[1] Queen Mary Univ London, Wolfson Inst Prevent Med, Prevent Neurol Unit, Charterhouse Sq, London EC1M 6BQ, England
[2] Royal Free Hosp NHS Trust, Dept Neurol, London, England
[3] Monash Univ, Dept Neurosci, Melbourne, Vic, Australia
[4] Ruhr Univ Bochum, St Josef Hosp, Dept Neurol, Bochum, Germany
[5] Barts Hlth NHS Trust, Dept Neurol, Royal London Hosp, London, England