EpiTools, A software suite for presurgical brain mapping in epilepsy: Intracerebral EEG

Villalon, Samuel Médina; Paz, Rodrigo Manuel; Roehri, Nicolas; Lagarde, Stanislas; Pizzo, Francesca; Colombet, Bruno; Bartolomei, Fabricē; Carron, Romain; Bénar, Christian‐George

doi:10.1016/j.jneumeth.2018.03.018

Cited by 108 publications

(99 citation statements)

References 29 publications

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“…We defined the EZ using visual analysis complemented by a quantitative method (epileptogenicity index, for detail see Bartolomei et al). Location of electrodes was defined by visual analysis of pre‐SEEG MRI fused with the postoperative computed tomographic scan performed <24 hours after electrode implantation . We classified epilepsies into 12 subgroups: mesial temporal, lateral temporal, mesiolateral temporal, temporal plus (temporal and frontal and/or parietal and/or occipital and/or insular, bitemporal), prefrontal, those involving motor systems (central, premotor, or both), frontal plus (frontal and temporal and/or parietal and/or insular, bifrontal), operculoinsular, parietal, parietal plus (parietofrontal), occipital, and occipital plus (occipital and temporal and/or parietal) …”

Section: Methodsmentioning

confidence: 99%

The repertoire of seizure onset patterns in human focal epilepsies: Determinants and prognostic values

et al. 2018

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Objective: In this study, we seek to analyze the determinants of the intracranial electroencephalography seizure onset pattern (SOP) and the impact of the SOP in predicting postsurgical seizure outcome. Methods: To this end, we analyzed 820 seizures from 252 consecutive patients explored by stereo-electroencephalography (total of 2148 electrodes), including various forms of focal refractory epilepsies. We used a reproducible method combining visual and time-frequency analyses. Results: We described eight SOPs: low-voltage fast activity (LVFA), preictal spiking followed by LVFA, burst of polyspikes followed by LVFA, slow wave/ DC shift followed by LVFA, sharp theta/alpha waves, beta sharp waves, rhythmic spikes/spike-waves, and delta-brush. LVFA occurred in 79% of patients. The seizure onset pattern was significantly associated with (1) underlying etiology (burst of polyspikes followed by LVFA with the presence of a focal cortical dysplasia, LVFA with malformation of cortical development, postvascular and undetermined epilepsies), (2) spatial organization of the epileptogenic zone (EZ; burst of polyspikes followed by LVFA with focal organization, slow wave/DC shift followed by LVFA with network organization), and (3) postsurgical seizure outcome (better outcome when LVFA present). Significance: This study demonstrates that the main determinants of the SOP are the underlying etiology and the spatial organization of the EZ. Concerning the postsurgical seizure outcome, the main determinant factor is the spatial organization of the EZ, but the SOP plays also a role, conferring better prognosis when LVFA is present. K E Y W O R D S epilepsy, epilepsy surgery, epileptogenic zone, focal drug-resistant epilepsy, SEEG, seizure onset | 85 SUPPORTING INFORMATION Additional supporting information may be found online in the Supporting Information section at the end of the article. How to cite this article: Lagarde S, Buzori S, Trebuchon A, et al. The repertoire of seizure onset patterns in human focal epilepsies: Determinants and prognostic values. Epilepsia. 2019;60:85-95.

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Section: Methodsmentioning

confidence: 99%

The repertoire of seizure onset patterns in human focal epilepsies: Determinants and prognostic values

et al. 2018

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“…SEEG exploration was performed using intracerebral multiple contacts electrodes (Dixi Medical or Alcis; 10–15 contacts, length: 2mm, diameter: 0.8mm, 1.5mm apart) placed intracranially according to Talairach stereotactic method (Fig ) . Postoperative computed tomography (CT) scan and pre‐operative MRI scan data were fused in order to accurately locate each contact along the electrode trajectory . Signals were recorded on a 128‐ or 256‐channel system (Natus/Deltamed TM) sampled at 512Hz (1 patient), 1,024Hz (7 patients), or 2,048Hz (12 patients) and recorded on a hard disk (16 bits/sample) using no digital filter.…”

