title: Network analysis of EEG related functional MRI changes due to medication withdrawal in focal epilepsy.
abstract: Anti-epileptic drugs (AEDs) have a global effect on the neurophysiology of the brain which is most likely reflected in functional brain activity recorded with EEG and fMRI. These effects may cause substantial inter-subject variability in studies where EEG correlated functional MRI (EEG-fMRI) is used to determine the epileptogenic zone in patients who are candidate for epilepsy surgery. In the present study the effects on resting state fMRI are quantified in conditions with AED administration and after withdrawal of AEDs. EEG-fMRI data were obtained from 10 patients in the condition that the patient was on the steady-state maintenance doses of AEDs as prescribed (condition A) and after withdrawal of AEDs (condition B), at the end of a clinically standard pre-surgical long term video-EEG monitoring session. Resting state networks (RSN) were extracted from fMRI. The epileptic component (ICE) was identified by selecting the RSN component with the largest overlap with the EEG-fMRI correlation pattern. Changes in RSN functional connectivity between conditions A and B were quantified. EEG-fMRI correlation analysis was successful in 30% and 100% of the cases in conditions A and B, respectively. Spatial patterns of ICEs are comparable in conditions A and B, except for one patient for whom it was not possible to identify the ICE in condition A. However, the resting state functional connectivity is significantly increased in the condition after withdrawal of AEDs (condition B), which makes resting state fMRI potentially a new tool to study AED effects. The difference in sensitivity of EEG-fMRI in conditions A and B, which is not related to the number of epileptic EEG events occurring during scanning, could be related to the increased functional connectivity in condition B.
authors.affiliation: Department of Research and Development, Academic Center for Epileptology, Kempenhaeghe & Maastricht UMC+, Heeze, The Netherlands ; Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Kees
authors.initials: K
authors.lastname: Hermans
authors.affiliation: Department of Clinical Physics, Academic Center for Epileptology, Kempenhaeghe & Maastricht UMC+, Heeze, The Netherlands.
authors.forename: Pauly
authors.initials: P
authors.lastname: Ossenblok
authors.affiliation: Department of Research and Development, Academic Center for Epileptology, Kempenhaeghe & Maastricht UMC+, Heeze, The Netherlands ; Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Petra
authors.initials: P
authors.lastname: van Houdt
authors.affiliation: MR Neuro Imaging, Philips Healthcare, Best, The Netherlands.
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Geerts
authors.affiliation: Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Verdaasdonk
authors.affiliation: Department of Research and Development, Academic Center for Epileptology, Kempenhaeghe & Maastricht UMC+, Heeze, The Netherlands.
authors.forename: Paul
authors.initials: P
authors.lastname: Boon
authors.affiliation: Department of Neurology, Academic Center for Epileptology, Kempenhaeghe & Maastricht UMC+, Heeze, The Netherlands.
authors.forename: Albert
authors.initials: A
authors.lastname: Colon
authors.affiliation: Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Jan C
authors.initials: JC
authors.lastname: de Munck
mesh_terms: D000328:Adult; D000368:Aged; D000927:Anticonvulsants / Q000008:administration & dosage / Q000494:pharmacology*; D004569:Electroencephalography / Q000379:methods*; D004828:Epilepsies, Partial / Q000188:drug therapy* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000187:drug effects* / Q000503:physiopathology*; D055815:Young Adult
chemical_list: D000927:Anticonvulsants
keywords: Anti-epileptic drugs; EEG–fMRI; Epilepsy; Functional connectivity; Resting-state fMRI