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Bolzan A, Benoit J, Pizzo F, Makhalova J, Villeneuve N, Carron R, Scavarda D, Bartolomei F, Lagarde S. Correspondence between scalp-EEG and stereoelectroencephalography seizure-onset patterns in patients with MRI-negative drug-resistant focal epilepsy. Epilepsia Open 2024; 9:568-581. [PMID: 38148028 PMCID: PMC10984298 DOI: 10.1002/epi4.12886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 11/28/2023] [Accepted: 12/14/2023] [Indexed: 12/28/2023] Open
Abstract
OBJECTIVE Our objective was to evaluate the relationship between scalp-EEG and stereoelectroencephalography (SEEG) seizure-onset patterns (SOP) in patients with MRI-negative drug-resistant focal epilepsy. METHODS We analyzed retrospectively 41 patients without visible lesion on brain MRI who underwent video-EEG followed by SEEG. We defined five types of SOPs on scalp-EEG and eight types on SEEG. We examined how various clinical variables affected scalp-EEG SOPs. RESULTS The most prevalent scalp SOPs were rhythmic sinusoidal activity (56.8%), repetitive epileptiform discharges (22.7%), and paroxysmal fast activity (15.9%). The presence of paroxysmal fast activity on scalp-EEG was always seen without delay from clinical onset and correlated with the presence of low-voltage fast activity in SEEG (sensitivity = 22.6%, specificity = 100%). The main factor explaining the discrepancy between the scalp and SEEG SOPs was the delay between clinical and scalp-EEG onset. There was a correlation between the scalp and SEEG SOPs when the scalp onset was simultaneous with the clinical onset (p = 0.026). A significant delay between clinical and scalp discharge onset was observed in 25% of patients and featured always with a rhythmic sinusoidal activity on scalp, corresponding to similar morphology of the discharge on SEEG. The presence of repetitive epileptiform discharges on scalp was associated with an underlying focal cortical dysplasia (sensitivity = 30%, specificity = 90%). There was no significant association between the scalp SOP and the epileptogenic zone location (deep or superficial), or surgical outcome. SIGNIFICANCE In patients with MRI-negative focal epilepsy, scalp SOP could suggest the SEEG SOP and some etiology (focal cortical dysplasia) but has no correlation with surgical prognosis. Scalp SOP correlates with the SEEG SOP in cases of simultaneous EEG and clinical onset; otherwise, scalp SOP reflects the propagation of the SEEG discharge. PLAIN LANGUAGE SUMMARY We looked at the correspondence between the electrical activity recorded during the start of focal seizure using scalp and intracerebral electrodes in patients with no visible lesion on MRI. If there is a fast activity on scalp, it reflects similar activity inside the brain. We found a good correspondence between scalp and intracerebral electrical activity for cases without significant delay between clinical and scalp electrical onset (seen in 75% of the cases we studied). Visualizing repetitive epileptic activity on scalp could suggest a particular cause of the epilepsy: a subtype of brain malformation called focal cortical dysplasia.
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Affiliation(s)
- Anna Bolzan
- APHM, Timone Hospital, Epileptology and Cerebral RhythmologyMarseilleFrance
| | - Jeanne Benoit
- CHU de Nice, Epileptology DepartmentUniversité Côte d'Azur, UMR2CA (URRIS)NiceFrance
| | - Francesca Pizzo
- APHM, Timone Hospital, Epileptology and Cerebral RhythmologyMarseilleFrance
- Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance
| | - Julia Makhalova
- APHM, Timone Hospital, Epileptology and Cerebral RhythmologyMarseilleFrance
- Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance
- APHM, Timone Hospital, CEMEREMMarseilleFrance
| | | | - Romain Carron
- Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance
- APHM, Timone Hospital, Stereotactic and Functional Neurosurgery, Gamma UnitMarseilleFrance
| | - Didier Scavarda
- Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance
- APHM, Timone Hospital, Paediatric NeurosurgeryMarseilleFrance
| | - Fabrice Bartolomei
- APHM, Timone Hospital, Epileptology and Cerebral RhythmologyMarseilleFrance
- Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance
| | - Stanislas Lagarde
- APHM, Timone Hospital, Epileptology and Cerebral RhythmologyMarseilleFrance
- Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance
- University Hospitals of Geneva (HUG), University of Geneva (UNIGE)GenevaSwitzerland
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Moradi N, Goodyear BG, Sotero RC. Deep EEG source localization via EMD-based fMRI high spatial frequency. PLoS One 2024; 19:e0299284. [PMID: 38427616 PMCID: PMC10906834 DOI: 10.1371/journal.pone.0299284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 02/07/2024] [Indexed: 03/03/2024] Open
Abstract
Brain imaging with a high-spatiotemporal resolution is crucial for accurate brain-function mapping. Electroencephalography (EEG) and functional Magnetic Resonance Imaging (fMRI) are two popular neuroimaging modalities with complementary features that record brain function with high temporal and spatial resolution, respectively. One popular non-invasive way to obtain data with both high spatial and temporal resolutions is to combine the fMRI activation map and EEG data to improve the spatial resolution of the EEG source localization. However, using the whole fMRI map may cause spurious results for the EEG source localization, especially for deep brain regions. Considering the head's conductivity, deep regions' sources with low activity are unlikely to be detected by the EEG electrodes at the scalp. In this study, we use fMRI's high spatial-frequency component to identify the local high-intensity activations that are most likely to be captured by the EEG. The 3D Empirical Mode Decomposition (3D-EMD), a data-driven method, is used to decompose the fMRI map into its spatial-frequency components. Different validation measurements for EEG source localization show improved performance for the EEG inverse-modeling informed by the fMRI's high-frequency spatial component compared to the fMRI-informed EEG source-localization methods. The level of improvement varies depending on the voxels' intensity and their distribution. Our experimental results also support this conclusion.
