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Ghimire S, Dhamala M, Epstein CM. A Stable EEG Epilepsy Network Spans From Infraslow to Ripple and From Interictal to Ictus. J Clin Neurophysiol 2024; 41:251-256. [PMID: 36731034 DOI: 10.1097/wnp.0000000000000971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
PURPOSE To characterize the epilepsy network as reflected in intracranial electroencephalography (iEEG) across the full spectrum of iEEG frequencies and different phases of epilepsy, using a single, conceptually straightforward mathematical measure. METHODS The authors applied the spectral Granger causality techniques to intracranial electroencephalography recordings and computed contact-by-contact inward, outward, and total causal flow across frequencies and seizure phases in a selected group of three patients with well-defined, nonlesional seizure foci and prolonged responses to invasive procedures. One seizure and one interictal sample were analyzed per subject. RESULTS A prominent intracranial electroencephalography network was identified by Granger causality at both high and low frequencies. This network persists during the preictal and interictal phases of epilepsy and closely matches the visible seizure onset. The causal inflow network corresponded to seizure onset electrode contacts in 8 of 12 conditions, including ripple, infraslow, preictal, and interictal phases of epilepsy. Its most striking feature is the consistent dominance of causal inflow rather than outflow in the vicinity of the seizure onset zone. CONCLUSIONS Findings of this study indicate that a stable intracranial electroencephalography epilepsy network persists, and it can be characterized by a single Granger causality measure from infraslow to ripple frequencies and from the interictal to the immediate preictal phases of epilepsy.
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Affiliation(s)
| | - Mukesh Dhamala
- Departments of Physics and Astronomy and
- Mathematics and Statistics, Georgia State University, Atlanta, Georgia, U.S.A
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, U.S.A.; and
| | - Charles M Epstein
- Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, U.S.A
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Izumi M, Kobayashi K, Kajikawa S, Kanazawa K, Takayama Y, Iijima K, Iwasaki M, Okahara Y, Mine S, Iwadate Y, Ikeda A. Focal ictal direct current shifts by a time constant of 2 seconds were clinically useful for resective epilepsy surgery. Epilepsia 2023; 64:3294-3306. [PMID: 37905469 DOI: 10.1111/epi.17782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 09/26/2023] [Accepted: 09/26/2023] [Indexed: 11/02/2023]
Abstract
OBJECTIVE Ictal direct current shifts (icDCs) and ictal high-frequency oscillations (icHFOs) have been reported as surrogate markers for better surgical outcomes in epilepsy surgery. icDCs have been classified into two types: rapid and slow development. icDCs have been investigated with a time constant of 10 s (TC10s); however, many institutes use electroencephalography with a time constant of 2 s (TC2s). This study aimed to evaluate whether icDCs can be observed adequately with TC2s; moreover, it examined the relationship between the resected core area of icDCs or icHFOs and surgical outcomes, occurrence rate of each type of icDCs, and relationship between each type of icDCs and pathology. METHODS Twenty-five patients with intractable focal epilepsy were analyzed retrospectively. icDCs and icHFOs were defined according to common metrics. The amplitude of icDCs was defined at >200 μV and even <200 μV. The two electrodes producing the most prominent icDCs and icHFOs were defined as core electrodes. The correlation between the resected core electrode area and degree of seizure control after surgery was analyzed. icDCs were classified into two types based on a peak latency value cutoff of 8.9 s, and the occurrence rates of both patterns were investigated. RESULTS icDCs (142/147 seizures [96.6%]) and icHFOs (135/147 seizures [91.8%]) occurred in all patients (100%). Compared with the amplitude of icDCs with TC10s reported in previous studies, the amplitude of icDCs with TC2s was attenuated in the current study. A significant positive correlation was observed between the resected core electrode area and degree of seizure control in both icDCs and icHFOs. A rapid development pattern was observed in 202 of 264 electrodes (76.5%). SIGNIFICANCE Similar to icDCs with TC10s, those with TC2s were observed adequately. Furthermore, favorable outcomes are expected using TC2s, which is currently available worldwide.
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Grants
- JPMH20FC1039 Ministry of Health, Labour and Welfare
- JP15H05874 Japan Ministry of Education, Culture, Sports, Science and Technology
- JP20K21573 Japan Ministry of Education, Culture, Sports, Science and Technology
- JP19H03574 Japan Ministry of Education, Culture, Sports, Science and Technology
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Affiliation(s)
- Masaki Izumi
- Department of Neurosurgery, Chiba University Graduate School of Medicine, Chiba, Japan
- Department of Neurosurgery, Chiba Cerebral and Cardiovascular Center, Chiba, Japan
| | - Katsuya Kobayashi
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Shunsuke Kajikawa
- Department of Neurology, National Hospital Organization Kyoto Medical Center, Kyoto, Japan
| | - Kyoko Kanazawa
- Department of Neurology, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Yutaro Takayama
- Department of Neurosurgery, Yokohama City University, Kanagawa, Japan
| | - Keiya Iijima
- Department of Neurosurgery, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Masaki Iwasaki
- Department of Neurosurgery, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Yoji Okahara
- Department of Neurosurgery, Chiba Cerebral and Cardiovascular Center, Chiba, Japan
| | - Seiichiro Mine
- Department of Neurosurgery, Gyotoku General Hospital, Chiba, Japan
| | - Yasuo Iwadate
- Department of Neurosurgery, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders, and Physiology, Kyoto University Graduate School of Medicine, Kyoto, Japan
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Ghulaxe Y, Joshi A, Chavada J, Huse S, Kalbande B, Sarda PP. Understanding Focal Seizures in Adults: A Comprehensive Review. Cureus 2023; 15:e48173. [PMID: 38046728 PMCID: PMC10693312 DOI: 10.7759/cureus.48173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 11/02/2023] [Indexed: 12/05/2023] Open
Abstract
Focal or partial seizures are a common neurological disorder affecting adults. This review aims to provide an in-depth understanding of focal seizures in adults, including their classification, clinical presentation, etiology, diagnosis, and management. This article seeks to enhance awareness and knowledge among medical professionals and the general public by exploring the latest research and clinical insights. Standard electroencephalography (EEG) and recordings in presurgical electrode depth in humans provide a clear definition of patterns similar to focal seizures. Models of animals with partial seizures and epilepsy mimic seizure patterns with comparable characteristics. However, the network factors supporting interictal spikes, as well as the start, development, and end of seizures remain obscure. According to recent research, inhibitory networks are heavily implicated at the beginning of seizures, and extracellular potassium alterations help start and maintain seizure continuation. An increase in network synchronization, which may be caused by both excitatory and inhibitory pathways, is correlated with the cessation of a partial seizure. Recent research on temporal lobe focal seizures in human and animal models leads to the hypothesis that the active blocking of subcortical arousal processes brings on unconsciousness. Brainstem, basal forebrain, and thalamic arousal networks' neuronal firing is diminished during focal limbic seizures, and cortical arousal can be recovered when subcortical arousal circuits are engaged. These results suggest that thalamic neurostimulation may be therapeutic to restore arousal and consciousness during and after seizures. Targeted subcortical stimulation may increase arousal and consciousness when current treatments cannot halt seizures, enhancing safety and psychosocial function for epileptic patients. We embark on an investigation into adult focal seizures in this thorough review that goes beyond a cursory knowledge of their clinical symptoms.
