1. Division of Emergency Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
2. Center for Injury Research and Prevention, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
3. Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.
4. Oregon Alzheimer's Disease Research Center & Department of Neurology, Oregon Health & Science University, Portland, Oregon, USA.
5. Research Service and VA RR&D VISN20 Northwest Mental Illness Research Education and Clinical Center (MIRECC), VA Portland Health Care System, Portland, Oregon, USA.
6. Department of Neurosurgery, University of Rochester Medical Center and Bassett Medical Center, Cooperstown, New York, USA.
7. Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
8. Department of Family Medicine, Suburban Community Hospital, East Norriton, Pennsylvania, USA.
9. Sports Medicine and Performance Center, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
10. Department of Anesthesiology and Critical Care Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.