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Affiliation(s)
- Narges Moradi
- Biomedical Engineering Department, University of Calgary, Calgary, AB, Canada
- Department of Radiology, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Bradley G. Goodyear
- Department of Radiology, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Roberto C. Sotero
- Department of Radiology, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
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Fahimi Hnazaee M, Wittevrongel B, Khachatryan E, Libert A, Carrette E, Dauwe I, Meurs A, Boon P, Van Roost D, Van Hulle MM. Localization of deep brain activity with scalp and subdural EEG. Neuroimage 2020; 223:117344. [PMID: 32898677 DOI: 10.1016/j.neuroimage.2020.117344] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 07/27/2020] [Accepted: 08/31/2020] [Indexed: 01/11/2023] Open
Abstract
To what extent electrocorticography (ECoG) and electroencephalography (scalp EEG) differ in their capability to locate sources of deep brain activity is far from evident. Compared to EEG, the spatial resolution and signal-to-noise ratio of ECoG is superior but its spatial coverage is more restricted, as is arguably the volume of tissue activity effectively measured from. Moreover, scalp EEG studies are providing evidence of locating activity from deep sources such as the hippocampus using high-density setups during quiet wakefulness. To address this question, we recorded a multimodal dataset from 4 patients with refractory epilepsy during quiet wakefulness. This data comprises simultaneous scalp, subdural and depth EEG electrode recordings. The latter was located in the hippocampus or insula and provided us with our "ground truth" for source localization of deep activity. We applied independent component analysis (ICA) for the purpose of separating the independent sources in theta, alpha and beta frequency band activity. In all patients subdural- and scalp EEG components were observed which had a significant zero-lag correlation with one or more contacts of the depth electrodes. Subsequent dipole modeling of the correlating components revealed dipole locations that were significantly closer to the depth electrodes compared to the dipole location of non-correlating components. These findings support the idea that components found in both recording modalities originate from neural activity in close proximity to the depth electrodes. Sources localized with subdural electrodes were ~70% closer to the depth electrode than sources localized with EEG with an absolute improvement of around ~2cm. In our opinion, this is not a considerable improvement in source localization accuracy given that, for clinical purposes, ECoG electrodes were implanted in close proximity to the depth electrodes. Furthermore, the ECoG grid attenuates the scalp EEG, due to the electrically isolating silastic sheets in which the ECoG electrodes are embedded. Our results on dipole modeling show that the deep source localization accuracy of scalp EEG is comparable to that of ECoG. SIGNIFICANCE STATEMENT: Deep and subcortical regions play an important role in brain function. However, as joint recordings at multiple spatial scales to study brain function in humans are still scarce, it is still unresolved to what extent ECoG and EEG differ in their capability to locate sources of deep brain activity. To the best of our knowledge, this is the first study presenting a dataset of simultaneously recorded EEG, ECoG and depth electrodes in the hippocampus or insula, with a focus on non-epileptiform activity (quiet wakefulness). Furthermore, we are the first study to provide experimental findings on the comparison of source localization of deep cortical structures between invasive and non-invasive brain activity measured from the cortical surface.
