An EEG-fMRI Study on the Termination of Generalized Spike-And-Wave Discharges in Absence Epilepsy

Francesca Benuzzi; Daniela Ballotta; Laura Mirandola; Andrea Ruggieri; Anna Elisabetta Vaudano; Micaela Zucchelli; Elisabetta Ferrari; Paolo Frigio Nichelli; Stefano Meletti

doi:10.1371/journal.pone.0130943

An EEG-fMRI Study on the Termination of Generalized Spike-And-Wave Discharges in Absence Epilepsy

PLoS One. 2015 Jul 8;10(7):e0130943. doi: 10.1371/journal.pone.0130943. eCollection 2015.

Authors

Francesca Benuzzi¹, Daniela Ballotta¹, Laura Mirandola², Andrea Ruggieri¹, Anna Elisabetta Vaudano², Micaela Zucchelli³, Elisabetta Ferrari⁴, Paolo Frigio Nichelli², Stefano Meletti²

Affiliations

¹ Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.
² Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy; Neurology Unit, NOCSAE Hospital-ASL, Modena, Italy.
³ Department of Psychology University of Bologna, Bologna, Italy.
⁴ IIT, Genova, Italy.

Abstract

Introduction: Different studies have investigated by means of EEG-fMRI coregistration the brain networks related to generalized spike-and-wave discharges (GSWD) in patients with idiopathic generalized epilepsy (IGE). These studies revealed a widespread GSWD-related neural network that involves the thalamus and regions of the default mode network. In this study we investigated which brain regions are critically involved in the termination of absence seizures (AS) in a group of IGE patients.

Methods: Eighteen patients (6 male; mean age 25 years) with AS were included in the EEG-fMRI study. Functional data were acquired at 3T with continuous simultaneous video-EEG recording. Event-related analysis was performed with SPM8 software, using the following regressors: (1) GSWD onset and duration; (2) GSWD offset. Data were analyzed at single-subject and at group level with a second level random effect analysis.

Results: A mean of 17 events for patient was recorded (mean duration of 4.2 sec). Group-level analysis related to GSWD onset respect to rest confirmed previous findings revealing thalamic activation and a precuneus/posterior cingulate deactivation. At GSWD termination we observed a decrease in BOLD signal over the bilateral dorsolateral frontal cortex respect to the baseline (and respect to GSWD onset). The contrast GSWD offset versus onset showed a BOLD signal increase over the precuneus-posterior cingulate region bilaterally. Parametric correlations between electro-clinical variables and BOLD signal at GSWD offset did not reveal significant effects.

Conclusion: The role of the decreased neural activity of lateral prefrontal cortex at GSWD termination deserve future investigations to ascertain if it has a role in promoting the discharge offset, as well as in the determination of the cognitive deficits often present in patients with AS. The increased BOLD signal at precuneal/posterior cingulate cortex might reflect the recovery of neural activity in regions that are "suspended" during spike and waves activity, as previously hypothesized.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Brain / physiopathology
Brain Mapping
Electroencephalography*
Epilepsy, Absence / diagnosis
Epilepsy, Absence / physiopathology*
Epilepsy, Generalized / diagnosis
Epilepsy, Generalized / physiopathology
Female
Gyrus Cinguli / physiopathology
Hemodynamics
Humans
Image Processing, Computer-Assisted
Magnetic Resonance Imaging*
Male
Nerve Net / physiopathology
Neurons / physiology
Signal Processing, Computer-Assisted
Thalamus / physiopathology
Video Recording
Young Adult

Supplementary concepts

Epilepsy, Idiopathic Generalized

Grants and funding

This work is part of a research program funded by a grant of Carismo Foundation (grant number: A.010@FCRMO RINT@MELFONINFO). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.