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

2018 ◽  
Vol 129 (1) ◽  
pp. 165-173 ◽  
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.

323 The Role of the Temporal Pole in Temporal Lobe Seizure Networks

Neurosurgery ◽  
2016 ◽  
Vol 63 ◽  
pp. 194 ◽  
Author(s):  
Taylor J. Abel ◽  
Royce Woodroffe ◽  
Toshio Moritani ◽  
Patricia Kirby ◽  
Matthew A. Howard ◽  
...  
Keyword(s):  
Temporal Lobe ◽  
Temporal Pole ◽  
Temporal Lobe Seizure

scholarly journals The comparative study of invasive electroencephalography modalities in temporal lobe epilepsy

2021 ◽  
Vol 23 (3) ◽  
pp. 14-22
Author(s):  
V. M. Dzhafarov ◽  
A. B. Dmitriev ◽  
N. P. Denisova ◽  
D. A. Rzaev
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Focal Epilepsy ◽  
Epileptogenic Zone ◽  
Foramen Ovale ◽  
Seizure Onset ◽  
Depth Electrodes ◽  
Seizure Onset Zone ◽  
Temporal Lobe Seizures ◽  
Mesial Temporal Lobe

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.

scholarly journals Temporal lobe epilepsy with unilateral hippocampal sclerosis and contralateral temporal scalp seizure onset: report of four patients with "burned-out hippocampus"

2005 ◽  
Vol 11 (2) ◽  
pp. 79-86 ◽  
Author(s):  
Luís Otávio Sales Ferreira Caboclo ◽  
Eliana Garzon ◽  
Flávia Saori Miyashira ◽  
Henrique Carrete Jr ◽  
Ricardo da Silva Centeno ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Hippocampal Sclerosis ◽  
Epileptogenic Zone ◽  
Invasive Monitoring ◽  
Eeg Monitoring ◽  
Ictal Eeg ◽  
High Resolution Mri ◽  
Surgical Evaluation ◽  
Video Eeg

ABSTRACT OBJECTIVES: Patients with temporal lobe epilepsy (TLE) and unilateral severe hippocampal sclerosis (HS) may have contralateral temporal scalp ictal onset. This has recently been called "burned-out hippocampus", which is believed to be a rare entity. In this study we report four patients with unilateral hippocampal sclerosis and contralateral ictal onset registered by scalp electrodes. We discuss the importance of such cases in presurgical evaluation of patients with TLE, as well as possible strategies used for evaluation of these particular cases. PATIENTS AND METHODS: We reviewed charts from all patients with TLE submitted to pre-surgical evaluation, which included high resolution MRI and prolonged video-electroencephalogram (video-EEG) monitoring with scalp and sphenoidal electrodes, during a three-year period (2002-2004). We looked for patients who only had seizures that were clearly contralateral in location to the atrophic hippocampus. RESULTS: Four patients fulfilled the criteria above. Two of these patients had semi-invasive video-EEG monitoring with foramen ovale (FO) electrodes, which revealed seizures originating from the temporal lobe with the atrophic hippocampus, hence confirming false lateralization in the scalp-sphenoidal EEG. These patients were submitted to surgical treatment and had favorable prognosis after surgery. CONCLUSIONS: Burned-out hippocampus syndrome may not be as rare as it was previously believed. Further studies will be necessary before one can affirm that patients with unilateral HS and scalp ictal EEG showing contralateral ictal onset may be operated without confirmation of the epileptogenic zone by invasive monitoring. In these patients, semi-invasive monitoring with FO electrodes might be an interesting alternative.

Neurophysiological phenotypes of pharmacoresistant temporal lobe epilepsy

2021 ◽  
pp. 9-12
Author(s):  
M. V. Aleksandrov ◽  
Y. V. Marchenko
Keyword(s):  
Surgical Treatment ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Epileptic Focus ◽  
Bioelectrical Activity ◽  
Epileptogenic Zone ◽  
Invasive Monitoring ◽  
Ictal Activity ◽  
The Brain

Patients with a drug-resistant form of epilepsy can be treated by neurosurgery through the destruction or separation of the epileptic focus. If the results of clinical, neuro-imaging and neurophysiological methods are discordant, then the localization of the epileptogenic zone is performed based on the results of long-term invasive monitoring of the bioelectrical activity of the cortex and deep structures of the brain. The aim of this work was the retrospective analysis of the results of invasive monitoring of the bioelectrical activity of the brain to clarify the mechanisms of the formation of patterns of interictal and ictal activity in structural epilepsy. The study included 35 patients (18 men, 17 women) with drug-resistant temporal lobe epilepsy, who were treated at the Polenov Neurosurgical Institute. The examination included video-EEG monitoring, long-term invasive monitoring of bioelectrical activity of the cortex, and deep brain structures. The patients were divided into two groups according to the type of surgical treatment: 1) micro-surgical resection of the epileptic focus, including the zone of structural changes (24 patients); 2) stereotactic destruction of the amygdala-hippocampal complex (6 patients). The follow-up of the outcomes of the surgical treatment took place over 2-3 years. Depending on the results of the surgical treatment, the patients were divided into two groups: 1) patients with a favorable outcome (Engel 1–2) — 15 patients and 2) patients with no positive dynamics and a relatively poor outcome (Engel 3–4) — 15 patients. The results obtained showed that the patterns of interictal and ictal activity in their totality determine the neurophysiology, i.e the phenotype of temporal lobe epilepsy, reflecting the interference of pathogenetic and sanogenetic mechanisms. The localization of the epileptogenic zone should be based on the cumulative assessment of interictal and ictal activity. The presence of more than one focus of interictal activity, the secondary spread of epileptiform activity from the primary focus, are prognostically unfavorable factors.

Temporal pole blurring in temporal lobe epilepsy revealed by 3D Edge-Enhancing Gradient Echo MRI

2022 ◽  
pp. 197140092110674
Author(s):  
Lela Okromelidze ◽  
Vivek Gupta ◽  
Ayushi Jain ◽  
Neethu Gopal ◽  
Anteneh M Feyissa ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Focal Cortical Dysplasia ◽  
Cortical Dysplasia ◽  
Early Age ◽  
Neuropsychological Performance ◽  
Gradient Echo ◽  
Seizure Onset ◽  
Lower Baseline ◽  
Temporal Pole

While abnormalities of the hippocampus have been well characterized in temporal lobe epilepsy, various additional temporal lobe abnormalities have also been described. One poorly understood entity, the so-called temporal pole blurring (TPB), is one of the more frequently described neocortical abnormalities in TLE and is thought to represent dysmyelination and axonal loss due to chronic electrical perturbations in early age-onset temporal lobe epilepsy. In this study, we describe the first reported cases of TPB diagnosed by a recently described MRI sequence known as 3D Edge-Enhancing Gradient Echo (3D-EDGE), which has an effective “myelin weighting” making it exquisitely sensitive to this temporal pole dysmyelination. The value of detection of TPB lies in lateralizing seizure onset, as well as predicting a lower baseline neuropsychological performance compared to temporal lobe epilepsy without TPB. Additionally, it is critical to not mistake TPB for alternative diagnoses, such as focal cortical dysplasia or neoplasm.

scholarly journals Synaptic Reshaping and Neuronal Outcomes in the Temporal Lobe Epilepsy

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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