scholarly journals EEG Signal Connectivity for Characterizing Interictal Activity in Patients With Mesial Temporal Lobe Epilepsy

2021 ◽  
Vol 12 ◽  
Author(s):  
Leonardo R. da Costa ◽  
Brunno M. de Campos ◽  
Marina K. M. Alvim ◽  
Gabriela Castellano
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Betweenness Centrality ◽  
Epileptiform Activity ◽  
Mesial Temporal Lobe Epilepsy ◽  
Eeg Signal ◽  
Eeg Signals ◽  
Graph Metrics ◽  
Epileptiform Discharges ◽  
Mesial Temporal Lobe

Over the last decade, several methods for analysis of epileptiform signals in electroencephalography (EEG) have been proposed. These methods mainly use EEG signal features in either the time or the frequency domain to separate regular, interictal, and ictal brain activity. The aim of this work was to evaluate the feasibility of using functional connectivity (FC) based feature extraction methods for the analysis of epileptiform discharges in EEG signals. These signals were obtained from EEG-fMRI sessions of 10 patients with mesial temporal lobe epilepsy (MTLE) with unilateral hippocampal atrophy. The connectivity functions investigated were motif synchronization, imaginary coherence, and magnitude squared coherence in the alpha, beta, and gamma bands of the EEG. EEG signals were sectioned into 1-s epochs and classified according to (using neurologist markers): activity far from interictal epileptiform discharges (IED), activity immediately before an IED and, finally, mid-IED activity. Connectivity matrices for each epoch for each FC function were built, and graph theory was used to obtain the following metrics: strength, cluster coefficient, betweenness centrality, eigenvector centrality (both local and global), and global efficiency. The statistical distributions of these metrics were compared among the three classes, using ANOVA, for each FC function. We found significant differences in all global (p < 0.001) and local (p < 0.00002) graph metrics of the far class compared with before and mid for motif synchronization on the beta band; local betweenness centrality also pointed to a degree of lateralization on the frontotemporal structures. This analysis demonstrates the potential of FC measures, computed using motif synchronization, for the characterization of epileptiform activity of MTLE patients. This methodology may be helpful in the analysis of EEG-fMRI data applied to epileptic foci localization. Nonetheless, the methods must be tested with a larger sample and with other epileptic phenotypes.

scholarly journals Periodic epileptiform discharges in mesial temporal lobe epilepsy with hippocampal sclerosis

Seizure ◽  
2013 ◽  
Vol 22 (9) ◽  
pp. 735-742 ◽  
Author(s):  
Daniel San-Juan ◽  
Adriana Patricia M. Mayorga ◽  
Juan de Dios Del Castillo Calcáneo ◽  
Maricarmen Fernández González-Aragón ◽  
Mario Alonso-Vanegas ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Hippocampal Sclerosis ◽  
Mesial Temporal Lobe Epilepsy ◽  
Epileptiform Discharges ◽  
Mesial Temporal Lobe

scholarly journals Analysis of Interictal Epileptiform Discharges in Mesial Temporal Lobe Epilepsy Using Quantitative EEG and Neuroimaging

2020 ◽  
Vol 11 ◽  
Author(s):  
Elaine Keiko Fujisao ◽  
Karen Fernanda Alves ◽  
Thais O. P. Rezende ◽  
Luiz Eduardo Betting
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Gray Matter ◽  
Quantitative Eeg ◽  
Mesial Temporal Lobe Epilepsy ◽  
Source Analysis ◽  
Epileptiform Discharges ◽  
Eeg Source Imaging ◽  
Mesial Temporal Lobe ◽  
Gray Matter Volumes

Objective: Investigate areas of correlation between gray matter volumes by MRI and interictal EEG source maps in subtypes of mesial temporal lobe epilepsy (MTLE).Method: 71 patients and 36 controls underwent 3T MRI and and routine EEG was performed. Voxel-based morphometry (VBM) was used for gray matter analysis and analysis of interictal discharge sources for quantitative EEG. Voxel-wise correlation analysis was conducted between the gray matter and EEG source maps in MTLE subtypes.Results: The claustrum was the main structure involved in the individual source analysis. Twelve patients had bilateral HA, VBM showed bilateral hippocampal. Twenty-one patients had right HA, VBM showed right hippocampal and thalamic atrophy and negatively correlated involving the right inferior frontal gyrus and insula. Twenty-two patients had left HA, VBM showed left hippocampal atrophy and negatively correlated involving the left temporal lobe and insula. Sixteen patients had MTLE without HA, VBM showed middle cingulate gyrus atrophy and were negatively correlated involving extra-temporal regions, the main one located in postcentral gyrus.Conclusions: Negative correlations between gray matter volumes and EEG source imaging. Neuroanatomical generators of interictal discharges are heterogeneous and vary according to MTLE subtype.Significance: These findings suggest different pathophysiological mechanisms among patients with different subtypes of MTLE.

