1Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, UCLH, London, United Kingdom, 2Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, United Kingdom, 3Imaging and Biophysics Unit, UCL Institute of Child Health, London, United Kingdom, 4Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, United Kingdom, 5Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, London, United Kingdom, 6Department of Neurophysiology, National Hospital for Neurology and Neurosurgery, London, United Kingdom