Transient seizure onset network for localization of epileptogenic zone: effective connectivity and graph theory-based analyses of ECoG data in temporal lobe epilepsy

Introduction. Invasive video-EEG monitoring (invasive EEG) is indicated in patients with refractory focal epilepsy while localization of the epileptogenic zone is unclear. Methods of invasive EEG in different groups of patients demonstrate variable results.Objective: to analyse the results of invasive EEG via subdural and depth electrodes in patients with refractory temporal lobe epilepsy with mesial temporal lobe seizures.Materials and methods. The series of 37 patients who underwent invasive EEG from 2013 to 2020 was retrospectively analysed. The study includes primary adult patients with structural refractory focal epilepsy with mesial temporal lobe seizures without tumor and vascular pathology. Patients were divided onto 3 groups: 1) with foramen ovale electrodes 2) subdural strip electrodes and 3) combination of subdural strips and depths electrodes. The results of anteromedial temporal lobectomy after 6 months were classified according to Engel scale.Results. A group with foramen ovale electrodes included 7 patients, subdural strips – 23, combination – 7. The seizure onset zone was detected in 36 (97 %) cases. Serious complications were observed in 2 (29 %) cases in the group with foramen ovale electrodes. The mean follow-up in 23 (76 %) patients after resective surgery was 28.3 months. Favourable results (Engel I, II) were observed in 4 (80 %) patients with foramen ovale electrodes, in 8 (67 %) patients with subdural electrodes, in 6 (100 %) with combination. Unfavourable results (Engel III, IV) were noted in 1 (20 %) patient with foramen ovale electrode, in 4 (33 %) patients with subdural strips.Conclusion. All the presented modalities of invasive EEG are effective for localizing of seizure onset zone in this category of patients. Foramen ovale electrode using may be limited due to increased risk of complications.

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Role of the temporal pole in temporal lobe epilepsy seizure networks: an intracranial electrode investigation

Journal of Neurosurgery ◽

10.3171/2017.3.jns162821 ◽

2018 ◽

Vol 129 (1) ◽

pp. 165-173 ◽

Cited By ~ 6

Author(s):

Taylor J. Abel ◽

Royce W. Woodroffe ◽

Kirill V. Nourski ◽

Toshio Moritani ◽

Aristides A. Capizzano ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Epileptogenic Zone ◽

Invasive Monitoring ◽

Seizure Onset ◽

Temporal Pole ◽

Interictal Discharges ◽

Temporal Lobe Seizure ◽

Clinical Records

OBJECTIVEA convergence of clinical research suggests that the temporal pole (TP) plays an important and potentially underappreciated role in the genesis and propagation of seizures in temporal lobe epilepsy (TLE). Understanding its role is becoming increasingly important because selective resections for medically intractable TLE spare temporopolar cortex (TPC). The purpose of this study was to characterize the role of the TPC in TLE after using dense electrocorticography (ECoG) recordings in patients undergoing invasive monitoring for medically intractable TLE.METHODSChronic ECoG recordings were obtained in 10 consecutive patients by using an array customized to provide dense coverage of the TP as part of invasive monitoring to localize the epileptogenic zone. All patients would eventually undergo cortico-amygdalohippocampectomy. A retrospective review of the patient clinical records including ECoG recordings, neuroimaging studies, neuropathology reports, and clinical outcomes was performed.RESULTSIn 7 patients (70%), the TP was involved at seizure onset; in 7 patients (70%), there were interictal discharges from the TP; and in 1 case, there was early spread to the TP. Seizure onset in the TP did not necessarily correlate with preoperative neuroimaging abnormalities of the TP.CONCLUSIONSThese data demonstrate that TPC commonly plays a crucial role in temporal lobe seizure networks. Seizure onset from the TP would not have been predicted based on available neuroimaging data or interictal discharges. These findings illustrate the importance of thoroughly considering the role of the TP prior to resective surgery for TLE, particularly when selective mesial resection is being considered.

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Identification of the epileptogenic zone of temporal lobe epilepsy from stereo-electroencephalography signals: A phase transfer entropy and graph theory approach

NeuroImage Clinical ◽

10.1016/j.nicl.2017.07.022 ◽

2017 ◽

Vol 16 ◽

pp. 184-195 ◽

Cited By ~ 14

Author(s):

Meng-yang Wang ◽

Jing Wang ◽

Jian Zhou ◽

Yu-guang Guan ◽

Feng Zhai ◽

...

