1. Headache Group, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK; NIHR-Wellcome Trust King’s Clinical Research Facility, King’s College Hospital, London, UK
2. Headache Group, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK; NIHR-Wellcome Trust King’s Clinical Research Facility, King’s College Hospital, London, UK; National University Hospital, Singapore