title: Altered brain rhythms and functional network disruptions involved in patients with generalized fixation-off epilepsy.
abstract: Generalized Fixation-off Sensitivity (CGE-FoS) patients present abnormal EEG patterns when losing fixation. In the present work, we studied two CGE-FoS epileptic patients with simultaneous EEG-fMRI. We aim to identify brain areas that are specifically related to the pathology by identifying the brain networks that are related to the EEG brain altered rhythms. Three main analyses were performed: EEG standalone, where the voltage fluctuations in delta, alpha, and beta EEG bands were obtained; fMRI standalone, where resting-state fMRI ICA analyses for opened and closed eyes conditions were computed per subject; and, EEG-informed fMRI, where EEG delta, alpha and beta oscillations were used to analyze fMRI. Patient 1 showed EEG abnormalities for lower beta band EEG brain rhythm. Fluctuations of this rhythm were correlated with a brain network mainly composed by temporo-frontal areas only found in the closed eyes condition. Patient 2 presented alterations in all the EEG brain rhythms (delta, alpha, beta) under study when closing eyes. Several biologically relevant brain networks highly correlated (r > 0.7) to each other in the closed eyes condition were found. EEG-informed fMRI results in patient 2 showed hypersynchronized patterns in the fMRI correlation spatial maps. The obtained findings allow a differential diagnosis for each patient and different profiles with respect to healthy volunteers. The results suggest a different disruption in the functional brain networks of these patients that depends on their altered brain rhythms. This knowledge could be used to treat these patients by novel brain stimulation approaches targeting specific altered brain networks in each patient.
authors.affiliation: Department of Neuroimaging, Center for Biomedical Technology, Universidad Politécnica de Madrid, Autopista M40 Km.38, 28223, Pozuelo de Alarcón, Spain. anabea.solana@gmail.com.|GE Global Research, Freisinger Landstrasse 50, 85748, Garching bei Munich, Bayern, Germany. anabea.solana@gmail.com.
authors.forename: Ana Beatriz
authors.initials: AB
authors.lastname: Solana
authors.affiliation: Research Unit, Instituto de Investigación Sanitaria del Hospital Gregorio Marañón (IISGM), Calle Doctor Esquerdo, 46, 28007, Madrid, Spain.
authors.forename: Kenia
authors.initials: K
authors.lastname: Martínez
authors.affiliation: Department of Electronical Technology, Universidad Rey Juan Carlos, Calle Tulipán s/n, 28933, Móstoles, Spain.
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Hernández-Tamames
authors.affiliation: Epilepsy Center, University Hospital Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany.
authors.forename: Victoria
authors.initials: V
authors.lastname: San Antonio-Arce
authors.affiliation: Department of Neurology, Hospital Ruber Internacional, Calle de la Maso, 38, 28034, Madrid, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Toledano
authors.affiliation: Department of Neurology, Hospital Ruber Internacional, Calle de la Maso, 38, 28034, Madrid, Spain.
authors.forename: Irene
authors.initials: I
authors.lastname: García-Morales
authors.affiliation: Department of Neuroradiology, Hospital Ruber Internacional, Calle de la Maso, 38, 28034, Madrid, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Alvárez-Linera
authors.affiliation: Department of Neurology, Hospital Ruber Internacional, Calle de la Maso, 38, 28034, Madrid, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Gil-Nágel
authors.affiliation: Department of Neuroimaging, Center for Biomedical Technology, Universidad Politécnica de Madrid, Autopista M40 Km.38, 28223, Pozuelo de Alarcón, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Del Pozo
mesh_terms: D000293:Adolescent; D000328:Adult; D001611:Beta Rhythm / Q000502:physiology; D001921:Brain / Q000503:physiopathology; D001931:Brain Mapping / Q000379:methods; D058256:Brain Waves / Q000502:physiology*; D016022:Case-Control Studies; D004569:Electroencephalography / Q000379:methods; D004827:Epilepsy; D004829:Epilepsy, Generalized / Q000503:physiopathology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D010100:Oxygen
chemical_list: D010100:Oxygen
keywords: EEG-informed fMRI; Fixation-off; ICA; Resting-state networks; Simultaneous EEG-fMRI