1 Department of Physical Medicine and Rehabilitation, Hospital for Special Surgery, New York City, NY, USA.
2 Rusk Rehabilitation, New York University School of Medicine, New York City, NY, USA.
3 Sports Therapy and Rehabilitation (STAR), Barnes Jewish West County Hospital, St. Louis, MO, USA.
4 Division of Neurorehabilitation, Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA.
5 Washington University School of Medicine, Departments of Orthopaedic Surgery and Neurology, Division of Physical Medicine and Rehabilitation, 660 S. Euclid Ave., Campus Box 8233, St. Louis, MO, USA. Electronic address: huntdm@wustl.edu.