1 NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology, London WC1N 3BG, UK; Stichting Epilepsie Instellingen Nederland, Achterweg, Heemstede, Netherlands.
2 NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology, London WC1N 3BG, UK; Stichting Epilepsie Instellingen Nederland, Achterweg, Heemstede, Netherlands; Epilepsy Society, Chalfont St Peter, UK. Electronic address: l.sander@ucl.ac.uk.