1Division of Child and Adolescent Psychiatry, University of Cape Town, Cape Town, South Africa;2Department of Statistics and Actuarial Science, Stellenbosch University, Stellenbosch, South Africa;3Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA;4Pediatric Neurology Unit, Department of Pediatrics, UZ Brussel, Vrije Universiteit Brussels, Brussels, Belgium;5Department of Neurology, F.M. Kirby Center for Neuroscience, Boston Children's Hospital, Boston, MA, USA;6Department of Neurology, Texas Scottish Rite Hospital for Children, The University of Texas Southwestern Medical Center, Dallas, TX, USA;7Department of Pediatric Neurology, University Hospitals Leuven, Leuven, Belgium