1. Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London, England
2. Unit of Functional Neurosurgery, The National Hospital for Neurology and Neurosurgery, London, England
3. UK Home Office, London, England
4. Lysholm Department of Neuroradiology, The National Hospital for Neurology and Neurosurgery, London, England