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Affiliation(s)
| | - Benjamin Wittevrongel
- Laboratory for Neuro- and Psychophysiology, Department of Neurosciences, KU Leuven, Belgium
| | - Elvira Khachatryan
- Laboratory for Neuro- and Psychophysiology, Department of Neurosciences, KU Leuven, Belgium
| | - Arno Libert
- Laboratory for Neuro- and Psychophysiology, Department of Neurosciences, KU Leuven, Belgium
| | - Evelien Carrette
- Faculty of Medicine and Health Sciences, Ghent University Hospital, Ghent, Belgium
| | - Ine Dauwe
- Faculty of Medicine and Health Sciences, Ghent University Hospital, Ghent, Belgium
| | - Alfred Meurs
- Faculty of Medicine and Health Sciences, Ghent University Hospital, Ghent, Belgium
| | - Paul Boon
- Faculty of Medicine and Health Sciences, Ghent University Hospital, Ghent, Belgium
| | - Dirk Van Roost
- Faculty of Medicine and Health Sciences, Ghent University Hospital, Ghent, Belgium
| | - Marc M Van Hulle
- Laboratory for Neuro- and Psychophysiology, Department of Neurosciences, KU Leuven, Belgium
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Bandarabadi M, Gast H, Rummel C, Bassetti C, Adamantidis A, Schindler K, Zubler F. Assessing Epileptogenicity Using Phase-Locked High Frequency Oscillations: A Systematic Comparison of Methods. Front Neurol 2019; 10:1132. [PMID: 31749757 PMCID: PMC6842969 DOI: 10.3389/fneur.2019.01132] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 10/10/2019] [Indexed: 01/21/2023] Open
Abstract
High frequency oscillations (HFOs) are traditional biomarkers to identify the epileptogenic tissue during presurgical evaluation in pharmacoresistant epileptic patients. Recently, the resection of brain tissue exhibiting coupling between the amplitude of HFOs and the phase of low frequencies demonstrated a more favorable surgical outcome. Here we compare the predictive value of ictal HFOs and four methods for quantifying the ictal phase-amplitude coupling, namely mean vector length, phase-locked high gamma, phase locking value, and modulation index (MI). We analyzed 32 seizures from 16 patients to identify the channels that exhibit HFOs and phase-locked HFOs during seizures. We compared the resection ratio, defined as the percentage of channels exhibiting coupling located in the resected tissue, with the postsurgical outcome. We found that the MI is the only method to show a significant difference between the resection ratios of patients with good and poor outcomes. We further show that the whole seizure, not only the onset, is critical to assess epileptogenicity using the phase-locked HFOs. We postulate that the superiority of MI stems from its capacity to assess coupling of discrete HFO events and its independence from the HFO power. These results confirm that quantitative analysis of HFOs can boost presurgical evaluation and indicate the paramount importance of algorithm selection for clinical applications.
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Affiliation(s)
- Mojtaba Bandarabadi
- Department of Neurology, Sleep-Wake-Epilepsy Center, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland.,Department of Neurology, Center for Experimental Neurology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Heidemarie Gast
- Department of Neurology, Sleep-Wake-Epilepsy Center, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Christian Rummel
- Support Center for Advanced Neuroimaging (SCAN), University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Claudio Bassetti
- Department of Neurology, Sleep-Wake-Epilepsy Center, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland.,Department of Neurology, Center for Experimental Neurology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Antoine Adamantidis
- Department of Neurology, Sleep-Wake-Epilepsy Center, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland.,Department of Neurology, Center for Experimental Neurology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Kaspar Schindler
- Department of Neurology, Sleep-Wake-Epilepsy Center, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Frederic Zubler
- Department of Neurology, Sleep-Wake-Epilepsy Center, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
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Abstract
Electroencephalographic (EEG) investigations are crucial in the diagnosis and management of patients with focal epilepsies. EEG may reveal different interictal epileptiform discharges (IEDs: abnormal spikes, sharp waves). The EEG visibility of a spike depends on the surface area of cortex involved (>10cm2) and the brain localization of cortical generators. Regions generating IEDs (defining the "irritative zone") are not necessarily equivalent to the seizure onset zone. Focal seizures are dynamic processes originating from one or several brain regions (that generate fast oscillations and are called the epileptogenic zone) before spreading to other structures (that generate lower frequency oscillations and are called the propagation zone). Several factors limit the expression of seizures on scalp EEG, such as the area involved, degree of synchronization, and depth of the cortical generators. Different scalp EEG seizure onset patterns may be observed: fast discharge, background flattening, rhythmic spikes, sinusoidal discharge, or sharp activity. However, to a large extent EEG changes are linked to seizure propagation. Finally, in the context of presurgical evaluation, the combination of interictal and ictal EEG features is crucial to provide an optimal hypothesis concerning the epileptogenic zone.
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Affiliation(s)
- Stanislas Lagarde
- Institut de Neurosciences des Systèmes, Aix Marseille Université, Marseille, France; Department of Clinical Neurophysiology, Timone Hospital, Marseille, France
| | - Fabrice Bartolomei
- Institut de Neurosciences des Systèmes, Aix Marseille Université, Marseille, France; Department of Clinical Neurophysiology, Timone Hospital, Marseille, France.