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Affiliation(s)
- Yash Ghulaxe
- Department of Community Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Abhishek Joshi
- Department of Community Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Jay Chavada
- Department of Community Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Shreyash Huse
- Department of Community Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Bhakti Kalbande
- Department of Dentistry, Sharad Pawar Dental College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Prayas P Sarda
- Department of Community Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
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Lee S, Henry J, Tryba AK, Esengul Y, Warnke P, Wu S, van Drongelen W. Digital reconstruction of infraslow activity in human intracranial ictal recordings using a deconvolution-based inverse filter. Sci Rep 2022; 12:13701. [PMID: 35953580 PMCID: PMC9372169 DOI: 10.1038/s41598-022-18071-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 08/04/2022] [Indexed: 11/30/2022] Open
Abstract
Infraslow activity (ISA) is a biomarker that has recently become of interest in the characterization of seizure recordings. Recent data from a small number of studies have suggested that the epileptogenic zone may be identified by the presence of ISA. Investigation of low frequency activity in clinical seizure recordings, however, has been hampered by technical limitations. EEG systems necessarily include a high-pass filter early in the measurement chain to remove large artifactual drifts that can saturate recording elements such as the amplifier. This filter, unfortunately, attenuates legitimately seizure-related low frequencies, making ISA difficult to study in clinical EEG recordings. In this study, we present a deconvolution-based digital inverse filter that allows recovery of attenuated low frequency activity in intracranial recordings of temporal lobe epilepsy patients. First, we show that the unit impulse response (UIR) of an EEG system can be characterized by differentiation of the system's step response. As proof of method, we present several examples that show that the low frequency component of a high-pass filtered signal can be restored by deconvolution with the UIR. We then demonstrate that this method can be applied to biologically relevant signals including clinical EEG recordings obtained from seizure patients. Finally, we discuss how this method can be applied to study ISA to identify and assess the seizure onset zone.
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Affiliation(s)
- Somin Lee
- Medical Scientist Training Program, The University of Chicago, Chicago, IL, 60637, USA
- Committee on Neurobiology, The University of Chicago, Chicago, IL, 60637, USA
| | - Julia Henry
- Department of Pediatrics, The University of Chicago, Chicago, IL, 60637, USA
| | - Andrew K Tryba
- Department of Pediatrics, The University of Chicago, Chicago, IL, 60637, USA
| | - Yasar Esengul
- Department of Neurology, The University of Chicago, Chicago, IL, 60637, USA
| | - Peter Warnke
- Department of Neurosurgery, The University of Chicago, Chicago, IL, 60637, USA
| | - Shasha Wu
- Department of Neurology, The University of Chicago, Chicago, IL, 60637, USA
| | - Wim van Drongelen
- Committee on Neurobiology, The University of Chicago, Chicago, IL, 60637, USA.
- Department of Pediatrics, The University of Chicago, Chicago, IL, 60637, USA.
- Committee On Computational Neuroscience, The University of Chicago, Chicago, IL, 60637, USA.
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5
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Kajikawa S, Matsuhashi M, Kobayashi K, Hitomi T, Daifu-Kobayashi M, Kobayashi T, Yamao Y, Kikuchi T, Yoshida K, Kunieda T, Matsumoto R, Kakita A, Namiki T, Tsuda I, Miyamoto S, Takahashi R, Ikeda A. Two types of clinical ictal direct current shifts in invasive EEG of intractable focal epilepsy identified by waveform cluster analysis. Clin Neurophysiol 2022; 137:113-121. [PMID: 35305495 DOI: 10.1016/j.clinph.2022.02.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 02/07/2022] [Accepted: 02/25/2022] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To determine clinically ictal direct current (DC) shifts that can be identified by a time constant (TC) of 2 s and to delineate different types of DC shifts by different attenuation patterns between TC of 10 s and 2 s. METHODS Twenty-one patients who underwent subdural electrode implantation for epilepsy surgery were investigated. For habitual seizures, we compared (1) the peak amplitude and (2) peak latency of the earliest ictal DC shifts between TC of 10 s and 2 s. Cluster and logistic regression analyses were performed based on the attenuation rate of amplitude and peak latency with TC 10 s. RESULTS Ictal DC shifts in 120 seizures were analyzed; 89.1% of which were appropriately depicted even by a TC of 2 s. Cluster and logistic regression analyses revealed two types of ictal DC shift. Namely, a rapid development pattern was defined as the ictal DC shifts with a shorter peak latency and they also showed smaller attenuation rate of amplitude (73/120 seizures). Slow development pattern was defined as the ictal DC shifts with crosscurrent of a rapid development pattern, i.e., a longer peak latency and larger attenuation rate of amplitude (47/120 seizures). Focal cortical dysplasia (FCD) 1A tended to show a rapid development pattern (22/29 seizures) and FCD2A tended to show a slow development pattern (13 /18 seizures), indicating there might be some correlations between two types of ictal DC shift and certain pathologies. CONCLUSIONS Ictal DC shifts, especially rapid development pattern, can be recorded and identified by the AC amplifiers of TC of 2 s which is widely used in many institutes compared to that of TC of 10 s. Two types of ictal DC shifts were identified with possibility of corresponding pathology. SIGNIFICANCE Ictal DC shifts can be distinguished by their attenuation patterns.
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Affiliation(s)
- Shunsuke Kajikawa
- Department of Neurology, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan.
| | - Masao Matsuhashi
- Department of Epilepsy, Movement Disorders and Physiology, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan.
| | - Katsuya Kobayashi
- Department of Neurology, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan.
| | - Takefumi Hitomi
- Department of Clinical Laboratory, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan.
| | - Masako Daifu-Kobayashi
- Department of Neurology, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan.
| | - Tamaki Kobayashi
- Department of Neurosurgery, Otsu City Hospital, 2 Motomiya, Otsu-shi, Shiga 520-0804, Japan; Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan.
| | - Yukihiro Yamao
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan.
| | - Takayuki Kikuchi
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan.
| | - Kazumichi Yoshida
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan.
| | - Takeharu Kunieda
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan; Department of Neurosurgery, Ehime University Graduate School of Medicine, 454 Shitsukawa, Touon-shi, Ehime 791-0295, Japan.
| | - Riki Matsumoto
- Department of Neurology, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan; Division of Neurology, Kobe University Graduate School of Medicine, 7 Kusunoki-cho, Chuou-ku, Kobe-shi, Hyougo 650-0017, Japan.
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research Institute, Niigata University, 757 Asahi-cho 1, Chuou-ku, Niigata-shi, Niigata 951-8585, Japan.
| | - Takao Namiki
- Department of Mathematics, Faculty of Science, Hokkaido University, 8 West, 10 North, Kita-ku, Sapporo-shi, Hokkaido 060-0810, Japan.
| | - Ichiro Tsuda
- Chubu University Academy of Emerging Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai-shi, Aichi 487-8501, Japan.
| | - Susumu Miyamoto
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan.
| | - Ryosuke Takahashi
- Department of Neurology, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan.
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders and Physiology, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan.
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6
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Bonaccini Calia A, Masvidal-Codina E, Smith TM, Schäfer N, Rathore D, Rodríguez-Lucas E, Illa X, De la Cruz JM, Del Corro E, Prats-Alfonso E, Viana D, Bousquet J, Hébert C, Martínez-Aguilar J, Sperling JR, Drummond M, Halder A, Dodd A, Barr K, Savage S, Fornell J, Sort J, Guger C, Villa R, Kostarelos K, Wykes RC, Guimerà-Brunet A, Garrido JA. Full-bandwidth electrophysiology of seizures and epileptiform activity enabled by flexible graphene microtransistor depth neural probes. NATURE NANOTECHNOLOGY 2022; 17:301-309. [PMID: 34937934 DOI: 10.1038/s41565-021-01041-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 11/02/2021] [Indexed: 06/14/2023]
Abstract
Mapping the entire frequency bandwidth of brain electrophysiological signals is of paramount importance for understanding physiological and pathological states. The ability to record simultaneously DC-shifts, infraslow oscillations (<0.1 Hz), typical local field potentials (0.1-80 Hz) and higher frequencies (80-600 Hz) using the same recording site would particularly benefit preclinical epilepsy research and could provide clinical biomarkers for improved seizure onset zone delineation. However, commonly used metal microelectrode technology suffers from instabilities that hamper the high fidelity of DC-coupled recordings, which are needed to access signals of very low frequency. In this study we used flexible graphene depth neural probes (gDNPs), consisting of a linear array of graphene microtransistors, to concurrently record DC-shifts and high-frequency neuronal activity in awake rodents. We show here that gDNPs can reliably record and map with high spatial resolution seizures, pre-ictal DC-shifts and seizure-associated spreading depolarizations together with higher frequencies through the cortical laminae to the hippocampus in a mouse model of chemically induced seizures. Moreover, we demonstrate the functionality of chronically implanted devices over 10 weeks by recording with high fidelity spontaneous spike-wave discharges and associated infraslow oscillations in a rat model of absence epilepsy. Altogether, our work highlights the suitability of this technology for in vivo electrophysiology research, and in particular epilepsy research, by allowing stable and chronic DC-coupled recordings.
