Increased cortical BOLD signal anticipates generalized spike and wave discharges in adolescents and adults with idiopathic generalized epilepsies

• Published in: Epilepsia (Copenhagen) Vol. 53; no. 4; pp. 622 - 630
• Main Authors: Benuzzi, Francesca, Mirandola, Laura, Pugnaghi, Matteo, Farinelli, Valentina, Tassinari, Carlo Alberto, Capovilla, Giuseppe, Cantalupo, Gaetano, Beccaria, Francesca, Nichelli, Paolo, Meletti, Stefano
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.04.2012; Wiley-Blackwell; Wiley Subscription Services, Inc
• Subjects: Absence seizure; Adolescence; Adolescent; Adult; Age; Biological and medical sciences; BOLD; Brain; Brain Mapping; Brain Waves - physiology; Cerebellum; Cerebral Cortex - blood supply; Cerebral Cortex - physiopathology; Cortex; Cortex (parietal); Deactivation; Default mode network; EEG; EEG-fMRI; Electroencephalography; Epilepsy; Epilepsy, Generalized - pathology; Epilepsy, Generalized - physiopathology; Female; Firing pattern; Follow-Up Studies; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; Hemodynamics; Humans; Idiopathic generalized epilepsy; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Malformations of the nervous system; Medical sciences; Nerve Net - blood supply; Nerve Net - physiopathology; Nervous system (semeiology, syndromes); Neurology; NMR; Nuclear magnetic resonance; Oxygen; Oxygen - blood; Retrospective Studies; Seizures; Thalamus; Young Adult; Human; Default mode network; Nervous system diseases; Absence seizure; Epilepsy; Idiopathic; Electrophysiology; Idiopathic generalized epilepsy; Electroencephalography; Nuclear magnetic resonance imaging; Cerebral disorder; Convulsion; EEG-fMRI; Central nervous system disease; Adolescent; Spike wave; BOLD; Neurological disorder
• ISSN: 0013-9580; 1528-1167; 1528-1167
• DOI: 10.1111/j.1528-1167.2011.03385.x

Summary Purpose:  Electroencephalography–functional magnetic resonance imaging (EEG‐fMRI) coregistration has recently revealed that several brain structures are involved in generalized spike and wave discharges (GSWDs) in idiopathic generalized epilepsies (IGEs). In particular, deactivations and activations have been observed within the so‐called brain default mode network (DMN) and thalamus, respectively. In the present study we analyzed the dynamic time course of blood oxygen level–dependent (BOLD) changes preceding and following 3 Hz GSWDs in a group of adolescent and adult patients with IGE who presented with absence seizures (AS). Our aim was to evaluate cortical BOLD changes before, during, and after GSWD onset. Methods:  Twenty‐one patients with IGE underwent EEG‐fMRI coregistration. EEG‐related analyses were run both at the single‐subject and at group level (random effect). The time‐course analysis was conducted for 3 s time windows before, during, and after GSWDs, and they were included until no further BOLD signal changes were observed. Key Findings:  Fifteen patients (nine female, mean age 28 years) had GSWDs during EEG‐fMRI coregistration (262 total events, mean duration 4 s). Time‐course group analysis showed BOLD increments starting approximately 10 s before GSWD onset located in frontal and parietal cortical areas, and especially in the precuneus‐posterior cingulate region. At GSWD onset, BOLD increments were located in thalamus, cerebellum, and anterior cingulate gyrus, whereas BOLD decrements were observed in the DMN regions persisting until 9 s after onset. Significance:  Hemodynamic changes (BOLD increments) occurred in specific cortical areas, namely the precuneus/posterior cingulate, lateral parietal, and frontal cortices, several seconds before EEG onset of GSWD. A dysfunction of these brain regions, some of which belongs to the DMN, may be crucial in generating GSWDs in patients with IGE.