scholarly journals Reiterating the role of corpus callosum in generalization of interictal and ictal epileptiform discharges: a case report with post-callosotomy intracranial electroencephalography in Lennox–Gastaut syndrome

2021 ◽  
Vol 13 (3) ◽  
pp. 249-253
Author(s):  
S. Gopinath ◽  
A. Pillai ◽  
A. G. Diwan ◽  
J. V. Pattisapu ◽  
K. Radhakrishnan
Keyword(s):  
Corpus Callosum ◽  
Epileptic Encephalopathy ◽  
Drop Attacks ◽  
Epileptiform Discharges ◽  
Interictal Epileptiform Discharges ◽  
Eeg Abnormalities ◽  
Before And After ◽  
Intracranial Electroencephalography ◽  
Electroencephalogram Eeg

Lennox–Gastaut syndrome (LGS) is an epileptic encephalopathy characterized by delayed mental development and intractable multiple seizure types, predominantly tonic. Drop attacks are the commonest and the most disabling type of seizures. Resective surgery is often not possible in LGS as the electroencephalogram (EEG) abnormalities are usually multifocal and generalized, and magnetic resonance image is often either normal or multilesional. We report a case of LGS with bilateral parieto-occipital gliosis where EEG before and after callosotomy demonstrated synchronized bilateral interictal epileptiform discharges and ictal discharges becoming desynchronized and running down. This phenomenon emphasizes the role of the corpus callosum in secondary bilateral synchrony.

scholarly journals Interictal discharges spread along local recurrent networks between tubers and surrounding cortex

2019 ◽  
Author(s):  
S Tumpa ◽  
R Thornton ◽  
M Tisdall ◽  
T Baldeweg ◽  
KJ Friston ◽  
...  
Keyword(s):  
Tuberous Sclerosis ◽  
Epilepsy Surgery ◽  
Local Network ◽  
Neural Mass Model ◽  
Model Parameters ◽  
Epileptiform Discharges ◽  
Interictal Epileptiform Discharges ◽  
Eeg Abnormalities ◽  
Neural Mass ◽  
Interictal Discharges

AbstractThe presence of interictal epileptiform discharges on electroencephalography (EEG) may indicate increased epileptic seizure risk and on invasive EEG are the signature of the irritative zone. In highly epileptogenic lesions – such as cortical tubers in tuberous sclerosis – these discharges can be recorded with intracranial stereotactic EEG as part of the evaluation for epilepsy surgery. Yet the network mechanisms that underwrite the generation and spread of these discharges remain poorly understood, limiting their current diagnostic use.Here, we investigate the dynamics of interictal epileptiform discharges using a combination of quantitative analysis of invasive EEG recordings and mesoscale neural mass modelling of cortical dynamics. We first characterise spatially organised local dynamics of discharges recorded from 36 separate tubers in 8 patients with tuberous sclerosis. We characterise these dynamics with a set of competing explanatory network models using dynamic causal modelling. Bayesian model comparison of plausible network architectures suggests that the recurrent coupling between neuronal populations within – and adjacent to – the tuber core explains the travelling wave dynamics observed in these patient recordings.Our results – based on interictal activity – unify competing theories about the pathological organisation of epileptic foci and surrounding cortex in patients with tuberous sclerosis. Coupled oscillator dynamics have previously been used to describe ictal activity, where fast travelling ictal discharges are commonly observed within the recruited seizure network. The interictal data analysed here add the insight that this functional architecture is already established in the interictal state. This links observations of interictal EEG abnormalities directly to pathological network coupling in epilepsy, with possible implications for epilepsy surgery approaches in tuberous sclerosis.Significance StatementInterictal epileptiform discharges (IEDs) are clinically important markers of an epileptic brain. Here we link local IED spread to network coupling through a combination of clinical recordings in paediatric patients with tuberous sclerosis complex, quantitative EEG analysis of interictal discharges spread, and Bayesian inference on coupled neural mass model parameters. We show that the kinds of interictal discharges seen in our patients require recurrent local network coupling extending beyond the putative seizure focus and that in fact only those recurrent coupled networks can support seizure-like and interictal dynamics when run in simulation. Our findings provide a novel integrated perspective on emergent epileptic dynamics in human patients.

scholarly journals The Role of Epilepsy Surgery in the Treatment of Childhood Epileptic Encephalopathy

