1. Department of Rehabilitation Sciences, University of Oklahoma Health Sciences, 1200 N Stonewall, Room 3092, Oklahoma City, OK 73117 (USA)
2. Department of Rehabilitation Medicine, University of Washington, Seattle, Washington
3. Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, Kentucky
4. Department of Physical Therapy and Rehabilitation Sciences, Drexel University, Philadelphia, Pennsylvania
5. Department of Statistics, University of Kentucky