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Affiliation(s)
- Andrea Bonaccini Calia
- Catalan Institute of Nanoscience and Nanotechnology, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, Spain
| | - Eduard Masvidal-Codina
- Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Bellaterra, Spain
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
| | - Trevor M Smith
- Department of Clinical and Experimental Epilepsy, Queen Square Institute of Neurology, University College London, London, UK
| | - Nathan Schäfer
- Catalan Institute of Nanoscience and Nanotechnology, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, Spain
| | - Daman Rathore
- Department of Clinical and Experimental Epilepsy, Queen Square Institute of Neurology, University College London, London, UK
| | - Elisa Rodríguez-Lucas
- Catalan Institute of Nanoscience and Nanotechnology, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, Spain
| | - Xavi Illa
- Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Bellaterra, Spain
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
| | - Jose M De la Cruz
- Catalan Institute of Nanoscience and Nanotechnology, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, Spain
| | - Elena Del Corro
- Catalan Institute of Nanoscience and Nanotechnology, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, Spain
| | - Elisabet Prats-Alfonso
- Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Bellaterra, Spain
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
| | - Damià Viana
- Catalan Institute of Nanoscience and Nanotechnology, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, Spain
| | - Jessica Bousquet
- Catalan Institute of Nanoscience and Nanotechnology, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, Spain
| | - Clement Hébert
- Catalan Institute of Nanoscience and Nanotechnology, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, Spain
| | - Javier Martínez-Aguilar
- Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Bellaterra, Spain
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
| | - Justin R Sperling
- Catalan Institute of Nanoscience and Nanotechnology, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, Spain
| | - Matthew Drummond
- Nanomedicine Lab, National Graphene Institute and Faculty of Biology Medicine and Health, University of Manchester, Manchester, UK
| | - Arnab Halder
- Nanomedicine Lab, National Graphene Institute and Faculty of Biology Medicine and Health, University of Manchester, Manchester, UK
| | - Abbie Dodd
- Nanomedicine Lab, National Graphene Institute and Faculty of Biology Medicine and Health, University of Manchester, Manchester, UK
| | - Katharine Barr
- Nanomedicine Lab, National Graphene Institute and Faculty of Biology Medicine and Health, University of Manchester, Manchester, UK
| | - Sinead Savage
- Nanomedicine Lab, National Graphene Institute and Faculty of Biology Medicine and Health, University of Manchester, Manchester, UK
| | - Jordina Fornell
- Departament de Fisica, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Jordi Sort
- Departament de Fisica, Universitat Autonoma de Barcelona, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
| | - Christoph Guger
- g.tec medical engineering, Guger Technologies, Schiedlberg, Austria
| | - Rosa Villa
- Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Bellaterra, Spain
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
| | - Kostas Kostarelos
- Catalan Institute of Nanoscience and Nanotechnology, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, Spain
- Nanomedicine Lab, National Graphene Institute and Faculty of Biology Medicine and Health, University of Manchester, Manchester, UK
| | - Rob C Wykes
- Department of Clinical and Experimental Epilepsy, Queen Square Institute of Neurology, University College London, London, UK.
- Nanomedicine Lab, National Graphene Institute and Faculty of Biology Medicine and Health, University of Manchester, Manchester, UK.
| | - Anton Guimerà-Brunet
- Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Bellaterra, Spain.
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain.
| | - Jose A Garrido
- Catalan Institute of Nanoscience and Nanotechnology, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, Spain.
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain.
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7
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Hashimoto H, Ming Khoo H, Yanagisawa T, Tani N, Oshino S, Hirata M, Kishima H. Frequency band coupling with high-frequency activities in tonic-clonic seizures shifts from θ to δ band. Clin Neurophysiol 2022; 137:122-131. [DOI: 10.1016/j.clinph.2022.02.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 01/24/2022] [Accepted: 02/15/2022] [Indexed: 11/25/2022]
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8
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Irannejad A, Chaitanya G, Toth E, Pizarro D, Pati S. Direct Cortical Stimulation to Probe the Ictogenicity of the Epileptogenic Nodes in Temporal Lobe Epilepsy. Front Neurol 2022; 12:761412. [PMID: 35095721 PMCID: PMC8793936 DOI: 10.3389/fneur.2021.761412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 12/09/2021] [Indexed: 11/13/2022] Open
Abstract
Accurate mapping of the seizure onset zone (SOZ) is critical to the success of epilepsy surgery outcomes. Epileptogenicity index (EI) is a statistical method that delineates hyperexcitable brain regions involved in the generation and early propagation of seizures. However, EI can overestimate the SOZ for particular electrographic seizure onset patterns. Therefore, using direct cortical stimulation (DCS) as a probing tool to identify seizure generators, we systematically evaluated the causality of the high EI nodes (>0.3) in replicating the patient's habitual seizures. Specifically, we assessed the diagnostic yield of high EI nodes, i.e., the proportion of high EI nodes that evoked habitual seizures. A retrospective single-center study that included post-stereo encephalography (SEEG) confirmed TLE patients (n = 37) that had all high EI nodes stimulated, intending to induce a seizure. We evaluated the nodal responses (true and false responder rate) to stimulation and correlated with electrographic seizure onset patterns (hypersynchronous-HYP and low amplitude fast activity patterns-LAFA) and clinically defined SOZ. The ictogenicity (i.e., the propensity to induce the patient's habitual seizure) of a high EI node was only 44.5%. The LAFA onset pattern had a significantly higher response rate to DCS (i.e., higher evoked seizures). The concordance of an evoked habitual seizure with a clinically defined SOZ with good outcomes was over 50% (p = 0.0025). These results support targeted mapping of SOZ in LAFA onset patterns by performing DCS in high EI nodes to distinguish seizure generators (true responders) from hyperexcitable nodes that may be involved in early propagation.
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Affiliation(s)
- Auriana Irannejad
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States
- Epilepsy and Cognitive Neurophysiology Laboratory, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ganne Chaitanya
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States
- Epilepsy and Cognitive Neurophysiology Laboratory, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Emilia Toth
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States
- Epilepsy and Cognitive Neurophysiology Laboratory, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Diana Pizarro
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States
- Epilepsy and Cognitive Neurophysiology Laboratory, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Sandipan Pati
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States
- Epilepsy and Cognitive Neurophysiology Laboratory, University of Alabama at Birmingham, Birmingham, AL, United States
- *Correspondence: Sandipan Pati
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9
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Hashimoto H, Khoo HM, Yanagisawa T, Tani N, Oshino S, Kishima H, Hirata M. Phase-amplitude coupling between infraslow and high-frequency activities well discriminates between the preictal and interictal states. Sci Rep 2021; 11:17405. [PMID: 34465798 PMCID: PMC8408139 DOI: 10.1038/s41598-021-96479-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 08/11/2021] [Indexed: 11/23/2022] Open
Abstract
Infraslow activity (ISA) and high-frequency activity (HFA) are key biomarkers for studying epileptic seizures. We aimed to elucidate the relationship between ISA and HFA around seizure onset. We enrolled seven patients with drug-resistant focal epilepsy who underwent intracranial electrode placement. We comparatively analyzed the ISA, HFA, and ISA-HFA phase-amplitude coupling (PAC) in the seizure onset zone (SOZ) or non-SOZ (nSOZ) in the interictal, preictal, and ictal states. We recorded 15 seizures. HFA and ISA were larger in the ictal states than in the interictal or preictal state. During seizures, the HFA and ISA of the SOZ were larger and occurred earlier than those of nSOZ. In the preictal state, the ISA-HFA PAC of the SOZ was larger than that of the interictal state, and it began increasing at approximately 87 s before the seizure onset. The receiver-operating characteristic curve revealed that the ISA-HFA PAC of the SOZ showed the highest discrimination performance in the preictal and interictal states, with an area under the curve of 0.926. This study demonstrated the novel insight that ISA-HFA PAC increases before the onset of seizures. Our findings indicate that ISA-HFA PAC could be a useful biomarker for discriminating between the preictal and interictal states.
