1. Dental Institute, King's College London, Denmark Hill, London SE5 9RS and Headache Group, Institute of Neurology, The National Hospital for Neurology and Neurosurgery
2. Senior Lecturer and Honorary Consultant Neurologist, Headache Group, Institute of Neurology, The National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG
3. Professor and Honorary Consultant, King's College Hospital, Denmark Hill, London, SE5 9RS, UK