Page 165 - MEGIN Book Of Abstracts - 2023

Cross-Frequency Coupling in Childhood Absence "diffuse" seizures are generated and maintained will be
Epilepsy (2022) necessary to provide optimal outcomes.

Tenney, Jeffrey R; Williamson, Brady J; Kadis, Darren S Keywords: absence epilepsy, connectivity, cross-frequen-
cy coupling, magnetoencephalography
Department of Pediatrics and University of Cincinnati College
of Medicine, Cincinnati, Ohio, USA; Department of Radiol- Brain connectivity (2022), Vol. 12, No. 5 (34405685) (4
ogy, University of Cincinnati College of Medicine, Cincinnati, citations)
Ohio, USA; Department of Physiology, University of Toronto,
Toronto, Ontario, Canada
MEG detection of high frequency oscillations and
ABSTRACT Objective: Absence seizures are the intracranial-EEG validation in pediatric epilepsy
prototypic primarily generalized seizures, but there is surgery (2021)
incomplete understanding regarding their generation
and maintenance. A core network for absence seizures Foley, Elaine; Quitadamo, Lucia R; Walsh, A Richard; Bill,
has been defined, including focal cortical and thalamic Peter; Hillebrand, Arjan; Seri, Stefano
regions that have frequency-dependent interactions.
The purpose of this study was to investigate within- Aston Institute of Health and Neurodevelopment, College of
frequency coupling and cross-frequency coupling (CFC) Health and Life Sciences, Aston University, Birmingham, UK.
during human absence seizures, to identify key regions Electronic address: [email protected]; Children's Epilepsy
(hubs) within the absence network that contribute Surgery Program, The Birmingham Women's and Children's
to propagation and maintenance. Methods: Thirteen NHS Foundation Trust, Birmingham, UK; Amsterdam UMC,
children with new-onset and untreated childhood Vrije Universiteit Amsterdam, Department of Clinical Neuro-
absence epilepsy had over 60 typical absence sei- physiology and MEG Center, Amsterdam Neuroscience, De
zures during both electroencephalography-functional Boelelaan, 1117 Amsterdam, the Netherlands; Aston Institute
magnetic resonance imaging (fMRI) and magnetoen- of Health and Neurodevelopment, College of Health and
cephalography (MEG) recordings. The spatial map of Life Sciences, Aston University, Birmingham, UK; Children's
the ictal network was defined using fMRI and used as Epilepsy Surgery Program, The Birmingham Women's and
prior information for MEG connectivity. A multilayer Children's NHS Foundation Trust, Birmingham, UK
network approach was used to investigate within-
frequency coupling and CFC for canonical frequency OBJECTIVE To assess the feasibility of automatically
bands. A rigorous null-modeling approach was used to detecting high frequency oscillations (HFOs) in magne-
determine connections outside the noise floor. Results: toencephalography (MEG) recordings in a group of ten
Strong coupling between beta and gamma frequen- paediatric epilepsy surgery patients who had under-
cies, within the left frontal cortex, and between the left gone intracranial electroencephalography (iEEG).
frontal and right parietal regions was observed. There
was also strong connectivity between left frontal and METHODS A beamforming source-analysis method
right parietal nodes within the gamma band. Multilayer was used to construct virtual sensors and an automatic
versatility analysis identified a cluster of network hubs algorithm was applied to detect HFOs (80-250 Hz). We
in the left frontal region. Interpretation: Cortical regions evaluated the concordance of MEG findings with the
commonly identified as being critical for absence sei- sources of iEEG HFOs, the clinically defined seizure
zure generation (frontal cortex, precuneus) have strong onset zone (SOZ), the location of resected brain struc-
CFC and within-frequency coupling between beta and tures, and with post-operative outcome.
gamma bands. As nonpharmacologic treatments, such
as neuromodulation, become available for generalized RESULTS In 8/9 patients there was good concordance
epilepsies, detailed mechanistic understanding of how between the sources of MEG HFOs and iEEG HFOs and

 ontents  Index 144
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