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Affiliation(s)
- Hiroaki Hashimoto
- Department of Neurological Diagnosis and Restoration, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita, Osaka, 565-0871, Japan. .,Department of Neurosurgery, Otemae Hospital, Osaka, Osaka, 540-0008, Japan.
| | - Hui Ming Khoo
- Department of Neurosurgery, Graduate School of Medicine, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Takufumi Yanagisawa
- Department of Neurosurgery, Graduate School of Medicine, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Naoki Tani
- Department of Neurosurgery, Graduate School of Medicine, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Satoru Oshino
- Department of Neurosurgery, Graduate School of Medicine, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Haruhiko Kishima
- Department of Neurosurgery, Graduate School of Medicine, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Masayuki Hirata
- Department of Neurological Diagnosis and Restoration, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita, Osaka, 565-0871, Japan.,Department of Neurosurgery, Graduate School of Medicine, Osaka University, Suita, Osaka, 565-0871, Japan
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10
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Hashimoto H, Khoo HM, Yanagisawa T, Tani N, Oshino S, Kishima H, Hirata M. Phase-amplitude coupling of ripple activities during seizure evolution with theta phase. Clin Neurophysiol 2021; 132:1243-1253. [PMID: 33867253 DOI: 10.1016/j.clinph.2021.03.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 02/25/2021] [Accepted: 03/09/2021] [Indexed: 02/07/2023]
Abstract
OBJECTIVE High-frequency activities (HFAs) and phase-amplitude coupling (PAC) are key neurophysiological biomarkers for studying human epilepsy. We aimed to clarify and visualize how HFAs are modulated by the phase of low-frequency bands during seizures. METHODS We used intracranial electrodes to record seizures of focal epilepsy (12 focal-to-bilateral tonic-clonic seizures and three focal-aware seizures in seven patients). The synchronization index, representing PAC, was used to analyze the coupling between the amplitude of ripples (80-250 Hz) and the phase of lower frequencies. We created a video in which the intracranial electrode contacts were scaled linearly to the power changes of ripple. RESULTS The main low frequency band modulating ictal-ripple activities was the θ band (4-8 Hz), and after completion of ictal-ripple burst, δ (1-4 Hz)-ripple PAC occurred. The ripple power increased simultaneously with rhythmic fluctuations from the seizure onset zone, and spread to other regions. CONCLUSIONS Ripple activities during seizure evolution were modulated by the θ phase. The PAC phenomenon was visualized as rhythmic fluctuations. SIGNIFICANCE Ripple power associated with seizure evolution increased and spread with fluctuations. The θ oscillations related to the fluctuations might represent the common neurophysiological processing involved in seizure generation.
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Affiliation(s)
- Hiroaki Hashimoto
- Department of Neurological Diagnosis and Restoration, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan; Department of Neurosurgery, Otemae Hospital, Osaka 540-0008, Japan; Endowed Research Department of Clinical Neuroengineering, Global Center for Medical Engineering and Informatics, Osaka University, Suita 565-0871, Japan.
| | - Hui Ming Khoo
- Department of Neurosurgery, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan
| | - Takufumi Yanagisawa
- Department of Neurosurgery, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan
| | - Naoki Tani
- Department of Neurosurgery, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan
| | - Satoru Oshino
- Department of Neurosurgery, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan
| | - Haruhiko Kishima
- Department of Neurosurgery, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan
| | - Masayuki Hirata
- Department of Neurological Diagnosis and Restoration, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan; Endowed Research Department of Clinical Neuroengineering, Global Center for Medical Engineering and Informatics, Osaka University, Suita 565-0871, Japan; Department of Neurosurgery, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan
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11
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Stereotactic EEG Practices: A Survey of United States Tertiary Referral Epilepsy Centers. J Clin Neurophysiol 2020; 39:474-480. [PMID: 33181594 DOI: 10.1097/wnp.0000000000000794] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
PURPOSE Stereotactic EEG (SEEG) is being increasingly used in the intracranial evaluation of refractory epilepsy in the United States. In this study, the authors describe current practice of SEEG among National Association of Epilepsy Centers tertiary referral (level IV) centers. METHODS Using the Survey Monkey platform, a survey was sent to all National Association of Epilepsy Centers level IV center directors. RESULTS Of 192 centers polled, 104 directors completed the survey (54% response rate). Ninety-two percent currently perform SEEG. Of these, 55% of institutions reported that greater than 75% of their invasive electrode cases used SEEG. Stereotactic EEG was commonly used over subdural electrodes in cases of suspected mesial temporal lobe epilepsy (87%), nonlesional frontal lobe epilepsy (79%), insular epilepsy (100%), and individuals with prior epilepsy surgery (74%). Most centers (72%) used single-lead electrocardiogram monitoring concurrently with SEEG, but less than half used continuous pulse oximetry (47%) and only a few used respiratory belts (3%). Other significant intercenter technical variabilities included electrode nomenclature and choice of reference electrode. Patient care protocols varied among centers in patient-to-nurse ratio and allowed patient activity. Half of all centers had personnel who had prior experience in SEEG (50.5%); 20% of centers had adopted SEEG without any formal training. CONCLUSIONS Stereotactic EEG has become the principal method for intracranial EEG monitoring in the majority of epilepsy surgery centers in the United States. Most report similar indications for use of SEEG, though significant variability exists in the utilization of concurrent cardiopulmonary monitoring as well as several technical and patient care practices. There is significant variability in level of background training in SEEG among practitioners. The study highlights the need for consensus statements and guidelines to benchmark SEEG practice and develop uniform standards in the United States.
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12
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Hashimoto H, Khoo HM, Yanagisawa T, Tani N, Oshino S, Kishima H, Hirata M. Coupling between infraslow activities and high-frequency oscillations precedes seizure onset. Epilepsia Open 2020; 5:501-506. [PMID: 32913958 PMCID: PMC7469835 DOI: 10.1002/epi4.12425] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 07/14/2020] [Accepted: 07/21/2020] [Indexed: 02/06/2023] Open
Abstract
Infraslow activities and high-frequency oscillations (HFOs) are observed in seizure-onset zones. However, the relation between them remains unclear. In this study, we investigated phase-amplitude coupling between infraslow phase (0.016-1 Hz) and HFOs' amplitude of focal impaired awareness seizures followed by focal to bilateral tonic-clonic seizures, in a 28-year-old right-handed man with a dysembryoplastic neuroepithelial tumor. We recorded five habitual seizures. After the time of seizure onset, a significant increase in the power of HFOs was observed, and the power was significantly coupled with θ (4-8 Hz) phase. In contrast, coupling of infraslow activities and HFOs surged a few minutes before the seizure-onset time, and ictal HFOs discharged after that. Collectively, our results show that coupling of infraslow activities and HFOs precedes the seizure-onset time. We infer that such coupling may be a potential biomarker for seizure prediction.
