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Chvojka J, Kudláček J, Liska K, Pant A, Jefferys JG, Jiruska P. Dissociation Between the Epileptogenic Lesion and Primary Seizure Onset Zone in the Tetanus Toxin Model of Temporal Lobe Epilepsy. Physiol Res 2024; 73:435-447. [PMID: 39027960 PMCID: PMC11299775 DOI: 10.33549/physiolres.935281] [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: 11/12/2023] [Accepted: 02/13/2024] [Indexed: 07/27/2024] Open
Abstract
Despite extensive temporal lobe epilepsy (TLE) research, understanding the specific limbic structures' roles in seizures remains limited. This weakness can be attributed to the complex nature of TLE and the existence of various TLE subsyndromes, including non-lesional TLE. Conventional TLE models like kainate and pilocarpine hinder precise assessment of the role of individual limbic structures in TLE ictogenesis due to widespread limbic damage induced by the initial status epilepticus. In this study, we used a non-lesional TLE model characterized by the absence of initial status and cell damage to determine the spatiotemporal profile of seizure initiation and limbic structure recruitment in TLE. Epilepsy was induced by injecting a minute dose of tetanus toxin into the right dorsal hippocampus in seven animals. Following injection, animals were implanted with bipolar recording electrodes in the amygdala, dorsal hippocampus, ventral hippocampus, piriform, perirhinal, and entorhinal cortices of both hemispheres. The animals were video-EEG monitored for four weeks. In total, 140 seizures (20 seizures per animal) were analyzed. The average duration of each seizure was 53.2+/-3.9 s. Seizure could initiate in any limbic structure. Most seizures initiated in the ipsilateral (41 %) and contralateral (18 %) ventral hippocampi. These two structures displayed a significantly higher probability of seizure initiation than by chance. The involvement of limbic structures in seizure initiation varied between individual animals. Surprisingly, only 7 % of seizures initiated in the injected dorsal hippocampus. The limbic structure recruitment into the seizure activity wasn't random and displayed consistent patterns of early recruitment of hippocampi and entorhinal cortices. Although ventral hippocampus represented the primary seizure onset zone, the study demonstrated the involvement of multiple limbic structures in seizure initiation in a non-lesional TLE model. The study also revealed the dichotomy between the primary epileptogenic lesion and main seizure onset zones and points to the central role of ventral hippocampi in temporal lobe ictogenesis.
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Affiliation(s)
- J Chvojka
- Department of Physiology, Second Faculty of Medicine, Charles University, Prague 5, Czech Republic. or
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2
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Urriola J, Bollmann S, Tremayne F, Burianová H, Marstaller L, Reutens D. Spikes with and without concurrent high-frequency oscillations: Topographic relationship and neural correlates using EEG-fMRI. Epilepsy Res 2022; 188:107039. [DOI: 10.1016/j.eplepsyres.2022.107039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 09/11/2022] [Accepted: 10/17/2022] [Indexed: 11/03/2022]
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Kim HJ, Ho JS. Wireless interfaces for brain neurotechnologies. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2022; 380:20210020. [PMID: 35658679 DOI: 10.1098/rsta.2021.0020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 12/13/2021] [Indexed: 06/15/2023]
Abstract
Wireless interfaces enable brain-implanted devices to remotely interact with the external world. They are critical components in modern research and clinical neurotechnologies and play a central role in determining their overall size, lifetime and functionality. Wireless interfaces use a wide range of modalities-including radio-frequency fields, acoustic waves and light-to transfer energy and data to and from an implanted device. These forms of energy interact with living tissue through distinct mechanisms and therefore lead to systems with vastly different form factors, operating characteristics, and safety considerations. This paper reviews recent advances in the development of wireless interfaces for brain neurotechnologies. We summarize the requirements that state-of-the-art brain-implanted devices impose on the wireless interface, and discuss the working principles and applications of wireless interfaces based on each modality. We also investigate challenges associated with wireless brain neurotechnologies and discuss emerging solutions permitted by recent developments in electrical engineering and materials science. This article is part of the theme issue 'Advanced neurotechnologies: translating innovation for health and well-being'.
