201
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Proix T, Jirsa VK, Bartolomei F, Guye M, Truccolo W. Predicting the spatiotemporal diversity of seizure propagation and termination in human focal epilepsy. Nat Commun 2018. [PMID: 29540685 PMCID: PMC5852068 DOI: 10.1038/s41467-018-02973-y] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Recent studies have shown that seizures can spread and terminate across brain areas via a rich diversity of spatiotemporal patterns. In particular, while the location of the seizure onset area is usually invariant across seizures in an individual patient, the source of traveling (2–3 Hz) spike-and-wave discharges during seizures can either move with the slower propagating ictal wavefront or remain stationary at the seizure onset area. Furthermore, although many focal seizures terminate synchronously across brain areas, some evolve into distinct ictal clusters and terminate asynchronously. Here, we introduce a unifying perspective based on a new neural field model of epileptic seizure dynamics. Two main mechanisms, the co-existence of wave propagation in excitable media and coupled-oscillator dynamics, together with the interaction of multiple time scales, account for the reported diversity. We confirm our predictions in seizures and tractography data obtained from patients with pharmacologically resistant epilepsy. Our results contribute toward patient-specific seizure modeling. A major goal of epilepsy research is understanding the spatiotemporal dynamics of seizure. Here, the authors extend the Epileptor neural mass model into a neural field model, in order to provide a unified and patient-specific model of seizure initiation, propagation, and termination.
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Affiliation(s)
- Timothée Proix
- Department of Neuroscience, Brown University, Providence, RI, 02912, USA.,Institute for Brain Science, Brown University, Providence, RI, 02912, USA.,Center for Neurorestoration & Neurotechnology, U.S. Department of Veterans Affairs, Providence, RI, 02912, USA
| | - Viktor K Jirsa
- Institut de Neurosciences des Systèmes (INS), Inserm, Aix Marseille Univ, Marseille, 13005, France
| | - Fabrice Bartolomei
- Institut de Neurosciences des Systèmes (INS), Inserm, Aix Marseille Univ, Marseille, 13005, France
| | - Maxime Guye
- CNRS, CRMBM UMR 7339, Aix Marseille Univ, Marseille, 13005, France
| | - Wilson Truccolo
- Department of Neuroscience, Brown University, Providence, RI, 02912, USA. .,Institute for Brain Science, Brown University, Providence, RI, 02912, USA. .,Center for Neurorestoration & Neurotechnology, U.S. Department of Veterans Affairs, Providence, RI, 02912, USA.
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202
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Abstract
The muscarinic receptor agonist carbachol (CCh) can induce activity in the theta range (4-15 Hz) in the entorhinal cortex (EC), but the underlying network mechanisms remain unclear. Here, we investigated the interplay between interneurons and principal cells in the EC during CCh-induced theta-like field oscillations in an in vitro brain slice preparation using tetrodes. Field oscillations at 10.1 Hz (IQR = 9.5-10.9 Hz) occurred during bath application of CCh (100 μM; n = 32 experiments) and were associated with single-unit (n = 189) firing. Interneuron activity increased before principal cell activity at the onset of the oscillations and both interneurons and principal cells fired at specific oscillation phases with interneurons preceding principal cells, suggesting that interneurons modulate principal cell activity during such oscillations. The regularity of occurrence of CCh-induced oscillations was abolished by applying the GABAA receptor antagonist picrotoxin (100 μM; n = 13). These effects were accompanied by changes in firing with principal cells discharging action potentials before interneurons, along with a loss of preferred firing phase for principal cells in relation to the oscillation peaks. Blocking ionotropic glutamatergic transmission abolished CCh-induced field oscillations (n = 6), suggesting that ionotropic glutamatergic receptor signaling is necessary for their generation. Our results show that neuronal network interactions leading to CCh-induced theta-like field oscillations rest on the close interplay between interneurons and principal cells and that interneurons modulate principal cell activity during such oscillatory activity. Moreover, they underscore the role of ionotropic glutamatergic transmission in this type of oscillations.
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203
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Lopes MA, Lee KE, Goltsev AV. Neuronal network model of interictal and recurrent ictal activity. Phys Rev E 2017; 96:062412. [PMID: 29347379 DOI: 10.1103/physreve.96.062412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Indexed: 02/04/2023]
Abstract
We propose a neuronal network model which undergoes a saddle node on an invariant circle bifurcation as the mechanism of the transition from the interictal to the ictal (seizure) state. In the vicinity of this transition, the model captures important dynamical features of both interictal and ictal states. We study the nature of interictal spikes and early warnings of the transition predicted by this model. We further demonstrate that recurrent seizures emerge due to the interaction between two networks.
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Affiliation(s)
- M A Lopes
- Living Systems Institute, University of Exeter, Exeter EX4 4QD, United Kingdom.,Wellcome Trust Centre for Biomedical Modelling and Analysis, University of Exeter, Exeter EX4 4QD, United Kingdom.,EPSRC Centre for Predictive Modelling in Healthcare, University of Exeter, Exeter EX4 4QD, United Kingdom.,Department of Physics and I3N, University of Aveiro, 3810-193 Aveiro, Portugal
| | - K-E Lee
- Department of Physics and I3N, University of Aveiro, 3810-193 Aveiro, Portugal.,Department of Anesthesiology and Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
| | - A V Goltsev
- Department of Physics and I3N, University of Aveiro, 3810-193 Aveiro, Portugal.,A.F. Ioffe Physico-Technical Institue, 194021 St. Petersburg, Russia
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204
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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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205
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Sun FT, Arcot Desai S, Tcheng TK, Morrell MJ. Changes in the electrocorticogram after implantation of intracranial electrodes in humans: The implant effect. Clin Neurophysiol 2017; 129:676-686. [PMID: 29233473 DOI: 10.1016/j.clinph.2017.10.036] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 09/29/2017] [Accepted: 10/22/2017] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Subacute and long-term electrocorticographic (ECoG) changes in ambulatory patients with depth and cortical strip electrodes were evaluated in order to determine the length of the implant effect. METHODS ECoG records were assessed in patients with medically intractable epilepsy who had depth and/or strip leads implanted in order to be treated with brain-responsive stimulation. Changes in total spectral power, band-limited spectral power, and spike rate were assessed. RESULTS 121 patients participating in trials of the RNS® System had a total of 93994 ECoG records analyzed. Significant changes in total spectral power occurred from the first to second months after implantation, involving 55% of all ECoG channels (68% of strip and 47% of depth lead channels). Significant, but less pronounced, changes continued over the 2nd to 5th post-implant months, after which total power became more stable. Similar patterns of changes were observed within frequency bands and spike rate. CONCLUSIONS ECoG spectral power and spike rates are not stable in the first 5 months after implantation, presumably due to neurophysiological and electrode-tissue interface changes. SIGNIFICANCE ECoG data collected in the first 5 months after implantation of intracranial electrodes may not be fully representative of chronic cortical electrophysiology.
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Affiliation(s)
| | | | | | - Martha J Morrell
- NeuroPace, Inc., Mountain View, CA 94043, USA; Department of Neurology and Neurological Sciences, Stanford University, Palo Alto, CA 94305, USA
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206
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Electrocorticographic Patterns in Epilepsy Surgery and Long-Term Outcome. J Clin Neurophysiol 2017; 34:520-526. [DOI: 10.1097/wnp.0000000000000407] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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207
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Murphy PM, von Paternos AJ, Santaniello S. A novel HFO-based method for unsupervised localization of the seizure onset zone in drug-resistant epilepsy. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2017:1054-1057. [PMID: 29060055 DOI: 10.1109/embc.2017.8037008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
High frequency oscillations (HFOs) are potential biomarkers of epileptic areas. In patients with drug-resistant epilepsy, HFO rates tend to be higher in the seizure onset zone (SOZ) than in other brain regions and the resection of HFO-generating areas positively correlates with seizure-free surgery outcome. Nonetheless, the development of robust unsupervised HFO-based tools for SOZ localization remains challenging. Current approaches predict the SOZ by processing small samples of intracranial EEG (iEEG) data and applying patient-specific thresholds on the HFO rate. The HFO rate, though, varies largely over time with the patient's conditions (e.g., sleep versus wakefulness) and across patients. We propose a novel localization method for SOZ that uses a time-varying, HFO-based index to estimate the epileptic susceptibility of the iEEG channels. The method is insensitive to the average HFO rate across channels (which is both patient- and condition-specific), tracks the channel susceptibility over time, and predicts the SOZ based on the temporal evolution of the HFO rate. Tested on a preliminary dataset of continuous multi-day multichannel interictal iEEG recordings from two epileptic patients (117±97.6 h/per patient, mean ± S.D.), the reported SOZ prediction had an average 0.70±0.18 accuracy and 0.67±0.07 area under the ROC curve (mean ± S.D.) across patients.
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208
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Traub RD, Whittington MA, Hall SP. Does Epileptiform Activity Represent a Failure of Neuromodulation to Control Central Pattern Generator-Like Neocortical Behavior? Front Neural Circuits 2017; 11:78. [PMID: 29093667 PMCID: PMC5651241 DOI: 10.3389/fncir.2017.00078] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 10/04/2017] [Indexed: 12/22/2022] Open
Abstract
Rhythmic motor patterns in invertebrates are often driven by specialized “central pattern generators” (CPGs), containing small numbers of neurons, which are likely to be “identifiable” in one individual compared with another. The dynamics of any particular CPG lies under the control of modulatory substances, amines, or peptides, entering the CPG from outside it, or released by internal constituent neurons; consequently, a particular CPG can generate a given rhythm at different frequencies and amplitudes, and perhaps even generate a repertoire of distinctive patterns. The mechanisms exploited by neuromodulators in this respect are manifold: Intrinsic conductances (e.g., calcium, potassium channels), conductance state of postsynaptic receptors, degree of plasticity, and magnitude and kinetics of transmitter release can all be affected. The CPG concept has been generalized to vertebrate motor pattern generating circuits (e.g., for locomotion), which may contain large numbers of neurons – a construct that is sensible, if there is enough redundancy: that is, the large number of neurons consists of only a small number of classes, and the cells within any one class act stereotypically. Here we suggest that CPG and modulator ideas may also help to understand cortical oscillations, normal ones, and particularly transition to epileptiform pathology. Furthermore, in the case illustrated, the mechanism of the transition appears to be an exaggerated form of a normal modulatory action used to influence sensory processing.
