FEATURES: ORIGINAL INVESTIGATION
Song, Jason J. MD, PhD; Twumasi-Ankrah, Philip PhD; Salcido, Richard MD
Jason J. Song, MD, PhD, is a National Institutes of Health T32 Postdoctoral Fellow, Department of Physical Medicine and Rehabilitation, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania. Philip Twumasi-Ankrah, PhD, is an Assistant Professor (Biostatistics), Department of Preventive Medicine and Public Health, University of Kansas School of Medicine, Wichita, Kansas. Richard Salcido, MD, is the William J. Erdman, II Professor of Rehabilitation, Department of Physical Medicine and Rehabilitation, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.
The authors have disclosed that they have no financial relationships related to this article.
Acknowledgments: The authors thank Dr Douglas D. Bradham for his constructive assistance and advice during the preparation of this article.
Submitted May 11, 2011; accepted June 16, 2011
