scholarly journals Epileptogenic Zone Location of Temporal Lobe Epilepsy by Cross-Frequency Coupling Analysis

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaotong Liu ◽  
Fang Han ◽  
Rui Fu ◽  
Qingyun Wang ◽  
Guoming Luan
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Single Channel ◽  
Brain Networks ◽  
Brain Regions ◽  
Functional Network ◽  
Epileptogenic Zone ◽  
Coupling Analysis ◽  
Frequency Coupling ◽  
Cross Frequency Coupling

Epilepsy is a chronic brain disease with dysfunctional brain networks, and electroencephalography (EEG) is an important tool for epileptogenic zone (EZ) identification, with rich information about frequencies. Different frequency oscillations have different contributions to brain function, and cross-frequency coupling (CFC) has been found to exist within brain regions. Cross-channel and inter-channel analysis should be both focused because they help to analyze how epilepsy networks change and also localize the EZ. In this paper, we analyzed long-term stereo-electroencephalography (SEEG) data from 17 patients with temporal lobe epilepsy. Single-channel and cross-channel CFC features were combined to establish functional brain networks, and the network characteristics under different periods and the localization of EZ were analyzed. It was observed that theta–gamma phase amplitude coupling (PAC) within the electrodes in the seizure region increased during the ictal (p < 0.05). Theta–gamma and delta–gamma PAC of cross-channel were enhanced in the early and mid-late ictal, respectively. It was also found that there was a strong cross-frequency coupling state between channels of EZ in the functional network during the ictal, along with a more regular network than interictal. The accuracy rate of EZ localization was 82.4%. Overall, the combination of single-channel and multi-channel cross-band coupling analysis can help identify seizures and localize EZ for temporal lobe epilepsy. Rhythmic coupling reveals a relationship between the functional network and the seizure status of epilepsy.

scholarly journals Recent developments in cognitive fMRI for temporal lobe epilepsy

2019 ◽  
Vol 33 (1) ◽  
pp. 30-36 ◽  
Author(s):  
Victor Schmidbauer ◽  
Silvia Bonelli
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Visual Memory ◽  
Imaging Modality ◽  
Memory Function ◽  
Brain Regions ◽  
Epileptogenic Zone ◽  
Brain Areas ◽  
Recent Developments ◽  
The Brain

AbstractEpilepsy is frequently accompanied by severe cognitive side effects. Temporal lobe epilepsy (TLE), and even successful surgical treatment, may affect cognitive function, in particular language as well as verbal and visual memory function. Epilepsy arising from the temporal lobe can be controlled surgically in up to 70% of patients. The goals of epilepsy surgery are to remove the brain areas generating the seizures without causing or aggravating neuropsychological deficits. This requires accurate localization of the brain areas generating the seizures (“epileptogenic zone”) and the areas responsible for motor and cognitive functions, such as language and memory (“essential brain regions”) during presurgical evaluation. In the past decades, functional magnetic resonance imaging (fMRI) has been increasingly used to noninvasively lateralize and localize not only primary motor and somatosensory areas, but also brain areas that are involved in everyday language and memory processes. The imaging modality also shows potential for predicting the effects of temporal lobe resection on language and memory function. Together with other MRI modalities, cognitive fMRI is a promising tool to improve surgical strategies tailored to individual patients with regard to functional outcome, by virtue of definition of epileptic cerebral areas that need to be resected and eloquent areas that need to be spared.The aim of this review is to provide an overview of recent developments and practical recommendations for the clinical use of cognitive fMRI in TLE.

scholarly journals Seizure Freedom After Epilepsy Surgery and Higher Baseline Cognition May Be Associated With a Negatively Correlated Epilepsy Network in Temporal Lobe Epilepsy

2021 ◽  
Vol 14 ◽  
Author(s):  
Elliot G. Neal ◽  
Mike R. Schoenberg ◽  
Stephanie Maciver ◽  
Yarema B. Bezchlibnyk ◽  
Fernando L. Vale
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Epilepsy Surgery ◽  
Memory Function ◽  
Brain Regions ◽  
Seizure Freedom ◽  
Epileptogenic Zone ◽  
Temporal Lobes ◽  
Scalp Eeg ◽  
The Brain

