scholarly journals Virtual localization of the seizure onset zone: Using non-invasive MEG virtual electrodes at stereo-EEG electrode locations in refractory epilepsy patients

2018 ◽  
Vol 19 ◽  
pp. 758-766 ◽  
Author(s):  
Erika L. Juárez-Martinez ◽  
Ida A. Nissen ◽  
Sander Idema ◽  
Demetrios N. Velis ◽  
Arjan Hillebrand ◽  
...  
Keyword(s):  
Refractory Epilepsy ◽  
Seizure Onset ◽  
Non Invasive ◽  
Seizure Onset Zone ◽  
Virtual Localization ◽  
Virtual Electrodes

scholarly journals Clinical Validation of the Champagne Algorithm for Epilepsy Spike Localization

2021 ◽  
Vol 15 ◽  
Author(s):  
Chang Cai ◽  
Jessie Chen ◽  
Anne M. Findlay ◽  
Danielle Mizuiri ◽  
Kensuke Sekihara ◽  
...  
Keyword(s):  
Refractory Epilepsy ◽  
Focal Epilepsy ◽  
Epileptiform Activity ◽  
Consecutive Series ◽  
Source Reconstruction ◽  
Seizure Onset ◽  
Current Dipole ◽  
Seizure Onset Zone ◽  
Complementary Techniques ◽  
Epilepsy Localization

Magnetoencephalography (MEG) is increasingly used for presurgical planning in people with medically refractory focal epilepsy. Localization of interictal epileptiform activity, a surrogate for the seizure onset zone whose removal may prevent seizures, is challenging and depends on the use of multiple complementary techniques. Accurate and reliable localization of epileptiform activity from spontaneous MEG data has been an elusive goal. One approach toward this goal is to use a novel Bayesian inference algorithm—the Champagne algorithm with noise learning—which has shown tremendous success in source reconstruction, especially for focal brain sources. In this study, we localized sources of manually identified MEG spikes using the Champagne algorithm in a cohort of 16 patients with medically refractory epilepsy collected in two consecutive series. To evaluate the reliability of this approach, we compared the performance to equivalent current dipole (ECD) modeling, a conventional source localization technique that is commonly used in clinical practice. Results suggest that Champagne may be a robust, automated, alternative to manual parametric dipole fitting methods for localization of interictal MEG spikes, in addition to its previously described clinical and research applications.

scholarly journals Localizing Epileptic Foci Using Simultaneous EEG-fMRI Recording: Template Component Cross-Correlation

2021 ◽  
Vol 12 ◽  
Author(s):  
Elias Ebrahimzadeh ◽  
Mohammad Shams ◽  
Masoud Seraji ◽  
Seyyed Mostafa Sadjadi ◽  
Lila Rajabion ◽  
...  
Keyword(s):  
Medical Records ◽  
Generalized Linear Model ◽  
Cross Correlation ◽  
Refractory Epilepsy ◽  
Brain Structures ◽  
Seizure Onset ◽  
Future Behavior ◽  
Seizure Onset Zone ◽  
Conventional Methods ◽  
Deep Brain

Conventional EEG-fMRI methods have been proven to be of limited use in the sense that they cannot reveal the information existing in between the spikes. To resolve this issue, the current study obtains the epileptic components time series detected on EEG and uses them to fit the Generalized Linear Model (GLM), as a substitution for classical regressors. This approach allows for a more precise localization, and equally importantly, the prediction of the future behavior of the epileptic generators. The proposed method approaches the localization process in the component domain, rather than the electrode domain (EEG), and localizes the generators through investigating the spatial correlation between the candidate components and the spike template, as well as the medical records of the patient. To evaluate the contribution of EEG-fMRI and concordance between fMRI and EEG, this method was applied on the data of 30 patients with refractory epilepsy. The results demonstrated the significant numbers of 29 and 24 for concordance and contribution, respectively, which mark improvement as compared to the existing literature. This study also shows that while conventional methods often fail to properly localize the epileptogenic zones in deep brain structures, the proposed method can be of particular use. For further evaluation, the concordance level between IED-related BOLD clusters and Seizure Onset Zone (SOZ) has been quantitatively investigated by measuring the distance between IED/SOZ locations and the BOLD clusters in all patients. The results showed the superiority of the proposed method in delineating the spike-generating network compared to conventional EEG-fMRI approaches. In all, the proposed method goes beyond the conventional methods by breaking the dependency on spikes and using the outside-the-scanner spike templates and the selected components, achieving an accuracy of 97%. Doing so, this method contributes to improving the yield of EEG-fMRI and creates a more realistic perception of the neural behavior of epileptic generators which is almost without precedent in the literature.

Neural fragility as an EEG marker of the seizure onset zone

2021 ◽  
Author(s):  
Adam Li ◽  
Chester Huynh ◽  
Zachary Fitzgerald ◽  
Iahn Cajigas ◽  
Damian Brusko ◽  
...  
Keyword(s):  
Seizure Onset ◽  
Seizure Onset Zone

scholarly journals Characterizing the seizure onset zone and epileptic network using EEG-fMRI in a rat seizure model

NeuroImage ◽  
2021 ◽  
pp. 118133
Author(s):  
Junling Wang ◽  
Bin Jing ◽  
Ru Liu ◽  
Donghong Li ◽  
Wei Wang ◽  
...  
Keyword(s):  
Seizure Onset ◽  
Seizure Onset Zone ◽  
Seizure Model
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