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Affiliation(s)
- Hiroaki Hashimoto
- Department of Neurological Diagnosis and RestorationGraduate School of MedicineOsaka UniversitySuitaJapan
- Department of NeurosurgeryOtemae HospitalOsakaJapan
- Endowed Research Department of Clinical NeuroengineeringGlobal Center for Medical Engineering and InformaticsOsaka UniversitySuitaJapan
| | - Hui Ming Khoo
- Department of NeurosurgeryGraduate School of MedicineOsaka UniversitySuitaJapan
| | - Takufumi Yanagisawa
- Department of NeurosurgeryGraduate School of MedicineOsaka UniversitySuitaJapan
| | - Naoki Tani
- Department of NeurosurgeryGraduate School of MedicineOsaka UniversitySuitaJapan
| | - Satoru Oshino
- Department of NeurosurgeryGraduate School of MedicineOsaka UniversitySuitaJapan
| | - Haruhiko Kishima
- Department of NeurosurgeryGraduate School of MedicineOsaka UniversitySuitaJapan
| | - Masayuki Hirata
- Department of Neurological Diagnosis and RestorationGraduate School of MedicineOsaka UniversitySuitaJapan
- Endowed Research Department of Clinical NeuroengineeringGlobal Center for Medical Engineering and InformaticsOsaka UniversitySuitaJapan
- Department of NeurosurgeryGraduate School of MedicineOsaka UniversitySuitaJapan
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13
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Salami P, Peled N, Nadalin JK, Martinet LE, Kramer MA, Lee JW, Cash SS. Seizure onset location shapes dynamics of initiation. Clin Neurophysiol 2020; 131:1782-1797. [PMID: 32512346 DOI: 10.1016/j.clinph.2020.04.168] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 03/24/2020] [Accepted: 04/13/2020] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Ictal electrographic patterns are widely thought to reflect underlying neural mechanisms of seizures. Here we studied the degree to which seizure patterns are consistent in a given patient, relate to particular brain regions and if two candidate biomarkers (high-frequency oscillations, HFOs; infraslow activity, ISA) and network activity, as assessed with cross-frequency interactions, can discriminate between seizure types. METHODS We analyzed temporal changes in low and high frequency oscillations recorded during seizures, as well as phase-amplitude coupling (PAC) to monitor the interactions between delta/theta and ripple/fast ripple frequency bands at seizure onset. RESULTS Seizures of multiple electrographic patterns were observed in a given patient and brain region. While there was an increase in HFO rate across different electrographic patterns, there are specific relationships between types of HFO activity and onset region. Similarly, changes in PAC dynamics were more closely related to seizure onset region than they were to electrographic patterns while ISA was a poor indicator for seizure onset. CONCLUSIONS Our findings suggest that the onset region sculpts neurodynamics at seizure initiation and that unique features of the cytoarchitecture and/or connectivity of that region play a significant role in determining seizure mechanism. SIGNIFICANCE To learn how seizures are initiated, researchers would do well to consider other aspects of their manifestation, in addition to their electrographic patterns. Examination of onset pattern in conjunction with the interactions between different oscillatory frequencies in the context of different brain regions might be more informative and lead to more reliable clinical inference as well as novel therapeutic approaches.
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Affiliation(s)
- Pariya Salami
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
| | - Noam Peled
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Jessica K Nadalin
- Department of Mathematics and Statistics, Boston University, Boston, MA, USA
| | - Louis-Emmanuel Martinet
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Mark A Kramer
- Department of Mathematics and Statistics, Boston University, Boston, MA, USA
| | - Jong W Lee
- Department of Neurology, Brigham and Women's Hospital, Boston, MA, USA
| | - Sydney S Cash
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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14
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Murai T, Hitomi T, Matsuhashi M, Matsumoto R, Kawamura Y, Kanda M, Takahashi R, Ikeda A. Scalp EEG Could Record Both Ictal Direct Current Shift and High-Frequency Oscillation Together Even With a Time Constant of 2 Seconds. J Clin Neurophysiol 2020; 37:191-194. [DOI: 10.1097/wnp.0000000000000670] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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15
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Job AS, David O, Minotti L, Bartolomei F, Chabardès S, Kahane P. Epileptogenicity Maps of Intracerebral Fast Activities (60-100 Hz) at Seizure Onset in Epilepsy Surgery Candidates. Front Neurol 2019; 10:1263. [PMID: 31849823 PMCID: PMC6892969 DOI: 10.3389/fneur.2019.01263] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 11/13/2019] [Indexed: 11/13/2022] Open
Abstract
Fast activities (FA) at seizure onset have been increasingly described as a useful signature of the epileptogenic zone (EZ) in patients undergoing intracranial EEG recordings. Different computer-based signal analysis methods have thus been developed for objectively quantifying ictal FA. Whether these methods detect FA in all forms of focal epilepsies, whether they provide similar information than visual analysis (VA), and whether they might help for the surgical decision remain crucial issues. We thus conducted a retrospective study in 21 consecutive patients suffering from drug-resistant seizures studied by SEEG recordings. Ictal FA were quantified using the Epileptogenicity Maps (EM) method that we recently developed and which generates, by adopting a neuroimaging approach, statistical parametric maps of FA ranging from 60 to 100 Hz (FA60−100). Ictal FA were analyzed blindly using VA and EM, and the prognostic significance of removing areas exhibiting FA60−100 at seizure onset was evaluated. A significant ictal FA60−100 activation was found in all patients, and in 92.6% of all the 68 seizures recorded, whatever the epilepsy type. The overlap ratio (OR) between VA and EM was significantly better for defining the regions spared at seizure onset than those from which seizure arose (p < 0.001), especially in temporal or temporal “plus” epilepsies. EM and VA were much more discordant to define the EZ, with a mean number of electrode contacts involved at seizure onset significantly higher with EM than with VA (p = <0.0001). Seizure outcome correlated with the resection ratio for FA60−100, which was significantly higher in seizure-free (Engel's class Ia) than in non seizure-free patients (class Ic-IV) (p = 0.048). The quantification of FA at seizure onset can bring information additional to clinical expertise that might contribute to define accurately the cortical region to be resected.
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Affiliation(s)
- Anne-Sophie Job
- Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Université Grenoble Alpes, Grenoble, France
| | - Olivier David
- Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Université Grenoble Alpes, Grenoble, France.,INS, Inserm, U1106, Marseille, France
| | - Lorella Minotti
- Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Université Grenoble Alpes, Grenoble, France
| | - Fabrice Bartolomei
- INS, Inserm, U1106, Marseille, France.,Neurophysiology Departement, La Timone Hospital, Marseille, France
| | - Stephan Chabardès
- Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Université Grenoble Alpes, Grenoble, France
| | - Philippe Kahane
- Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Université Grenoble Alpes, Grenoble, France
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16
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Park CJ, Hong SB. High Frequency Oscillations in Epilepsy: Detection Methods and Considerations in Clinical Application. J Epilepsy Res 2019; 9:1-13. [PMID: 31482052 PMCID: PMC6706641 DOI: 10.14581/jer.19001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 01/02/2019] [Accepted: 01/04/2019] [Indexed: 01/10/2023] Open
Abstract
High frequency oscillations (HFOs) is a brain activity observed in electroencephalography (EEG) in frequency ranges between 80–500 Hz. HFOs can be classified into ripples (80–200 Hz) and fast ripples (200–500 Hz) by their distinctive characteristics. Recent studies reported that both ripples and fast fipples can be regarded as a new biomarker of epileptogenesis and ictogenesis. Previous studies verified that HFOs are clinically important both in patients with mesial temporal lobe epilepsy and neocortical epilepsy. Also, in epilepsy surgery, patients with higher resection ratio of brain regions with HFOs showed better outcome than a group with lower resection ratio. For clinical application of HFOs, it is important to delineate HFOs accurately and discriminate them from artifacts. There have been technical improvements in detecting HFOs by developing various detection algorithms. Still, there is a difficult issue on discriminating clinically important HFOs among detected HFOs, where both quantitative and subjective approaches are suggested. This paper is a review on published HFO studies focused on clinical findings and detection techniques of HFOs as well as tips for clinical applications.
