1. Department of Epidemiology, University of Pittsburgh, Pittsburgh, PA, USA
2. Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, USA
3. Department of Rehabilitation Counseling, University of Texas Southwestern Medical Center, Dallas TX, USA
4. Department of Physical Medicine and Rehabilitation, Center for Neuroscience, Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, USA