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Affiliation(s)
- Roger D Traub
- Department of Physical Sciences, IBM Thomas J. Watson Research Center, New York City, NY, United States
| | - Miles A Whittington
- Department of Biology, Hull York Medical School, University of York, York, United Kingdom
| | - Stephen P Hall
- Department of Biology, Hull York Medical School, University of York, York, United Kingdom
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209
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Irimia A, Goh SYM, Wade AC, Patel K, Vespa PM, Van Horn JD. Traumatic Brain Injury Severity, Neuropathophysiology, and Clinical Outcome: Insights from Multimodal Neuroimaging. Front Neurol 2017; 8:530. [PMID: 29051745 PMCID: PMC5633783 DOI: 10.3389/fneur.2017.00530] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Accepted: 09/22/2017] [Indexed: 11/24/2022] Open
Abstract
Background The relationship between the acute clinical presentation of patients with traumatic brain injury (TBI), long-term changes in brain structure prompted by injury and chronic functional outcome is insufficiently understood. In this preliminary study, we investigate how acute Glasgow coma score (GCS) and epileptic seizure occurrence after TBIs are statistically related to functional outcome (as quantified using the Glasgow Outcome Score) and to the extent of cortical thinning observed 6 months after the traumatic event. Methods Using multivariate linear regression, the extent to which the acute GCS and epileptic seizure occurrence (predictor variables) correlate with structural brain changes (relative cortical atrophy) was examined in a group of 33 TBI patients. The statistical significance of the correlation between relative cortical atrophy and the Glasgow Outcome Score was also investigated. Results A statistically significant correlative relationship between cortical thinning and the predictor variables (acute GCS and seizure occurrence) was identified in the study sample. Regions where the statistical model was found to have highest statistical reliability in predicting both gray matter atrophy and neurological outcome include the frontopolar, middle frontal, postcentral, paracentral, middle temporal, angular, and lingual gyri. In addition, relative atrophy and GOS were also found to be significantly correlated over large portions of the cortex. Conclusion This study contributes to our understanding of the relationship between clinical descriptors of acute TBI, the extent of injury-related chronic brain changes and neurological outcome. This is partly because the brain areas where cortical thinning was found to be correlated with GCS and with seizure occurrence are implicated in executive control, sensory function, motor acuity, memory, and language, all of which may be affected by TBI. Thus, our quantification suggests the existence of a statistical relationship between acute clinical presentation, on the one hand, and structural/functional brain features which are particularly susceptible to post-injury degradation, on the other hand.
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Affiliation(s)
- Andrei Irimia
- Ethel Percy Andrus Gerontology Center, USC Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, United States
| | - Sheng-Yang Matthew Goh
- Laboratory of Neuro Imaging, Mark and Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Adam C Wade
- Laboratory of Neuro Imaging, Mark and Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Kavi Patel
- Laboratory of Neuro Imaging, Mark and Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Paul M Vespa
- Brain Injury Research Center, Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - John D Van Horn
- Laboratory of Neuro Imaging, Mark and Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
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210
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Behr C, Lévesque M, Stroh T, Avoli M. Time-dependent evolution of seizures in a model of mesial temporal lobe epilepsy. Neurobiol Dis 2017; 106:205-213. [DOI: 10.1016/j.nbd.2017.07.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 07/03/2017] [Accepted: 07/10/2017] [Indexed: 01/21/2023] Open
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211
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212
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Wang MY, Wang J, Zhou J, Guan YG, Zhai F, Liu CQ, Xu FF, Han YX, Yan ZF, Luan GM. Identification of the epileptogenic zone of temporal lobe epilepsy from stereo-electroencephalography signals: A phase transfer entropy and graph theory approach. NEUROIMAGE-CLINICAL 2017; 16:184-195. [PMID: 28794979 PMCID: PMC5542420 DOI: 10.1016/j.nicl.2017.07.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 06/15/2017] [Accepted: 07/22/2017] [Indexed: 01/09/2023]
Abstract
The aim of this research is to apply an approach based on phase transfer entropy (PTE) and graph theory to study the interactions between the stereo-electroencephalography (SEEG) activities recorded in multilobar origin, in order to evaluate their ability to detect the epileptogenic zone (EZ) of temporal lobe epilepsies (TLE). Forty-three patients were included in this retrospective study. Five to sixteen (median = 12) multilead electrodes were implanted per patient, and, for each patient, a sub-set of between 10 and 32 (median = 22) bipolar derivations was selected for analysis. The leads were classified into the onset leads (OLs), the early propagation leads (EPLs), and the rest of the leads (RLs). The results showed that a significantly different dynamic trend of the out/in ratio (more obvious in the gamma band) distinguishes the OLs from RLs in the 23 patients who were seizure-free not only during the ictal event (significant elevation), but also during the inter-,pre-, late-ictal periods, and especially in the post-ictal (sharp decline) state. However, in the 20 patients who were not-seizure-free, the differences between the OLs and RLs during the post-ictal period were not found in any frequency band. The dynamic trend was used to predict surgical outcome, and the results showed that the sensitivity was 91% and the specificity was 70%. In brief, this study indicates that our approach may add new and valuable information, providing efficient quantitative measures useful for localizing the EZ.
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Affiliation(s)
- Meng-Yang Wang
- Epilepsy Center and Department of Neurology, Sanbo Brain Hospital, Capital Medical University, Beijing Key Laboratory of Epilepsy, Beijing Institute for Brain Disorders, 50, Xiang-shan-yi-ke-song, Haidian District, Beijing 100093, China
| | - Jing Wang
- Epilepsy Center and Department of Neurology, Sanbo Brain Hospital, Capital Medical University, Beijing Key Laboratory of Epilepsy, Beijing Institute for Brain Disorders, 50, Xiang-shan-yi-ke-song, Haidian District, Beijing 100093, China
| | - Jian Zhou
- Epilepsy Center and Department of Functional Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing Key Laboratory of Epilepsy, Beijing Institute for Brain Disorders, 50, Xiang-shan-yi-ke-song, Haidian District, Beijing 100093, China
| | - Yu-Guang Guan
- Epilepsy Center and Department of Functional Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing Key Laboratory of Epilepsy, Beijing Institute for Brain Disorders, 50, Xiang-shan-yi-ke-song, Haidian District, Beijing 100093, China
| | - Feng Zhai
- Epilepsy Center and Department of Functional Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing Key Laboratory of Epilepsy, Beijing Institute for Brain Disorders, 50, Xiang-shan-yi-ke-song, Haidian District, Beijing 100093, China
| | - Chang-Qing Liu
- Epilepsy Center and Department of Functional Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing Key Laboratory of Epilepsy, Beijing Institute for Brain Disorders, 50, Xiang-shan-yi-ke-song, Haidian District, Beijing 100093, China
| | - Fei-Fei Xu
- Epilepsy Center and Department of Neurology, Sanbo Brain Hospital, Capital Medical University, Beijing Key Laboratory of Epilepsy, Beijing Institute for Brain Disorders, 50, Xiang-shan-yi-ke-song, Haidian District, Beijing 100093, China
| | - Yi-Xian Han
- Epilepsy Center and Department of Neurology, Sanbo Brain Hospital, Capital Medical University, Beijing Key Laboratory of Epilepsy, Beijing Institute for Brain Disorders, 50, Xiang-shan-yi-ke-song, Haidian District, Beijing 100093, China
| | - Zhao-Fen Yan
- Epilepsy Center and Department of Neurology, Sanbo Brain Hospital, Capital Medical University, Beijing Key Laboratory of Epilepsy, Beijing Institute for Brain Disorders, 50, Xiang-shan-yi-ke-song, Haidian District, Beijing 100093, China
| | - Guo-Ming Luan
- Epilepsy Center and Department of Functional Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing Key Laboratory of Epilepsy, Beijing Institute for Brain Disorders, 50, Xiang-shan-yi-ke-song, Haidian District, Beijing 100093, China
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213
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Lévesque M, Salami P, Shiri Z, Avoli M. Interictal oscillations and focal epileptic disorders. Eur J Neurosci 2017. [DOI: 10.1111/ejn.13628] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Maxime Lévesque
- Department of Neurology & Neurosurgery; Montreal Neurological Institute; McGill University; 3801 University Street Montréal QC Canada H3A 2B4
| | - Pariya Salami
- Department of Neurology & Neurosurgery; Montreal Neurological Institute; McGill University; 3801 University Street Montréal QC Canada H3A 2B4
| | - Zahra Shiri
- Department of Neurology & Neurosurgery; Montreal Neurological Institute; McGill University; 3801 University Street Montréal QC Canada H3A 2B4
| | - Massimo Avoli
- Department of Neurology & Neurosurgery; Montreal Neurological Institute; McGill University; 3801 University Street Montréal QC Canada H3A 2B4
- Dipartimento di Medicina Sperimentale; Sapienza University of Rome; Roma Italy
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214
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Jiruska P, Alvarado-Rojas C, Schevon CA, Staba R, Stacey W, Wendling F, Avoli M. Update on the mechanisms and roles of high-frequency oscillations in seizures and epileptic disorders. Epilepsia 2017; 58:1330-1339. [PMID: 28681378 DOI: 10.1111/epi.13830] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2017] [Indexed: 12/11/2022]
Abstract
High-frequency oscillations (HFOs) are a type of brain activity that is recorded from brain regions capable of generating seizures. Because of the close association of HFOs with epileptogenic tissue and ictogenesis, understanding their cellular and network mechanisms could provide valuable information about the organization of epileptogenic networks and how seizures emerge from the abnormal activity of these networks. In this review, we summarize the most recent advances in the field of HFOs and provide a critical evaluation of new observations within the context of already established knowledge. Recent improvements in recording technology and the introduction of optogenetics into epilepsy research have intensified experimental work on HFOs. Using advanced computer models, new cellular substrates of epileptic HFOs were identified and the role of specific neuronal subtypes in HFO genesis was determined. Traditionally, the pathogenesis of HFOs was explored mainly in patients with temporal lobe epilepsy and in animal models mimicking this condition. HFOs have also been reported to occur in other epileptic disorders and models such as neocortical epilepsy, genetically determined epilepsies, and infantile spasms, which further support the significance of HFOs in the pathophysiology of epilepsy. It is increasingly recognized that HFOs are generated by multiple mechanisms at both the cellular and network levels. Future studies on HFOs combining novel high-resolution in vivo imaging techniques and precise control of neuronal behavior using optogenetics or chemogenetics will provide evidence about the causal role of HFOs in seizures and epileptogenesis. Detailed understanding of the pathophysiology of HFOs will propel better HFO classification and increase their information yield for clinical and diagnostic purposes.