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Affiliation(s)
- Chae Jung Park
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.,Samsung Biomedical Research Institute (SBRI), Seoul, Korea
| | - Seung Bong Hong
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.,Samsung Biomedical Research Institute (SBRI), Seoul, Korea
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17
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Lee S, Issa NP, Rose S, Tao JX, Warnke PC, Towle VL, van Drongelen W, Wu S. DC shifts, high frequency oscillations, ripples and fast ripples in relation to the seizure onset zone. Seizure 2019; 77:52-58. [PMID: 31101405 DOI: 10.1016/j.seizure.2019.05.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/22/2019] [Accepted: 05/02/2019] [Indexed: 10/26/2022] Open
Abstract
Efforts to improve epilepsy surgery outcomes have led to increased interest in the study of electroencephalographic oscillations outside the conventional EEG bands. These include fast activity above the gamma band, known as high frequency oscillations (HFOs), and infraslow activity (ISA) below the delta band, sometimes referred to as direct current (DC) or ictal baseline shifts (IBS). HFOs in particular have been extensively studied as potential biomarkers for epileptogenic tissue in light of evidence showing that resection of brain tissue containing HFOs is associated with good surgical outcomes. Not all HFOs are conclusively pathological, however, as they can be recorded in nonepileptic tissue and induced by cognitive, visual, or motor tasks. Consequently, efforts to distinguish between pathological and physiological HFOs have identified several traits specific to pathological HFOs, such as coupling with interictal spikes, association with delta waves, and stereotypical morphologies. On the opposite end of the EEG spectrum, sub-delta oscillations have been shown to co-localize with the seizure onset zones (SOZ) and appear in a narrower spatial distribution than activity in the conventional EEG frequency bands. In this report, we review studies that implicate HFOs and ISA in ictogenesis and discuss current limitations such as inter-observer variability and poor standardization of recording techniques. Furthermore, we propose that HFOs and ISA should be analyzed in addition to activity in the conventional EEG band during intracranial presurgical EEG monitoring to identify the best possible surgical margin.
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Affiliation(s)
- Somin Lee
- Department of Pediatrics, The University of Chicago, Chicago, IL, 60607, USA; Committee on Neurobiology, The University of Chicago, Chicago, IL, 60607, USA
| | - Naoum P Issa
- Department of Neurology, The University of Chicago, Chicago, IL, 60607, USA
| | - Sandra Rose
- Department of Neurology, The University of Chicago, Chicago, IL, 60607, USA
| | - James X Tao
- Department of Neurology, The University of Chicago, Chicago, IL, 60607, USA
| | - Peter C Warnke
- Department of Surgery, The University of Chicago, Chicago, IL, 60607, USA
| | - Vernon L Towle
- Department of Neurology, The University of Chicago, Chicago, IL, 60607, USA; Department of Surgery, The University of Chicago, Chicago, IL, 60607, USA; Committee on Computational Neuroscience, The University of Chicago, Chicago, IL, 60607, USA
| | - Wim van Drongelen
- Department of Pediatrics, The University of Chicago, Chicago, IL, 60607, USA; Committee on Neurobiology, The University of Chicago, Chicago, IL, 60607, USA; Department of Neurology, The University of Chicago, Chicago, IL, 60607, USA; Committee on Computational Neuroscience, The University of Chicago, Chicago, IL, 60607, USA
| | - Shasha Wu
- Department of Neurology, The University of Chicago, Chicago, IL, 60607, USA.
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18
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Grinenko O, Li J, Mosher JC, Wang IZ, Bulacio JC, Gonzalez-Martinez J, Nair D, Najm I, Leahy RM, Chauvel P. A fingerprint of the epileptogenic zone in human epilepsies. Brain 2019; 141:117-131. [PMID: 29253102 PMCID: PMC5837527 DOI: 10.1093/brain/awx306] [Citation(s) in RCA: 118] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 09/27/2017] [Indexed: 11/14/2022] Open
Abstract
Defining a bio-electrical marker for the brain area responsible for initiating a seizure remains an unsolved problem. Fast gamma activity has been identified as the most specific marker for seizure onset, but conflicting results have been reported. In this study, we describe an alternative marker, based on an objective description of interictal to ictal transition, with the aim of identifying a time-frequency pattern or ‘fingerprint’ that can differentiate the epileptogenic zone from areas of propagation. Seventeen patients who underwent stereoelectroencephalography were included in the study. Each had seizure onset characterized by sustained gamma activity and were seizure-free after tailored resection or laser ablation. We postulated that the epileptogenic zone was always located inside the resection region based on seizure freedom following surgery. To characterize the ictal frequency pattern, we applied the Morlet wavelet transform to data from each pair of adjacent intracerebral electrode contacts. Based on a visual assessment of the time-frequency plots, we hypothesized that a specific time-frequency pattern in the epileptogenic zone should include a combination of (i) sharp transients or spikes; preceding (ii) multiband fast activity concurrent; with (iii) suppression of lower frequencies. To test this hypothesis, we developed software that automatically extracted each of these features from the time-frequency data. We then used a support vector machine to classify each contact-pair as being within epileptogenic zone or not, based on these features. Our machine learning system identified this pattern in 15 of 17 patients. The total number of identified contacts across all patients was 64, with 58 localized inside the resected area. Subsequent quantitative analysis showed strong correlation between maximum frequency of fast activity and suppression inside the resection but not outside. We did not observe significant discrimination power using only the maximum frequency or the timing of fast activity to differentiate contacts either between resected and non-resected regions or between contacts identified as epileptogenic versus non-epileptogenic. Instead of identifying a single frequency or a single timing trait, we observed the more complex pattern described above that distinguishes the epileptogenic zone. This pattern encompasses interictal to ictal transition and may extend until seizure end. Its time-frequency characteristics can be explained in light of recent models emphasizing the role of fast inhibitory interneurons acting on pyramidal cells as a prominent mechanism in seizure triggering. The pattern clearly differentiates the epileptogenic zone from areas of propagation and, as such, represents an epileptogenic zone ‘fingerprint’.
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Affiliation(s)
- Olesya Grinenko
- Epilepsy Center, Cleveland Clinic Neurological Institute, Cleveland OH, USA
| | - Jian Li
- Signal and Image Processing Institute, University of Southern California, Los Angeles CA, USA
| | - John C Mosher
- Epilepsy Center, Cleveland Clinic Neurological Institute, Cleveland OH, USA
| | - Irene Z Wang
- Epilepsy Center, Cleveland Clinic Neurological Institute, Cleveland OH, USA
| | - Juan C Bulacio
- Epilepsy Center, Cleveland Clinic Neurological Institute, Cleveland OH, USA
| | | | - Dileep Nair
- Epilepsy Center, Cleveland Clinic Neurological Institute, Cleveland OH, USA
| | - Imad Najm
- Epilepsy Center, Cleveland Clinic Neurological Institute, Cleveland OH, USA
| | - Richard M Leahy
- Signal and Image Processing Institute, University of Southern California, Los Angeles CA, USA
| | - Patrick Chauvel
- Epilepsy Center, Cleveland Clinic Neurological Institute, Cleveland OH, USA
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19
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McGovern RA, Knight EP, Gupta A, Moosa ANV, Wyllie E, Bingaman WE, Gonzalez-Martinez J. Robot-assisted stereoelectroencephalography in children. J Neurosurg Pediatr 2019; 23:288-296. [PMID: 30544342 DOI: 10.3171/2018.7.peds18305] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 07/11/2018] [Indexed: 11/06/2022]
Abstract
OBJECTIVEThe goal in the study was to describe the clinical outcomes associated with robot-assisted stereoelectroencephalography (SEEG) in children.METHODSThe authors performed a retrospective, single-center study in consecutive children with medically refractory epilepsy who were undergoing robot-assisted SEEG. Kaplan-Meier survival analysis was used to calculate the probability of seizure freedom. Both univariate and multivariate methods were used to analyze the preoperative and operative factors associated with seizure freedom.RESULTSFifty-seven children underwent a total of 64 robot-assisted procedures. The patients' mean age was 12 years, an average of 6.4 antiepileptic drugs (AEDs) per patient had failed prior to implantation, and in 56% of the patients the disease was considered nonlesional. On average, children had 12.4 electrodes placed per implantation, with an implantation time of 9.6 minutes per electrode and a 10-day postoperative stay. SEEG analysis yielded a definable epileptogenic zone in 51 (89%) patients; 42 (74%) patients underwent surgery, half of whom were seizure free at last follow-up, 19.6 months from resection. In a multivariate generalized linear model, resective surgery, older age, and shorter SEEG-related hospital length of stay were associated with seizure freedom. In a Cox proportional hazards model including only the children who underwent resective surgery, older age was the only significant factor associated with seizure freedom. Complications related to bleeding were the major contributors to morbidity. One patient (1.5%) had a symptomatic hemorrhage resulting in a permanent neurological deficit.CONCLUSIONSThe authors report one of the largest pediatric-specific SEEG series demonstrating that the modern surgical management of medically refractory epilepsy in children can lead to seizure freedom in many patients, while also highlighting the challenges posed by this difficult patient population.
