health System, Falls Church, VA, USA
3. Department of Rehabilitation Medicine, Spaulding Rehabilitation Hospital, Charlestown, MA, USA
4. Department of Rehabilitation Medicine, New York University Grossman School of Medicine, New York, USA
5. American Institute for Research, Arlington, VA, USA