Epileptogenic networks in nodular heterotopia: A stereoelectroencephalography study

Pizzo, Francesca; Roehri, Nicolas; Catenoix, Hélène; Medina, Sixtina Gil Diez de; McGonigal, Aileen; Giusiano, Bernard; Carron, Romain; Scavarda, Didier; Ostrowsky, Karine; Lépine, Anne; Boulogne, Sébastien; Scholly, Julia; Hirsch, Édouard; Rheims, Sylvain; Bénar, Christian‐George; Bartolomei, Fabricē

doi:10.1111/epi.13919

Cited by 69 publications

(103 citation statements)

References 39 publications

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“…Insular epilepsy in patient 2. (A) SEEG recordings of entry or target cortex in one seizure episode, including insular cortex, opercular cortex, mesial frontal cortex (SMA and ACC) and OFC; (B) EI map of the same seizure event presents the increased ER at the ictal onset (from blue to yellow scale) and the detection parameters (circle, alarm time; cross, detection time) 15,16 in each chosen channel. The map showed that the middle and posterior insular short gyri were highly epileptogenic; (C) mean highest EI value of insular cortex, operculum and SMA in two seizure episodes; (D) frequency-specific (40-180 Hz) epileptogenicity maps were used here to show the cortical distribution of high frequency oscillation at the seizure onset (the map here was used to show the involvement of insular and opercular cortex in the present case, with mean T score (color scale) in two seizure episodes.…”

Section: Resultsmentioning

confidence: 99%

“…In this context, the present PET analysis showed that the ventral rolandic cortex was significantly hypometabolic in patients with insulo-opercular epilepsy, which is of interest given the tendency to observe facio-cervical ictal motor signs. We also observed 15,16 in each chosen channel. The map showed that PSG, ALG, PLG and posterior central operculum were highly epileptogenic; (C) mean highest EI value of insular cortex, operculum, and SMA in two seizure episodes; (D) frequency-specific (80-200 Hz) epileptogenicity maps were used here to show the cortical distribution of high-frequency oscillation at the seizure onset (the map here was used to show the involvement of the insular and opercular cortex in the present case, with mean T score (color scale) in two seizure episodes.…”

Section: Discussionmentioning

confidence: 99%

“…3 From an epileptological point of view, it seems useful to consider the insulo-opercular zones as an integrated system and accordingly, particular consideration should be given to sampling both insular and opercular cortices when attempting to define the epileptogenic zone. SEEG is thus a particularly valuable approach for evaluation of insulo-opercular epilepsy: orthogonal trajectories allow exploration of opercula and 15,16 in each chosen channel. The map showed that the posterior central operculum and opercular part of central sulcus were highly epileptogenic; (C) mean highest EI value of insular cortex, operculum and SMA in two seizure episodes; (D) frequency-specific (60-180 Hz) epileptogenicity maps were used here to show the cortical distribution of high-frequency oscillation at the seizure onset (the map here was used to show the involvement of the insular and opercular cortex in the present case, with mean T score (color scale) in two seizure episodes.…”

Section: Discussionmentioning

confidence: 99%

“…SEEG exploration was performed using intracerebral multiple contact electrodes (Huake Hengsheng [China, [8][9][10][11][12][13][14][15][16] contacts] or Alcis [France, 10-15 contacts], length: 2 mm, diameter: 0.8 mm, 1.5 mm apart) placed through a CRW stereotactic frame. Long-term recordings were performed after implantation using a NIHON KOHDEN video-EEG monitoring system.…”

Section: Seeg Acquisition and Data Analysismentioning

confidence: 99%

“…The EI was to quantify the epileptogenicity of brain structures, and has been previously described in detail. 15,16 In brief, the EI is a normalized quantity ranging from 0 (no epileptogenicity) to 1 (maximal epileptogenicity). The EI combines two pieces of information into a single quantity: (i) the generation of a rapid discharge estimated by signal energy ratio (ER) between high (beta [12][13][14][15][16][17][18][19][20][21][22][23][24], gamma ) and low (theta [4-7.4 Hz] and alpha [7.4-12 Hz]) frequency bands, (ii) change-points in the ER[n] quantity.…”

Section: Seeg Acquisition and Data Analysismentioning

confidence: 99%

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Electroclinical features of insulo‐opercular epilepsy: an SEEG and PET study

Wang

McGonigal

et al. 2019

Ann Clin Transl Neurol

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Objective To report clinical experience with presurgical evaluation in patients with insulo‐opercular epilepsy. Quantitative analysis on PET imaging and stereoelectroencephalography (SEEG) signals was used to summarize their electroclinical features. Methods Twenty‐two patients with focal epilepsy arising from the insular and/or opercular cortex according to SEEG were retrospectively analyzed. Presurgical noninvasive data were analyzed in detail. Interictal PET data of patients were then statistically compared with those of healthy controls to identify the interictal hypometabolic network. The epileptogenicity index (EI) of ictal SEEG signal was computed to identify areas of spread at the beginning of seizure onset. Results Focal tonic seizures of the face and/or neck (16/22, 73%) were the most prevalent early objective signs. Epileptic discharges in the interictal and ictal scalp‐EEG mostly showed an ipsilateral perisylvian distribution. Statistical analysis of interictal PET showed significant hypometabolism in the insular lobe, central operculum, supplementary motor area, middle cingulate cortex, bilateral caudate nuclei, and putamen. According to the EI analysis, insulo‐opercular epilepsy could be classified as insulo‐opercular epilepsy (50%), opercular epilepsy (41%), and insular cortex epilepsy (9%). Significance Clinical diagnosis of insulo‐opercular epilepsy is challenging because of its complex seizure semiology and nonlocalizing discharges on scalp‐EEG. A common hypometabolic network involving the insulo‐opercular cortex, mesial frontal cortex and subcortical nuclei may be involved in the organization of the insulo‐opercular epilepsy network. Furthermore, quantified SEEG analysis suggested that pure insular epilepsy is rare, and the close connection between insular and opercular cortex necessitates SEEG implantation to define the epileptogenic zone.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Seeg Acquisition and Data Analysismentioning

