Introducing the epileptome: Dynamic seizure onset zone connectome as revealed by single pulse electrical stimulation in stereoelectroencephalography

2016 ◽  
Vol 127 (3) ◽  
pp. e42
Author(s):  
M.D. Maliia ◽  
C. Donos ◽  
A. Barborica ◽  
I. Popa ◽  
J. Ciurea ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Single Pulse ◽  
Seizure Onset ◽  
Seizure Onset Zone

scholarly journals The Connectivity Index: An Effective Metric for Grading Epileptogenicity

2019 ◽  
Author(s):  
Qi Yan ◽  
Nicolas Gaspard ◽  
Hitten P Zaveri ◽  
Hal Blumenfeld ◽  
Lawrence J. Hirsch ◽  
...  
Keyword(s):  
Average Distance ◽  
Single Pulse ◽  
Brain Regions ◽  
Control Site ◽  
Connectivity Index ◽  
Evoked Responses ◽  
Seizure Onset ◽  
Seizure Onset Zone ◽  
Site Of Stimulation ◽  
Stimulation Of

AbstractObjectiveTo investigate the performance of a metric of functional connectivity to classify and grade the excitability of brain regions based on evoked potentials to single pulse electrical stimulation (SPES).MethodsPatients who received 1-Hz frequency stimulation between 2003 and 2014 at Yale at prospectively selected contacts were included. The stimulated contacts were classified as seizure onset zone (SOZ), highly irritative zone (IZp) or control. Response contacts were classified as seizure onset zone (SOZ), active interictal (IZp), quiet or other. The normalized number of responses was defined as the number of contacts with any evoked responses divided by the total number of recorded contacts, and the normalized distance is the ratio of the average distance between the site of stimulation and sites of evoked responses to the average distances between the site of stimulation and all other recording contacts. A new metric we labeled the connectivity index (CI) is defined as the product of the two values.Results57 stimulation-sessions in 22-patients were analyzed. The connectivity index (CI) of the SOZ was higher than control (median CI of 0.74 vs. 0.16, p = 0.0002). The evoked responses after stimulation of SOZ were seen at further distance compared to control (median normalized distance 0.96 vs. 0.62, p = 0.0005). It was 1.8 times more likely to record a response at SOZ than in non-epileptic contacts after stimulation of a control site. Habitual seizures were triggered in 27% of patients and 35 % of SOZ contacts (median stimulation intensity 4 mA) but in none of the control or IZp contacts. Non-SOZ contacts in multifocal or poor surgical outcome cases had a higher CI than non-SOZ contacts in those with localizable onsets (medians CI of 0.5 vs. 0.12, p = 0.04). There was a correlation between the stimulation current intensity and the normalized number of evoked responses (r = + 0.49, p 0.01) but not with distance (r = + 0.1, p 0.64)ConclusionsWe found enhanced connectivity when stimulating the SOZ compared to stimulating control contacts; responses were more distant as well. Habitual auras and seizures provoked by SPES were highly predictive of brain sites involved in seizure generation.

scholarly journals Electrical Stimulation Mapping of Brain Function: A Comparison of Subdural Electrodes and Stereo-EEG

2020 ◽  
Vol 14 ◽  
Author(s):  
Krista M. Grande ◽  
Sarah K. Z. Ihnen ◽  
Ravindra Arya
Keyword(s):  
Electrical Stimulation ◽  
Clinical Decision Making ◽  
Cerebral Hemispheres ◽  
Cortical Surface ◽  
Functional Neuroanatomy ◽  
Functional Responses ◽  
Seizure Onset ◽  
Subdural Electrodes ◽  
Depth Electrodes ◽  
Seizure Onset Zone