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Husam R. Kayyali ◽  
Ahmed Abdelmoity ◽  
Saleh Baeesa
Keyword(s):  
Clinical Features ◽  
Developmental Disability ◽  
Epilepsy Surgery ◽  
Surgical Approach ◽  
Brain Function ◽  
Brain Lesion ◽  
Epileptic Encephalopathy ◽  
Intractable Seizures ◽  
Electroencephalogram Eeg

Children with epileptic encephalopathy often have global impairment of brain function and frequent intractable seizures, which contribute further to their developmental disability. Many of these children have identifiable brain lesion on neurological imaging. In such cases, epilepsy surgery may be considered as a treatment option despite the lack of localized epileptic pattern on electroencephalogram (EEG). In this paper, we summarize the clinical features of epileptic encephalopathy syndromes and review the reported literature on the surgical approach to some of these disorders.

scholarly journals On the role of the corpus callosum in interhemispheric functional connectivity in humans

2017 ◽  
Vol 114 (50) ◽  
pp. 13278-13283 ◽  
Author(s):  
Jarod L. Roland ◽  
Abraham Z. Snyder ◽  
Carl D. Hacker ◽  
Anish Mitra ◽  
Joshua S. Shimony ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Corpus Callosum ◽  
Parietal Lobe ◽  
Brain Regions ◽  
Resting State Functional Connectivity ◽  
Limited Sample ◽  
Temporal Correlations ◽  
Before And After

Resting state functional connectivity is defined in terms of temporal correlations between physiologic signals, most commonly studied using functional magnetic resonance imaging. Major features of functional connectivity correspond to structural (axonal) connectivity. However, this relation is not one-to-one. Interhemispheric functional connectivity in relation to the corpus callosum presents a case in point. Specifically, several reports have documented nearly intact interhemispheric functional connectivity in individuals in whom the corpus callosum (the major commissure between the hemispheres) never develops. To investigate this question, we assessed functional connectivity before and after surgical section of the corpus callosum in 22 patients with medically refractory epilepsy. Section of the corpus callosum markedly reduced interhemispheric functional connectivity. This effect was more profound in multimodal associative areas in the frontal and parietal lobe than primary regions of sensorimotor and visual function. Moreover, no evidence of recovery was observed in a limited sample in which multiyear, longitudinal follow-up was obtained. Comparison of partial vs. complete callosotomy revealed several effects implying the existence of polysynaptic functional connectivity between remote brain regions. Thus, our results demonstrate that callosal as well as extracallosal anatomical connections play a role in the maintenance of interhemispheric functional connectivity.

scholarly journals Automated Inter-Ictal Epileptiform Discharge Detection from Routine EEG

2021 ◽  
Author(s):  
Duong Nhu ◽  
Mubeen Janmohamed ◽  
Lubna Shakhatreh ◽  
Ofer Gonen ◽  
Patrick Kwan ◽  
...  
Keyword(s):  
Royal Melbourne Hospital ◽  
Epileptiform Discharges ◽  
Interictal Epileptiform Discharges ◽  
Model Variant ◽  
Eeg Recordings ◽  
Generalized Epilepsy ◽  
Electroencephalogram Eeg ◽  
Health Hospital ◽  
Epilepsy Monitoring

Epilepsy is the most common neurological disorder. The diagnosis commonly requires manual visual electroencephalogram (EEG) analysis which is time-consuming. Deep learning has shown promising performance in detecting interictal epileptiform discharges (IED) and may improve the quality of epilepsy monitoring. However, most of the datasets in the literature are small (n≤100) and collected from single clinical centre, limiting the generalization across different devices and settings. To better automate IED detection, we cross-evaluated a Resnet architecture on 2 sets of routine EEG recordings from patients with idiopathic generalized epilepsy collected at the Alfred Health Hospital and Royal Melbourne Hospital (RMH). We split these EEG recordings into 2s windows with or without IED and evaluated different model variants in terms of how well they classified these windows. The results from our experiment showed that the architecture generalized well across different datasets with an AUC score of 0.894 (95% CI, 0.881–0.907) when trained on Alfred’s dataset and tested on RMH’s dataset, and 0.857 (95% CI, 0.847–0.867) vice versa. In addition, we compared our best model variant with Persyst and observed that the model was comparable.

scholarly journals A STUDY ON COMPARATIVE YIELDS OF STANDARD SHORT TERM ELECTROENCEPHALOGRAM AND LONG TERM ELECTROENCEPHALOGRAM RECORDING IN SUSPECTED EPILEPSY PATIENTS