confidence: 99%

Section: Seeg Acquisition and Data Analysismentioning

confidence: 99%

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Electroclinical features of insulo‐opercular epilepsy: an SEEG and PET study

Wang

McGonigal

et al. 2019

Ann Clin Transl Neurol

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Internodular functional connectivity in heterotopia‐related epilepsy

Khoo

Ellenrieder

Zazubovits

et al. 2019

Ann Clin Transl Neurol

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Objective A vast network involving the nodules and overlying cortices is believed to be responsible for the epileptogenicity in gray matter heterotopia with multiple nodules, which often associated with difficult‐to‐treat epilepsy. We sought to determine if functional magnetic resonance imaging (fMRI) could detect internodular functional connectivity (FC), and if this connectivity reflects an actual synchronized neuronal activity and partakes in epileptogenicity. Methods We studied 16 epilepsy patients with multiple heterotopic nodules; eight underwent subsequent intracerebral EEG. We examined the internodular FC using fMRI and its correspondence with internodular synchrony of intracerebral interictal activity. We then compared the spreading speed of ictal activity between connected and unconnected nodules; and the FC among possible combinations of nodule pairs in terms of their involvement at seizure onset. Results Seventy nodules were studied: 83% have significant connection to at least one other nodule. Among the 49 pairs studied with intracerebral EEG, (1) synchronized interictal activity is more prevalent in fMRI‐connected pairs (P < 0.05), (2) ictal activity spreads faster between connected pairs (P < 0.0001), and (3) stronger FC was observed between pairs in which both nodules were involved at seizure onset (P < 0.01). Interpretation fMRI could reliably and noninvasively detect the FC between heterotopic nodules. These functional connections correspond to the synchrony of interictal epileptic activity between the nodules and to the ability of nodules to generate synchronous seizure onsets or rapid seizure spread. These findings may help in understanding the complexity of the epileptogenic network in multiple heterotopic nodules and better targeting the likely epileptogenic nodules.

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Laser Ablation of Periventricular Nodular Heterotopia for Medically Refractory Epilepsy

McCormack,

Chandran,

Lhatoo

et al. 2024

Annals of Neurology

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ObjectivePeriventricular nodular heterotopia (PVNH) is the most common neuronal heterotopia, frequently resulting in pharmaco‐resistant epilepsy. Here, we characterize variables that predict good epilepsy outcomes following surgical intervention using stereo‐electroencephalography (SEEG) ‐informed magnetic resonance‐guided laser interstitial thermal therapy (MRgLITT).MethodsA retrospective review of consecutive cases from a single high‐volume epilepsy referral center identified patients who underwent SEEG evaluation for PVNH to characterize the intervention and outcomes.ResultsThirty‐nine patients underwent SEEG‐guided MRgLITT of the seizure onset zone (SoZ) in PVNH and associated epileptic tissue. PVNH and polymicrogyria (PMG) were densely sampled with a mean of 16.5 (SD = 2)/209.4 (SD = 36.9) SEEG probes/recording contacts per patient. Ablation principally targeted just the PVNH and cortex that was abnormal on imaging was ablated (5 patients) only if implicated in the SoZ. Volumetric analyses revealed a high percentage of PVNH SoZ ablation (96.6%, SD = 5.3%) in unilateral and bilateral (92.9%, SD = 7.2%) cases. Mean follow‐up duration was 31.4 months (SD = 20.9). Seizure freedom (ILAE 1) was excellent: unilateral PVNH without other imaging abnormalities, 80%; PVNH with mesial temporal sclerosis (MTS) or PMG, 63%; bilateral PVNH, 50%. SoZ ablation percentage significantly impacted surgical outcomes (p < 0.001).InterpretationPVNH plays a central role in seizure genesis as revealed by dense recordings and selective targeting by LITT. MRgLITT represents a transformative technological advance in PVNH‐associated epilepsy with seizure control outcomes consistent with those seen in focal lesional epilepsies. In localized unilateral cases and otherwise normal imaging, PVNH ablation without invasive recordings may be considered, and this approach deserves to be explored further. ANN NEUROL 2024

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Epileptogenic networks in nodular heterotopia: A stereoelectroencephalography study

Cited by 69 publications

References 39 publications

Electroclinical features of insulo‐opercular epilepsy: an SEEG and PET study

Electroclinical features of insulo‐opercular epilepsy: an SEEG and PET study

Internodular functional connectivity in heterotopia‐related epilepsy

Laser Ablation of Periventricular Nodular Heterotopia for Medically Refractory Epilepsy

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