1. Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, Gainesville FL, Department of Physical Therapy, Brooks Center for Rehabilitation Studies,
2. Rehabilitation Outcomes Research Center, University of Florida, Gainesville, Department of Aging and Geriatric Research, University of Florida, Gainesville
3. Division of Geriatric Medicine, University of Pittsburgh, Pittsburgh, PA
4. Department of Mechanical Engineering, University of Texas, Austin
5. Department of Internal Medicine, University of Pittsburgh, Pittsburgh, PA, Department of Veteran Affairs Medical Center, Pittsburgh, PA