scholarly journals Electroencephalography in Mesial Temporal Lobe Epilepsy: A Review

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Manouchehr Javidan
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Mesial Temporal Lobe Epilepsy ◽  
General Information ◽  
Seizure Freedom ◽  
Temporal Region ◽  
Epileptiform Discharges ◽  
Mesial Temporal Lobe ◽  
Magnetic Resonance Imaging Mri ◽  
Sensitivity Specificity

Electroencephalography (EEG) has an important role in the diagnosis and classification of epilepsy. It can provide information for predicting the response to antiseizure drugs and to identify the surgically remediable epilepsies. In temporal lobe epilepsy (TLE) seizures could originate in the medial or lateral neocortical temporal region, and many of these patients are refractory to medical treatment. However, majority of patients have had excellent results after surgery and this often relies on the EEG and magnetic resonance imaging (MRI) data in presurgical evaluation. If the scalp EEG data is insufficient or discordant, invasive EEG recording with placement of intracranial electrodes could identify the seizure focus prior to surgery. This paper highlights the general information regarding the use of EEG in epilepsy, EEG patterns resembling epileptiform discharges, and the interictal, ictal and postictal findings in mesial temporal lobe epilepsy using scalp and intracranial recordings prior to surgery. The utility of the automated seizure detection and computerized mathematical models for increasing yield of non-invasive localization is discussed. This paper also describes the sensitivity, specificity, and predictive value of EEG for seizure recurrence after withdrawal of medications following seizure freedom with medical and surgical therapy.

scholarly journals Hippocampal transection for stereo-electroencephalography–proven dominant mesial temporal lobe epilepsy in a child: a detailed case report and critical review

2018 ◽  
Vol 22 (5) ◽  
pp. 497-503
Author(s):  
Jun T. Park ◽  
Guadalupe Fernandez Baca Vaca ◽  
Rachel Tangen ◽  
Jonathan Miller
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Verbal Memory ◽  
Mesial Temporal Lobe Epilepsy ◽  
Hemispheric Dominance ◽  
Seizure Outcome ◽  
Temporal Region ◽  
Detailed Case ◽  
Epileptiform Discharges ◽  
Mesial Temporal Lobe

Resection of the hippocampus ipsilateral to the verbal memory–dominant hemisphere frequently results in severe memory deficits. In adults with epilepsy, multiple hippocampal transections (MHTs) have resulted in excellent seizure outcome with preservation of verbal memory. The authors report the first detailed case of a child undergoing MHTs for mesial temporal lobe epilepsy. A 13-year-old right-handed boy had intractable seizures characterized by epigastric discomfort evolving to unresponsiveness and chewing automatisms, lasting 1 minute and occurring 2–3 times weekly, sometimes ending in a generalized tonic-clonic seizure. He had no seizure risk factors and nonfocal examination results. Interictal electroencephalography (EEG) showed frequent left temporal epileptiform discharges (maximum FT9) and intermittent slowing. Video EEG, FDG-PET, and 1.5-T MRI were nonlocalizing. Neuropsychological evaluation suggested left temporal lobe dysfunction. A stereo-EEG investigation using 8 electrodes localized the seizure onset zone to the anterior mesial temporal region, immediately involving the hippocampus. The temporal pole and amygdala were resected en bloc with 3 MHTs. Comparison of neuropsychological tests 4 months before and 6 months after the surgery showed a significant decline only in confrontational naming and no significant change in verbal memory. Six and a half years later, the patient remains seizure free with no antiepileptic drugs. In children with established hemispheric dominance suffering from mesial temporal lobe epilepsy, MHTs may be an option.