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Affiliation(s)
- Han-Joon Kim
- Department of Electrical and Computer Engineering National University of Singapore, Queenstown, Singapore
| | - John S Ho
- Department of Electrical and Computer Engineering National University of Singapore, Queenstown, Singapore
- The N.1 Institute for Health National University of Singapore, Queenstown, Singapore
- Institute for Health Innovation and Technology, National University of Singapore, Queenstown, Singapore
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4
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Chiang S, Fan JM, Rao VR. Bilateral temporal lobe epilepsy: How many seizures are required in chronic ambulatory electrocorticography to estimate the laterality ratio? Epilepsia 2022; 63:199-208. [PMID: 34723396 PMCID: PMC9056258 DOI: 10.1111/epi.17113] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 10/17/2021] [Accepted: 10/18/2021] [Indexed: 11/30/2022]
Abstract
OBJECTIVE This study was undertaken to measure the duration of chronic electrocorticography (ECoG) needed to attain stable estimates of the seizure laterality ratio in patients with drug-resistant bilateral temporal lobe epilepsy (BTLE). METHODS We studied 13 patients with drug-resistant BTLE who were implanted for at least 1 year with a responsive neurostimulation device (RNS System) that provides chronic ambulatory ECoG. Bootstrap analysis and nonlinear regression were applied to model the relationship between chronic ECoG duration and the probability of capturing at least one seizure. Laterality of electrographic seizures in chronic ECoG was compared with the seizure laterality ratio from Phase 1 scalp video-electroencephalographic (vEEG) monitoring. The Kaplan-Meier estimator was used to evaluate time to seizure laterality ratio convergence. RESULTS Seizure laterality ratios from Phase 1 scalp vEEG monitoring correlated poorly with those from RNS chronic ECoG (r = .31, p = .30). Across the 13 patients, average electrographic seizure frequencies ranged from 1.4 seizures/month to 5.1 seizures/day. A 50% probability of recording at least one electrographic seizure required 9.1 days of chronic ECoG, and 90% probability required 44.3 days of chronic ECoG. A median recording duration of 150.9 days (5 months), corresponding to a median of 16 seizures, was needed before confidence intervals for the seizure laterality ratio reliably contained the long-term value. The median recording duration before the point estimate of the seizure laterality ratio converged to a stationary value was 236.8 days (7.9 months). SIGNIFICANCE RNS chronic ECoG overcomes temporal sampling limitations intrinsic to inpatient Phase 1 vEEG evaluations. In patients with drug-resistant BTLE, approximately 8 months of chronic RNS ECoG are needed to precisely estimate the seizure laterality ratio, with 75% of people with BTLE achieving convergence after 1 year of RNS recording. For individuals who are candidates for unilateral resection based on seizure laterality, optimized recording duration may help avert morbidity associated with delay to definitive treatment.
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Affiliation(s)
- Sharon Chiang
- Department of Neurology and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, USA
| | - Joline M Fan
- Department of Neurology and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, USA
| | - Vikram R Rao
- Department of Neurology and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, USA
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Frazzini V, Cousyn L, Navarro V. Semiology, EEG, and neuroimaging findings in temporal lobe epilepsies. HANDBOOK OF CLINICAL NEUROLOGY 2022; 187:489-518. [PMID: 35964989 DOI: 10.1016/b978-0-12-823493-8.00021-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Temporal lobe epilepsy (TLE) is the most common type of focal epilepsy. First descriptions of TLE date back in time and detailed portraits of epileptic seizures of temporal origin can be found in early medical reports as well as in the works of various artists and dramatists. Depending on the seizure onset zone, several subtypes of TLE have been identified, each one associated with peculiar ictal semiology. TLE can result from multiple etiological causes, ranging from genetic to lesional ones. While the diagnosis of TLE relies on detailed analysis of clinical as well as electroencephalographic (EEG) features, the lesions responsible for seizure generation can be highlighted by multiple brain imaging modalities or, in selected cases, by genetic investigations. TLE is the most common cause of refractory epilepsy and despite the great advances in diagnostic tools, no lesion is found in around one-third of patients. Surgical treatment is a safe and effective option, requiring presurgical investigations to accurately identify the seizure onset zone (SOZ). In selected cases, presurgical investigations need intracerebral investigations (such as stereoelectroencephalography) or dedicated metabolic imaging techniques (interictal PET and ictal SPECT) to correctly identify the brain structures to be removed.
