1. a The Medstat Group , Santa Barbara, CA, USA
2. b Wayne State University School of Medicine , Detroit, MI, USA
3. c Department of Physical Medicine and Rehabilitation , University of Medicine and Dentistry of New Jersey , West Orange, NJ, USA
4. d Kessler Medical Rehabilitation Research and Education Corporation , West Orange, NJ, USA
5. e Rehabilitation Institute of Medicine , University of Alabama at Birmingham , Birmingham, AL, USA
6. f Moss Rehabilitation Research Institute , Philadelphia, PA, USA