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Affiliation(s)
- Premysl Jiruska
- Department of Developmental Epileptology, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
| | | | | | - Richard Staba
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, U.S.A
| | - William Stacey
- Department of Neurology, Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, U.S.A
| | - Fabrice Wendling
- Laboratory of Signal and Image Processing, INSERM U1099, Rennes, France.,Laboratoire de Traitement du Signal et de l'Image, University of Rennes 1, Rennes, France
| | - Massimo Avoli
- Montreal Neurological Institute and Departments of Neurology & Neurosurgery and of Physiology, McGill University, Montréal, Québec, Canada.,Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
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215
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Different seizure-onset patterns in mesiotemporal lobe epilepsy have a distinct interictal signature. Clin Neurophysiol 2017; 128:1282-1289. [DOI: 10.1016/j.clinph.2017.04.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/28/2017] [Accepted: 04/26/2017] [Indexed: 11/15/2022]
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216
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Donos C, Mîndruţă I, Malîia MD, Raşină A, Ciurea J, Barborica A. Co-occurrence of high-frequency oscillations and delayed responses evoked by intracranial electrical stimulation in stereo-EEG studies. Clin Neurophysiol 2017; 128:1043-1052. [DOI: 10.1016/j.clinph.2016.11.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 11/23/2016] [Accepted: 11/30/2016] [Indexed: 10/20/2022]
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217
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Characteristics of EEG Seizure-Onset Patterns Recorded From Subdural Electrodes Over MRI-Visible Frontal Focal Cortical Dysplasia Type IIb Lesions. J Clin Neurophysiol 2017; 34:427-433. [PMID: 28557904 DOI: 10.1097/wnp.0000000000000384] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Focal cortical dysplasia (FCD) is intrinsically epileptogenic, and an MRI-visible lesion typically constitutes the core part of the epileptogenic zone. We aimed to identify ictal EEG patterns that represent the epileptogenic zone by using subdural electrodes placed over the MRI-visible FCD lesion. METHODS We selected seven patients with frontal lobe epilepsy caused by pathologically proven FCD type IIb who underwent preoperative intracranial EEG evaluation with subdural electrodes followed by resection surgery with seizure-free outcome. The characteristics of ictal EEG patterns, interictal/ictal high-frequency oscillations, and ictal direct current shifts from intracranial electrodes placed over the MRI-visible lesion were analyzed. RESULTS Two seizure-onset patterns (low voltage fast activity and fast spike activity) were identified. Low voltage fast activity was seen in all patients with a lateral frontal lesion, and it was always preceded by preictal spikes. Fast spike activity occurred only in patients with a mesial frontal lesion. Interictal/ictal high-frequency oscillations and ictal direct current shifts were seen in all patients. CONCLUSIONS The epileptogenic zone of frontal FCD type IIb may be characterized by EEG seizure-onset patterns consisting of low voltage fast activity and fast spike activity accompanied by ictal high-frequency oscillations and ictal direct current shifts. Further study is needed to determine whether other seizure-onset patterns exist in patients with FCD type IIb.
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Bartolomei F, Lagarde S, Wendling F, McGonigal A, Jirsa V, Guye M, Bénar C. Defining epileptogenic networks: Contribution of SEEG and signal analysis. Epilepsia 2017; 58:1131-1147. [DOI: 10.1111/epi.13791] [Citation(s) in RCA: 262] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/10/2017] [Indexed: 12/25/2022]
Affiliation(s)
- Fabrice Bartolomei
- Institut de Neurosciences des Systèmes; Aix Marseille University; Marseille France
- AP-HM; Service de Neurophysiologie Clinique; Hôpital de la Timone; Marseille France
| | - Stanislas Lagarde
- Institut de Neurosciences des Systèmes; Aix Marseille University; Marseille France
- AP-HM; Service de Neurophysiologie Clinique; Hôpital de la Timone; Marseille France
| | - Fabrice Wendling
- U1099; INSERM; Rennes France
- Laboratoire de Traitement du Signal et de l'Image; Université de Rennes 1; Rennes France
| | - Aileen McGonigal
- Institut de Neurosciences des Systèmes; Aix Marseille University; Marseille France
- AP-HM; Service de Neurophysiologie Clinique; Hôpital de la Timone; Marseille France
| | - Viktor Jirsa
- Institut de Neurosciences des Systèmes; Aix Marseille University; Marseille France
| | - Maxime Guye
- Centre d'Exploration Métabolique par Résonance Magnétique (CEMEREM); APHM; Hôpitaux de la Timone; Marseille France
| | - Christian Bénar
- Institut de Neurosciences des Systèmes; Aix Marseille University; Marseille France
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Wang Y, Trevelyan AJ, Valentin A, Alarcon G, Taylor PN, Kaiser M. Mechanisms underlying different onset patterns of focal seizures. PLoS Comput Biol 2017; 13:e1005475. [PMID: 28472032 PMCID: PMC5417416 DOI: 10.1371/journal.pcbi.1005475] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 03/23/2017] [Indexed: 02/07/2023] Open
Abstract
Focal seizures are episodes of pathological brain activity that appear to arise from a localised area of the brain. The onset patterns of focal seizure activity have been studied intensively, and they have largely been distinguished into two types-low amplitude fast oscillations (LAF), or high amplitude spikes (HAS). Here we explore whether these two patterns arise from fundamentally different mechanisms. Here, we use a previously established computational model of neocortical tissue, and validate it as an adequate model using clinical recordings of focal seizures. We then reproduce the two onset patterns in their most defining properties and investigate the possible mechanisms underlying the different focal seizure onset patterns in the model. We show that the two patterns are associated with different mechanisms at the spatial scale of a single ECoG electrode. The LAF onset is initiated by independent patches of localised activity, which slowly invade the surrounding tissue and coalesce over time. In contrast, the HAS onset is a global, systemic transition to a coexisting seizure state triggered by a local event. We find that such a global transition is enabled by an increase in the excitability of the "healthy" surrounding tissue, which by itself does not generate seizures, but can support seizure activity when incited. In our simulations, the difference in surrounding tissue excitability also offers a simple explanation of the clinically reported difference in surgical outcomes. Finally, we demonstrate in the model how changes in tissue excitability could be elucidated, in principle, using active stimulation. Taken together, our modelling results suggest that the excitability of the tissue surrounding the seizure core may play a determining role in the seizure onset pattern, as well as in the surgical outcome.
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Affiliation(s)
- Yujiang Wang
- Interdisciplinary Computing and Complex BioSystems (ICOS) research group, School of Computing Science, Newcastle University, Newcastle upon Tyne, United Kingdom
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
- Institute of Neurology, University College London, London, United Kingdom
| | - Andrew J Trevelyan
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Antonio Valentin
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
| | - Gonzalo Alarcon
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
- Comprehensive Epilepsy Center, Neuroscience Institute, Academic Health Systems, Hamad Medical Corporation, Doha, Qatar
| | - Peter N Taylor
- Interdisciplinary Computing and Complex BioSystems (ICOS) research group, School of Computing Science, Newcastle University, Newcastle upon Tyne, United Kingdom
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
- Institute of Neurology, University College London, London, United Kingdom
| | - Marcus Kaiser
- Interdisciplinary Computing and Complex BioSystems (ICOS) research group, School of Computing Science, Newcastle University, Newcastle upon Tyne, United Kingdom
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
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220
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Human seizures couple across spatial scales through travelling wave dynamics. Nat Commun 2017; 8:14896. [PMID: 28374740 PMCID: PMC5382286 DOI: 10.1038/ncomms14896] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 02/08/2017] [Indexed: 11/21/2022] Open
Abstract
Epilepsy—the propensity toward recurrent, unprovoked seizures—is a devastating disease affecting 65 million people worldwide. Understanding and treating this disease remains a challenge, as seizures manifest through mechanisms and features that span spatial and temporal scales. Here we address this challenge through the analysis and modelling of human brain voltage activity recorded simultaneously across microscopic and macroscopic spatial scales. We show that during seizure large-scale neural populations spanning centimetres of cortex coordinate with small neural groups spanning cortical columns, and provide evidence that rapidly propagating waves of activity underlie this increased inter-scale coupling. We develop a corresponding computational model to propose specific mechanisms—namely, the effects of an increased extracellular potassium concentration diffusing in space—that support the observed spatiotemporal dynamics. Understanding the multi-scale, spatiotemporal dynamics of human seizures—and connecting these dynamics to specific biological mechanisms—promises new insights to treat this devastating disease. The authors record both local and long-range neural activity during human epileptic seizures to study the underlying multi-scale dynamics. They find that coupling of activity across spatial scales increases during seizures through propagating waves that are fit by a model that combines neural activity and potassium concentration dynamics.
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Abstract
Stereotactic electroencephalography is a method for the invasive study for the human epileptic brain as a prelude to epilepsy surgery. The discipline of stereotactic electroencephalography is underpinned by an anatomo-electro-clinical analysis of epileptic seizures of focal origin and goes beyond simple stereotactic placement of depth electrodes. Stringent analysis of semiological and electrophysiological features is coupled with an understanding of this information in 3D anatomical space. Stereotactic electroencephalography offers significant advantages over subdural grid implantations, allowing pinpoint accuracy access to sulcal areas and deep brain structures, such as the insula, cingulate, basal and mesial brain regions, while associated with lower complication rates. Recent times have seen an exponential growth in stereotactic electroencephalography interest, driven in part by increasing complexity of typical epilepsy surgery patients in epilepsy surgery centers. Such patients are much more likely to be magnetic resonance imaging negative, or reoperations, or to have multifocal or widespread areas of cortical abnormalities. Herein, we discuss the advantages of stereotactic electroencephalography, principles of patient selection, implantation, and interpretation.
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A Novel Focal Seizure Pattern Generated in Superficial Layers of the Olfactory Cortex. J Neurosci 2017; 37:3544-3554. [PMID: 28264979 DOI: 10.1523/jneurosci.2239-16.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 12/06/2016] [Accepted: 12/16/2016] [Indexed: 02/03/2023] Open
Abstract
Seizure patterns identified in focal epilepsies caused by diverse etiologies are likely due to different pathogenic mechanisms. We describe here a novel, region-specific focal seizure pattern that mimics seizure activity observed in a subpopulation of patients submitted to presurgical monitoring with intracerebral electrodes. Distinctive seizure-like events (SLEs) are induced in the olfactory regions by acute treatment of both tangential brain slices and the isolated guinea pig brain with the potassium channel blocker 4-aminopyridine. Analysis of field potentials, intracellular activities, and extracellular potassium changes demonstrates that SLEs in the piriform cortex initiate in the superficial layer 1 lacking principal neurons with an activity-dependent increase of extracellular potassium. SLE progression (but not onset) does not require the participation of synaptic transmission and is mediated by diffusion of potassium to deep cortical layers. The novel seizure pattern here described is not observed in other cortical regions; it is proposed to rely on the peculiar organization of the superficial piriform cortex layers, which are characterized by unmyelinated axons and perisynaptic astroglial envelopes. This study reveals a sequence of ictogenic events in the olfactory cortex that were never described before in other cortical structures and supports the notion that altered potassium homeostasis and unmyelinated fibers may represent a potential vehicle for focal ictogenesis.SIGNIFICANCE STATEMENT We describe a novel seizure pattern peculiar of the olfactory cortex that resembles focal seizures with low-voltage fast activity at onset observed in humans. The findings suggest that network mechanisms responsible for seizure onset can be region specific.
