scholarly journals The role of interictal epileptiform discharges in epilepsy surgery outcome

2019 ◽  
Vol 10 (1) ◽  
pp. 101 ◽  
Author(s):  
Nasim Tabrizi ◽  
JafarMehvari Habibabadi ◽  
Mohamad Zare
Keyword(s):  
Epilepsy Surgery ◽  
Surgery Outcome ◽  
Epileptiform Discharges ◽  
Interictal Epileptiform Discharges

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 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.

scholarly journals A game theory based analysis of network connectivity reveals that state transition is crucial for epilepsy surgery outcome prediction

2021 ◽  
Author(s):  
Karla Ivankovic ◽  
Alessandro Principe ◽  
Justo Montoya ◽  
Linus Manubens-Gil ◽  
Mara Dierssen ◽  
...  
Keyword(s):  
Game Theory ◽  
Epilepsy Surgery ◽  
Crucial Role ◽  
Outcome Prediction ◽  
State Transition ◽  
Network Connectivity ◽  
Surgery Outcome

Seizures recur in half of patients who undergo epilepsy surgery. Presurgical workup mainly focuses on seizures, but only partially helps predicting outcomes, even after invasive electroencephalography. We conceived a generalizable model to detect epileptogenic networks through connectivity changes and identified the crucial role of the transition from pre-seizure to seizure, achieving the highest outcome prediction (93%) to date in a chronological cohort of 21 patients with 3-year follow-up or more.

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.

The role of matrix metalloproteinase 9 and its inhibitors in scarring processes following surgery for primary open-angle glaucoma

2019 ◽  
pp. 72-80
Author(s):  
Е.В. Маркелова ◽  
О.В. Овчинникова ◽  
А.С. Хохлова ◽  
Л.П. Догадова ◽  
А.В. Костюшко ◽  
...  
Keyword(s):  
Matrix Metalloproteinase ◽  
Postoperative Period ◽  
Open Angle Glaucoma ◽  
Matrix Metalloproteinase 9 ◽  
Tissue Inhibitors Of Metalloproteinases ◽  
Open Angle ◽  
Tissue Inhibitors ◽  
Surgery Outcome ◽  
Metalloproteinase 9

