1 Division of Pediatric Neurology, Department of Neurology, Washington University School of Medicine, St Louis, Missouri.
2 Division of Developmental Paediatrics, Department of Paediatrics, Holland Bloorview Kids Rehabilitation Hospital, University of Toronto, Toronto, Ontario, Canada.
3 Division of Neurology, Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Children's Mercy Kansas City, Kansas City, Missouri.
4 Barrow Neurologic Institute, Phoenix Children's Hospital, Departments of Child Health, Cellular and Molecular Medicine, Genetics, and Neurology, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona.
5 Pittsford, New York.
6 H. Ben Taub Department of Physical Medicine and Rehabilitation and Departments of Neurosurgery and Pediatrics, Baylor College of Medicine, Houston, Texas.
7 Department of Epidemiology, Epidemiology Data Center, University of Pittsburgh, Pittsburgh, Pennsylvania.