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The Hippocampus and Cortex Together Generate the Scalp EEG Ictal Discharge in Temporal Lobe Epilepsy. J Clin Neurophysiol 2018; 34:448-455. [PMID: 28574952 DOI: 10.1097/wnp.0000000000000394] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
PURPOSE The scalp EEG ictal discharge in temporal lobe epilepsy is reportedly visible only after the intracranial discharge becomes well synchronized and present over 10 to 30 cm of cortex. We investigated the role of the hippocampal formation in the generation of the scalp EEG ictal discharge. METHODS Intracranial EEG video monitors were recorded using simultaneous scalp, stereotaxic depth, and subdural strip electrodes in 19 subjects with temporal lobe epilepsy. The location, frequency, morphology, and timing of the initial ictal discharge, and subsequent ictal patterns, were examined in hippocampal formation, medial paleocortex, and lateral temporal neocortex electrocorticographic and scalp temporal EEG recordings. RESULTS In every subject, a scalp ictal discharge was visible only after the intracranial ictal discharge had spread to involve the whole temporal lobe (hippocampal formation, medial paleocortex, and lateral temporal neocortex). Beta/gamma frequency and decremental electrocorticographic ictal discharges were never visualized in the EEG. The scalp EEG ictal discharge frequency was 2.4 to 10 Hz and appeared a median of 18 seconds after a faster frequency electrocorticographic initial ictal discharge, once the intracranial discharge slowed to an alpha, theta, or delta frequency. CONCLUSIONS In temporal lobe epilepsy, an ictal pattern is not readily visible in the scalp EEG until the intracranial ictal discharge is ≤10 Hz and has propagated from its site of onset to involve the hippocampus, medial paleocortex, and lateral temporal neocortex.
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7
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Roehri N, Pizzo F, McGonigal A, Bartolomei F, Bénar CG. Reply to "are spikes noninferior to high-frequency oscillations?". Ann Neurol 2018. [PMID: 29518267 DOI: 10.1002/ana.25200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Nicolas Roehri
- Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France
| | - Francesca Pizzo
- Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France
| | - Aileen McGonigal
- APHM, Timone hospital, Clinical Neurophysiology, Marseille, France
| | | | - Christian G Bénar
- Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France
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8
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Fan X, Gaspard N, Legros B, Lucchetti F, Ercek R, Nonclercq A. Dynamics underlying interictal to ictal transition in temporal lobe epilepsy: insights from a neural mass model. Eur J Neurosci 2018; 47:258-268. [PMID: 29282779 DOI: 10.1111/ejn.13812] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 11/27/2017] [Accepted: 12/18/2017] [Indexed: 12/15/2022]
Abstract
We propose an approach that combines a neural mass model and clinical intracranial electroencephalographic (iEEG) recordings to explore the potential pathophysiological mechanisms (at the neuronal population level) of ictogenesis. Thirty iEEG recordings from 10 temporal lobe epilepsy (TLE) patients around seizure onset were investigated. Physiologically meaningful parameters [average excitatory (Ae ), slow (B), and fast (G) inhibitory synaptic gain] were identified during interictal to ictal transition. Four ratios (Ae /G, Ae /B, Ae /(B + G), and B/G) were derived from these parameters, and their evolution over time was analyzed. The excitation/inhibition ratio increased around seizure onset and decreased before seizure offset, indicating the impairment and re-emergence of excitation/inhibition balance around seizure onset and before seizure offset, respectively. Moreover, the slow inhibition may have an earlier effect on excitation/inhibition imbalance. We confirm the decrease in excitation/inhibition ratio upon seizure termination in human temporal lobe epilepsy, as revealed by optogenetic approaches both in vivo in animal models and in vitro. The increase in excitation/inhibition ratio around seizure occurrence could be an indicator to detect seizures.
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Affiliation(s)
- Xiaoya Fan
- Bio, Electro And Mechanical Systems (BEAMS), Université Libre de Bruxelles (ULB), Avenue F.D. Roosevelt 50 CP165/56, 1050, Brussels, Belgium
| | - Nicolas Gaspard
- Department of Neurology, Hôpital Erasme, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Benjamin Legros
- Department of Neurology, Hôpital Erasme, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Federico Lucchetti
- Bio, Electro And Mechanical Systems (BEAMS), Université Libre de Bruxelles (ULB), Avenue F.D. Roosevelt 50 CP165/56, 1050, Brussels, Belgium.,Laboratoire de Neurophysiologie Sensorielle et Cognitive, Hôpital Brugmann, Brussels, Belgium
| | - Rudy Ercek
- Laboratories of Image, Signal processing and Acoustics (LISA), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Antoine Nonclercq
- Bio, Electro And Mechanical Systems (BEAMS), Université Libre de Bruxelles (ULB), Avenue F.D. Roosevelt 50 CP165/56, 1050, Brussels, Belgium
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9