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Affiliation(s)
- Valerio Frazzini
- AP-HP, Department of Neurology and Department of Clinical Neurophysiology, Epilepsy and EEG Unit, Reference Center for Rare Epilepsies, Pitié-Salpêtrière Hospital, Paris, France; Sorbonne Université, Paris Brain Institute, Team "Dynamics of Neuronal Networks and Neuronal Excitability", Paris, France
| | - Louis Cousyn
- AP-HP, Department of Neurology and Department of Clinical Neurophysiology, Epilepsy and EEG Unit, Reference Center for Rare Epilepsies, Pitié-Salpêtrière Hospital, Paris, France; Sorbonne Université, Paris Brain Institute, Team "Dynamics of Neuronal Networks and Neuronal Excitability", Paris, France
| | - Vincent Navarro
- AP-HP, Department of Neurology and Department of Clinical Neurophysiology, Epilepsy and EEG Unit, Reference Center for Rare Epilepsies, Pitié-Salpêtrière Hospital, Paris, France; Sorbonne Université, Paris Brain Institute, Team "Dynamics of Neuronal Networks and Neuronal Excitability", Paris, France.
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Khoo A, de Tisi J, Mannan S, O'Keeffe AG, Sander JW, Duncan JS. Reasons for not having epilepsy surgery. Epilepsia 2021; 62:2909-2919. [PMID: 34558079 DOI: 10.1111/epi.17083] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 09/12/2021] [Accepted: 09/13/2021] [Indexed: 02/05/2023]
Abstract
OBJECTIVE This study was undertaken to determine reasons for adults with drug-resistant focal epilepsy who undergo presurgical evaluation not proceeding with surgery, and to identify predictors of this course. METHODS We retrospectively analyzed data on 617 consecutive individuals evaluated for epilepsy surgery at a tertiary referral center between January 2015 and December 2019. We compared the characteristics of those in whom a decision not to proceed with surgical treatment was made with those who underwent definitive surgery in the same period. Multivariate logistic regression was performed to identify predictors of not proceeding with surgery. RESULTS A decision not to proceed with surgery was reached in 315 (51%) of 617 individuals evaluated. Common reasons for this were an inability to localize the epileptogenic zone (n = 104) and the presence of multifocal epilepsy (n = 74). An individual choice not to proceed with intracranial electroencephalography (icEEG; n = 50) or surgery (n = 39), risk of significant deficit (n = 33), declining noninvasive investigation (n = 12), and coexisting neurological comorbidity (n = 3) accounted for the remainder. Compared to 166 surgically treated patients, those who did not proceed to surgery were more likely to have a learning disability (odds ratio [OR] = 2.35, 95% confidence interval [CI] = 1.07-5.16), normal magnetic resonance imaging (OR = 4.48, 95% CI = 1.68-11.94), extratemporal epilepsy (OR = 2.93, 95% CI = 1.82-4.71), bilateral seizure onset zones (OR = 3.05, 95% CI = 1.41-6.61) and to live in more deprived socioeconomic areas (median deprivation decile = 40%-50% vs. 50%-60%, p < .05). SIGNIFICANCE Approximately half of those evaluated for surgical treatment of drug-resistant focal epilepsy do not proceed to surgery. Early consideration and discussion of the likelihood of surgical suitability or need for icEEG may help direct referral for presurgical evaluation.