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Anti-Epileptic Drug Combination Efficacy in an In Vitro Seizure Model - Phenytoin and Valproate, Lamotrigine and Valproate. PLoS One 2017; 12:e0169974. [PMID: 28076384 PMCID: PMC5226812 DOI: 10.1371/journal.pone.0169974] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 12/24/2016] [Indexed: 11/30/2022] Open
Abstract
In this study, we investigated the relative efficacy of different classes of commonly used anti-epileptic drugs (AEDs) with different mechanisms of action, individually and in combination, to suppress epileptiform discharges in an in vitro model. Extracellular field potential were recorded in 450 μm thick transverse hippocampal slices prepared from juvenile Wistar rats, in which “epileptiform discharges” (ED’s) were produced with a high-K+ (8.5 mM) bicarbonate-buffered saline solution. Single and dual recordings in stratum pyramidale of CA1 and CA3 regions were performed with 3–5 MΩ glass microelectrodes. All drugs—lamotrigine (LTG), phenytoin (PHT) and valproate (VPA)—were applied to the slice by superfusion at a rate of 2 ml/min at 32°C. Effects upon frequency of ED’s were assessed for LTG, PHT and VPA applied at different concentrations, in isolation and in combination. We demonstrated that high-K+ induced ED frequency was reversibly reduced by LTG, PHT and VPA, at concentrations corresponding to human therapeutic blood plasma concentrations. With a protocol using several applications of drugs to the same slice, PHT and VPA in combination displayed additivity of effect with 50μM PHT and 350μM VPA reducing SLD frequency by 44% and 24% individually (n = 19), and together reducing SLD frequency by 66% (n = 19). 20μM LTG reduced SLD frequency by 32% and 350μM VPA by 16% (n = 18). However, in combination there was a supra-linear suppression of ED’s of 64% (n = 18). In another independent set of experiments, similar results of drug combination responses were also found. In conclusion, a combination of conventional AEDs with different mechanisms of action, PHT and VPA, displayed linear additivity of effect on epileptiform activity. More intriguingly, a combination of LTG and VPA considered particularly efficacious clinically showed a supra-additive suppression of ED’s. This approach may be useful as an in vitro platform for assessing drug combination efficacy.
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Uva L, Boido D, Avoli M, de Curtis M, Lévesque M. High-frequency oscillations and seizure-like discharges in the entorhinal cortex of the in vitro isolated guinea pig brain. Epilepsy Res 2017; 130:21-26. [PMID: 28107659 DOI: 10.1016/j.eplepsyres.2017.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 12/07/2016] [Accepted: 01/04/2017] [Indexed: 10/20/2022]
Abstract
We analyzed the patterns of seizure-like activity and associated high-frequency oscillations (HFOs) induced by the K+ channel blocker 4-aminopyridine (4AP, 50μM) or the GABAA receptor antagonist bicuculline methiodide (BMI, 50μM) in the in vitro isolated guinea pig brain preparation. Extracellular field recordings were obtained from the medial entorhinal cortex (EC) using glass pipettes or silicon probes; 4AP or BMI were applied through the basilar artery. Ripples (80-200Hz) or fast ripples (250-500Hz) occurred at higher rates shortly before ictal events induced by 4AP or BMI, respectively. In addition, during the ictal period, ripples were mostly associated with 4AP-induced ictal events whereas fast ripples predominated during ictal discharges induced by BMI. Finally, ripples occurred at higher rates during the clonic phase of 4AP-induced ictal events compared to the tonic phase, while higher rates of fast ripples characterized the clonic phase in both 4AP- and BMI-induced ictal discharges. These differences in HFO occurrence presumably reflect the diverse action of these two convulsants on GABAA receptor signaling.
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Affiliation(s)
- Laura Uva
- Unit of Experimental Neurophysiology and Epileptology, Fondazione Istituto Neurologico, Carlo Besta, Milan, Italy
| | - Davide Boido
- Unit of Experimental Neurophysiology and Epileptology, Fondazione Istituto Neurologico, Carlo Besta, Milan, Italy
| | - Massimo Avoli
- Montreal Neurological Institute and Department of Neurology & Neurosurgery, McGill University, Montreal, Canada
| | - Marco de Curtis
- Unit of Experimental Neurophysiology and Epileptology, Fondazione Istituto Neurologico, Carlo Besta, Milan, Italy
| | - Maxime Lévesque
- Montreal Neurological Institute and Department of Neurology & Neurosurgery, McGill University, Montreal, Canada.
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225
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High frequency spectral changes induced by single-pulse electric stimulation: Comparison between physiologic and pathologic networks. Clin Neurophysiol 2016; 128:1053-1060. [PMID: 28131532 DOI: 10.1016/j.clinph.2016.12.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 12/05/2016] [Accepted: 12/15/2016] [Indexed: 01/09/2023]
Abstract
OBJECTIVE To investigate functional coupling between brain networks using spectral changes induced by single-pulse electric stimulation (SPES). METHOD We analyzed 20 patients with focal epilepsy, implanted with depth electrodes. SPES was applied to each pair of adjacent contacts, and responses were recorded from all other contacts. The mean response amplitude value was quantified in three time-periods after stimulation (10-60, 60-255, 255-500ms) for three frequency-ranges (Gamma, Ripples, Fast-Ripples), and compared to baseline. A total of 30,755 responses were analyzed, taking into consideration three dichotomous pairs: stimulating in primary sensory areas (S1-V1) vs. outside them, to test the interaction in physiologic networks; stimulating in seizure onset zone (SOZ) vs. non-SOZ, to test pathologic interactions; recording in default mode network (DMN) vs. non-DMN. RESULTS Overall, we observed an early excitation (10-60ms) and a delayed inhibition (60-500ms). More specifically, in the delayed period, stimulation in S1-V1 produced a higher gamma-inhibition in the DMN, while stimulation in the SOZ induced a higher inhibition in the epilepsy-related higher frequencies (Ripples and Fast-Ripples). CONCLUSION Physiologic and pathologic interactions can be assessed using spectral changes induced by SPES. SIGNIFICANCE This is a promising method for connectivity studies in patients with drug-resistant focal epilepsy.
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226
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Intracranial EEG seizure onset-patterns correlate with high-frequency oscillations in patients with drug-resistant epilepsy. Epilepsy Res 2016; 127:200-206. [DOI: 10.1016/j.eplepsyres.2016.09.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 08/18/2016] [Accepted: 09/06/2016] [Indexed: 11/19/2022]
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227
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Weiss SA, Orosz I, Salamon N, Moy S, Wei L, Van't Klooster MA, Knight RT, Harper RM, Bragin A, Fried I, Engel J, Staba RJ. Ripples on spikes show increased phase-amplitude coupling in mesial temporal lobe epilepsy seizure-onset zones. Epilepsia 2016; 57:1916-1930. [PMID: 27723936 PMCID: PMC5118142 DOI: 10.1111/epi.13572] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/29/2016] [Indexed: 01/22/2023]
Abstract
OBJECTIVE Ripples (80-150 Hz) recorded from clinical macroelectrodes have been shown to be an accurate biomarker of epileptogenic brain tissue. We investigated coupling between epileptiform spike phase and ripple amplitude to better understand the mechanisms that generate this type of pathologic ripple (pRipple) event. METHODS We quantified phase amplitude coupling (PAC) between epileptiform electroencephalography (EEG) spike phase and ripple amplitude recorded from intracranial depth macroelectrodes during episodes of sleep in 12 patients with mesial temporal lobe epilepsy. PAC was determined by (1) a phasor transform that corresponds to the strength and rate of ripples coupled with spikes, and a (2) ripple-triggered average to measure the strength, morphology, and spectral frequency of the modulating and modulated signals. Coupling strength was evaluated in relation to recording sites within and outside the seizure-onset zone (SOZ). RESULTS Both the phasor transform and ripple-triggered averaging methods showed that ripple amplitude was often robustly coupled with epileptiform EEG spike phase. Coupling was found more regularly inside than outside the SOZ, and coupling strength correlated with the likelihood a macroelectrode's location was within the SOZ (p < 0.01). The ratio of the rate of ripples coupled with EEG spikes inside the SOZ to rates of coupled ripples in non-SOZ was greater than the ratio of rates of ripples on spikes detected irrespective of coupling (p < 0.05). Coupling strength correlated with an increase in mean normalized ripple amplitude (p < 0.01), and a decrease in mean ripple spectral frequency (p < 0.05). SIGNIFICANCE Generation of low-frequency (80-150 Hz) pRipples in the SOZ involves coupling between epileptiform spike phase and ripple amplitude. The changes in excitability reflected as epileptiform spikes may also cause clusters of pathologically interconnected bursting neurons to grow and synchronize into aberrantly large neuronal assemblies.
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Affiliation(s)
- Shennan A Weiss
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania, U.S.A
| | - Iren Orosz
- Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
| | - Noriko Salamon
- Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
| | - Stephanie Moy
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
| | - Linqing Wei
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
| | - Maryse A Van't Klooster
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
- Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Robert T Knight
- Department of Psychology, University of California Berkeley, Berkeley, California, U.S.A
- Department of Neuroscience, University of California Berkeley, Berkeley, California, U.S.A
| | - Ronald M Harper
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
| | - Anatol Bragin
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
| | - Itzhak Fried
- Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
| | - Jerome Engel
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
- Brain Research Institute, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
| | - Richard J Staba
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
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Activation of GABA A receptors controls mesiotemporal lobe epilepsy despite changes in chloride transporters expression: In vivo and in silico approach. Exp Neurol 2016; 284:11-28. [DOI: 10.1016/j.expneurol.2016.07.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 07/12/2016] [Accepted: 07/16/2016] [Indexed: 12/16/2022]
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229
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Y Ho EC, Truccolo W. Interaction between synaptic inhibition and glial-potassium dynamics leads to diverse seizure transition modes in biophysical models of human focal seizures. J Comput Neurosci 2016; 41:225-44. [PMID: 27488433 PMCID: PMC5002283 DOI: 10.1007/s10827-016-0615-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 06/18/2016] [Accepted: 07/06/2016] [Indexed: 11/10/2022]
Abstract
How focal seizures initiate and evolve in human neocortex remains a fundamental problem in neuroscience. Here, we use biophysical neuronal network models of neocortical patches to study how the interaction between inhibition and extracellular potassium ([K (+)] o ) dynamics may contribute to different types of focal seizures. Three main types of propagated focal seizures observed in recent intracortical microelectrode recordings in humans were modelled: seizures characterized by sustained (∼30-60 Hz) gamma local field potential (LFP) oscillations; seizures where the onset in the propagated site consisted of LFP spikes that later evolved into rhythmic (∼2-3 Hz) spike-wave complexes (SWCs); and seizures where a brief stage of low-amplitude fast-oscillation (∼10-20 Hz) LFPs preceded the SWC activity. Our findings are fourfold: (1) The interaction between elevated [K (+)] o (due to abnormal potassium buffering by glial cells) and the strength of synaptic inhibition plays a predominant role in shaping these three types of seizures. (2) Strengthening of inhibition leads to the onset of sustained narrowband gamma seizures. (3) Transition into SWC seizures is obtained either by the weakening of inhibitory synapses, or by a transient strengthening followed by an inhibitory breakdown (e.g. GABA depletion). This reduction or breakdown of inhibition among fast-spiking (FS) inhibitory interneurons increases their spiking activity and leads them eventually into depolarization block. Ictal spike-wave discharges in the model are then sustained solely by pyramidal neurons. (4) FS cell dynamics are also critical for seizures where the evolution into SWC activity is preceded by low-amplitude fast oscillations. Different levels of elevated [K (+)] o were important for transitions into and maintenance of sustained gamma oscillations and SWC discharges. Overall, our modelling study predicts that the interaction between inhibitory interneurons and [K (+)] o glial buffering under abnormal conditions may explain different types of ictal transitions and dynamics during propagated seizures in human focal epilepsy.