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Tanaka H, Khoo HM, Dubeau F, Gotman J. Association between scalp and intracerebral electroencephalographic seizure-onset patterns: A study in different lesional pathological substrates. Epilepsia 2017; 59:420-430. [PMID: 29226305 DOI: 10.1111/epi.13979] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2017] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Our purpose was to determine the correlation between scalp electroencephalography (EEG) and intracerebral EEG (iEEG) seizure-onset patterns in patients with focal lesional epilepsy to determine whether scalp seizure-onset patterns can be specific to intracerebral seizure-onset patterns and to lesion type. METHODS We retrospectively analyzed 61 patients with focal epilepsy and a structural magnetic resonance imaging (MRI)-visible lesion, who first underwent extensive scalp recordings and then iEEG studies (stereo-EEG) for presurgical evaluation, and who showed an iEEG seizure onset in the lesional/perilesional area. Five seizure-onset patterns were recognized on scalp EEG, and 7 on iEEG, and in each patient, only the predominant scalp and iEEG seizure-onset patterns were compared. Because scalp and iEEG recordings were acquired at different times, we followed strict criteria based on semiology and topography to match scalp with intracerebral seizures. RESULTS Seventy-one pairs of seizure-onset patterns matched between scalp and iEEG were identified. Each scalp pattern did not correspond to a single intracerebral pattern, but there were significant associations: (1) paroxysmal fast activity (≥13 Hz) at scalp onset was associated with low-voltage fast activity at iEEG onset (P < .001), with malformations of cortical development (P < .001), and with superficial seizure-onset zone based on iEEG (P < .001); (2) rhythmic slow activity (<13 Hz) at scalp onset was associated with low-frequency high-amplitude periodic spikes at iEEG onset (P = .0014), with medial temporal atrophy/sclerosis (P < .001), and with deep seizure-onset zone (P < .001); and (3) repetitive epileptiform discharge at scalp onset was associated with a burst of high-amplitude polyspikes at iEEG onset (P = .0002). SIGNIFICANCE Our results disclosed that in focal epilepsy patients with seizures generated in an MRI-visible lesion, some scalp seizure-onset patterns are highly associated with a specific intracerebral pattern, with specific pathologies, and with the depth of seizure-onset zone. These findings allow the interpretation of scalp seizure-onset patterns to be significantly more informative.
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Affiliation(s)
- Hideaki Tanaka
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada.,Department of Neurosurgery, Fukuoka University Hospital, Fukuoka City, Japan
| | - Hui Ming Khoo
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada.,Department of Neurosurgery, Osaka University Graduate School of Medicine, Suita, Japan
| | - François Dubeau
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Jean Gotman
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
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Cosandier-Rimélé D, Ramantani G, Zentner J, Schulze-Bonhage A, Dümpelmann M. A realistic multimodal modeling approach for the evaluation of distributed source analysis: application to sLORETA. J Neural Eng 2017; 14:056008. [DOI: 10.1088/1741-2552/aa7db1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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11
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Besson P, Bandt SK, Proix T, Lagarde S, Jirsa VK, Ranjeva JP, Bartolomei F, Guye M. Anatomic consistencies across epilepsies: a stereotactic-EEG informed high-resolution structural connectivity study. Brain 2017; 140:2639-2652. [DOI: 10.1093/brain/awx181] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 06/12/2017] [Indexed: 11/12/2022] Open
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12
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Kurbatova P, Wendling F, Kaminska A, Rosati A, Nabbout R, Guerrini R, Dulac O, Pons G, Cornu C, Nony P, Chiron C, Benquet P. Dynamic changes of depolarizing GABA in a computational model of epileptogenic brain: Insight for Dravet syndrome. Exp Neurol 2016; 283:57-72. [PMID: 27246997 DOI: 10.1016/j.expneurol.2016.05.037] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 05/12/2016] [Accepted: 05/26/2016] [Indexed: 10/21/2022]
Abstract
Abnormal reemergence of depolarizing GABAA current during postnatal brain maturation may play a major role in paediatric epilepsies, Dravet syndrome (DS) being among the most severe. To study the impact of depolarizing GABA onto distinct patterns of EEG activity, we extended a neural mass model as follows: one sub-population of pyramidal cells was added as well as two sub-populations of interacting interneurons, perisomatic-projecting interneurons (basket-like) with fast synaptic kinetics GABAA (fast, I1) and dendritic-projecting interneurons with slow synaptic kinetics GABAA (slow, I2). Basket-like cells were interconnected to reproduce mutual inhibition mechanisms (I1➔I1). The firing rate of interneurons was adapted to mimic the genetic alteration of voltage gated sodium channels found in DS patients, SCN1A(+/-). We implemented the "dynamic depolarizing GABAA" mediated post-synaptic potential in the model, as some studies reported that the chloride reversal potential can switch from negative to more positive value depending on interneuron activity. The "shunting inhibition" promoted by GABAA receptor activation was also implemented. We found that increasing the proportion of depolarizing GABAA mediated IPSP (I1➔I1 and I1➔P) only (i.e., other parameters left unchanged) was sufficient to sequentially switch the EEG activity from background to (1) interictal isolated polymorphic epileptic spikes, (2) fast onset activity, (3) seizure like activity and (4) seizure termination. The interictal and ictal EEG patterns observed in 4 DS patients were reproduced by the model via tuning the amount of depolarizing GABAA postsynaptic potential. Finally, we implemented the modes of action of benzodiazepines and stiripentol, two drugs recommended in DS. Both drugs blocked seizure-like activity, partially and dose-dependently when applied separately, completely and with a synergic effect when combined, as has been observed in DS patients. This computational modeling study constitutes an innovative approach to better define the role of depolarizing GABA in infantile onset epilepsy and opens the way for new therapeutic hypotheses, especially in Dravet syndrome.
