1. UCL Stroke Research Centre, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology and the National Hospital for Neurology and Neurosurgery, Russell Square House, 10–12 Russell Square, London WC1B 5EH, UK
2. Department of Neurology, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Korea
3. Neuroscience Center, Samsung Medical Center, Seoul, Korea
4. Biostatistics Group, University College London Hospitals and University College London Research Support Centre, University College London, Gower Street, London, WC1E 6BT, UK
5. Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London, WC1N 3BG, UK