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Affiliation(s)
- E C Y Ho
- Department of Neuroscience & Institute for Brain Science, Brown University, Providence, RI, USA.
- U.S. Department of Veterans Affairs, Center for Neurorestoration and Neurotechnology, Providence, RI, USA.
| | - Wilson Truccolo
- Department of Neuroscience & Institute for Brain Science, Brown University, Providence, RI, USA.
- U.S. Department of Veterans Affairs, Center for Neurorestoration and Neurotechnology, Providence, RI, USA.
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Kannan L, Vogrin S, Bailey C, Maixner W, Harvey AS. Centre of epileptogenic tubers generate and propagate seizures in tuberous sclerosis. Brain 2016; 139:2653-2667. [DOI: 10.1093/brain/aww192] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 06/20/2016] [Indexed: 01/14/2023] Open
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Janáčková S, Boyd S, Yozawitz E, Tsuchida T, Lamblin MD, Gueden S, Pressler R. Electroencephalographic characteristics of epileptic seizures in preterm neonates. Clin Neurophysiol 2016; 127:2721-2727. [DOI: 10.1016/j.clinph.2016.05.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Revised: 04/28/2016] [Accepted: 05/09/2016] [Indexed: 10/21/2022]
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Lagarde S, Bonini F, McGonigal A, Chauvel P, Gavaret M, Scavarda D, Carron R, Régis J, Aubert S, Villeneuve N, Giusiano B, Figarella-Branger D, Trebuchon A, Bartolomei F. Seizure-onset patterns in focal cortical dysplasia and neurodevelopmental tumors: Relationship with surgical prognosis and neuropathologic subtypes. Epilepsia 2016; 57:1426-35. [PMID: 27406939 DOI: 10.1111/epi.13464] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2016] [Indexed: 01/04/2023]
Abstract
OBJECTIVES The study of intracerebral electroencephalography (EEG) seizure-onset patterns is crucial to accurately define the epileptogenic zone and guide successful surgical resection. It also raises important pathophysiologic issues concerning mechanisms of seizure generation. Until now, several seizure-onset patterns have been described using distinct recording methods (subdural, depth electrode), mostly in temporal lobe epilepsies or with heterogeneous neocortical lesions. METHODS We analyzed data from a cohort of 53 consecutive patients explored by stereoelectroencephalography (SEEG) and with pathologically confirmed malformation of cortical development (MCD; including focal cortical dysplasia [FCD] and neurodevelopmental tumors [NDTs]). RESULTS We identified six seizure-onset patterns using visual and time-frequency analysis: low-voltage fast activity (LVFA); preictal spiking followed by LVFA; burst of polyspikes followed by LVFA; slow wave/DC shift followed by LVFA; theta/alpha sharp waves; and rhythmic spikes/spike-waves. We found a high prevalence of patterns that included LVFA (83%), indicating nevertheless that LVFA is not a constant characteristic of seizure onset. An association between seizure-onset patterns and histologic types was found (p = 001). The more prevalent patterns were as follows: (1) in FCD type I LVFA (23.1%) and slow wave/baseline shift followed by LVFA (15.4%); (2) in FCD type II burst of polyspikes followed by LVFA (31%), LVFA (27.6%), and preictal spiking followed by LVFA (27.6%); (3) in NDT, LVFA (54.5%). We found that a seizure-onset pattern that included LVFA was associated with favorable postsurgical outcome, but the completeness of the EZ resection was the sole independent predictive variable. SIGNIFICANCE Six different seizure-onset patterns can be described in FCD and NDT. Better postsurgical outcome is associated with patterns that incorporate LVFA.
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Affiliation(s)
- Stanislas Lagarde
- Clinical Neurophysiology and Epileptology Department, APHM, Timone Hospital, Marseille, France.,Inserm, Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | - Francesca Bonini
- Clinical Neurophysiology and Epileptology Department, APHM, Timone Hospital, Marseille, France.,Inserm, Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | - Aileen McGonigal
- Clinical Neurophysiology and Epileptology Department, APHM, Timone Hospital, Marseille, France.,Inserm, Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | - Patrick Chauvel
- Clinical Neurophysiology and Epileptology Department, APHM, Timone Hospital, Marseille, France.,Inserm, Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | - Martine Gavaret
- Clinical Neurophysiology and Epileptology Department, APHM, Timone Hospital, Marseille, France.,Inserm, Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | - Didier Scavarda
- Department of Pediatric Neurosurgery, APHM, Timone Hospital, Marseille, France
| | - Romain Carron
- Inserm, Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France.,Department of Functional and Stereotactic Neurosurgery, APHM, Timone Hospital, Marseille, France
| | - Jean Régis
- Inserm, Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France.,Department of Functional and Stereotactic Neurosurgery, APHM, Timone Hospital, Marseille, France
| | - Sandrine Aubert
- Clinical Neurophysiology and Epileptology Department, APHM, Timone Hospital, Marseille, France
| | - Nathalie Villeneuve
- Clinical Neurophysiology and Epileptology Department, APHM, Timone Hospital, Marseille, France
| | - Bernard Giusiano
- Inserm, Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | | | - Agnès Trebuchon
- Clinical Neurophysiology and Epileptology Department, APHM, Timone Hospital, Marseille, France.,Inserm, Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | - Fabrice Bartolomei
- Clinical Neurophysiology and Epileptology Department, APHM, Timone Hospital, Marseille, France.,Inserm, Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France
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233
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Davis MC, Broadwater DR, Mathews WH, Paige AL, DeWolfe JL, Elgavish RA, Riley KO, Ver Hoef LW. Statistical modeling of ICEEG features that determine resection planning. Clin Neurol Neurosurg 2016; 147:18-23. [PMID: 27249656 DOI: 10.1016/j.clineuro.2016.05.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 02/18/2016] [Accepted: 05/16/2016] [Indexed: 11/26/2022]
Abstract
OBJECT The interpretation of intracranial EEG (ICEEG) recordings is a complex balance of the significance of specific rhythms and their relative timing to seizure onset. Ictal and interictal findings are evaluated in light of findings from cortical stimulation of eloquent cortex to determine the area of resection. PATIENTS AND METHODS Patients with ICEEG electrodes and subsequent surgical resection were retrospectively identified. Only the first 15s of ictal activity, which was divided into five 3-s epochs, was considered. Every electrode in each patient was considered a separate observation in a logistic regression model to predict whether the cortex under a given electrode was included in the planned resection. RESULTS 19 included patients had a total of 37 unique seizures. Recordings from a total of 1306 electrodes were analyzed. The strongest predictors of resection of cortex underlying a given electrode was the presence of low-voltage fast activity in Epoch 1, rhythmic spikes in Epoch 1, interictal paroxysmal fast activity, and low-voltage fast activity in Epoch 2. High-amplitude beta spikes and rhythmic slow waves were also significant predictors in Epoch 1. Interictal spikes had a higher odds ratio of affecting the planned resection if described as "continuous" or "very frequent". The presence of motor or language cortex were the strongest negative predictors of resecting underlying cortex. CONCLUSIONS Here we describe a novel model of ictal and interictal patterns significantly associated with the inclusion of cortex underlying a given ICEEG electrode in the surgical resection plan.
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Affiliation(s)
- Matthew C Davis
- Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Devin R Broadwater
- University of Alabama at Birmingham School of Medical, Birmingham, AL, United States.
| | - Winn H Mathews
- School of Medicine, University of South Alabama, Mobile, AL, United States
| | - A Lebron Paige
- UAB Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jennifer L DeWolfe
- UAB Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ro A Elgavish
- UAB Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Kristen O Riley
- Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Lawrence W Ver Hoef
- UAB Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
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234
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Zhang Z, Parhi KK. Low-Complexity Seizure Prediction From iEEG/sEEG Using Spectral Power and Ratios of Spectral Power. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2016; 10:693-706. [PMID: 26529783 DOI: 10.1109/tbcas.2015.2477264] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Prediction of seizures is a difficult problem as the EEG patterns are not wide-sense stationary and change from seizure to seizure, electrode to electrode, and from patient to patient. This paper presents a novel patient-specific algorithm for prediction of seizures in epileptic patients from either one or two single-channel or bipolar channel intra-cranial or scalp electroencephalogram (EEG) recordings with low hardware complexity. Spectral power features are extracted and their ratios are computed. For each channel, a total of 44 features including 8 absolute spectral powers, 8 relative spectral powers and 28 spectral power ratios are extracted every two seconds using a 4-second window with a 50% overlap. These features are then ranked and selected in a patient-specific manner using a two-step feature selection. Selected features are further processed by a second-order Kalman filter and then input to a linear support vector machine (SVM) classifier. The algorithm is tested on the intra-cranial EEG (iEEG) from the Freiburg database and scalp EEG (sEEG) from the MIT Physionet database. The Freiburg database contains 80 seizures among 18 patients in 427 hours of recordings. The MIT EEG database contains 78 seizures from 17 children in 647 hours of recordings. It is shown that the proposed algorithm can achieve a sensitivity of 100% and an average false positive rate (FPR) of 0.0324 per hour for the iEEG (Freiburg) database and a sensitivity of 98.68% and an average FPR of 0.0465 per hour for the sEEG (MIT) database. These results are obtained with leave-one-out cross-validation where the seizure being tested is always left out from the training set. The proposed algorithm also has a low complexity as the spectral powers can be computed using FFT. The area and power consumption of the proposed linear SVM are 2 to 3 orders of magnitude less than a radial basis function kernel SVM (RBF-SVM) classifier. Furthermore, the total energy consumption of a system using linear SVM is reduced by 8% to 23% compared to system using RBF-SVM.
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235
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Advances of Intracranial Electroencephalography in Localizing the Epileptogenic Zone. Neurosci Bull 2016; 32:493-500. [PMID: 27197648 DOI: 10.1007/s12264-016-0035-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 04/21/2016] [Indexed: 10/21/2022] Open
Abstract
Intracranial electroencephalography (iEEG) provides the best precision in estimating the location and boundary of an epileptogenic zone. Analysis of iEEG in the routine EEG frequency range (0.5-70 Hz) remains the basis in clinical practice. Low-voltage fast activity is the most commonly reported ictal onset pattern in neocortical epilepsy, and low-frequency high-amplitude repetitive spiking is the most commonly reported ictal onset pattern in mesial temporal lobe epilepsy. Recent studies using wideband EEG recording have demonstrated that examining higher (80-1000 Hz) and lower (0.016-0.5 Hz) EEG frequencies can provide additional diagnostic information and help to improve the surgical outcome. In addition, novel computational techniques of iEEG signal analysis have provided new insights into the epileptic network. Here, we review some of these recent advances. Although these sophisticated and advanced techniques of iEEG analysis show promise in localizing the epileptogenic zone, their utility needs to be further validated in larger studies.
