Focal Seizures Induced by Intracranial Electroencephalogram Grids

Hudgins, Eric; Brown, Mesha-Gay; Litt, Brian; Davis, Kathryn A.; Richardson, Andrew G.; Lucas, Timothy H.

doi:10.7759/cureus.831

Cited by 4 publications

(4 citation statements)

References 8 publications

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“…While iEEG can record seizures at high spatial and temporal resolution, it has important limitations. For example, seizures are often provoked during the recording period via medication withdrawal and sleep deprivation; in some patients, these provoked seizures may be fundamentally different from stereotypical spontaneous seizures, and can misinform localization attempts (Hudgins et al, 2016). Additionally, seizure provocation and prolonged implantation while waiting to record seizures increases the risk of complications such as infection, deep vein thrombosis, musculoskeletal injury, and postictal psychosis (Sperling, 1997; Hamer et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

High interictal connectivity within the resection zone is associated with favorable post-surgical outcomes in focal epilepsy patients

Shah

Bernabei

Kini

et al. 2019

NeuroImage: Clinical

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Patients with drug-resistant focal epilepsy are often candidates for invasive surgical therapies. In these patients, it is necessary to accurately localize seizure generators to ensure seizure freedom following intervention. While intracranial electroencephalography (iEEG) is the gold standard for mapping networks for surgery, this approach requires inducing and recording seizures, which may cause patient morbidity. The goal of this study is to evaluate the utility of mapping interictal (non-seizure) iEEG networks to identify targets for surgical treatment. We analyze interictal iEEG recordings and neuroimaging from 27 focal epilepsy patients treated via surgical resection. We generate interictal functional networks by calculating pairwise correlation of iEEG signals across different frequency bands. Using image coregistration and segmentation, we identify electrodes falling within surgically resected tissue (i.e. the resection zone), and compute node-level and edge-level synchrony in relation to the resection zone. We further associate these metrics with post-surgical outcomes. Greater overlap between resected electrodes and highly synchronous electrodes is associated with favorable post-surgical outcomes. Additionally, good-outcome patients have significantly higher connectivity localized within the resection zone compared to those with poorer postoperative seizure control. This finding persists following normalization by a spatially-constrained null model. This study suggests that spatially-informed interictal network synchrony measures can distinguish between good and poor post-surgical outcomes. By capturing clinically-relevant information during interictal periods, our method may ultimately reduce the need for prolonged invasive implants and provide insights into the pathophysiology of an epileptic brain. We discuss next steps for translating these findings into a prospectively useful clinical tool.

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Section: Introductionmentioning

confidence: 99%

High interictal connectivity within the resection zone is associated with favorable post-surgical outcomes in focal epilepsy patients

Shah

Bernabei

Kini

et al. 2019

NeuroImage: Clinical

Self Cite

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show abstract

“…For example, seizures are often provoked during the recording period via medication withdrawal and sleep deprivation; in some patients, these provoked seizures may be fundamentally different from stereotypical spontaneous seizures, with the potential to misinform localization attempts. 7 Additionally, seizure provocation and prolonged implantation while waiting to record seizures increases the risk of complications such as infection, deep vein thrombosis, musculoskeletal injury, and postictal psychosis. 8,9 In some cases, seizures may not occur during the implant period, rendering the study inconclusive.…”

Section: Introductionmentioning

confidence: 99%

High interictal connectivity within the resection zone is associated with favorable post-surgical outcomes in focal epilepsy patients

Shah

Bernabei

Kini

et al. 2018

Preprint

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Objective: Patients with drug-resistant focal epilepsy are often candidates for invasive surgical therapies. In these patients, it is necessary to accurately localize seizure-generators to ensure seizure freedom following intervention. While intracranial electroencephalography (iEEG) is the gold standard for mapping networks for surgery, this approach requires inducing and recording seizures, which may cause patient morbidity. The goal of this study is to evaluate the utility of mapping interictal (non-seizure) iEEG networks to identify targets for surgical treatment. Methods:We analyze interictal iEEG recordings and neuroimaging from 27 focal epilepsy patients treated via surgical resection. We generate interictal functional networks by calculating pairwise correlation of iEEG signals across different frequency bands. We identify electrodes falling within surgically resected tissue (i.e. the resection zone), and compute node-level and edge-level synchrony in relation to the resection zone. We associate these metrics with postsurgical outcomes.Results: Greater overlap between resected electrodes and highly synchronous electrodes is associated with favorable post-surgical outcomes. Additionally, good outcome patients have significantly higher connectivity localized within the resection zone compared to those with poorer postoperative seizure control. This finding persists following normalization by a spatiallyconstrained null model. Conclusions:This study suggests that spatially-informed interictal network synchrony measures can distinguish between good and poor post-surgical outcomes. By capturing clinically relevant information during interictal periods, our method may ultimately reduce the need for prolonged invasive implants and provide insights into the pathophysiology of an epileptic brain. We discuss next steps for translating these findings into a prospectively useful clinical tool.

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“…However, the SOZ may not represent the full EZ extent, and its delineation requires the recording of several stereotyped seizures at the expense of considerable human and nancial resources 49 . Moreover, seizures are provoked through withdrawal of antiepileptic drugs and sleep deprivation 9 ; these seizures may be fundamentally different from the stereotypical spontaneous seizures of the patient and thus can misinform localization attempts 50 .…”

Section: Discussionmentioning

confidence: 99%

Functional connectivity discriminates epileptogenic states and predicts surgical outcome in children with drug resistant epilepsy

Rijal

Corona

Perry

et al. 2022

Preprint

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Normal brain functioning emerges from a complex interplay among regions forming networks. In epilepsy, these networks are disrupted causing seizures. Nodes of these networks are the target of epilepsy surgery. Here, we assess whether functional connectivity (FC) using intracranial electroencephalography (iEEG) can quantify epileptogenicity and predict surgical outcome in children with drug-resistant epilepsy (DRE). We computed Amplitude Envelope Correlation (AEC) and Phase Locking Value (PLV) for different states (i.e., interictal with no spikes, interictal with spikes, pre-ictal, ictal, and post-ictal) and for different frequency bands. We then computed each node’s strength (i.e., AEC or PLV at iEEG electrodes). We observed differences in nodal strength among the different states following a hierarchical epileptogenic organization: lower FC in interictal and pre-ictal states followed by higher FC values in ictal and post-ictal states (p < 0.05). We also observed higher nodal strength within resection for patients with good outcome (n = 22, Engel I), but not for poor outcome (n = 9, Engel II-IV), for all states (except ictal) and all bands (p < 0.05). Resection of hubs with high nodal strength was predictive of outcome (75–92% positive and 47–63% negative predictive values). Our findings suggest that FC can discriminate epileptogenic states and predict outcome in children with DRE.

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Focal Seizures Induced by Intracranial Electroencephalogram Grids

Cited by 4 publications

References 8 publications

High interictal connectivity within the resection zone is associated with favorable post-surgical outcomes in focal epilepsy patients

High interictal connectivity within the resection zone is associated with favorable post-surgical outcomes in focal epilepsy patients

High interictal connectivity within the resection zone is associated with favorable post-surgical outcomes in focal epilepsy patients

Functional connectivity discriminates epileptogenic states and predicts surgical outcome in children with drug resistant epilepsy

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