Increased Within Connectivity of the Epileptogenic Zone in Pediatric Focal Epilepsy Patients Using Intracranial Electroencephalography
Abstract number :
2.062
Submission category :
3. Neurophysiology / 3G. Computational Analysis & Modeling of EEG
Year :
2022
Submission ID :
2204296
Source :
www.aesnet.org
Presentation date :
12/4/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:24 AM
Authors :
Kanupriya Gupta, BA – University of Pittsburgh School of Medicine; Hope Reecher, BA – Department of Neurosurgery – UPMC Children's Hospital of Pittsburgh; Kyle Rupp, PhD – Department of Neurosurgery – UPMC Children's Hospital of Pittsburgh; William Welch, MD – Department of Neurosurgery – UPMC Children's Hospital of Pittsburgh; Pulkit Grover, PhD – Department of Electrical and Computer Engineering – Carnegie Mellon University; Thandar Aung, MD, MS – Department of Neurology – University of Pittsburgh School of Medicine; Patrick Chauvel, MD – Department of Neurology – University of Pittsburgh School of Medicine; Taylor Abel, MD – Department of Neurosurgery – UPMC Children's Hospital of Pittsburgh
Rationale: In pediatric patients with focal epilepsy, up to 1 in 10 will have seizures that are not controlled with medications. For patients with intractable epilepsy, intracranial electroencephalography (iEEG) is a minimally invasive tool that can be used to localize the Epileptogenic Zone, or EZ, which is responsible for the generation and propagation of seizures. However, in many patients the location of the EZ is not clear despite capturing multiple seizures with iEEG. Therefore, we studied the connectivity of the EZ during resting, pre-ictal, ictal, and post-ictal states in order to better understand how the connectivity of the EZ changes with time state and region receiving the connection.
Methods: We collected 5 minutes of resting-state data, as well as data starting from 5 minutes before a seizure to 5 minutes after a seizure, from 15 pediatric patients with focal epilepsy. The iEEG data was pre-processed in Matlab, which included applying a bandpass filter from 1-100 Hz, notch filter at 60 Hz, and downsampling to 100 Hz. Using the FieldTrip Matlab toolbox, we measured the h2, a measure of nonlinear correlation, in order to determine how the connectivity differed within the EZ and between the EZ and areas of Rapid Spread (RS), Interictal Epileptiform Discharges (IED), and Non-Epileptogenic Zones (NEZ) during resting, pre-ictal, ictal, and post-ictal states.
Results: In our cohort of 15 pediatric focal epilepsy patients, there was a main effect of region receiving the connection from the EZ but not of time state on EZ connectivity (F = 39.206, p < .001, Two-way repeated measures ANOVA). Connectivity within the EZ was significantly greater than connectivity between the EZ and RS, EZ and IED, and EZ and NEZ. In a subset of 13 patients with post-surgical outcomes (n = 7 Engel I/II outcome, n = 6 Engel III/IV outcome), there was a significant interaction between region and surgical outcome (F = 8.538, p = .006, Mixed-Factor ANOVA). In patients with an Engel I/II outcome, within EZ connectivity was higher than connectivity between EZ-RS, EZ-IED, and EZ-NEZ regions, whereas in Engel III/IV patients within EZ connectivity was only greater than EZ-NEZ connectivity. Furthermore, within EZ and EZ-NEZ connectivity were higher in patients with Engel I/II outcomes compared to Engel III/IV outcomes.
Neurophysiology