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236
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Avoli M, de Curtis M, Gnatkovsky V, Gotman J, Köhling R, Lévesque M, Manseau F, Shiri Z, Williams S. Specific imbalance of excitatory/inhibitory signaling establishes seizure onset pattern in temporal lobe epilepsy. J Neurophysiol 2016; 115:3229-37. [PMID: 27075542 DOI: 10.1152/jn.01128.2015] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 04/06/2016] [Indexed: 11/22/2022] Open
Abstract
Low-voltage fast (LVF) and hypersynchronous (HYP) patterns are the seizure-onset patterns most frequently observed in intracranial EEG recordings from mesial temporal lobe epilepsy (MTLE) patients. Both patterns also occur in models of MTLE in vivo and in vitro, and these studies have highlighted the predominant involvement of distinct neuronal network/neurotransmitter receptor signaling in each of them. First, LVF-onset seizures in epileptic rodents can originate from several limbic structures, frequently spread, and are associated with high-frequency oscillations in the ripple band (80-200 Hz), whereas HYP onset seizures initiate in the hippocampus and tend to remain focal with predominant fast ripples (250-500 Hz). Second, in vitro intracellular recordings from principal cells in limbic areas indicate that pharmacologically induced seizure-like discharges with LVF onset are initiated by a synchronous inhibitory event or by a hyperpolarizing inhibitory postsynaptic potential barrage; in contrast, HYP onset is associated with a progressive impairment of inhibition and concomitant unrestrained enhancement of excitation. Finally, in vitro optogenetic experiments show that, under comparable experimental conditions (i.e., 4-aminopyridine application), the initiation of LVF- or HYP-onset seizures depends on the preponderant involvement of interneuronal or principal cell networks, respectively. Overall, these data may provide insight to delineate better therapeutic targets in the treatment of patients presenting with MTLE and, perhaps, with other epileptic disorders as well.
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Affiliation(s)
- Massimo Avoli
- Montreal Neurological Institute and Departments of Neurology & Neurosurgery and of Physiology, McGill University, Montréal, Québec, Canada; Facoltà di Medicina e Odontoiatria, Sapienza Università di Roma, Rome, Italy;
| | - Marco de Curtis
- Epilepsy Unit, Fondazione Istituto Neurologico Carlo Besta, Milan, Italy
| | - Vadym Gnatkovsky
- Epilepsy Unit, Fondazione Istituto Neurologico Carlo Besta, Milan, Italy
| | - Jean Gotman
- Montreal Neurological Institute and Departments of Neurology & Neurosurgery and of Physiology, McGill University, Montréal, Québec, Canada
| | - Rüdiger Köhling
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Rostock, Germany; and
| | - Maxime Lévesque
- Montreal Neurological Institute and Departments of Neurology & Neurosurgery and of Physiology, McGill University, Montréal, Québec, Canada
| | - Frédéric Manseau
- Douglas Mental Health University Institute, McGill University, Montréal, Québec, Canada
| | - Zahra Shiri
- Montreal Neurological Institute and Departments of Neurology & Neurosurgery and of Physiology, McGill University, Montréal, Québec, Canada
| | - Sylvain Williams
- Douglas Mental Health University Institute, McGill University, Montréal, Québec, Canada
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237
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de Curtis M, Avoli M. GABAergic networks jump-start focal seizures. Epilepsia 2016; 57:679-87. [PMID: 27061793 DOI: 10.1111/epi.13370] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/19/2016] [Indexed: 01/20/2023]
Abstract
Abnormally enhanced glutamatergic excitation is commonly believed to mark the onset of a focal seizure. This notion, however, is not supported by firm evidence, and it will be challenged here. A general reduction of unit firing has been indeed observed in association with low-voltage fast activity at the onset of seizures recorded during presurgical intracranial monitoring in patients with focal, drug-resistant epilepsies. Moreover, focal seizures in animal models start with increased γ-aminobutyric acid (GABA)ergic interneuronal activity that silences principal cells. In vitro studies have shown that synchronous activation of GABAA receptors occurs at seizure onset and causes sizeable elevations in extracellular potassium, thus facilitating neuronal recruitment and seizure progression. A paradoxical involvement of GABAergic networks is required for the initiation of focal seizures characterized by low-voltage fast activity, which represents the most common seizure-onset pattern in focal epilepsies.
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Affiliation(s)
| | - Massimo Avoli
- Montreal Neurological Institute, McGill University, Montréal, Quebec, Canada.,Faculty of Medicine and Dentistry, La Sapienza University, Rome, Italy
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238
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Iimura Y, Sugano H, Nakajima M, Higo T, Suzuki H, Nakanishi H, Arai H. Analysis of Epileptic Discharges from Implanted Subdural Electrodes in Patients with Sturge-Weber Syndrome. PLoS One 2016; 11:e0152992. [PMID: 27054715 PMCID: PMC4824532 DOI: 10.1371/journal.pone.0152992] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 03/22/2016] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVE Almost two-thirds of patients with Sturge-Weber syndrome (SWS) have epilepsy, and half of them require surgery for it. However, it is well known that scalp electroencephalography (EEG) does not demonstrate unequivocal epileptic discharges in patients with SWS. Therefore, we analyzed interictal and ictal discharges from intracranial subdural EEG recordings in patients treated surgically for SWS to elucidate epileptogenicity in this disorder. METHODS Five intractable epileptic patients with SWS who were implanted with subdural electrodes for presurgical evaluation were enrolled in this study. We examined the following seizure parameters: seizure onset zone (SOZ), propagation speed of seizure discharges, and seizure duration by visual inspection. Additionally, power spectrogram analysis on some frequency bands at SOZ was performed from 60 s before the visually detected seizure onset using the EEG Complex Demodulation Method (CDM). RESULTS We obtained 21 seizures from five patients for evaluation, and all seizures initiated from the cortex under the leptomeningeal angioma. Most of the patients presented with motionless staring and respiratory distress as seizure symptoms. The average seizure propagation speed and duration were 3.1 ± 3.6 cm/min and 19.4 ± 33.6 min, respectively. Significant power spectrogram changes at the SOZ were detected at 10-30 Hz from 15 s before seizure onset, and at 30-80 Hz from 5 s before seizure onset. SIGNIFICANCE In patients with SWS, seizures initiate from the cortex under the leptomeningeal angioma, and seizure propagation is slow and persists for a longer period. CDM indicated beta to low gamma-ranged seizure discharges starting from shortly before the visually detected seizure onset. Our ECoG findings indicate that ischemia is a principal mechanism underlying ictogenesis and epileptogenesis in SWS.
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Affiliation(s)
- Yasushi Iimura
- Department of Neurosurgery, Epilepsy Center, Juntendo University, Tokyo, Japan
| | - Hidenori Sugano
- Department of Neurosurgery, Epilepsy Center, Juntendo University, Tokyo, Japan
| | - Madoka Nakajima
- Department of Neurosurgery, Epilepsy Center, Juntendo University, Tokyo, Japan
| | - Takuma Higo
- Department of Neurosurgery, Epilepsy Center, Juntendo University, Tokyo, Japan
| | - Hiroharu Suzuki
- Department of Neurosurgery, Epilepsy Center, Juntendo University, Tokyo, Japan
| | - Hajime Nakanishi
- Department of Neurosurgery, Epilepsy Center, Juntendo University, Tokyo, Japan
| | - Hajime Arai
- Department of Neurosurgery, Epilepsy Center, Juntendo University, Tokyo, Japan
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239
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Pellegrino G, Hedrich T, Chowdhury R, Hall JA, Lina JM, Dubeau F, Kobayashi E, Grova C. Source localization of the seizure onset zone from ictal EEG/MEG data. Hum Brain Mapp 2016; 37:2528-46. [PMID: 27059157 DOI: 10.1002/hbm.23191] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 03/07/2016] [Accepted: 03/10/2016] [Indexed: 11/08/2022] Open
Abstract
INTRODUCTION Surgical treatment of drug-resistant epilepsy relies on the identification of the seizure onset zone (SOZ) and often requires intracranial EEG (iEEG). We have developed a new approach for non-invasive magnetic and electric source imaging of the SOZ (MSI-SOZ and ESI-SOZ) from ictal magnetoencephalography (MEG) and EEG recordings, using wavelet-based Maximum Entropy on the Mean (wMEM) method. We compared the performance of MSI-SOZ and ESI-SOZ with interictal spike source localization (MSI-spikes and ESI-spikes) and clinical localization of the SOZ (i.e., based on iEEG or lesion topography, denoted as clinical-SOZ). METHODS A total of 46 MEG or EEG seizures from 13 patients were analyzed. wMEM was applied around seizure onset, centered on the frequency band showing the strongest power change. Principal component analysis applied to spatiotemporal reconstructed wMEM sources (0.4-1 s around seizure onset) identified the main spatial pattern of ictal oscillations. Qualitative sublobar concordance and quantitative measures of distance and spatial overlaps were estimated to compare MSI/ESI-SOZ with MSI/ESI-Spikes and clinical-SOZ. RESULTS MSI/ESI-SOZ were concordant with clinical-SOZ in 81% of seizures (MSI 90%, ESI 64%). MSI-SOZ was more accurate and identified sources closer to the clinical-SOZ (P = 0.012) and to MSI-Spikes (P = 0.040) as compared with ESI-SOZ. MSI/ESI-SOZ and MSI/ESI-Spikes did not differ in terms of concordance and distance from the clinical-SOZ. CONCLUSIONS wMEM allows non-invasive localization of the SOZ from ictal MEG and EEG. MSI-SOZ performs better than ESI-SOZ. MSI/ESI-SOZ can provide important additional information to MSI/ESI-Spikes during presurgical evaluation. Hum Brain Mapp 37:2528-2546, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Giovanni Pellegrino
- Multimodal Functional Imaging Lab, Biomedical Engineering Department, McGill University, Montreal, Québec, Canada.,Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Québec, Canada
| | - Tanguy Hedrich
- Multimodal Functional Imaging Lab, Biomedical Engineering Department, McGill University, Montreal, Québec, Canada
| | - Rasheda Chowdhury
- Multimodal Functional Imaging Lab, Biomedical Engineering Department, McGill University, Montreal, Québec, Canada
| | - Jeffery A Hall
- Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Québec, Canada
| | - Jean-Marc Lina
- Département de Génie Electrique, École de Technologie Supérieure, Montreal, Québec, Canada.,Centre De Recherches En Mathématiques, Montreal, Québec, Canada.,Centre D'etudes Avancées En Médecine Du Sommeil, Centre De Recherche De L'hôpital Sacré-Coeur De Montréal, Montreal, Québec, Canada
| | - Francois Dubeau
- Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Québec, Canada
| | - Eliane Kobayashi
- Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Québec, Canada
| | - Christophe Grova
- Multimodal Functional Imaging Lab, Biomedical Engineering Department, McGill University, Montreal, Québec, Canada.,Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Québec, Canada.,Centre De Recherches En Mathématiques, Montreal, Québec, Canada.,Physics Department and PERFORM Centre, Concordia University, Montreal, Québec, Canada
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240
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Malali A, Chaitanya G, Gowda S, Majumdar K. Analysis of cortical rhythms in intracranial EEG by temporal difference operators during epileptic seizures. Biomed Signal Process Control 2016. [DOI: 10.1016/j.bspc.2016.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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241
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Shiri Z, Manseau F, Lévesque M, Williams S, Avoli M. Activation of specific neuronal networks leads to different seizure onset types. Ann Neurol 2016; 79:354-65. [PMID: 26605509 DOI: 10.1002/ana.24570] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 11/12/2015] [Accepted: 11/15/2015] [Indexed: 01/21/2023]
Abstract
OBJECTIVE Ictal events occurring in temporal lobe epilepsy patients and in experimental models mimicking this neurological disorder can be classified, based on their onset pattern, into low-voltage, fast versus hypersynchronous onset seizures. It has been suggested that the low-voltage, fast onset pattern is mainly contributed by interneuronal (γ-aminobutyric acidergic) signaling, whereas the hypersynchronous onset involves the activation of principal (glutamatergic) cells. METHODS Here, we tested this hypothesis using the optogenetic control of parvalbumin-positive or somatostatin-positive interneurons and of calmodulin-dependent, protein kinase-positive, principal cells in the mouse entorhinal cortex in the in vitro 4-aminopyridine model of epileptiform synchronization. RESULTS We found that during 4-aminopyridine application, both spontaneous seizure-like events and those induced by optogenetic activation of interneurons displayed low-voltage, fast onset patterns that were associated with a higher occurrence of ripples than of fast ripples. In contrast, seizures induced by the optogenetic activation of principal cells had a hypersynchronous onset pattern with fast ripple rates that were higher than those of ripples. INTERPRETATION Our results firmly establish that under a similar experimental condition (ie, bath application of 4-aminopyridine), the initiation of low-voltage, fast and of hypersynchronous onset seizures in the entorhinal cortex depends on the preponderant involvement of interneuronal and principal cell networks, respectively.
