Jennifer A Foley1, Thomas T Warner2, Lisa Cipolotti3. 1. National Hospital for Neurology and Neurosurgery, London, UK; UCL Institute of Neurology, London, UK. 2. Reta Lila Weston Institute of Neurological Studies, UCL Institute of Neurology, London, UK. 3. National Hospital for Neurology and Neurosurgery, London, UK; Dipartimento di Scienze Psicologiche, Pedagogiche e della Formazione, Università degli Studi di Palermo, Palermo, Italy.