Differential Gray Matter Changes Between Depth Electrode-Recorded Ictal EEG Onset Patterns in Human Temporal Lobe Epilepsy
Abstract number :
V.059
Submission category :
5. Neuro Imaging / 5A. Structural Imaging
Year :
2021
Submission ID :
1826084
Source :
www.aesnet.org
Presentation date :
12/9/2021 12:00:00 PM
Published date :
Nov 22, 2021, 06:51 AM
Authors :
Conor Owens-Walton, PhD - Imaging Genetics Center, Stevens Neuroimaging & Informatics Institute, University of Southern California; Hong Zheng - Keck School of Medicine - University of Southern California; Kevin Low - Keck School of Medicine - University of Southern California; Itzhak Fried - Department of Neurosurgery - University of California, Los Angeles; Noriko Salamon - Department of Radiology - University of California, Los Angeles; Jerome Engel, Jr - Department of Neurology - University of California, Los Angeles; Paul Thompson - Departments of Neurology, Pediatrics, Psychiatry, Radiology, Engineering, and Ophthalmology - University of Southern California; Richard Staba - Department of Neurology - University of California, Los Angeles
Rationale: Direct brain recordings in patients and experimental models of temporal lobe epilepsy (TLE) indicate different ictal EEG onset patterns are generated by different mechanisms, though the structural abnormalities associated with several of the common seizure onset patterns are unclear. The current research sought to determine whether different seizure onset patterns are associated with unique or shared spatial distribution of MRI gray matter abnormalities.
Methods: Subjects for this research were patients with medication-resistant, unilateral focal temporal lobe seizures who had invasive EEG tests as part of their presurgical diagnostic evaluation. Depth ictal EEG was reviewed, and patients grouped according to their predominant ictal EEG onset pattern as follows: low voltage fast (LVF), hypersynchronous (HYP), and rhythmic spiking sharp (RS) patterns. We evaluated cortical thicknesses and subcortical volumes between patient and age- and sex-matched control groups using mass univariate general linear models, with p-values adjusted with a false-discovery rate correction using the Benjamini-Hochberg method.
Results: Compared to controls, patients with HYP EEG onset patterns (n=14) had reduced MRI gray matter thickness in ipsilateral entorhinal, fusiform, and postcentral gyri and contralateral lingual cortices. These subjects also showed significantly reduced ipsilateral thalamic and contralateral n. accumbens volumes (Figure 1). Patients with LVF EEG onset patterns (n=37) had reduced thickness of the bilateral entorhinal, paracentral, and precentral gyri, ipsilateral temporal-pole, and increased thickness of the ipsilateral transverse temporal, pericalcarine and supramarginal cortices. Low-voltage fast EEG participants had significantly reduced ipsilateral thalamic and n. accumbens, and bilateral putamen, hippocampus, and amygdala (Figure 1). Patients with RS EEG onset (n=21) had reduced thickness of the bilateral entorhinal, inferior temporal, precentral, superiorfrontal, temporal poles and contralateral rostral anterior cingulate cortices. These participants had significantly reduced ipsilateral thalamus, bilateral hippocampus, contralateral amygdala and n. accumbens (Figure 1).
Conclusions: In complicated cases of TLE, MRI abnormalities in temporal and extra-temporal lobe areas indicate a more extensive, possibly bilateral, structural network supporting LVF and RS onset seizures than in patients with HYP. Results are consistent with the hypothesis that the thalamus is an important hub in the TLE, and abnormalities in specific thalamic nuclei could be an anatomical link between temporal and extra-temporal lobe nodes of the network generating these seizures.
Funding: Please list any funding that was received in support of this abstract.: RS was supported by NINDS award 5R01NS106957-02.
Neuro Imaging