1 From the Department of Physical Medicine and Rehabilitation, Vanderbilt University Medical Center, Nashville, Tennessee (WRF); Department of Physical Medicine, Rehabilitation, and Sports Medicine, University of Puerto Rico School of Medicine, San Juan, Puerto Rico (WRF); Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, and New England GRECC, VA Boston Healthcare System, Massachusetts (JFB); Department of Rehabilitation Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland (DD); Department of Physical Medicine and Rehabilitation, Northwestern Feinberg Medical School and Rehabilitation Institute of Chicago, Illinois (LE-J, RLL); Departments of Neurology, Pediatrics, BME, ENT, Oregon Health & Science University, Portland (MF-O); Health and Disability Research Institute, School of Public Health, Boston University, Massachusetts (AJ); Department of Biomedical Engineering, Florida International University, Miami (RJ); Department of Physical Medicine and Rehabilitation, Indiana University School of Medicine and Rehabilitation Hospital of Indiana, Indianapolis (JFM); Program in Physical Therapy and Department of Radiology, Washington University School of Medicine, St. Louis, Missouri (MJM); Division of Rehabilitation Sciences, School of Health Professions, University of Texas Medical Branch, Galveston (KJO); Methodist Rehabilitation Center, University of Mississippi Medical Center, Jackson Veteran's Administration Medical Center (KET); and Department of Health Science and Research, College of Health Professions, Medical University of South Carolina, Charleston (AT).