Spike patterns surrounding sleep and seizures localize the seizure‐onset zone in focal epilepsy

Conrad, Erin C.; Revell, Andrew Y; Greenblatt, Adam; Gallagher, Ryan S; Pattnaik, Akash R; Hartmann, Nicole; Gugger, James J; Shinohara, Russell T.; Litt, Brian; Marsh, Eric D.; Davis, Kathryn A.

doi:10.1111/epi.17482

Cited by 25 publications

(13 citation statements)

References 53 publications

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“…Interictal activity is consistently recorded in most patients with epilepsy and experimental models. Interictal activity is also brain state‐dependent, with a higher occurrence rate during NREM than in REM or wake 10 . Although interictal activity is regulated in a circadian pattern in a patient‐specific manner, 3,4 a high spike rate does not necessarily correlate with an increased seizure probability during the night and day cycle; they can even be in anti‐phase 3,4 .…”

Section: Sleep Wake and Seizuresmentioning

confidence: 99%

“…Interictal activity is also brain state-dependent, with a higher occurrence rate during NREM than in REM or wake. 10 Although interictal activity is regulated in a circadian pattern in a patient-specific manner, 3,4 a high spike rate does not necessarily correlate with an increased seizure probability during the night and day cycle; they can even be in anti-phase. 3,4 Similar findings in terms of circadian regulation of interictal activity have been found in rodent models of epilepsy.…”

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confidence: 99%

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Sleep, oscillations, and epilepsy

et al. 2023

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Sleep and wake are defined through physiological and behavioral criteria and can be typically separated into non‐rapid eye movement (NREM) sleep stages N1, N2, and N3, rapid eye movement (REM) sleep, and wake. Sleep and wake states are not homogenous in time. Their properties vary during the night and day cycle. Given that brain activity changes as a function of NREM, REM, and wake during the night and day cycle, are seizures more likely to occur during NREM, REM, or wake at a specific time? More generally, what is the relationship between sleep–wake cycles and epilepsy? We will review specific examples from clinical data and results from experimental models, focusing on the diversity and heterogeneity of these relationships. We will use a top‐down approach, starting with the general architecture of sleep, followed by oscillatory activities, and ending with ionic correlates selected for illustrative purposes, with respect to seizures and interictal spikes. The picture that emerges is that of complexity; sleep disruption and pathological epileptic activities emerge from reorganized circuits. That different circuit alterations can occur across patients and models may explain why sleep alterations and the timing of seizures during the sleep–wake cycle are patient‐specific.

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Section: Sleep Wake and Seizuresmentioning

confidence: 99%

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confidence: 99%

Sleep, oscillations, and epilepsy

et al. 2023

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“…44,45 In line with these investigations, Conrad et al explored whether sleep and seizure-related changes in spikes allow for localization of the seizure-onset zone. 46 Bou Assi et al explored functional connectivity (in terms of phase-locking value) during interictal spikes and showed a decrease in global connectivity (in the gamma frequency band) time-locked to the spike peak. 47 Authors reported that functional connectivity was lower within the epileptic focus than outside the focus.…”

Section: Intracranial Eeg Recordingsmentioning

confidence: 99%

“…More recently, subpopulations of spikes were investigated based on features such as spike rate, line length, skewness of the spike distribution, and energy for the prediction of surgical outcomes 44,45 . In line with these investigations, Conrad et al explored whether sleep and seizure‐related changes in spikes allow for localization of the seizure‐onset zone 46 . Bou Assi et al explored functional connectivity (in terms of phase‐locking value) during interictal spikes and showed a decrease in global connectivity (in the gamma frequency band) time‐locked to the spike peak 47 .…”

Section: Recent Advances In Quantitative Eeg Analysismentioning

confidence: 99%

From basic sciences and engineering to epileptology: A translational approach

et al. 2023

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Collaborative efforts between basic scientists, engineers, and clinicians are enabling translational epileptology. In this article, we summarize the recent advances presented at the International Conference for Technology and Analysis of Seizures (ICTALS 2022): (1) novel developments of structural magnetic resonance imaging; (2) latest electroencephalography signal‐processing applications; (3) big data for the development of clinical tools; (4) the emerging field of hyperdimensional computing; (5) the new generation of artificial intelligence (AI)–enabled neuroprostheses; and (6) the use of collaborative platforms to facilitate epilepsy research translation. We highlight the promise of AI reported in recent investigations and the need for multicenter data‐sharing initiatives.

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“…We additionally replicated this analysis with interictal epochs that were matched for state of wakefulness (see supplementary information). Briefly, bivariate features from each preictal epoch were normalized by those from ten interictal epochs with similar states of wakefulness (measured as alpha-delta ratio [40]) instead of 20 awake interictal epochs. At the group level, we refit a linear mixed effects model with the median absolute z scores and compared the outputs of the linear mixed effects models from the supplementary analysis (figure S7(A)) with the main text result (figure 4(A)).…”

Section: Deviations In Preictal Ieeg Network Node Strength From Basel...mentioning

confidence: 99%

The seizure severity score: a quantitative tool for comparing seizures and their response to therapy

Pattnaik,

Ghosn,

Ong

et al. 2023

J. Neural Eng.

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Objective: Epilepsy is a neurological disorder characterized by recurrent seizures which vary widely in severity, from clinically silent to prolonged convulsions. Measuring severity is crucial for guiding therapy, particularly when complete control is not possible. Seizure diaries, the current standard for guiding therapy, are insensitive to the duration of events or the propagation of seizure activity across the brain. We present a quantitative seizure severity score that incorporates EEG and clinical data and demonstrate how it can guide epilepsy therapies.Approach: We collected intracranial EEG and clinical semiology data from 54 epilepsy patients who had 256 seizures during invasive, in-hospital presurgical evaluation. We applied an absolute slope algorithm to EEG recordings to identify seizing channels. From this data, we developed a seizure severity score that combines seizure duration, spread, and semiology using non-negative matrix factorization. For validation, we assessed its correlation with independent measures of epilepsy burden: seizure types, epilepsy duration, a pharmacokinetic model of medication load, and response to epilepsy surgery. We investigated the association between the seizure severity score and pre-ictal network features.Main results: The seizure severity score augmented clinical classification by objectively delineating seizure duration and spread from recordings in available electrodes. Lower preictal medication loads were associated with higher seizure severity scores (p = 0.018, 97.5% CI = [-1.242, -0.116]) and lower pre-surgical severity was associated with better surgical outcome (p = 0.042). In 85% of patients with multiple seizure types, greater preictal change from baseline was associated with higher severity.Significance: We present a quantitative measure of seizure severity that includes EEG and clinical features, validated on gold standard in-patient recordings. We provide a framework for extending our tool’s utility to ambulatory EEG devices, for linking it to seizure semiology measured by wearable sensors, and as a tool to advance data-driven epilepsy care.

show abstract

Spike patterns surrounding sleep and seizures localize the seizure‐onset zone in focal epilepsy

Cited by 25 publications

References 53 publications

Sleep, oscillations, and epilepsy

Sleep, oscillations, and epilepsy

From basic sciences and engineering to epileptology: A translational approach

The seizure severity score: a quantitative tool for comparing seizures and their response to therapy

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