Graeme J Hankey1, Chee-Keong Wee2. 1. School of Medicine and Pharmacology, The University of Western Australia, Perth2Department of Neurology, Sir Charles Gairdner Hospital, Perth, Australia3Western Australian Neuroscience Research Institute, Perth. 2. Department of Neurology, Sir Charles Gairdner Hospital, Perth, Australia4Department of Neurology, National Neuroscience Institute, Singapore.