Section: Methodsmentioning

confidence: 99%

Hippocampal Interictal Spikes during Sleep Impact Long‐Term Memory Consolidation

Lambert

Tramoni-Negre

Lagarde

et al. 2020

Annals of Neurology

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Objective: Non-rapid eye movement (NREM) sleep is supposed to play a key role in long-term memory consolidation transferring information from hippocampus to neocortex. However, sleep also activates epileptic activities in medial temporal regions. This study investigated whether interictal hippocampal spikes during sleep would impair long-term memory consolidation. Method: We prospectively measured visual and verbal memory performance in 20 patients with epilepsy investigated with stereoelectroencephalography (SEEG) at immediate, 30-minute, and 1-week delays, and studied the correlations between interictal hippocampal spike frequency during waking and the first cycle of NREM sleep and memory performance, taking into account the number of seizures occurring during the consolidation period and other possible confounding factors, such as age and epilepsy duration. Results: Retention of verbal memory over 1 week was negatively correlated with hippocampal spike frequency during sleep, whereas no significant correlation was found with hippocampal interictal spikes during waking. No significant result was found for visual memory. Regression tree analysis showed that the number of seizures was the first factor that impaired the verbal memory retention between 30 minutes and 1 week. When the number of seizures was below 5, spike frequency during sleep higher than 13 minutes was associated with impaired memory retention over 1 week. Interpretation: Our results show that activation of interictal spikes in the hippocampus during sleep and seizures specifically impair long-term memory consolidation. We hypothesize that hippocampal interictal spikes during sleep interrupt hippocampal-neocortical transfer of information.

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“…We first selected a subset of all stereotactic-EEG channels. To this purpose, we co-registered pre-implantation MRI and postimplantation CT (using the maximization of normalized mutual information and trilinear interpolation) (Medina Villalon et al, 2018) and visually defined the anatomical area using the Mai et al (2015) atlas. First, we selected only the contacts within the grey matter, because the exact origin of the signal recorded in white matter is not well understood.…”

Section: Functional Connectivity Analysismentioning

confidence: 99%

Interictal stereotactic-EEG functional connectivity in refractory focal epilepsies

Lagarde

Roehri

Lambert

et al. 2018

Brain

149

138

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Drug-refractory focal epilepsies are network diseases associated with functional connectivity alterations both during ictal and interictal periods. A large majority of studies on the interictal/resting state have focused on functional MRI-based functional connectivity. Few studies have used electrophysiology, despite its high temporal capacities. In particular, stereotactic-EEG is highly suitable to study functional connectivity because it permits direct intracranial electrophysiological recordings with relative large-scale sampling. Most previous studies in stereotactic-EEG have been directed towards temporal lobe epilepsy, which does not represent the whole spectrum of drug-refractory epilepsies. The present study aims at filling this gap, investigating interictal functional connectivity alterations behind cortical epileptic organization and its association with post-surgical prognosis. To this purpose, we studied a large cohort of 59 patients with malformation of cortical development explored by stereotactic-EEG with a wide spatial sampling (76 distinct brain areas were recorded, median of 13.2 per patient). We computed functional connectivity using non-linear correlation. We focused on three zones defined by stereotactic-EEG ictal activity: the epileptogenic zone, the propagation zone and the non-involved zone. First, we compared within-zone and between-zones functional connectivity. Second, we analysed the directionality of functional connectivity between these zones. Third, we measured the associations between functional connectivity measures and clinical variables, especially post-surgical prognosis. Our study confirms that functional connectivity differs according to the zone under investigation. We found: (i) a gradual decrease of the within-zone functional connectivity with higher values for epileptogenic zone and propagation zone, and lower for non-involved zones; (ii) preferential coupling between structures of the epileptogenic zone; (iii) preferential coupling between epileptogenic zone and propagation zone; and (iv) poorer post-surgical outcome in patients with higher functional connectivity of non-involved zone (within- non-involved zone, between non-involved zone and propagation zone functional connectivity). Our work suggests that, even during the interictal state, functional connectivity is reinforced within epileptic cortices (epileptogenic zone and propagation zone) with a gradual organization. Moreover, larger functional connectivity alterations, suggesting more diffuse disease, are associated with poorer post-surgical prognosis. This is consistent with computational studies suggesting that connectivity is crucial in order to model the spatiotemporal dynamics of seizures.10.1093/brain/awy214_video1awy214media15833456182001.

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EpiTools, A software suite for presurgical brain mapping in epilepsy: Intracerebral EEG

Abstract: EpiTools can help speeding up the interpretation of SEEG data and improving its precision.

Cited by 108 publications

References 29 publications

The repertoire of seizure onset patterns in human focal epilepsies: Determinants and prognostic values

The repertoire of seizure onset patterns in human focal epilepsies: Determinants and prognostic values

Hippocampal Interictal Spikes during Sleep Impact Long‐Term Memory Consolidation

Interictal stereotactic-EEG functional connectivity in refractory focal epilepsies

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