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.

scholarly journals Surgical Outcomes and EEG Prognostic Factors After Stereotactic Laser Amygdalohippocampectomy for Mesial Temporal Lobe Epilepsy

2021 ◽  
Vol 12 ◽  
Author(s):  
Shasha Wu ◽  
Naoum P. Issa ◽  
Maureen Lacy ◽  
David Satzer ◽  
Sandra L. Rose ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Surgical Outcomes ◽  
Mesial Temporal Lobe Epilepsy ◽  
Seizure Freedom ◽  
Seizure Recurrence ◽  
Factors Associated ◽  
Scalp Eeg ◽  
Mesial Temporal Lobe

Objective: To assess the seizure outcomes of stereotactic laser amygdalohippocampectomy (SLAH) in consecutive patients with mesial temporal lobe epilepsy (mTLE) in a single center and identify scalp EEG and imaging factors in the presurgical evaluation that correlate with post-surgical seizure recurrence.Methods: We retrospectively reviewed the medical and EEG records of 30 patients with drug-resistant mTLE who underwent SLAH and had at least 1 year of follow-up. Surgical outcomes were classified using the Engel scale. Univariate hazard ratios were used to evaluate the risk factors associated with seizure recurrence after SLAH.Results: The overall Engel class I outcome after SLAH was 13/30 (43%), with a mean postoperative follow-up of 48.9 ± 17.6 months. Scalp EEG findings of interictal regional slow activity (IRSA) on the side of surgery (HR = 4.05, p = 0.005) and non-lateralizing or contra-lateralizing seizure onset (HR = 4.31, p = 0.006) were negatively correlated with postsurgical seizure freedom. Scalp EEG with either one of the above features strongly predicted seizure recurrence after surgery (HR = 7.13, p < 0.001) with 100% sensitivity and 71% specificity.Significance: Understanding the factors associated with good or poor surgical outcomes can help choose the best candidates for SLAH. Of the variables assessed, scalp EEG findings were the most clearly associated with seizure outcomes after SLAH.

scholarly journals Patterns of seizure control in patients with mesial temporal lobe epilepsy with and without hippocampus sclerosis

2015 ◽  
Vol 73 (2) ◽  
pp. 79-82 ◽  
Author(s):  
Ana Carolina Coan ◽  
Brunno M. Campos ◽  
Felipe P.G Bergo ◽  
Bruno Y. Kubota ◽  
Clarissa L. Yasuda ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Seizure Control ◽  
Hippocampal Sclerosis ◽  
Mesial Temporal Lobe Epilepsy ◽  
Similar Proportion ◽  
Seizure Freedom ◽  
Seizure Recurrence ◽  
Prolonged Seizure ◽  
Mesial Temporal Lobe

Objective Patients with mesial temporal lobe epilepsy (MTLE) may present unstable pattern of seizures. We aimed to evaluate the occurrence of relapse-remitting seizures in MTLE with (MTLE-HS) and without (MTLE-NL) hippocampal sclerosis. Method We evaluated 172 patients with MTLE-HS (122) or MTLE-NL (50). Relapse-remitting pattern was defined as periods longer than two years of seizure-freedom intercalated with seizure recurrence. “Infrequent seizures” was considered as up to three seizures per year and “frequent seizures” as any period of seizures higher than that. Results Thirty-seven (30%) MTLE-HS and 18 (36%) MTLE-NL patients had relapse-remitting pattern (X2, p = 0.470). This was more common in those with infrequent seizures (X2, p < 0.001). Twelve MTLE-HS and one MTLE-NL patients had prolonged seizure remission between the first and second decade of life (X2, p = 0.06). Conclusion Similar proportion of MTLE-HS or MTLE-NL patients present relapse-remitting seizures and this occurs more often in those with infrequent seizures.

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.

Resection of Temporal Neocortex During Multiple Hippocampal Transections for Mesial Temporal Lobe Epilepsy Does not Affect Seizure or Memory Outcome

2017 ◽  
Vol 13 (6) ◽  
pp. 711-717 ◽  
Author(s):  
Fady Girgis ◽  
Madeline E Greil ◽  
Philip S Fastenau ◽  
Jennifer Sweet ◽  
Hans Lüders ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Visual Memory ◽  
Mesial Temporal Lobe Epilepsy ◽  
Seizure Outcome ◽  
Seizure Freedom ◽  
Visual Spatial ◽  
Mesial Temporal Lobe ◽  
Postoperative Seizure ◽  
Temporal Neocortex

Abstract BACKGROUND Multiple hippocampal transection (MHT) is a surgical treatment for mesial temporal lobe epilepsy associated with improved postoperative neuropsychological outcomes compared with lobectomy. OBJECTIVE To determine whether resection of the amygdala and anterior temporal neocortex during MHT affects postoperative seizure/memory outcome. METHODS Seventeen patients with normal magnetic resonance imaging and stereo-electroencephalogram-proven drug-resistant dominant mesial temporal lobe epilepsy were treated with MHT. Nine patients underwent MHT alone (MHT–) and 8 patients underwent MHT plus removal of the amygdala and anterior 4.5 cm of temporal neocortex lateral to the fusiform gyrus (MHT+). Verbal and visual-spatial memory were assessed in all patients preoperatively and in 14 patients postoperatively using the Wechsler Memory Scale. Postoperative seizure control was assessed at 12 months for all patients. RESULTS Overall, 11 of 17 patients (64.7%) were Engel class 1 at 1 year (6/9 MHT–, 5/8 MHT+, P = .38), and 10 of 14 patients (71.4%) had no significant postoperative decline in either verbal or visual memory (6/8 MHT–, 4/6 MHT+, P = .42). Verbal memory declined in 2 of 8 MHT– and 1 of 6 MHT+ patients, and visual memory declined in 1 of 8 MHT– and 2 of 6 MHT+ patients. Two patients had improved visual memory postoperatively, both in the MHT+ group. CONCLUSION MHT on the dominant side is associated with high rates of seizure freedom and favorable memory preservation outcomes regardless of the extent of neocortical resection. Preservation of the temporal neocortex and amygdala during MHT does not appear to decrease the risk of postoperative memory decline, nor does it alter seizure outcome.

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 &lt; 0.001) and local (p &lt; 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.

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