2021 ◽  
Vol 71 (5) ◽  
pp. 1727-31
Author(s):  
Saima Shafait ◽  
Wasim Alamgir ◽  
Imran Ahmad ◽  
Saeed Arif ◽  
Jahanzeb Liaqat ◽  
...  
Keyword(s):  
Diagnostic Yield ◽  
Extended Period ◽  
Final Analysis ◽  
Epileptiform Discharge ◽  
Military Hospital ◽  
Recording Time ◽  
Epileptiform Discharges ◽  
Interictal Epileptiform Discharges ◽  
Interictal Epileptiform Discharge ◽  
Electroencephalogram Eeg

Objective: To compare the yield of interictal epileptiform discharges on prolonged (1-2 hours) electroencephalogram (EEG) as compared to standard routine (30 minutes) electroencephalogram (EEG). Study Design: Comparative observational study. Place and Duration of Study: Pak Emirates Military Hospital, Rawalpindi from Oct 2019 to Sep 2020. Methodology: A total of 364 outdoor patients with suspected epilepsy were recruited for the study. Out of these 55 electroencephalograms were excluded after applying exclusion criteria and 309 were included for final analysis. Electro-encephalograms were recorded using a 10-20 international system of electrode placement. The duration of each standard electroencephalogram was 30 minutes. It was followed by recording for an extended period of 60 minutes at least. The time to the appearance of the first abnormal interictal epileptiform discharge was noted. For analytical purposes, epileptiform discharges were classified as “early” if they appeared within the first 30 minutes and as “late” if appeared afterward. All electro-encephalograms were evaluated independently by two neurologists. Results: A total of 309 electroencephalograms were included for final analysis. Interictal epileptiform discharges were seen in 48 (15.6%) recordings. The mean time to appearance of first interictal epileptiform discharge was 14.6 ± 19.09 minutes. In 36 (11.7%) cases, discharges appeared early (within the first 30 minutes) whereas in the remaining 12 (3.9%) cases, discharges appeared late. This translates into a 33% increase in the diagnostic yield of electroencephalogram with an extended period of recording. Conclusion: Extending the electroencephalogram recording time results in a significantly better diagnostic yield of outdoor electroencephalogram.

scholarly journals The Oscillatory Basis of Working Memory Function and Dysfunction in Epilepsy

2021 ◽  
Vol 14 ◽  
Author(s):  
Olivia N. Arski ◽  
Julia M. Young ◽  
Mary-Lou Smith ◽  
George M. Ibrahim
Keyword(s):  
Working Memory ◽  
High Frequency ◽  
Large Scale ◽  
Memory Function ◽  
Epileptic Activity ◽  
Functional Roles ◽  
High Frequency Oscillations ◽  
Epileptiform Discharges ◽  
Interictal Epileptiform Discharges

Working memory (WM) deficits are pervasive co-morbidities of epilepsy. Although the pathophysiological mechanisms underpinning these impairments remain elusive, it is thought that WM depends on oscillatory interactions within and between nodes of large-scale functional networks. These include the hippocampus and default mode network as well as the prefrontal cortex and frontoparietal central executive network. Here, we review the functional roles of neural oscillations in subserving WM and the putative mechanisms by which epilepsy disrupts normative activity, leading to aberrant oscillatory signatures. We highlight the particular role of interictal epileptic activity, including interictal epileptiform discharges and high frequency oscillations (HFOs) in WM deficits. We also discuss the translational opportunities presented by greater understanding of the oscillatory basis of WM function and dysfunction in epilepsy, including potential targets for neuromodulation.

KCNQ2 Encephalopathy and Responsiveness to Pyridoxal-5′-Phosphate

2020 ◽  
Author(s):  
Chit Kwong ◽  
Ho Ming ◽  
Suet Na
Keyword(s):  
Viral Infection ◽  
Early Onset ◽  
Vitamin B6 ◽  
Neonatal Period ◽  
Epileptic Encephalopathy ◽  
Neonatal Seizure ◽  
Eeg Monitoring ◽  
Epileptiform Discharges ◽  
Wide Range ◽  
Electroencephalogram Eeg

Abstract KCNQ2 mutations encompass a wide range of phenotypes, ranging from benign familial neonatal seizure to a clinical spectrum of early-onset epileptic encephalopathy that occurs in the early neonatal period. We report an infant with KCNQ2 encephalopathy presenting as neonatal seizure, initially controlled by two anticonvulsants. Electroencephalogram (EEG) showed repetitive multifocal epileptiform discharges, which remained similar after administration of intravenous pyridoxine injection. Seizure recurred at the age of 3 months preceded by an episode of minor viral infection, which occurred multiple times per day. No significant change in seizure frequency was observed after 5-day oral pyridoxine trial, but subsequently, there was dramatic seizure improvement with oral pyridoxal-5′-phosphate (PLP). We hope to alert clinicians that in patients with neonatal epileptic encephalopathy, particularly with known KCNQ2 mutations, intravenous injection of pyridoxine (preferably with EEG monitoring), followed by both oral trial of pyridoxine and PLP should be considered. KCNQ2 mutations should also be considered in vitamin B6-responsive patients.

