1. Department of Neurology; Feinberg School of Medicine; Northwestern University; Chicago Illinois U.S.A
2. Departments of Pediatrics and Neurology; Children's Hospital of Philadelphia and Perelman School of Medicine at the University of Pennsylvania; Philadelphia Pennsylvania U.S.A
3. Department of Neurology; Emory University School of Medicine; Atlanta Georgia U.S.A
4. Division of Neurology; The Hospital for Sick Children and University of Toronto; Toronto Ontario Canada
5. Department of Neurology; Beth Israel Deaconess Medical Center; Boston Massachusetts U.S.A
6. Department of Neurology; Neurological Institute; Columbia University College of Physicians and Surgeons; New York New York U.S.A