Strong "intrinsic" functional connectivity of epileptic networks independent of scalp interictal epileptiform EEG discharges. Issue 3 (March 2016)

• Record Type: Journal Article
• Authors: Iannotti, G.R.; Pittau, F.; Grouiller, F.; Centeno, M.; Abela, E.; Seeck, M.; Wiest, R.; Carmichael, D.; Michel, C.; Vulliemoz, S.
• Is Part Of: Clinical neurophysiology. Volume 127:Issue 3(2016:Mar.)
• Page Start: e41
• Page End: e42
• Publication Date: 2016-03
• Subjects: Neurophysiology -- Periodicals; Electroencephalography -- Periodicals; Electromyography -- Periodicals; Neurology -- Periodicals; 612.8
• DOI: 10.1016/j.clinph.2015.11.132
• Languages: English
• ISSNs: 1388-2457

Abstract

Abstract : Objective: Epileptic activity arises from dysfunction of pathological neuronal network (epileptic network). Aim: to assess maintenance of epileptic network in between IEDs occurrence. Methods: We acquired simultaneous EEG-fMRI resting state in 10 drug-resistant focal epilepsy patients, having multifocal BOLD response and maximal t -value in the IED field. We compared results of functional connectivity (FC) before and after removing IEDs effect for two seed types: a 10mm-diameter sphere drawn in the BOLD map maximum and the epileptic component obtained by Indipendent component analysis. We evaluated the results in terms of mean t -value and the percentage of overlap between the FC maps. Results: Mean t -value was significant lower after regressing out the IEDs at group level ( p = 0.008 for sphere; p = 0.0004 for epileptic component). Overlap extent was 85% ± 12% and 87% ± 12% for the sphere and the epileptic component, respectively. Conclusions: Regions involved in a specific epileptic network show coherent oscillation independent of the occurrence of interictal activity. This could indicate the presence of epileptic activity invisible to the scalp-EEG or the presence of new and pathological resting state networks. Key message: Regions involved in a specific epileptic network show functional coupling independently of the occurrence of interictal activity as revealed on scalp EEG.