Background: Brain regions positively correlated with the epileptogenic zone in patients with temporal lobe epilepsy vary in spread across the brain and in the degree of correlation to the temporal lobes, thalamus, and limbic structures, and these parameters have been associated with pre-operative cognitive impairment and seizure freedom after epilepsy surgery, but negatively correlated regions have not been as well studied. We hypothesize that connectivity within a negatively correlated epilepsy network may predict which patients with temporal lobe epilepsy will respond best to surgery.Methods: Scalp EEG and resting state functional MRI (rsfMRI) were collected from 19 patients with temporal lobe epilepsy and used to estimate the irritative zone. Using patients’ rsfMRI, the negatively correlated epilepsy network was mapped by determining all the brain voxels that were negatively correlated with the voxels in the epileptogenic zone and the spread and average connectivity within the network was determined.Results: Pre-operatively, connectivity within the negatively correlated network was inversely related to the spread (diffuseness) of that network and positively associated with higher baseline verbal and logical memory. Pre-operative connectivity within the negatively correlated network was also significantly higher in patients who would go on to be seizure free.Conclusion: Patients with higher connectivity within brain regions negatively correlated with the epilepsy network had higher baseline memory function, narrower network spread, and were more likely to be seizure free after surgery.

Automated lateralization of temporal lobe epilepsy with cross frequency coupling using magnetoencephalography

2022 ◽  
Vol 72 ◽  
pp. 103294
Author(s):  
Bhargava K. Gautham ◽  
Joydeep Mukherjee ◽  
Mariyappa Narayanan ◽  
Raghavendra Kenchaiah ◽  
Ravindranadh C Mundlamuri ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Frequency Coupling ◽  
Cross Frequency Coupling

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.

scholarly journals Localization of epileptogenic zone in temporal lobe epilepsy by ictal scalp EEG

Seizure ◽  
2002 ◽  
Vol 11 (3) ◽  
pp. 163-168 ◽  
Author(s):  
Yuzo Sakai ◽  
Hiromi Nagano ◽  
Ayumi Sakata ◽  
Sachiko Kinoshita ◽  
Naotaka Hamasaki ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Epileptogenic Zone ◽  
Scalp Eeg

scholarly journals The superficial white matter in temporal lobe epilepsy: a key link between structural and functional network disruptions

Brain ◽  
2016 ◽  
Vol 139 (9) ◽  
pp. 2431-2440 ◽  
Author(s):  
Min Liu ◽  
Boris C. Bernhardt ◽  
Seok-Jun Hong ◽  
Benoit Caldairou ◽  
Andrea Bernasconi ◽  
...  
Keyword(s):  
White Matter ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Functional Network ◽  
Network Disruptions

scholarly journals A method for placing Heschl gyrus depth electrodes

2010 ◽  
Vol 112 (6) ◽  
pp. 1301-1307 ◽  
Author(s):  
Chandan G. Reddy ◽  
Nader S. Dahdaleh ◽  
Gregory Albert ◽  
Fangxiang Chen ◽  
Daniel Hansen ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Refractory Epilepsy ◽  
Brain Regions ◽  
Frameless Stereotaxy ◽  
Functional Connections ◽  
Depth Electrodes ◽  
Wide Range ◽  
Implantation Method ◽  
Heschl Gyrus

A wide range of devices is used to obtain intracranial electrocorticography recordings in patients with medically refractory epilepsy, including subdural strip and grid electrodes and depth electrodes. Penetrating depth electrodes are required to access some brain regions, and 1 target site that presents a particular technical challenge is the first transverse temporal gyrus, or Heschl gyrus (HG). The HG is located within the supratemporal plane and has an oblique orientation relative to the sagittal and coronal planes. Large and small branches of the middle cerebral artery abut the pial surface of the HG and must be avoided when planning the electrode trajectory. Auditory cortex is located within the HG, and there are functional connections between this dorsal temporal lobe region and medial sites commonly implicated in the pathophysiology of temporal lobe epilepsy. At some surgical centers, depth electrodes are routinely placed within the supratemporal plane, and the HG, in patients who require intracranial electrocorticography monitoring for presumed temporal lobe epilepsy. Information from these recordings is reported to facilitate the identification of seizure patterns in patients with or without auditory auras. To date, only one implantation method has been reported to be safe and effective for placing HG electrodes in a large series of patients undergoing epilepsy surgery. This well-established approach involves inserting the electrodes from a lateral trajectory while using stereoscopic stereotactic angiography to avoid vascular injury. In this report, the authors describe an alternative method for implantation. They use frameless stereotaxy and an oblique insertion trajectory that does not require angiography and allows for the simultaneous placement of subdural grid arrays. Results in 19 patients demonstrate the safety and efficacy of the method.

Ictal vocalizations occur more often in temporal lobe epilepsy with dominant (left-sided) epileptogenic zone

Epilepsia ◽  
2009 ◽  
Vol 50 (6) ◽  
pp. 1542-1546 ◽  
Author(s):  
Reka A. Horvath ◽  
Andras Fogarasi ◽  
Reinhard Schulz ◽  
Gabor Perlaki ◽  
Zsuzsa Kalmar ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Epileptogenic Zone
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