1. Discipline of General Practice, University of Newcastle, Callaghan, NSW, Australia
2. Department of Primary Care Health Sciences, University of Oxford, Oxford, UK
3. Discipline of Medicine, University of Newcastle, Callaghan, NSW, Australia
4. Department of Neurology, John Hunter Hospital, Newcastle, NSW, Australia
5. School of Medicine and Public Health, Hunter Medical Research Institute, University of Newcastle, Callaghan, NSW, Australia