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Affiliation(s)
- P Kurbatova
- University Lyon 1, UMR 5558, CRNS, Lyon, France
| | - F Wendling
- UMR 1099, Inserm-University Rennes1, LTSI, Rennes, France
| | - A Kaminska
- UMR 1129, Inserm-Paris Descartes University-CEA, Paris, France
| | - A Rosati
- Pediatric Neurology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Firenze, Italy
| | - R Nabbout
- UMR 1129, Inserm-Paris Descartes University-CEA, Paris, France
| | - R Guerrini
- Pediatric Neurology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Firenze, Italy; IRCCS Fondazione Stella Maris, Pisa, Italy
| | - O Dulac
- UMR 1129, Inserm-Paris Descartes University-CEA, Paris, France
| | - G Pons
- UMR 1129, Inserm-Paris Descartes University-CEA, Paris, France
| | - C Cornu
- Hôpital Louis Pradel, Centre d'Investigation Clinique, INSERM CIC201/UMR5558, Bron, France; CHU Lyon, Service de Pharmacologie Clinique, Lyon, France; University Lyon 1, UMR 5558, CRNS, Lyon, France
| | - P Nony
- CHU Lyon, Service de Pharmacologie Clinique, Lyon, France; University Lyon 1, UMR 5558, CRNS, Lyon, France
| | | | - C Chiron
- UMR 1129, Inserm-Paris Descartes University-CEA, Paris, France
| | - P Benquet
- UMR 1099, Inserm-University Rennes1, LTSI, Rennes, France
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Keles HO, Barbour RL, Omurtag A. Hemodynamic correlates of spontaneous neural activity measured by human whole-head resting state EEG+fNIRS. Neuroimage 2016; 138:76-87. [PMID: 27236081 DOI: 10.1016/j.neuroimage.2016.05.058] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 05/18/2016] [Accepted: 05/24/2016] [Indexed: 02/05/2023] Open
Abstract
The brains of awake, resting human subjects display spontaneously occurring neural activity patterns whose magnitude is typically many times greater than those triggered by cognitive or perceptual performance. Evoked and resting state activations affect local cerebral hemodynamic properties through processes collectively referred to as neurovascular coupling. Its investigation calls for an ability to track both the neural and vascular aspects of brain function. We used scalp electroencephalography (EEG), which provided a measure of the electrical potentials generated by cortical postsynaptic currents. Simultaneously we utilized functional near-infrared spectroscopy (NIRS) to continuously monitor hemoglobin concentration changes in superficial cortical layers. The multi-modal signal from 18 healthy adult subjects allowed us to investigate the association of neural activity in a range of frequencies over the whole-head to local changes in hemoglobin concentrations. Our results verified the delayed alpha (8-16Hz) modulation of hemodynamics in posterior areas known from the literature. They also indicated strong beta (16-32Hz) modulation of hemodynamics. Analysis revealed, however, that beta modulation was likely generated by the alpha-beta coupling in EEG. Signals from the inferior electrode sites were dominated by scalp muscle related activity. Our study aimed to characterize the phenomena related to neurovascular coupling observable by practical, cost-effective, and non-invasive multi-modal techniques.
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Affiliation(s)
- Hasan Onur Keles
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, United States
| | - Randall L Barbour
- Department of Pathology, Optical Tomography Group, State University of New York, NY, 11203, United States
| | - Ahmet Omurtag
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, United States.
