1. Department of Neurology, Princess Margaret Hospital for Children, Perth, and Centre for Neuromuscular and Neurological Disorders, QEII Medical Centre, University of Western Australia, Nedlands, Western Australia,
2. Department of Neurology, Princess Margaret Hospital for Children, Perth, Western Australia
3. Centre for Neuromuscular and Neurological Disorders, QEII Medical Centre, University of Western Australia, Nedlands, Western Australia