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20
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Abel TJ, Varela Osorio R, Amorim-Leite R, Mathieu F, Kahane P, Minotti L, Hoffmann D, Chabardes S. Frameless robot-assisted stereoelectroencephalography in children: technical aspects and comparison with Talairach frame technique. J Neurosurg Pediatr 2018; 22:37-46. [PMID: 29676681 DOI: 10.3171/2018.1.peds17435] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Robot-assisted stereoelectroencephalography (SEEG) is gaining popularity as a technique for localization of the epileptogenic zone (EZ) in children with pharmacoresistant epilepsy. Here, the authors describe their frameless robot-assisted SEEG technique and report preliminary outcomes and relative complications in children as compared to results with the Talairach frame-based SEEG technique. METHODS The authors retrospectively analyzed the results of 19 robot-assisted SEEG electrode implantations in 17 consecutive children (age < 17 years) with pharmacoresistant epilepsy, and compared these results to 19 preceding SEEG electrode implantations in 18 children who underwent the traditional Talairach frame-based SEEG electrode implantation. The primary end points were seizure-freedom rates, operating time, and complication rates. RESULTS Seventeen children (age < 17 years) underwent a total of 19 robot-assisted SEEG electrode implantations. In total, 265 electrodes were implanted. Twelve children went on to have EZ resection: 4 demonstrated Engel class I outcomes, whereas 2 had Engel class II outcomes, and 6 had Engel class III-IV outcomes. Of the 5 patients who did not have resection, 2 underwent thermocoagulation. One child reported transient paresthesia associated with 2 small subdural hematomas, and 3 other children had minor asymptomatic intracranial hemorrhages. There were no differences in complication rates, rates of resective epilepsy surgery, or seizure freedom rates between this cohort and the preceding 18 children who underwent Talairach frame-based SEEG. The frameless robot-assisted technique was associated with shorter operating time (p < 0.05). CONCLUSIONS Frameless robot-assisted SEEG is a safe and effective means of identifying the EZ in children with pharmacoresistant partial epilepsy. Robot-assisted SEEG is faster than the Talairach frame-based method, and has equivalent safety and efficacy. The former, furthermore, facilitates more electrode trajectory possibilities, which may improve the localization of epileptic networks.
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Affiliation(s)
- Taylor J Abel
- 1Clinique de Neurochirurgie, and.,2Division of Neurosurgery, The Hospital for Sick Children, Toronto, Ontario, Canada
| | | | - Ricardo Amorim-Leite
- 3Clinique Neurologique, Centre Hospitalier Universitaire Grenoble-Alpes, Grenoble, France; and
| | - Francois Mathieu
- 2Division of Neurosurgery, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Philippe Kahane
- 3Clinique Neurologique, Centre Hospitalier Universitaire Grenoble-Alpes, Grenoble, France; and
| | - Lorella Minotti
- 3Clinique Neurologique, Centre Hospitalier Universitaire Grenoble-Alpes, Grenoble, France; and
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Anyanwu C, Motamedi GK. Diagnosis and Surgical Treatment of Drug-Resistant Epilepsy. Brain Sci 2018; 8:E49. [PMID: 29561756 PMCID: PMC5924385 DOI: 10.3390/brainsci8040049] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 03/12/2018] [Accepted: 03/16/2018] [Indexed: 11/29/2022] Open
Abstract
Despite appropriate trials of at least two antiepileptic drugs, about a third of patients with epilepsy remain drug resistant (intractable; refractory). Epilepsy surgery offers a potential cure or significant improvement to those with focal onset drug-resistant seizures. Unfortunately, epilepsy surgery is still underutilized which might be in part because of the complexity of presurgical evaluation. This process includes classifying the seizure type, lateralizing and localizing the seizure onset focus (epileptogenic zone), confirming the safety of the prospective brain surgery in terms of potential neurocognitive deficits (language and memory functions), before devising a surgical plan. Each one of the above steps requires special tests. In this paper, we have reviewed the process of presurgical evaluation in patients with drug-resistant focal onset epilepsy.
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Affiliation(s)
- Chinekwu Anyanwu
- Department of Neurology, Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA.
| | - Gholam K Motamedi
- Department of Neurology, Georgetown University Medical Center, Washington, DC 20007, USA.
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Wennberg R, Steriade C, Chen R, Andrade D. Frontal infraslow activity marks the motor spasms of anti-LGI1 encephalitis. Clin Neurophysiol 2018; 129:59-68. [DOI: 10.1016/j.clinph.2017.10.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 09/15/2017] [Accepted: 10/12/2017] [Indexed: 02/01/2023]
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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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Rodin E, Bornfleth H, Johnson M. DC-EEG recordings of mindfulness. Clin Neurophysiol 2017; 128:512-519. [PMID: 28222345 DOI: 10.1016/j.clinph.2016.12.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/25/2016] [Accepted: 12/29/2016] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To assess the frequency spectrum of the normal waking human eyes-closed EEG while concentrating on a mental task. METHODS Ten adult normal volunteers listened to a CD encouraging mindfulness for one hour and five minutes while their EEG was recorded on a 128 channel DC based ANT system. The software package BESA Research version 6.1 was used for data analysis. The data were subjected to topographic display, frequency as well as independent component analysis. RESULTS Near-DC activity that extended beyond one hour, as well as rhythmic wave durations ranging from about 10 to 35min, was observed in all subjects. For this task the major topographic distribution was mainly in frontal near midline areas and the inferior portions of the hemispheres. CONCLUSIONS The study demonstrated that rhythms below the infraslow band, as well as a near-DC component, exist in the normal human EEG. Their significance for health and disease now needs to be explored. SIGNIFICANCE Since DC-based EEG/MEG systems are already in use by some laboratories, investigators are encouraged to include the exploration of these ultra-slow waves in the review of their data.
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Affiliation(s)
- Ernst Rodin
- University of Utah, Department of Neurology, 175 N Medical Drive East, Salt Lake City, UT 84132, USA.
| | | | - Michael Johnson
- University of Utah, Department of Psychiatry, 501 Chipeta Way, Salt Lake City, UT, USA.
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Interictal Infraslow Activity in Stereoelectroencephalography: From Focus to Network. J Clin Neurophysiol 2017; 33:141-8. [PMID: 26491857 DOI: 10.1097/wnp.0000000000000236] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
PURPOSE Infraslow activity (ISA) occurring during the interictal state in focal epilepsy is largely unstudied. In this exploratory analysis, the authors aimed to characterize features of interictal ISA in a cohort of patients studied by stereoelectroencephography. METHODS The interictal stereoelectroencephography records for 15 consecutive adult patients were retrospectively analyzed, after application of both conventional (1.6-70 Hz) and infraslow (0.01-0.1 Hz) bandpass filters. Visual analysis was complemented by time-frequency analysis to quantify the change in ISA power over hours. Linear correlation coefficient (R) calculations were used to map interictal connectivity in the infraslow band. RESULTS Interictal ISA background fluctuations were present throughout the interictal state in all patients, manifesting as recurrent and stereotyped oscillations. These oscillations had an apparent modulatory effect on conventional-band activities and spikes ("spike-crested oscillations"). In the infraslow band, the correlations between electrode contacts were shown to have a stable structure over time. CONCLUSIONS Infraslow activity exists as a fundamental component of wideband cortical dynamics in focal epilepsy, with features suggestive of scale-free (1/f) dynamics: evidence of phase-amplitude coupling and functional connectivity in the infraslow band. Rather than viewed as a focal paroxysmal activity, interictal ISA may be better understood as a network process, although this requires further study.