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14
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Computational models of epileptiform activity. J Neurosci Methods 2016; 260:233-51. [DOI: 10.1016/j.jneumeth.2015.03.027] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 03/23/2015] [Accepted: 03/24/2015] [Indexed: 12/24/2022]
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15
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Petroff OA, Spencer DD, Goncharova II, Zaveri HP. A comparison of the power spectral density of scalp EEG and subjacent electrocorticograms. Clin Neurophysiol 2016; 127:1108-1112. [DOI: 10.1016/j.clinph.2015.08.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 07/06/2015] [Accepted: 08/05/2015] [Indexed: 11/29/2022]
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16
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Dynamic mechanisms of neocortical focal seizure onset. PLoS Comput Biol 2014; 10:e1003787. [PMID: 25122455 PMCID: PMC4133160 DOI: 10.1371/journal.pcbi.1003787] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Accepted: 06/23/2014] [Indexed: 01/20/2023] Open
Abstract
Recent experimental and clinical studies have provided diverse insight into the mechanisms of human focal seizure initiation and propagation. Often these findings exist at different scales of observation, and are not reconciled into a common understanding. Here we develop a new, multiscale mathematical model of cortical electric activity with realistic mesoscopic connectivity. Relating the model dynamics to experimental and clinical findings leads us to propose three classes of dynamical mechanisms for the onset of focal seizures in a unified framework. These three classes are: (i) globally induced focal seizures; (ii) globally supported focal seizures; (iii) locally induced focal seizures. Using model simulations we illustrate these onset mechanisms and show how the three classes can be distinguished. Specifically, we find that although all focal seizures typically appear to arise from localised tissue, the mechanisms of onset could be due to either localised processes or processes on a larger spatial scale. We conclude that although focal seizures might have different patient-specific aetiologies and electrographic signatures, our model suggests that dynamically they can still be classified in a clinically useful way. Additionally, this novel classification according to the dynamical mechanisms is able to resolve some of the previously conflicting experimental and clinical findings. According to the WHO fact sheet, epilepsy is a neurological disorder affecting about 50 million people worldwide. Even today 30% of epilepsy patients do not respond well to drug therapies. Neocortical focal epilepsy is a particular type of epilepsy in which drug treatments fail and surgical success rate is low. Hence, research is essential to improve the treatment of this type of epilepsy. Recent advances in brain recording methods have led to new observations regarding the nature of neocortical focal epilepsy. However, some of the observations appear to be contradictory. Here, we develop a computational modelling framework that can explain the different observations as different aspects of possible mechanisms that can all lead to seizure onset. Specifically, we classify three main conditions under which focal seizure onset can happen. This classification is clinically important, as our model predicts different treatment strategies for each class. We conclude that focal seizures are diverse, not only in their electrographic appearance and aetiology, but also in their onset mechanism. Combined multiscale recordings as well as stimulation studies are required to elucidate the onset mechanism in each patient. Our work provides the first classification of possible onset mechanism.
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Dubarry AS, Badier JM, Trébuchon-Da Fonseca A, Gavaret M, Carron R, Bartolomei F, Liégeois-Chauvel C, Régis J, Chauvel P, Alario FX, Bénar CG. Simultaneous recording of MEG, EEG and intracerebral EEG during visual stimulation: from feasibility to single-trial analysis. Neuroimage 2014; 99:548-58. [PMID: 24862073 DOI: 10.1016/j.neuroimage.2014.05.055] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 04/21/2014] [Accepted: 05/17/2014] [Indexed: 11/28/2022] Open
Abstract
Electroencephalography (EEG), magnetoencephalography (MEG), and intracerebral stereotaxic EEG (SEEG) are the three neurophysiological recording techniques, which are thought to capture the same type of brain activity. Still, the relationships between non-invasive (EEG, MEG) and invasive (SEEG) signals remain to be further investigated. In early attempts at comparing SEEG with either EEG or MEG, the recordings were performed separately for each modality. However such an approach presents substantial limitations in terms of signal analysis. The goal of this technical note is to investigate the feasibility of simultaneously recording these three signal modalities (EEG, MEG and SEEG), and to provide strategies for analyzing this new kind of data. Intracerebral electrodes were implanted in a patient with intractable epilepsy for presurgical evaluation purposes. This patient was presented with a visual stimulation paradigm while the three types of signals were simultaneously recorded. The analysis started with a characterization of the MEG artifact caused by the SEEG equipment. Next, the average evoked activities were computed at the sensor level, and cortical source activations were estimated for both the EEG and MEG recordings; these were shown to be compatible with the spatiotemporal dynamics of the SEEG signals. In the average time-frequency domain, concordant patterns between the MEG/EEG and SEEG recordings were found below the 40 Hz level. Finally, a fine-grained coupling between the amplitudes of the three recording modalities was detected in the time domain, at the level of single evoked responses. Importantly, these correlations have shown a high level of spatial and temporal specificity. These findings provide a case for the ability of trimodal recordings (EEG, MEG, and SEEG) to reach a greater level of specificity in the investigation of brain signals and functions.