Despite technological and interpretative advances, the non-invasive modalities used for pre-surgical evaluation of patients with drug-resistant epilepsy (DRE), fail to generate a concordant anatomo-electroclinical hypothesis for the location of the seizure onset zone in many patients. This requires chronic monitoring with intracranial electroencephalography (EEG), which facilitates better localization of the seizure onset zone, and allows evaluation of the functional significance of cortical regions-of-interest by electrical stimulation mapping (ESM). There are two principal modalities for intracranial EEG, namely subdural electrodes and stereotactic depth electrodes (stereo-EEG). Although ESM is considered the gold standard for functional mapping with subdural electrodes, there have been concerns about its utility with stereo-EEG. This is mainly because subdural electrodes allow contiguous sampling of the dorsolateral convexity of cerebral hemispheres, and permit delineation of the extent of eloquent functional areas on the cortical surface. Stereo-EEG, while having relatively sparse sampling on the cortical surface, offers the ability to access the depth of sulci, mesial and basal surfaces of cerebral hemispheres, and deep structures such as the insula, which are largely inaccessible to subdural electrodes. As stereo-EEG is increasingly the preferred modality for intracranial monitoring, we find it opportune to summarize the literature for ESM with stereo-EEG in this narrative review. Emerging evidence shows that ESM for defining functional neuroanatomy is feasible with stereo-EEG, but probably requires a different approach for interpretation and clinical decision making compared to ESM with subdural electrodes. We have also compared ESM with stereo-EEG and subdural electrodes, for current thresholds required to evoke desired functional responses vs. unwanted after-discharges. In this regard, there is preliminary evidence that ESM with stereo-EEG may be safer than ESM with subdural grids. Finally, we have highlighted important unanswered clinical and scientific questions for ESM with stereo-EEG in the hope to encourage future research and collaborative efforts.

scholarly journals Distinction of Physiologic and Epileptic Ripples: An Electrical Stimulation Study

2021 ◽  
Vol 11 (5) ◽  
pp. 538
Author(s):  
Jan Schönberger ◽  
Anja Knopf ◽  
Kerstin Alexandra Klotz ◽  
Matthias Dümpelmann ◽  
Andreas Schulze-Bonhage ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Slow Wave Sleep ◽  
Focal Epilepsy ◽  
Epileptic Activity ◽  
Interictal Spikes ◽  
Seizure Onset ◽  
Receiver Operating Characteristic Curves ◽  
Seizure Onset Zone ◽  
Intracranial Electroencephalography ◽  
Better Than

Ripple oscillations (80–250 Hz) are a promising biomarker of epileptic activity, but are also involved in memory consolidation, which impairs their value as a diagnostic tool. Distinguishing physiologic from epileptic ripples has been particularly challenging because usually, invasive recordings are only performed in patients with refractory epilepsy. Here, we identified ‘healthy’ brain areas based on electrical stimulation and hypothesized that these regions specifically generate ‘pure’ ripples not coupled to spikes. Intracranial electroencephalography (EEG) recorded with subdural grid electrodes was retrospectively analyzed in 19 patients with drug-resistant focal epilepsy. Interictal spikes and ripples were automatically detected in slow-wave sleep using the publicly available Delphos software. We found that rates of spikes, ripples and ripples coupled to spikes (‘spike–ripples’) were higher inside the seizure-onset zone (p < 0.001). A comparison of receiver operating characteristic curves revealed that spike–ripples slightly delineated the seizure-onset zone channels, but did this significantly better than spikes (p < 0.001). Ripples were more frequent in the eloquent neocortex than in the remaining non-seizure onset zone areas (p < 0.001). This was due to the higher rates of ‘pure’ ripples (p < 0.001; median rates 3.3/min vs. 1.4/min), whereas spike–ripple rates were not significantly different (p = 0.87). ‘Pure’ ripples identified ‘healthy’ channels significantly better than chance (p < 0.001). Our findings suggest that, in contrast to epileptic spike–ripples, ‘pure’ ripples are mainly physiological. They may be considered, in addition to electrical stimulation, to delineate eloquent cortex in pre-surgical patients. Since we applied open source software for detection, our approach may be generally suited to tackle a variety of research questions in epilepsy and cognitive science.

scholarly journals Single-pulse electrical stimulation methodology in freely moving rat

2021 ◽  
Vol 353 ◽  
pp. 109092
Author(s):  
Eloïse Gronlier ◽  
Estelle Vendramini ◽  
Julien Volle ◽  
Agata Wozniak-Kwasniewska ◽  
Noelia Antón Santos ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Single Pulse ◽  
Freely Moving

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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