1. Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, USA.
2. Department of Neurological Surgery, University of Louisville School of Medicine, University of Louisville, Louisville, Kentucky, USA.
3. Department of Research and Development, James J. Peters VA Medical Center, Bronx, New York, USA.
4. Departments of Rehabilitation and Human Performance and Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
5. Department of Health Management and System Science, University of Louisville, Louisville, Kentucky, USA.