Characteristics of Epileptic Neuronal Ensembles on Simultaneous Scalp, Subdural and Intracerebral EEG Electrodes
Abstract number :
1.262
Submission category :
3. Neurophysiology / 3C. Other Clinical EEG
Year :
2024
Submission ID :
1081
Source :
www.aesnet.org
Presentation date :
12/7/2024 12:00:00 AM
Published date :
Authors :
Presenting Author: Diji Johnson, MBBS, MPH – Jersey Shore University Medical Center, Hackensack Meridian Health System, New Jersey, USA
Rajesh Sachdeo, MD – Jersey Shore University Medical Center, Hackensack Meridian Health System
Rahul Guha, MD – Jersey Shore University Medical Center, Hackensack Meridian Health System
Roopal Karia, MD – Jersey Shore University Medical Center, Hackensack Meridian Health System
Marina Khrizman, DO – Jersey Shore University Medical Center, Hackensack Meridian Health System
Jan Wollack, MD – Jersey Shore University Medical Center, Hackensack Meridian Health System
Jasdeep Hundal, PsyD – Hackensack Meridian Medical Group
Eric Hargreaves, PhD – Jersey Shore University Medical Center
Shabbar Danish, MD – Jersey Shore University Medical Center
Arun Antony, MD – Jersey Shore University Medical Center, Hackensack School of Medicine, Hackensack Meridian Health System.
Rationale: The characteristics of neuronal ensembles participating in ictal networks recorded on intracranial EEG have been reported in several studies, but its reflections on simultaneous scalp and subdural electrodes in addition to intracerebral depth recording have not been described in detail.
Methods: Twelve seizures recorded with simultaneous scalp, subdural and intracerebral EEG were reviewed and the seizure onset time, seizure onset pattern, recruitment, and network characteristics including connectivity were analyzed.
Results: Four seizures with onset in the right hippocampus, and eight seizures with left hippocampus onset were studied. Multiple EEG patterns were noted in the intracranial EEG when the seizure onset was noted on the scalp electrodes. The locations of seizure onset were concordant in the scalp and intracranial EEG. The seizures spread from the onset on intracranial EEG to the subdural strips in 0 to 72 seconds (Total seizures,12; mean, 10.67s; standard deviation SD, 19.91s) (Left hippocampus seizures- mean, 16s; SD, 22.57s; range, 1- 72s). No lag in the right hippocampus seizures because the first electrode of the subdural strips, recorded from the right temporal pole, was involved simultaneously.
Seizures appeared on the scalp EEG in 1- 72 seconds after onset on intracranial EEG (Total seizures,9; mean, 24.89s; SD,24.55s) (Right hippocampus seizures - mean, 4.33s; SD, 4.03s; range, 1-10s) (Left hippocampus seizures- mean, 35.17s; SD, 24.06s; range, 11-72s). The lag could not be assessed in two seizures due to artifacts. One seizure appeared earlier on the scalp EEG compared to the intracerebral EEG, possibly because the seizure onset zone was distant from the intracerebral electrodes.
Contralateral spread was noted in 1-122 seconds (Total seizures-9; mean, 28.33s; SD, 47.76s) (Right hippocampus seizures- mean, 3.75s; SD, 3.03s; range, 2-9s) (Left hippocampus seizures - mean, 48s; SD, 56.82s; range ,1-122s). Rhythmic delta (RD) activity was noted in 5 seizures prior to paroxysmal fast activity with lag time ranging from 51-104s.
Conclusions: Features of neural ensembles forming epileptic networks during onset, evolution and cessation of seizures are broadly visible on scalp recordings and strongly correlate with the intracranial EEG, confirming our prior work. Several finer and earlier features of the epilepsy network were not discernible since the ictal network, as detected by the intracranial EEG, was formed before the seizure appears on the scalp EEG. The speed of seizure spread, and the ictal network characteristics vary widely between seizures, based on several factors including the region of onset.
Funding: No funding
Neurophysiology