title: Responders to vagus nerve stimulation (VNS) in refractory epilepsy have reduced interictal cortical synchronicity on scalp EEG.
abstract: EEG desynchronization has been proposed to be an important mechanism for antiepileptic effect of vagus nerve stimulation (VNS) but has never been clearly documented in human. The aim of this study was to evaluate impact of VNS on the synchronicity of interictal EEG rhythms. We estimated synchronization between scalp EEG signals using phase lag index (PLI) in 19 patients with chronic VNS therapy. We estimated changes in synchronization between ON and OFF phases and between responder (R) and non-responder (NR) patients. We found that R have a lower global level of synchronization (EEG broadband) than NR (p<0.0001) In addition, ON periods were characterized by lower values in comparison with OFF periods (p<0.001). R had significantly lower global synchronization levels in delta and alpha frequency bands (p<0.0001). Patients responding to VNS have thus a lower level of broadband EEG synchronization than non-responders. Estimating changes of synchronization level is thus a promising tool for predicting response to VNS.
authors.affiliation: CHU Timone, Service de Neurophysiologie Clinique, Assistance Publique des Hôpitaux de Marseille, Marseille F-13005, France.
authors.forename: Clémentine
authors.initials: C
authors.lastname: Bodin
authors.affiliation: CHU Timone, Service de Neurophysiologie Clinique, Assistance Publique des Hôpitaux de Marseille, Marseille F-13005, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Aubert
authors.affiliation: Hôpital Henri Gastaut, 13009 Marseille, France.
authors.forename: Géraldine
authors.initials: G
authors.lastname: Daquin
authors.affiliation: CHU Timone, Stereotactic and Functional Neurosurgery Department, Assistance Publique des Hôpitaux de Marseille, Marseille F-13005, France.
authors.forename: Romain
authors.initials: R
authors.lastname: Carron
authors.affiliation: CHU Timone, Pediatric Neurosurgery Department, Assistance Publique des Hôpitaux de Marseille, Marseille F-13005, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Scavarda
authors.affiliation: CHU Timone, Service de Neurophysiologie Clinique, Assistance Publique des Hôpitaux de Marseille, Marseille F-13005, France.
authors.forename: Aileen
authors.initials: A
authors.lastname: McGonigal
authors.affiliation: CHU Timone, Service de Neurophysiologie Clinique, Assistance Publique des Hôpitaux de Marseille, Marseille F-13005, France; Institut de Neurosciences des Systèmes, INSERM UMR 1106, Marseille, France. Electronic address: fabrice.bartolomei@ap-hm.fr.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Bartolomei
mesh_terms: D000293:Adolescent; D000328:Adult; D001703:Biophysics; D003344:Cortical Synchronization / Q000502:physiology*; D000069279:Drug Resistant Epilepsy / Q000503:physiopathology* / Q000628:therapy*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012535:Scalp; D018709:Statistics, Nonparametric; D055536:Vagus Nerve Stimulation / Q000379:methods*; D055815:Young Adult
keywords: EEG; Epilepsy; Functional connectivity; Synchrony; VNS