Brief potentially ictal rhythmic discharges and paroxysmal fast activity as scalp electroencephalographic biomarkers of seizure activity and seizure onset zone

Low-voltage fast (LVF)- and hypersynchronous (HYP)-seizure onset patterns can be recognized in the EEG of epileptic animals and patients with temporal lobe epilepsy. Ripples (80–200 Hz) and fast ripples (250–500 Hz) have been linked to each pattern, with ripples predominating during LVF seizures and fast ripples predominating during HYP seizures in the rat pilocarpine model. This evidence led us to hypothesize that these two seizure-onset patterns reflect the contribution of neural networks with distinct transmitter signaling characteristics. Here, we tested this hypothesis by analyzing the seizure activity induced with the K+ channel blocker 4-aminopyridine (4AP, 4–5 mg/kg ip), which enhances both glutamatergic and GABAergic transmission, or the GABAA receptor antagonist picrotoxin (3–5 mg/kg ip); rats were implanted with electrodes in the hippocampus, the entorhinal cortex, and the subiculum. We found that LVF onset occurred in 82% of 4AP-induced seizures whereas seizures after picrotoxin were always HYP. In addition, high-frequency oscillation analysis revealed that 4AP-induced LVF seizures were associated with higher ripple rates compared with fast ripples ( P < 0.05), whereas picrotoxin-induced seizures contained higher rates of fast ripples compared with ripples ( P < 0.05). These results support the hypothesis that two distinct patterns of seizure onset result from different pathophysiological mechanisms.

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Erratum to “Semiology of temporal lobe epilepsy in children and adolescents. Value in lateralizing the seizure onset zone”

Epilepsy Research ◽

10.1016/s0920-1211(02)00082-7 ◽

2002 ◽

Vol 51 (1-2) ◽

pp. 211

Author(s):

Achim Olbrich ◽

Lydia Urak ◽

Gudrun Gröppel ◽

Wolfgang Serles ◽

Klaus Novak ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Children And Adolescents ◽

Temporal Lobe ◽

Seizure Onset ◽

Seizure Onset Zone

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Temporal Pattern of Ripple Events in Temporal Lobe Epilepsy: Towards a Pattern-based Localization of the Seizure Onset Zone

2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) ◽

10.1109/embc.2018.8512742 ◽

2018 ◽

Cited By ~ 1

Author(s):

Stefan L. Sumsky ◽

Sabato Santaniello

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Temporal Pattern ◽

Seizure Onset ◽

Seizure Onset Zone

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Slowing less than 1 Hz is decreased near the seizure onset zone

Scientific Reports ◽

10.1038/s41598-019-42347-y ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Brian Nils Lundstrom ◽

Melanie Boly ◽

Robert Duckrow ◽

Hitten P. Zaveri ◽

Hal Blumenfeld

Keyword(s):

Seizure Onset ◽

Seizure Onset Zone

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The proportion of seizure onset zone contacts resected is not associated with outcome following SEEG-guided resective epilepsy surgery in children

10.1101/2021.09.18.21263722 ◽

2021 ◽

Author(s):

Mehdi Khan ◽

Aswin Chari ◽

Kiran Seunarine ◽

Christin Eltze ◽

Friederike Moeller ◽

...

Keyword(s):

Epilepsy Surgery ◽

Univariate Analysis ◽

Seizure Outcome ◽

Epileptogenic Zone ◽

Imaging Data ◽

Seizure Onset ◽

Binary Logistic Regression Model ◽

Primary Analysis ◽

Seizure Onset Zone

AbstractPurposeChildren undergoing stereoelectroencephalography (SEEG)-guided epilepsy surgery represent a complex cohort. We aimed to determine whether the proportion of putative seizure onset zone (SOZ) contacts resected associates with seizure outcome in a cohort of children undergoing SEEG-guided resective epilepsy surgery.MethodsPatients who underwent SEEG-guided resective surgery over a six-year period were included. The proportion of SOZ contacts resected was determined by co-registration of pre- and post-operative imaging. Seizure outcomes were classified as seizure free (SF, Engel class I) or not seizure-free (NSF, Engel class II-IV) at last clinical follow-up.ResultsOf 94 patients undergoing SEEG, 29 underwent subsequent focal resection of whom 22 had sufficient imaging data to be included in the primary analysis (median age at surgery of 10 years, range 5-18). Fifteen (68.2%) were SF and 7 (31.8%) NSF at median follow-up of 19.5 months (range 12-46). On univariate analysis, histopathology, was the only significant factor associated with SF (p<0.05). The percentage of defined SOZ contacts resected ranged from 25-100% and was not associated with SF (p=0.89). In a binary logistic regression model, it was highly likely that histology was the only independent predictor of outcome, although the interpretation was limited by pseudo-complete separation of the data.ConclusionHistopathology is a significant predictor of surgical outcomes in children undergoing SEEG-guided resective epilepsy surgery. The percentage of SOZ contacts resected was not associated with SF. Factors such as spatial organisation of the epileptogenic zone, neurophysiological biomarkers and the prospective identification of pathological tissue may therefore play an important role.

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