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Affiliation(s)
- Zahra Shiri
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, and Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Frédéric Manseau
- Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Maxime Lévesque
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, and Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Sylvain Williams
- Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Massimo Avoli
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, and Department of Physiology, McGill University, Montreal, Quebec, Canada
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242
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Weiss SA, Alvarado-Rojas C, Bragin A, Behnke E, Fields T, Fried I, Engel J, Staba R. Ictal onset patterns of local field potentials, high frequency oscillations, and unit activity in human mesial temporal lobe epilepsy. Epilepsia 2016; 57:111-21. [PMID: 26611159 PMCID: PMC4862409 DOI: 10.1111/epi.13251] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2015] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To characterize local field potentials, high frequency oscillations, and single unit firing patterns in microelectrode recordings of human limbic onset seizures. METHODS Wide bandwidth local field potential recordings were acquired from microelectrodes implanted in mesial temporal structures during spontaneous seizures from six patients with mesial temporal lobe epilepsy. RESULTS In the seizure onset zone, distinct epileptiform discharges were evident in the local field potential prior to the time of seizure onset in the intracranial EEG. In all three seizures with hypersynchronous (HYP) seizure onset, fast ripples with incrementally increasing power accompanied epileptiform discharges during the transition to the ictal state (p < 0.01). In a single low voltage fast (LVF) onset seizure a triad of evolving HYP LFP discharges, increased single unit activity, and fast ripples of incrementally increasing power were identified ~20 s prior to seizure onset (p < 0.01). In addition, incrementally increasing fast ripples occurred after seizure onset just prior to the transition to LVF activity (p < 0.01). HYP onset was associated with an increase in fast ripple and ripple rate (p < 0.05) and commonly each HYP discharge had a superimposed ripple followed by a fast ripple. Putative excitatory and inhibitory single units could be distinguished during limbic seizure onset, and heterogeneous shifts in firing rate were observed during LVF activity. SIGNIFICANCE Epileptiform activity is detected by microelectrodes before it is detected by depth macroelectrodes, and the one clinically identified LVF ictal onset was a HYP onset at the local level. Patterns of incrementally increasing fast ripple power are consistent with observations in rats with experimental hippocampal epilepsy, suggesting that limbic seizures arise when small clusters of synchronously bursting neurons increase in size, coalesce, and reach a critical mass for propagation.
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Affiliation(s)
- Shennan Aibel Weiss
- Department of Neurology, University of California Los Angeles, Los Angeles, California, U.S.A
| | - Catalina Alvarado-Rojas
- Department of Neurology, University of California Los Angeles, Los Angeles, California, U.S.A
| | - Anatol Bragin
- Department of Neurology, University of California Los Angeles, Los Angeles, California, U.S.A
| | - Eric Behnke
- Department of Neurology, University of California Los Angeles, Los Angeles, California, U.S.A
- Department of Neurosurgery, University of California Los Angeles, Los Angeles, California, U.S.A
| | - Tony Fields
- Department of Neurology, University of California Los Angeles, Los Angeles, California, U.S.A
- Department of Neurosurgery, University of California Los Angeles, Los Angeles, California, U.S.A
| | - Itzhak Fried
- Department of Neurology, University of California Los Angeles, Los Angeles, California, U.S.A
- Department of Neurosurgery, University of California Los Angeles, Los Angeles, California, U.S.A
| | - Jerome Engel
- Department of Neurology, University of California Los Angeles, Los Angeles, California, U.S.A
- Department of Neurobiology, University of California Los Angeles, Los Angeles, California, U.S.A
- Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, California, U.S.A
- the Brain Research Institute David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, U.S.A
| | - Richard Staba
- Department of Neurology, University of California Los Angeles, Los Angeles, California, U.S.A
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243
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Seizures induced by direct electrical cortical stimulation – Mechanisms and clinical considerations. Clin Neurophysiol 2016; 127:31-39. [DOI: 10.1016/j.clinph.2014.12.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 11/02/2014] [Accepted: 12/07/2014] [Indexed: 11/19/2022]
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244
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Hypersynchronous ictal onset in the perirhinal cortex results from dynamic weakening in inhibition. Neurobiol Dis 2015; 87:1-10. [PMID: 26699817 DOI: 10.1016/j.nbd.2015.12.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 11/23/2015] [Accepted: 12/10/2015] [Indexed: 11/23/2022] Open
Abstract
We obtained field, K(+) selective and "sharp" intracellular recordings from the rat entorhinal (EC) and perirhinal (PC) cortices in an in vitro brain slice preparation to identify the events occurring at interictal-to-ictal transition during 4-aminopyridine application. Field recordings revealed interictal- (duration: 1.1 to 2.2s) and ictal-like (duration: 31 to 103s) activity occurring synchronously in EC and PC; in addition, interictal spiking in PC increased in frequency shortly before the onset of ictal oscillatory activity thus resembling the hypersynchronous seizure onset seen in epileptic patients and in in vivo animal models. Intracellular recordings with K-acetate+QX314-filled pipettes in PC principal cells showed that spikes at ictal onset had post-burst hyperpolarizations (presumably mediated by postsynaptic GABAA receptors), which gradually decreased in amplitude. This trend was associated with a progressive positive shift of the post-burst hyperpolarization reversal potential. Finally, the transient elevations in [K(+)]o (up to 4.4mM from a base line of 3.2mM) - which occurred with the interictal events in PC - progressively increased (up to 7.3mM) with the spike immediately preceding ictal onset. Our findings indicate that hypersynchronous seizure onset in rat PC is caused by dynamic weakening of GABAA receptor signaling presumably resulting from [K(+)]o accumulation.
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Cognitive impairment and spontaneous epilepsy in rats with malformations of cortical development. Seizure 2015; 33:29-34. [PMID: 26540232 DOI: 10.1016/j.seizure.2015.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 09/29/2015] [Accepted: 10/10/2015] [Indexed: 11/21/2022] Open
Abstract
PURPOSE To examine the cognition, spontaneous epilepsy, and electroencephalography (EEG) characteristics of rats with malformations of cortical development (MCD) and their use as an animal model for investigating the pathogenesis of intractable epilepsy and screening novel antiepileptic drugs. METHODS An epileptic rat model of MCD was established with the F1 generation of pregnant rats after X-irradiation with 175 cGy (Group L), 195 cGy (Group M), or 215 cGy (Group H). Long-term video-EEG monitoring was used to record the seizures in the rats with MCD. Cognition was assessed with the Morris water maze. The EEGs were recorded and analyzed in the frontal and parietal lobes and hippocampi of adult rats. Finally, the brain tissues were processed for Nissl staining. RESULTS The model groups exhibited markedly prolonged escape latencies and distinct decrements in the percent distance traveled in the target quadrant and platform-crossing frequency. These findings were dose-dependent. Frequent interictal epileptiform discharges were observed in the frontal and parietal lobes and hippocampi of adult rats, and their incidences were markedly higher in the model groups compared with that in the normal controls, with Group M having the highest incidence. Spontaneous seizures were observed in the model groups (mean incidence, 46.7%). The daily mean frequency of seizures and the incidence of spontaneous seizures were highest in Group M. Nissl staining revealed a dose-dependent pattern of hippocampal abnormalities, cortical and subcortical nodular heterotopia, and callosal agenesis in the model groups. CONCLUSION The 195 cGy dose was most appropriate for establishing an epileptic model of MCD with X-irradiation.
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Rummel C, Abela E, Andrzejak RG, Hauf M, Pollo C, Müller M, Weisstanner C, Wiest R, Schindler K. Resected Brain Tissue, Seizure Onset Zone and Quantitative EEG Measures: Towards Prediction of Post-Surgical Seizure Control. PLoS One 2015; 10:e0141023. [PMID: 26513359 PMCID: PMC4626164 DOI: 10.1371/journal.pone.0141023] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 10/02/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Epilepsy surgery is a potentially curative treatment option for pharmacoresistent patients. If non-invasive methods alone do not allow to delineate the epileptogenic brain areas the surgical candidates undergo long-term monitoring with intracranial EEG. Visual EEG analysis is then used to identify the seizure onset zone for targeted resection as a standard procedure. METHODS Despite of its great potential to assess the epileptogenicty of brain tissue, quantitative EEG analysis has not yet found its way into routine clinical practice. To demonstrate that quantitative EEG may yield clinically highly relevant information we retrospectively investigated how post-operative seizure control is associated with four selected EEG measures evaluated in the resected brain tissue and the seizure onset zone. Importantly, the exact spatial location of the intracranial electrodes was determined by coregistration of pre-operative MRI and post-implantation CT and coregistration with post-resection MRI was used to delineate the extent of tissue resection. Using data-driven thresholding, quantitative EEG results were separated into normally contributing and salient channels. RESULTS In patients with favorable post-surgical seizure control a significantly larger fraction of salient channels in three of the four quantitative EEG measures was resected than in patients with unfavorable outcome in terms of seizure control (median over the whole peri-ictal recordings). The same statistics revealed no association with post-operative seizure control when EEG channels contributing to the seizure onset zone were studied. CONCLUSIONS We conclude that quantitative EEG measures provide clinically relevant and objective markers of target tissue, which may be used to optimize epilepsy surgery. The finding that differentiation between favorable and unfavorable outcome was better for the fraction of salient values in the resected brain tissue than in the seizure onset zone is consistent with growing evidence that spatially extended networks might be more relevant for seizure generation, evolution and termination than a single highly localized brain region (i.e. a "focus") where seizures start.