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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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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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Thompson S, Krishnan B, Gonzalez-Martinez J, Bulacio J, Jehi L, Mosher J, Alexopoulos A, Burgess R. Ictal infraslow activity in stereoelectroencephalography: Beyond the “DC shift”. Clin Neurophysiol 2016; 127:117-128. [DOI: 10.1016/j.clinph.2015.03.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 03/08/2015] [Accepted: 03/27/2015] [Indexed: 11/28/2022]
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Munyon C, Sweet J, Luders H, Lhatoo S, Miller J. The 3-dimensional grid: a novel approach to stereoelectroencephalography. Neurosurgery 2015; 11 Suppl 2:127-33; discussion 133-4. [PMID: 25599199 DOI: 10.1227/neu.0000000000000649] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Successful surgical treatment of epilepsy requires accurate definition of areas of ictal onset and eloquent brain. Although invasive monitoring can help, subdural grids cannot sample sulci or subcortical tissue; traditional stereoelectroencephalography depth electrodes are usually placed too far apart to provide sufficient resolution for mapping. OBJECTIVE To report a strategy of depth electrode placement in a dense array to allow precise anatomic localization of epileptic and eloquent cortex. METHODS Twenty patients with medically intractable epilepsy either poorly localized or found to arise adjacent to eloquent areas underwent placement of arrays of depth electrodes into and around the putative area of seizure onset with the use of framed stereotaxy. Each array consisted of a "grid" of parallel electrodes in a rectangular pattern with 1 cm between entry sites. In a subset of patients, a few electrodes were placed initially, with additional electrodes placed in a second stage. Trajectories were modified to avoid cortical vessels defined on magnetic resonance imaging. Patients were monitored for 4 to 21 days to establish the precise location of seizure onset. Stimulation was performed to map cortical and subcortical eloquent regions. Electrode locations were coregistered for frameless stereotaxy during subsequent resection of seizure focus. RESULTS Two hundred fifty-four electrodes were implanted. Discrete regions of seizure onset and functional cortex were identified, which were used during resection to remove epileptogenic tissue while preserving eloquent areas. There were no hemorrhagic or infectious complications; no patient suffered permanent neurological deficit. CONCLUSION The 3-dimensional intraparenchymal grid is useful for identifying the location and extent of epileptic and eloquent brain.
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Affiliation(s)
- Charles Munyon
- *Department of Neurological Surgery and ‡Neurology, University Hospitals Case Medical Center, Cleveland, Ohio
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de Curtis M, Avoli M. Initiation, Propagation, and Termination of Partial (Focal) Seizures. Cold Spring Harb Perspect Med 2015; 5:a022368. [PMID: 26134843 PMCID: PMC4484951 DOI: 10.1101/cshperspect.a022368] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The neurophysiological patterns that correlate with partial (focal) seizures are well defined in humans by standard electroencephalogram (EEG) and presurgical depth electrode recordings. Seizure patterns with similar features are reproduced in animal models of partial seizures and epilepsy. However, the network determinants that support interictal spikes, as well as the initiation, progression, and termination of seizures, are still elusive. Recent findings show that inhibitory networks are prominently involved at the onset of these seizures, and that extracellular changes in potassium contribute to initiate and sustain seizure progression. The end of a partial seizure correlates with an increase in network synchronization, which possibly involves both excitatory and inhibitory mechanisms.
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Affiliation(s)
- Marco de Curtis
- Unit of Epileptology and Experimental Neurophysiology and Fondazione Istituto Neurologico Carlo Besta, 20133 Milano, Italy
| | - Massimo Avoli
- Montreal Neurological Institute and Departments of Neurology and Neurosurgery and Physiology, McGill University, Montréal, H3A 2B4 Québec, Canada Department of Experimental Medicine, Facoltà di Medicina e Odontoiatria, Sapienza Università di Roma, 00185 Roma, Italy
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Guirgis M, Chinvarun Y, Del Campo M, Carlen PL, Bardakjian BL. Defining regions of interest using cross-frequency coupling in extratemporal lobe epilepsy patients. J Neural Eng 2015; 12:026011. [PMID: 25768723 DOI: 10.1088/1741-2560/12/2/026011] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
OBJECTIVE Clinicians identify seizure onset zones (SOZs) for resection in an attempt to localize the epileptogenic zone (EZ), which is the cortical tissue that is indispensible for seizure generation. An automated system is proposed to objectively localize this EZ by identifying regions of interest (ROIs). METHODS Intracranial electroencephalogram recordings were obtained from seven patients presenting with extratemporal lobe epilepsy and the interaction between neuronal rhythms in the form of phase-amplitude coupling was investigated. Modulation of the amplitude of high frequency oscillations (HFOs) by the phase of low frequency oscillations was measured by computing the modulation index (MI). Delta- (0.5-4 Hz) and theta- (4-8 Hz) modulation of HFOs (30-450 Hz) were examined across the channels of a 64-electrode subdural grid. Surrogate analysis was performed and false discovery rates were computed to determine the significance of the modulation observed. Mean MI values were subjected to eigenvalue decomposition (EVD) and channels defining the ROIs were selected based on the components of the eigenvector corresponding to the largest eigenvalue. ROIs were compared to the SOZs identified by two independent neurologists. Global coherence values were also computed. MAIN RESULTS MI was found to capture the seizure in time for six of seven patients and identified ROIs in all seven. Patients were found to have a poorer post-surgical outcome when the number of EVD-selected channels that were not resected increased. Moreover, in patients who experienced a seizure-free outcome (i.e., Engel Class I) all EVD-selected channels were found to be within the resected tissue or immediately adjacent to it. In these Engel Class I patients, delta-modulated HFOs were found to identify more of the channels in the resected tissue compared to theta-modulated HFOs. However, for the Engel Class IV patient, the delta-modulated HFOs did not identify any of the channels in the resected tissue suggesting that the resected tissue was not appropriate, which was also suggested by the Engel Class IV outcome. A sensitivity of 75.4% and a false positive rate of 15.6% were achieved using delta-modulated HFOs in an Engel Class I patient. SIGNIFICANCE LFO-modulated HFOs can be used to identify ROIs in extratemporal lobe patients. Moreover, delta-modulated HFOs may provide more accurate localization of the EZ. These ROIs may result in better surgical outcomes when used to compliment the SOZs identified by clinicians for resection.
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Affiliation(s)
- Mirna Guirgis
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, M5S 3G9, Canada
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Intracranially recorded ictal direct current shifts may precede high frequency oscillations in human epilepsy. Clin Neurophysiol 2014; 126:47-59. [PMID: 25034473 DOI: 10.1016/j.clinph.2014.05.028] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 05/04/2014] [Accepted: 05/10/2014] [Indexed: 01/14/2023]
Abstract
OBJECTIVE We assessed the temporal-spatial characteristics of ictal direct current (DC) shifts (or infraslow activity) and high frequency oscillations (HFOs) in 16 patients with intractable focal epilepsy. METHODS The underlying etiology consisted of cortical dysplasia, glioma, hippocampal sclerosis, and low-grade neuroepithelial tumor in nine, four, two, and one patients, respectively. The median number of analyzed seizure events was 8.0 per patient (range: 2-10). Chronic electrocorticographic recording was performed with (1) a band-pass filter of 0.016-600Hz (or 0.016-300Hz) and a sampling rate of 2000Hz (or 1000Hz). RESULTS Ictal DC shifts and a sustained form of ictal HFOs were observed in 75.0% and 50.0% of the patients, and 71.3% and 46.3% of the analyzed seizures. Visual assessment revealed that the onset of ictal DC shifts preceded that of ictal HFOs with statistical significance in 5/7 patients. The spatial extent of ictal DC shifts or HFOs was smaller than that of the conventionally defined seizure onset zone in 9/12 patients. CONCLUSION Both ictal DC shifts and HFOs might represent the core of tissue generating seizures. SIGNIFICANCE The early occurrence of ictal DC shifts warrants further studies to determine the role of glia (possibly mediating ictal DC shifts) in seizure generation.
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