How Long Should Routine EEG Be Recorded to Get Relevant Information?

2017 ◽  
Vol 49 (5) ◽  
pp. 335-341
Author(s):  
Hannah Doudoux ◽  
Kristina Skaare ◽  
Thomas Geay ◽  
Philippe Kahane ◽  
Jean L. Bosson ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Relevant Information ◽  
The Other ◽  
Neurologic Manifestation ◽  
Epileptiform Discharges ◽  
Interictal Epileptiform Discharges ◽  
Eeg Abnormalities ◽  
Eeg Recordings ◽  
Time Required ◽  
Over Time

Objective. The optimal duration of routine EEG (rEEG) has not been determined on a clinical basis. This study aims to determine the time required to obtain relevant information during rEEG with respect to the clinical request. Method. All rEEGs performed over 3 months in unselected patients older than 14 years in an academic hospital were analyzed retrospectively. The latency required to obtain relevant information was determined for each rEEG by 2 independent readers blinded to the clinical data. EEG final diagnoses and latencies were analyzed with respect to the main clinical requests: subacute cognitive impairment, spells, transient focal neurologic manifestation or patients referred by epileptologists. Results. From 430 rEEGs performed in the targeted period, 364 were analyzed: 92% of the pathological rEEGs were provided within the first 10 minutes of recording. Slowing background activity was diagnosed from the beginning, whereas interictal epileptiform discharges were recorded over time. Moreover, the time elapsed to demonstrate a pattern differed significantly in the clinical groups: in patients with subacute cognitive impairment, EEG abnormalities appeared within the first 10 minutes, whereas in the other groups, data could be provided over time. Conclusion. Patients with subacute cognitive impairment differed from those in the other groups significantly in the elapsed time required to obtain relevant information during rEEG, suggesting that 10-minute EEG recordings could be sufficient, arguing in favor of individualized rEEG. However, this conclusion does not apply to intensive care unit patients.

Single-Epileptic Spasms with or without Hypsarrhythmia: A Study of 16 Patients

2017 ◽  
Vol 06 (03) ◽  
pp. 149-155
Author(s):  
Raffaele Falsaperla ◽  
Robinson Gutierrez ◽  
Gabriela Valenzuela ◽  
Piero Pavone ◽  
Sebastian Fortini ◽  
...  
Keyword(s):  
Antiepileptic Drugs ◽  
Ketogenic Diet ◽  
Adrenocorticotropic Hormone ◽  
Main Type ◽  
Epileptic Encephalopathy ◽  
Unknown Etiology ◽  
Epileptic Spasms ◽  
Before And After ◽  
Eeg Recordings ◽  
Electroencephalogram Eeg

Objective We evaluated the electroclinical features, etiology, treatment, and outcome of 16 patients with single-epileptic spasms (ESs) with or without hypsarrhythmia (WoH). Methods Nine boys and seven girls had single-ESs. ESs were considered as single epileptic spasm variants when no other spasm occurred for 1 minute before and after each spasm. Age at the onset of ESs was between 2 and 84 months, with a mean age of 11 months. Results We recognized a group of 15 patients with single-ESs as the main type of seizure; 6 patients with WoH and 9 patients with hypsarrhythmia, respectively. Nine of these 15 patients had other types of seizures before the onset of single-ESs, and 12 patients had other types of seizures during the period in which the ESs occurred. Nine of 15 patients had a structural and seven had an unknown etiology. In 10 cases, the ESs were refractory to antiepileptic drugs, while 4 patients responded well to adrenocorticotropic hormone (ACTH), 1 to pyridoxine, and 2 to the ketogenic diet (KD). The remaining patient (patient.16) had single-ESs and electroclinical features of Lennox–Gastaut syndrome (LGS). Conclusion In this article, we present a series of infants who had daily single-ESs with or WoH. Those with single-ESs with hypsarrhythmia evolved to an epileptic encephalopathy. Video-electroencephalogram (EEG) and polygraphic-EEG recordings are crucial to identify the single-ESs.

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