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Affiliation(s)
- Anne-Sophie Dubarry
- Aix-Marseille Université, Faculté de Médecine La Timone, 13005 Marseille, France; Aix-Marseille Université, CNRS, LPC UMR 7290, 13331 Marseille, France; INSERM, UMR 1106, Institut de Neurosciences des Systèmes, 13005 Marseille, France
| | - Jean-Michel Badier
- Aix-Marseille Université, Faculté de Médecine La Timone, 13005 Marseille, France; INSERM, UMR 1106, Institut de Neurosciences des Systèmes, 13005 Marseille, France
| | - Agnès Trébuchon-Da Fonseca
- Aix-Marseille Université, Faculté de Médecine La Timone, 13005 Marseille, France; INSERM, UMR 1106, Institut de Neurosciences des Systèmes, 13005 Marseille, France; APHM, Hôpital de la Timone, Service de Neurophysiologie Clinique, 13385 Marseille, France
| | - Martine Gavaret
- Aix-Marseille Université, Faculté de Médecine La Timone, 13005 Marseille, France; INSERM, UMR 1106, Institut de Neurosciences des Systèmes, 13005 Marseille, France; APHM, Hôpital de la Timone, Service de Neurophysiologie Clinique, 13385 Marseille, France
| | - Romain Carron
- Aix-Marseille Université, Faculté de Médecine La Timone, 13005 Marseille, France; APHM, Hôpital de la Timone, Service de Neurochirurgie Fonctionnelle, 13385 Marseille, France
| | - Fabrice Bartolomei
- Aix-Marseille Université, Faculté de Médecine La Timone, 13005 Marseille, France; INSERM, UMR 1106, Institut de Neurosciences des Systèmes, 13005 Marseille, France; APHM, Hôpital de la Timone, Service de Neurophysiologie Clinique, 13385 Marseille, France
| | - Catherine Liégeois-Chauvel
- INSERM, UMR 1106, Institut de Neurosciences des Systèmes, 13005 Marseille, France; APHM, Hôpital de la Timone, Service de Neurophysiologie Clinique, 13385 Marseille, France
| | - Jean Régis
- Aix-Marseille Université, Faculté de Médecine La Timone, 13005 Marseille, France; APHM, Hôpital de la Timone, Service de Neurophysiologie Clinique, 13385 Marseille, France; APHM, Hôpital de la Timone, Service de Neurochirurgie Fonctionnelle, 13385 Marseille, France
| | - Patrick Chauvel
- Aix-Marseille Université, Faculté de Médecine La Timone, 13005 Marseille, France; INSERM, UMR 1106, Institut de Neurosciences des Systèmes, 13005 Marseille, France; APHM, Hôpital de la Timone, Service de Neurophysiologie Clinique, 13385 Marseille, France
| | - F-Xavier Alario
- Aix-Marseille Université, CNRS, LPC UMR 7290, 13331 Marseille, France
| | - Christian-G Bénar
- Aix-Marseille Université, Faculté de Médecine La Timone, 13005 Marseille, France; INSERM, UMR 1106, Institut de Neurosciences des Systèmes, 13005 Marseille, France
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Nikiforova AS. Stress-induced gastrointestinal motility is responsible for epileptic susceptibility. Med Hypotheses 2014; 82:442-51. [PMID: 24566236 DOI: 10.1016/j.mehy.2014.01.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 01/20/2014] [Accepted: 01/21/2014] [Indexed: 11/26/2022]
Abstract
In order to explain observations linking epileptic EEG patterns (3 Hz spike wave complexes and β-γ activity of 25-40 Hz) and the involuntary slow wave of the gut (3 c/min) and colonic contractile electrical complexes (25-40 c/min), the physiological and pathological electrographic patterns recorded from different anatomical structures were compared. The similarities in shape and pattern provided the basis to hypothesise that these waves exist as a continuum associated with different cell types and that stress induces high-force involuntary tonic contractions and resistance to the segmental rhythmic contractions of the gut's circular muscles. As a consequence, electrographic patterns with a waveform of 3 c/min and 25-40 c/min are organised in the periphery and transmitted to the central nervous system via visceral afferents with the same shape. The electrical interactions between the adjacent neurons of the enteric network, as well as between the interconnected gut/brain neuronal circuits, facilitate synchronisation of neuronal activity by the frequencies of the stress-induced patterns. In this way, the peripherally organised electrographic patterns actively participate in creating epileptic susceptibility with expressed gut symptoms.
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Ramantani G, Dümpelmann M, Koessler L, Brandt A, Cosandier-Rimélé D, Zentner J, Schulze-Bonhage A, Maillard LG. Simultaneous subdural and scalp EEG correlates of frontal lobe epileptic sources. Epilepsia 2014; 55:278-88. [DOI: 10.1111/epi.12512] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2013] [Indexed: 11/26/2022]
Affiliation(s)
| | | | - Laurent Koessler
- Research Center for Automatic Control (CRAN); University of Lorraine; CNRS; UMR 7039; Vandoeuvre France
| | - Armin Brandt
- Epilepsy Center; University Hospital Freiburg; Freiburg Germany
| | | | - Josef Zentner
- Department of Neurosurgery; University Hospital Freiburg; Freiburg Germany
| | | | - Louis Georges Maillard
- Research Center for Automatic Control (CRAN); University of Lorraine; CNRS; UMR 7039; Vandoeuvre France
- Department of Neurology, Central University Hospital; CHU de Nancy; Nancy France
- Medical Faculty; University of Lorraine; Nancy France
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20
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Ramantani G, Cosandier-Rimélé D, Schulze-Bonhage A, Maillard L, Zentner J, Dümpelmann M. Source reconstruction based on subdural EEG recordings adds to the presurgical evaluation in refractory frontal lobe epilepsy. Clin Neurophysiol 2013; 124:481-91. [DOI: 10.1016/j.clinph.2012.09.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 08/28/2012] [Accepted: 09/02/2012] [Indexed: 11/17/2022]
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