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Affiliation(s)
- Christian Rummel
- Support Center for Advanced Neuroimaging (SCAN), University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland
| | - Eugenio Abela
- Support Center for Advanced Neuroimaging (SCAN), University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland
- Department of Neurology, Inselspital, Bern, Switzerland
| | - Ralph G. Andrzejak
- Universitat Pompeu Fabra, Department of Information and Communication Technologies, Barcelona, Spain
| | - Martinus Hauf
- Support Center for Advanced Neuroimaging (SCAN), University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland
- Bethesda Epilepsy Clinic, Tschugg, Switzerland
| | - Claudio Pollo
- Department of Neurosurgery, Inselspital, Bern, Switzerland
| | - Markus Müller
- Centro de Investigaciones en Ciencias, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
- Centro Internacional de Ciencias, Universidad Autónoma de México, Cuernavaca, Mexico
| | - Christian Weisstanner
- Support Center for Advanced Neuroimaging (SCAN), University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland
| | - Roland Wiest
- Support Center for Advanced Neuroimaging (SCAN), University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland
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Höller Y, Kutil R, Klaffenböck L, Thomschewski A, Höller PM, Bathke AC, Jacobs J, Taylor AC, Nardone R, Trinka E. High-frequency oscillations in epilepsy and surgical outcome. A meta-analysis. Front Hum Neurosci 2015; 9:574. [PMID: 26539097 PMCID: PMC4611152 DOI: 10.3389/fnhum.2015.00574] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 10/02/2015] [Indexed: 01/14/2023] Open
Abstract
High frequency oscillations (HFOs) are estimated as a potential marker for epileptogenicity. Current research strives for valid evidence that these HFOs could aid the delineation of the to-be resected area in patients with refractory epilepsy and improve surgical outcomes. In the present meta-analysis, we evaluated the relation between resection of regions from which HFOs can be detected and outcome after epilepsy surgery. We conducted a systematic review of all studies that related the resection of HFO-generating areas to postsurgical outcome. We related the outcome (seizure freedom) to resection ratio, that is, the ratio between the number of channels on which HFOs were detected and, among these, the number of channels that were inside the resected area. We compared the resection ratio between seizure free and not seizure free patients. In total, 11 studies were included. In 10 studies, ripples (80-200 Hz) were analyzed, and in 7 studies, fast ripples (>200 Hz) were studied. We found comparable differences (dif) and largely overlapping confidence intervals (CI) in resection ratios between outcome groups for ripples (dif = 0.18; CI: 0.10-0.27) and fast ripples (dif = 0.17; CI: 0.01-0.33). Subgroup analysis showed that automated detection (dif = 0.22; CI: 0.03-0.41) was comparable to visual detection (dif = 0.17; CI: 0.08-0.27). Considering frequency of HFOs (dif = 0.24; CI: 0.09-0.38) was related more strongly to outcome than considering each electrode that was showing HFOs (dif = 0.15; CI = 0.03-0.27). The effect sizes found in the meta-analysis are small but significant. Automated detection and application of a detection threshold in order to detect channels with a frequent occurrence of HFOs is important to yield a marker that could be useful in presurgical evaluation. In order to compare studies with different methodological approaches, detailed and standardized reporting is warranted.
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Affiliation(s)
- Yvonne Höller
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Austria
| | - Raoul Kutil
- Department of Mathematics, Paris Lodron University Salzburg, Austria
| | - Lukas Klaffenböck
- Department of Mathematics, Paris Lodron University Salzburg, Austria
| | - Aljoscha Thomschewski
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Austria
| | - Peter M Höller
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Austria
| | - Arne C Bathke
- Department of Mathematics, Paris Lodron University Salzburg, Austria
| | - Julia Jacobs
- Department of Neuropediatrics and Muscular Diseases and Epilepsy Center, University Medical Center Freiburg, Germany
| | - Alexandra C Taylor
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Austria
| | - Raffaele Nardone
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Austria ; Department of Neurology, Franz Tappeiner Hospital Merano, Italy
| | - Eugen Trinka
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Austria
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248
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Guerrini R, Duchowny M, Jayakar P, Krsek P, Kahane P, Tassi L, Melani F, Polster T, Andre VM, Cepeda C, Krueger DA, Cross JH, Spreafico R, Cosottini M, Gotman J, Chassoux F, Ryvlin P, Bartolomei F, Bernasconi A, Stefan H, Miller I, Devaux B, Najm I, Giordano F, Vonck K, Barba C, Blumcke I. Diagnostic methods and treatment options for focal cortical dysplasia. Epilepsia 2015; 56:1669-86. [DOI: 10.1111/epi.13200] [Citation(s) in RCA: 139] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2015] [Indexed: 12/16/2022]
Affiliation(s)
- Renzo Guerrini
- Pediatric Neurology and Neurogenetics Unit and Laboratories; Children's Hospital Meyer-University of Florence; Florence Italy
- IRCCS Stella Maris Foundation; Pisa Italy
| | - Michael Duchowny
- Neuroscience Program and the Comprehensive Epilepsy Center; Miami Children's Hospital; Miami Florida U.S.A
| | - Prasanna Jayakar
- Department of Neurology; Miami Children's Hospital; Miami Florida U.S.A
| | - Pavel Krsek
- Department of Pediatric Neurology; 2nd Faculty of Medicine; Motol University Hospital; Charles University; Prague Czech Republic
| | - Philippe Kahane
- INSERM U836; University of Grenoble Alpes, GIN; Grenoble; France
- Epilepsy Unit; Michallon Hospital; Grenoble France
| | - Laura Tassi
- Epilepsy Surgery Center; Niguarda Hospital; Milan Italy
| | - Federico Melani
- Pediatric Neurology and Neurogenetics Unit and Laboratories; Children's Hospital Meyer-University of Florence; Florence Italy
| | - Tilman Polster
- Department of Child Neurology; Bethel Epilepsy Center; Bielefeld Germany
| | | | - Carlos Cepeda
- Intellectual and Developmental Disabilities Research Center; David Geffen School of Medicine; University of California at Los Angeles; Los Angeles California U.S.A
| | - Darcy A. Krueger
- Division of Neurology; Department of Pediatrics; Cincinnati Children's Hospital Medical Center; University of Cincinnati College of Medicine; Cincinnati Ohio U.S.A
| | - J. Helen Cross
- UCL-Institute of Child Health; Great Ormond Street Hospital for Children NHS Foundation Trust; London United Kingdom
- Young Epilepsy; Lingfield United Kingdom
| | - Roberto Spreafico
- Clinical Epileptology and Experimental Neurophysiology Unit; Neurological InstituteC. Besta”; Milan Italy
| | - Mirco Cosottini
- Department of Translational Research and New Technologies in Medicine and Surgery; University of Pisa; Pisa Italy
| | - Jean Gotman
- Montreal Neurological Institute and Hospital; McGill University; Montreal Quebec Canada
| | | | - Philippe Ryvlin
- Department of Clinical Neurosciences; CHUV; Lausanne Switzerland
- Translational and Integrative Group in Epilepsy Research (TIGER) and Institute for Epilepsies (IDEE); Lyon's Neuroscience Center; INSERM U1028; CNRS 5292; UCBL; Le Vinatier Hospital; Bron; Lyon France
| | - Fabrice Bartolomei
- Faculty of Medicine; INSERM, U1106; Institute of Neurosciences of Systems; Marseille France
- Faculty of Medicine; Aix Marseille University; Marseille France
- Clinical Neurophysiology Unit; Department of Clinical Neurosciences; CHU Timone; Marseille France
- Henri-Gastaut Hospital; Saint-Paul Center; Marseille France
| | - Andrea Bernasconi
- Neuroimaging of Epilepsy Laboratory; McConnell Brain Imaging Center; Montreal Neurological Institute and Hospital; McGill University; Montreal Quebec Canada
| | - Hermann Stefan
- Epilepsy Center Erlangen (ZEE); University Erlangen-Nürnberg; Erlangen Germany
| | - Ian Miller
- Department of Neurology and Comprehensive Epilepsy Program; Brain Institute; Miami Children's Hospital; Miami Florida U.S.A
| | | | - Imad Najm
- Epilepsy Center; Neurological Institute; Cleveland Clinic; Cleveland OH U.S.A
| | - Flavio Giordano
- Pediatric Neurosurgery Unit; Children's Hospital Meyer-University of Florence; Florence Italy
| | - Kristl Vonck
- Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology; Department of Neurology; Ghent University; Ghent Belgium
| | - Carmen Barba
- Pediatric Neurology and Neurogenetics Unit and Laboratories; Children's Hospital Meyer-University of Florence; Florence Italy
| | - Ingmar Blumcke
- Department of Neuropathology; University Hospital Erlangen; Erlangen Germany
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Slow Spatial Recruitment of Neocortex during Secondarily Generalized Seizures and Its Relation to Surgical Outcome. J Neurosci 2015; 35:9477-90. [PMID: 26109670 DOI: 10.1523/jneurosci.0049-15.2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Understanding the spatiotemporal dynamics of brain activity is crucial for inferring the underlying synaptic and nonsynaptic mechanisms of brain dysfunction. Focal seizures with secondary generalization are traditionally considered to begin in a limited spatial region and spread to connected areas, which can include both pathological and normal brain tissue. The mechanisms underlying this spread are important to our understanding of seizures and to improve therapies for surgical intervention. Here we study the properties of seizure recruitment-how electrical brain activity transitions to large voltage fluctuations characteristic of spike-and-wave seizures. We do so using invasive subdural electrode arrays from a population of 16 patients with pharmacoresistant epilepsy. We find an average delay of ∼30 s for a broad area of cortex (8 × 8 cm) to be recruited into the seizure, at an estimated speed of ∼4 mm/s. The spatiotemporal characteristics of recruitment reveal two categories of patients: one in which seizure recruitment of neighboring cortical regions follows a spatially organized pattern consistent from seizure to seizure, and a second group without consistent spatial organization of activity during recruitment. The consistent, organized recruitment correlates with a more regular, compared with small-world, connectivity pattern in simulation and successful surgical treatment of epilepsy. We propose that an improved understanding of how the seizure recruits brain regions into large amplitude voltage fluctuations provides novel information to improve surgical treatment of epilepsy and highlights the slow spread of massive local activity across a vast extent of cortex during seizure.
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250
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Sonvenso DK, Itikawa EN, Santos MV, Santos LA, Trevisan AC, Bianchin MM, Pitella FA, Kato M, Carlotti CG, Busatto GF, Velasco TR, Santos AC, Leite JP, Sakamoto AC, Machado HR, Nunes AA, Wichert-Ana L. Systematic review of the efficacy in seizure control and safety of neuronavigation in epilepsy surgery: The need for well-designed prospective studies. Seizure 2015; 31:99-107. [DOI: 10.1016/j.seizure.2015.07.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 07/14/2015] [Accepted: 07/16/2015] [Indexed: 10/23/2022] Open
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