Virtual Cortical Resection Elucidates Epileptic Network Characteristics in Pediatric Patients
Abstract number :
3.182
Submission category :
3. Neurophysiology / 3G. Computational Analysis & Modeling of EEG
Year :
2019
Submission ID :
2422080
Source :
www.aesnet.org
Presentation date :
12/9/2019 1:55:12 PM
Published date :
Nov 25, 2019, 12:14 PM
Authors :
Jeremy Wong, CHOP; Samuel B. Tomlinson, University of Rochester; Erin Conrad, University of Pennsylvania; Ankit N. Khambhati, University of California, San Francisco; Eric Marsh, MD, PhD, Children's Hospital of Philadelphia
Rationale: Synchronizability measures the efficiency of signal diffusion through the epileptic network. Brain regions differ in their tendency to promote (‘synchronize’) or impede (‘desynchronize’) overall network synchronizability. Understanding the interplay between synchronizing and desynchronizing brain regions may shed light upon mechanisms of seizure onset, propagation, and epilepsy surgery failure. This study uses the virtual cortical resection technique to study network synchronizability in children with intractable epilepsy. Methods: 30 seizures (17 focal, 13 with secondary generalization) from fifteen pediatric patients with intractable epilepsy underwent invasive intracranial grid EEG monitoring. Two electrophysiologists blinded to histopathological diagnosis retrospectively marked the seizure onset electrodes. Functional connectivity networks were derived from pre-ictal and ictal segments using a magnitude-squared coherence technique, from which overall network synchronizability was calculated. Each node’s ‘synchronizing’ or ‘desynchronizing’ influence was determined by removing the node and calculating the change in network synchronizability. Results: Overall network synchronizability in the low gamma frequency was higher in focal seizures than those that had secondary generalization in the pre-ictal period (p < 0.02). It did not significantly differ in the ictal period or between diffuse and focal histopathologies. For some patients, regions that were significant contributors to synchronizability were highly localized in the seizure onset zone (CHOP38, p < 0.001), but this was not a consistent finding. Conclusions: Epilepsy is a complex disorder involving dynamic interactions between brain regions. The interplay between ‘synchronizing’ and ‘desynchronizing’ brain regions likely influences seizure activity. This study suggests that there are fundamental differences in the network prior to a seizure that help determine whether it secondarily generalizes. The location of synchronizability control regions relative to the seizure onset zone varies considerably among patients and requires greater study. Funding: No funding
Neurophysiology