Analysis of Reoperation in Mesial Temporal Lobe Epilepsy With Hippocampal Sclerosis

Neurosurgery ◽  
2011 ◽  
Vol 68 (1) ◽  
pp. 89-97 ◽  
Author(s):  
Reinhard. Schulz ◽  
Matthias. Hoppe ◽  
Frank. Boesebeck ◽  
Csilla. Gyimesi ◽  
Heinz W. Pannek ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Hippocampal Sclerosis ◽  
Mesial Temporal Lobe Epilepsy ◽  
Incomplete Resection ◽  
T2 Relaxometry ◽  
Epileptiform Discharges ◽  
Interictal Epileptiform Discharges ◽  
Mesial Temporal Lobe

Abstract BACKGROUND: Most patients do well after epilepsy surgery for mesial temporal lobe sclerosis, and in only 8 to 12% of all operations, the outcome is classified as not improved. OBJECTIVE: To analyze the outcome of reoperation in cases of incomplete resection of mesial temporal lobe structures in patients with mesial temporal lobe sclerosis in temporal lobe epilepsy. METHODS: We analyzed 22 consecutive patients who underwent reoperation for mesial temporal lobe sclerosis (follow-up, 23-112 months; mean, 43.18 months) by evaluating noninvasive electroencephalographic/video monitoring before the first and second surgeries (semiology, interictal epileptiform discharges, ictal electroencephalography with special attention to the secondary contralateral evolution of the electroencephalographic seizure pattern after the initial regionalization), and magnetic resonance imaging (resection indices after the first and second surgeries on the amygdala, hippocampus, lateral temporal lobe). In 18 of 22 patients T2 relaxometry of the contralateral hippocampus was performed. RESULTS: Nine of 22 patients became seizure free; another 4 patients had a decrease in seizures and eventually became seizure free (range, 16-51 months; mean, 30.3). Recurrence of seizures is associated with (1) ictal electroencephalography with later evolution of an independent pattern over the contralateral temporal lobe (0 of 5 patients seizure free vs 5 of 7 patients non–seizure free; P = .046) and (2) a smaller amount of lateral temporal lobe resection in the second surgery (1.06 ± 0.59 cm vs 2.18 ± 1.37 cm; P = .019). No significant correlation with outcome was found for lateralization of interictal epileptiform discharges, change in semiology, other resection indices, T2 relaxometry, onset and duration of epilepsy, duration of follow-up, and side of surgery. CONCLUSION: Patients have a less favorable outcome with a reoperation if they show ictal scalp electroencephalography with secondary contralateral propagation and if only a small second resection of the lateral temporal lobe is performed.

The Prognostic Significance of Interictal Epileptiform Activity in Postoperative EEGs of Patients with Mesial Temporal Lobe Epilepsy

2007 ◽  
Vol 38 (3) ◽  
pp. 137-142 ◽  
Author(s):  
Svetlana Kipervasser ◽  
Sari Nagar ◽  
Vladimir Chistik ◽  
Uri Kramer ◽  
Itzhak Fried ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Epileptiform Activity ◽  
Prognostic Significance ◽  
Mesial Temporal Lobe Epilepsy ◽  
Seizure Recurrence ◽  
Group 3 ◽  
Mesial Temporal Lobe ◽  
Eeg Recordings ◽  
A Prospective Study

It has not been established whether electroencephalography (EEG) is a contributing factor in predicting the outcome of surgery for epilepsy. We conducted a prospective study on 26 patients (M/F 14/12, age: 33 ± 7.5 years, range 19–48) with mesial temporal lobe epilepsy (MTLE) who were followed for 2 years after surgery and who underwent routine EEG recordings 5.6 ± 3 months (range 3–12) postoperatively. Interictal epileptiform activity (IEA) on the EEG was compared in 17 seizure-free patients to 9 patients with recurrent seizures. The two groups were similar in gender, age, febrile convulsions, trauma, family history, seizure frequency prior to surgery, epilepsy duration and number of antiepileptic drugs. Following surgery, 17 study patients (65%) became seizure free; 9 (35%) had seizure recurrence. Postoperative EEG recordings showed IEA in 8/26 study patients (31%), 3 of whom were from the seizure-free group (3/17, 18%); 5 had seizure recurrence (5/9, 56%) (p=0.078). IEAs in postoperative EEGs were less frequently demonstrated in patients who were seizure free, but the presence of postoperative IEAs does not preclude successful surgical outcome.

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