1. Headache and Facial Pain Group, University College London (UCL), Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
2. Department of Neuromuscular Diseases, Institute of Neurology, University College London, UK
3. Peninsula Technology Assessment Group (PenTAG), University of Exeter, UK
4. Department of Neurology, Rouen University Hospital, Rouen, France