Оперативное вмешательство - один из основных методов лечения глаукомы. Однако развитие избыточного рубцевания созданных путей оттока определяет результат хирургического лечения в отдаленные сроки. Процессы рубцевания на данный момент недостаточно изучены. Цель исследования - оценка роли матриксной металлопротеиназы-9, ее ингибиторов в процессах рубцевания у больных с первичной открытоугольной глаукомой после оперативного лечения. Методика. Для выявления возможных маркеров избыточного рубцевания методом твердофазного иммуноферментного анализа определяли содержание матриксных металлопротеиназ-9, тканевых ингибиторов металлопротеиназ 2 и -3 в слезной жидкости у 37 пациентов с активной стадией первичной остроугольной глаукомы в динамике послеоперационного периода. Средний возраст пациентов составил 52,8 лет. В зависимости от исхода оперативного вмешательства все пациенты были разделены на 2 группы - с благоприятным исходом (без избыточного рубцевания) и с неблагоприятным исходом (с избыточным рубцеванием) на месте сформированных дополнительных путей оттока внутриглазной жидкости в послеоперационном периоде. Группа контроля включала 20 человек в возрасте от 50 до 66 лет без сопутствующей офтальмологической и соматической патологии в стадии обострения. Результаты. В динамике показано изменение концентрации матриксной металлопротеиназы-9 и ее ингибиторов в послеоперационном периоде. Анализ данных свидетельствует об обратной зависимости уровня матриксной металлопротеиназы-9 и тканевых ингибиторов металлопротеиназы 2 и 3 типов с исходом операции - чем выше концентрация металлопротеиназы-9 и ниже концентрация тканевых ингибиторов металлопротеиназ 2, -3 в слезной жидкости, тем выше вероятность неблагоприятного исхода в виде рубцевания сформированных дополнительных путей оттока внутриглазной жидкости в послеоперационном периоде. Заключение. Мониторинг уровня металлопротеиназ и их тканевых ингибиторов после проведения хирургического лечения пациентов с первичной открытоугольной глаукомой позволяет прогнозировать раннее рубцевание, дает возможность разработки новых методов лечения как в раннем, так и в позднем послеоперационном периоде. Surgery is one of the major treatments for glaucoma; however excessive scarring of created outflow patways affects the long-term outcome. At the present time, scarring processes are not sufficiently studied. Aim. To evaluate the role of matrix metalloproteinase 9 and its inhibitors in scarring after surgical treatment of open-angle glaucoma. Methods. Concentrations of matrix metalloproteinase 9 and tissue inhibitors of metalloproteinases 2 and 3 were measured in tear fluid of 37 patients (mean age, 52.8) with active primary open-angle glaucoma in dynamics during the postoperative period to identify possible markers of excessive scarring. Based on the surgery outcome, all patients were divided into two groups, with a favorable outcome (without excessive scarring) and an unfavorable outcome (with excessive scarring) in the created additional outflow pathways for the intraocular fluid in the postoperative period. The control group included 20 subjects aged 50-66 without eye disease or somatic disease at exacerbation stage. Results. Analysis of changes in concentrations of matrix metalloproteinase 9 and its inhibitors in the postoperative period showed their inverse relationship with the surgery outcome. The higher was the metalloproteinase 9 level and the lower the level of tissue inhibitors of metalloproteinases 2 and 3 the higher was the probability of unfavorable outcome evident as excessive scarring of the formed additional pathways for tear fluid outflow in the postoperative period. Conclusion. Postoperative monitoring of metalloproteinases and their tissue inhibitors allows to predict early scarring and to develop new treatments both in early and late postoperative periods.

Prevalence of Interictal Epileptiform Discharges in Children Less Than One Year of Age Referred for Polysomnography

2015 ◽  
Vol 55 (2) ◽  
pp. 122-132
Author(s):  
Adetayo Adeleye ◽  
Alice W. Ho ◽  
Alberto Nettel-Aguirre ◽  
Valerie Kirk ◽  
Jeffrey Buchhalter
Keyword(s):  
Epileptiform Discharges ◽  
Interictal Epileptiform Discharges ◽  
One Year

scholarly journals Zero-crossing patterns reveal subtle epileptiform discharges in the scalp EEG

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jan Pyrzowski ◽  
Jean- Eudes Le Douget ◽  
Amal Fouad ◽  
Mariusz Siemiński ◽  
Joanna Jędrzejczak ◽  
...  
Keyword(s):  
Normal Subjects ◽  
Intracranial Eeg ◽  
Zero Crossing ◽  
Temporal Precision ◽  
Scalp Eeg ◽  
Epileptiform Discharges ◽  
Interictal Epileptiform Discharges ◽  
Eeg Recordings ◽  
Patients With Epilepsy ◽  
Low Amplitude

AbstractClinical diagnosis of epilepsy depends heavily on the detection of interictal epileptiform discharges (IEDs) from scalp electroencephalographic (EEG) signals, which by purely visual means is far from straightforward. Here, we introduce a simple signal analysis procedure based on scalp EEG zero-crossing patterns which can extract the spatiotemporal structure of scalp voltage fluctuations. We analyzed simultaneous scalp and intracranial EEG recordings from patients with pharmacoresistant temporal lobe epilepsy. Our data show that a large proportion of intracranial IEDs manifest only as subtle, low-amplitude waveforms below scalp EEG background and could, therefore, not be detected visually. We found that scalp zero-crossing patterns allow detection of these intracranial IEDs on a single-trial level with millisecond temporal precision and including some mesial temporal discharges that do not propagate to the neocortex. Applied to an independent dataset, our method discriminated accurately between patients with epilepsy and normal subjects, confirming its practical applicability.

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