Quantitative Analysis of Focal and Focal to Bilateral Tonic Clonic Seizures with Epileptogenicity Index
Abstract number :
1.2
Submission category :
3. Neurophysiology / 3G. Computational Analysis & Modeling of EEG
Year :
2022
Submission ID :
2204121
Source :
www.aesnet.org
Presentation date :
12/3/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:23 AM
Authors :
Lane Fry, BA – University of Kansas School of Medicine; Nathaniel Cameron, BA – Neurosurgery – University of Kansas Medical Center; Brian Schatmeyer, MD – Neurosurgery – University of Kansas Medical Center, Department of Neurosurgery; Christopher Miller, MD – Neurosurgery – Thomas Jefferson School of Medicine; Carol Ulloa, MD – Neurology – University of Kansas Medical Center; Utku Uysal, MD, MS – Neurology – University of Kansas Medical Center; Jennifer Cheng, MD, MS – Neurosurgery – University of Kansas Medical Center; Michael Kinsman, MD – Neurosurgery – University of Kansas Medical Center; Patrick Landazuri, MD – Neurology – University of Kansas Medical Center; Adam Rouse, MD, PhD – Neurosurgery – University of Kansas Medical Center
Rationale: Focal to bilateral tonic clonic (FBTC) seizures are associated with substantial morbidity and mortality, with patients less likely seizure free after surgery. A visual analysis of mesial temporal lobe seizure patterns comparing FBTC to focal only seizures (FS) demonstrated similar onset and propagation patterns at the patient level while identifying the posterolateral temporal lobe as a “gateway” to generalization. We sought to quantitatively characterize FBTC seizures and FBTC seizure propagation. We used a semi-automatic detection algorithm, the Epileptogenicity Index (EI), developed to identify epileptogenic onset zones, in hopes it would quantify seizure propagation as well. We hypothesized FBTC seizures would have higher EI magnitudes, more diffuse electrode involvement, and faster propagation speed compared to FS.
Methods: Patients with both FS and FBTC seizures captured by stereo electroencephalography (sEEG) at KUMC from 2016 to 2019 with at least two lobes implanted were included. Using EI, we quantified the brain structures at seizure onset and progression. We also measured propagation speed from seizure onset through early spread. Only electrodes that were considered highly epileptogenic (EI ≥ 0.3) were included in statistical analysis. Both EI values and subsequent 3D reconstructions of EI propagation were analyzed.
Results: Eighteen patients fitting inclusion criteria were identified resulting in 22 FBTC and 26 focal seizures. Larger EI values were identified in FS while FBTC tended to have a greater proportion of brain structures involved, although neither significantly differed from the other. There was no significant difference in the speed of propagation between the groups.
Conclusions: Our study did not demonstrate significant differences at the group level in EI magnitude, speed of propagation, or proportion of highly epileptogenic brain structures in global analysis. This suggests the EI metric, developed to identify seizure onset, may not directly translate to mapping propagation. We did observe a trend where FS appeared to have increased quantitative epileptic activity while FBTC seizures involved more electrodes. Future analysis will examine these variables by comparing individual electrode contacts by FS vs. FBTC.
Funding: Kansas University Training Program in Neurological and Rehabilitation Sciences (NIH T32 award) supported by NIH Award Number T32HD057850
Neurophysiology