1. Neurorehabilitation Unit, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1 3BG, UK
2. Audit Department, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1 3BG, UK
3. Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1 3BG, UK