1. Department of Veterans Affairs Puget Sound Health Care System, Seattle, Washington, USA
2. Department of Rehabilitation Medicine, University of Washington School of Medicine, Seattle, Washington, USA
3. Department of Physical Medicine and Rehabilitation, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
4. Stanbro Healthcare Group, Edmond, Oklahoma, USA
5. Physical Medicine and Rehabilitation, Arroyo Grande Community Hospital, Arroyo Grande, California