Keyword(s):

Graph Theory ◽

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Phase Transfer ◽

Transfer Entropy ◽

Epileptogenic Zone ◽

Theory Approach

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Voxel-based morphometry (VBM) in unilateral mesial temporal lobe epilepsy (mTLE): Volume loss beyond the seizure onset zone and neuropsychological implications

Aktuelle Neurologie ◽

10.1055/s-2007-987716 ◽

2007 ◽

Vol 34 (S 2) ◽

Author(s):

N Embacher ◽

C Brenneis ◽

I Unterberger ◽

J Dobesberger ◽

G Walser ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Mesial Temporal Lobe Epilepsy ◽

Volume Loss ◽

Voxel Based Morphometry ◽

Seizure Onset ◽

Seizure Onset Zone ◽

Mesial Temporal Lobe

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Synaptic Reshaping and Neuronal Outcomes in the Temporal Lobe Epilepsy

International Journal of Molecular Sciences ◽

10.3390/ijms22083860 ◽

2021 ◽

Vol 22 (8) ◽

pp. 3860

Author(s):

Elisa Ren ◽

Giulia Curia

Keyword(s):

Animal Models ◽

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Current Knowledge ◽

Focal Epilepsy ◽

Ex Vivo ◽

Hippocampal Sclerosis ◽

Control Group ◽

Epileptogenic Zone ◽

Epileptiform Discharges

Temporal lobe epilepsy (TLE) is one of the most common types of focal epilepsy, characterized by recurrent spontaneous seizures originating in the temporal lobe(s), with mesial TLE (mTLE) as the worst form of TLE, often associated with hippocampal sclerosis. Abnormal epileptiform discharges are the result, among others, of altered cell-to-cell communication in both chemical and electrical transmissions. Current knowledge about the neurobiology of TLE in human patients emerges from pathological studies of biopsy specimens isolated from the epileptogenic zone or, in a few more recent investigations, from living subjects using positron emission tomography (PET). To overcome limitations related to the use of human tissue, animal models are of great help as they allow the selection of homogeneous samples still presenting a more various scenario of the epileptic syndrome, the presence of a comparable control group, and the availability of a greater amount of tissue for in vitro/ex vivo investigations. This review provides an overview of the structural and functional alterations of synaptic connections in the brain of TLE/mTLE patients and animal models.

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Disrupted Structural and Functional Networks and Their Correlation with Alertness in Right Temporal Lobe Epilepsy: A Graph Theory Study

Frontiers in Neurology ◽

10.3389/fneur.2017.00179 ◽

2017 ◽

Vol 8 ◽

Cited By ~ 10

Author(s):

Wenyu Jiang ◽

Jianping Li ◽

Xuemei Chen ◽

Wei Ye ◽

Jinou Zheng

Keyword(s):

Graph Theory ◽

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Functional Networks ◽

Right Temporal Lobe Epilepsy

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Electroencephalographic Features of Temporal Lobe Epilepsy

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques ◽

10.1017/s0317167100010441 ◽

2010 ◽

Vol 37 (4) ◽

pp. 439-448 ◽

Cited By ~ 19

Author(s):

Mohammed M. Jan ◽

Mark Sadler ◽

Susan R. Rahey

Keyword(s):

Temporal Lobe Epilepsy ◽

Surgical Management ◽

Temporal Lobe ◽

Seizure Onset ◽

Resective Surgery ◽

Accurate Localization ◽

Epileptiform Discharges ◽

Ictal Eeg ◽

Temporal Lobe Seizures ◽

Eeg Recordings

Electroencephalography (EEG) is an important tool for diagnosing, lateralizing and localizing temporal lobe seizures. In this paper, we review the EEG characteristics of temporal lobe epilepsy (TLE). Several “non-standard” electrodes may be needed to further evaluate the EEG localization, Ictal EEG recording is a major component of preoperative protocols for surgical consideration. Various ictal rhythms have been described including background attenuation, start-stop-start phenomenon, irregular 2-5 Hz lateralized activity, and 5-10 Hz sinusoidal waves or repetitive epileptiform discharges. The postictal EEG can also provide valuable lateralizing information. Postictal delta can be lateralized in 60% of patients with TLE and is concordant with the side of seizure onset in most patients. When patients are being considered for resective surgery, invasive EEG recordings may be needed. Accurate localization of the seizure onset in these patients is required for successful surgical management.

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