title: Suppression of interictal spikes during phasic rapid eye movement sleep: a quantitative stereo-electroencephalography study.
abstract: Tonic and phasic rapid eye movement (REM) sleep seem to represent two different brain states exerting different effects on epileptic activity. In particular, interictal spikes are suppressed strongly during phasic REM sleep. The reason for this effect is not understood completely. A different level of synchronization in phasic and tonic REM sleep has been postulated, yet never measured directly. Here we assessed the interictal spike rate across non-REM (NREM) sleep, phasic and tonic REM sleep in nine patients affected by drug resistant focal epilepsy: five with type II focal cortical dysplasia and four with hippocampal sclerosis. Moreover, we applied different quantitative measures to evaluate the level of synchronization at the local and global scale during phasic and tonic REM sleep. We found a lower spike rate in phasic REM sleep, both within and outside the seizure onset zone. This effect seems to be independent from the histopathological substrate and from the brain region, where epileptic activity is produced (temporal versus extra-temporal). A higher level of synchronization was observed during tonic REM sleep both on a large (global) and small (local) spatial scale. Phasic REM sleep appears to be an interesting model for understanding the mechanisms of suppression of epileptic activity.
authors.affiliation: 'C. Munari' Epilepsy Surgery Centre, Niguarda Hospital, Milan, Italy.|Department of Biomedical and Clinical Sciences 'Luigi Sacco', University of Milan, Milan, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Campana
authors.affiliation: 'C. Munari' Epilepsy Surgery Centre, Niguarda Hospital, Milan, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Zubler
authors.affiliation: 'C. Munari' Epilepsy Surgery Centre, Niguarda Hospital, Milan, Italy.|Center for Advanced Research in Sleep Medicine, University of Montreal, Montreal, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Gibbs
authors.affiliation: Institute of Bioimaging and Molecular Physiology, Genoa Section, National Research Council, Genoa, Italy.
authors.forename: F
authors.identifier: 0000-0002-1841-5146
authors.initials: F
authors.lastname: de Carli
authors.affiliation: 'C. Munari' Epilepsy Surgery Centre, Niguarda Hospital, Milan, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Proserpio
authors.affiliation: 'C. Munari' Epilepsy Surgery Centre, Niguarda Hospital, Milan, Italy.|Department of Biomedical and Clinical Sciences 'Luigi Sacco', University of Milan, Milan, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Rubino
authors.affiliation: 'C. Munari' Epilepsy Surgery Centre, Niguarda Hospital, Milan, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Cossu
authors.affiliation: 'C. Munari' Epilepsy Surgery Centre, Niguarda Hospital, Milan, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Tassi
authors.affiliation: Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
authors.forename: K
authors.initials: K
authors.lastname: Schindler
authors.affiliation: 'C. Munari' Epilepsy Surgery Centre, Niguarda Hospital, Milan, Italy.
authors.forename: L
authors.identifier: 0000-0001-9317-5405
authors.initials: L
authors.lastname: Nobili
mesh_terms: D001921:Brain / Q000473:pathology / Q000503:physiopathology; D004569:Electroencephalography; D004828:Epilepsies, Partial / Q000473:pathology / Q000503:physiopathology*; D004827:Epilepsy / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006624:Hippocampus / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008297:Male; D065703:Malformations of Cortical Development, Group I / Q000473:pathology / Q000503:physiopathology; D012640:Seizures / Q000503:physiopathology; D012895:Sleep, REM / Q000502:physiology*
keywords: epilepsy; interictal epileptiform discharges; phasic REM sleep; stereo-EEG; synchronization; tonic REM sleep