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Affiliation(s)
- Anthony Khoo
- Department of Neurology, National Hospital for Neurology and Neurosurgery, London, UK.,Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, UK
| | - Jane de Tisi
- Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, UK
| | - Shahidul Mannan
- Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, UK
| | | | - Josemir W Sander
- Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Chalfont St Peter, UK.,Stichting Epilepsie Instellingen Nederland, Heemstede, Netherlands.,Department of Neurology, West China Hospital, and Institute of Brain Science and Brain-Inspired Technology, Sichuan University, Chengdu, China
| | - John S Duncan
- Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Chalfont St Peter, UK
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Mascia A, Casciato S, De Risi M, Quarato PP, Morace R, D'Aniello A, Grammaldo LG, Pavone L, Picardi A, Esposito V, Di Gennaro G. Bilateral epileptogenesis in temporal lobe epilepsy due to unilateral hippocampal sclerosis: A case series. Clin Neurol Neurosurg 2021; 208:106868. [PMID: 34388593 DOI: 10.1016/j.clineuro.2021.106868] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 07/23/2021] [Accepted: 08/02/2021] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Bitemporal epilepsy (biTLE), a potential cause of failure in TLE surgery, is rarely associated with unilateral HS and could be suggested by not lateralizing ictal scalp EEG/interictal PET-FDG findings. We evaluated the proportion of biTLE in a population of drug-resistant TLE-HS subjects who underwent intracranial investigation for lateralizing purpose. METHODS We retrospectively included all consecutive refractory TLE-HS patients and not lateralizing ictal scalp EEG/interictal PET-FDG findings, investigated by intracranial bilateral longitudinal hippocampal electrodes. Demographic characteristics, electroclinical findings and seizure outcome were evaluated. RESULTS We identified 14 subjects (7 males; mean age 39.5 years; mean age at disease onset 14.4 years), 7 of them had biTLE diagnosed after intracranial investigations. In the remaining 7 with unilateral epileptogenesis (uniTLE) anterior temporal lobectomy was performed (6/7 were in Engel class I). Preoperative neuropsychological assessment differentiated biTLE from uniTLE, as it was normal in six uniTLE patients but only in one with biTLE (p < 0.05). CONCLUSIONS Not lateralizing ictal scalp EEG and functional imaging findings in TLEHS should alert about the possibility of a true biTLE also in presence of unilateral findings at MRI. Intracranial investigations with bilateral longitudinal hippocampal electrodes can localize the EZ with a good risk-benefit profile. Consistently with the warning on memory functions in TLE patients explored by using longitudinal hippocampal electrodes, further studies are needed to better define the optimal investigation strategy.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Angelo Picardi
- Centre of Behavioural Sciences and Mental Health, Italian National Institute of Health, Rome, Italy
| | - Vincenzo Esposito
- IRCCS NEUROMED, Pozzilli, Isernia, Italy; Department of Neurosurgery, "Sapienza" University, Rome, Italy
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Miró J, Ripollés P, Sierpowska J, Santurino M, Juncadella M, Falip M, Rodríguez-Fornells A. Autobiographical memory in epileptic patients after temporal lobe resection or bitemporal hippocampal sclerosis. Brain Imaging Behav 2021; 14:1074-1088. [PMID: 31102166 DOI: 10.1007/s11682-019-00113-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The human hippocampus is believed to be a crucial node in the neural network supporting autobiographical memory retrieval. Structural mesial temporal damage associated with temporal lobe epilepsy (TLE) provides an opportunity to systematically investigate and better understand the local and distal functional consequences of mesial temporal damage in the engagement of the autobiographical memory network. We examined 19 TLE patients (49.21 ± 11.55 years; 12 females) with unilateral mesial TLE (MTLE; 12 with anterior temporal lobe resection: 6 right MTLE, 6 left MTLE) or bilateral mesial TLE (7 BMTLE) and 18 matched healthy subjects. We used functional MRI (fMRI) with an adapted autobiographical memory paradigm and a specific neuropsychological test (Autobiographical Memory Interview, AMI). While engaged in the fMRI autobiographical memory paradigm, all groups activated a large fronto-temporo-parietal network. However, while this network was left lateralized for healthy participants and right MTLE patients, left MTLE and patients with BMTLE also showed strong activation in right temporal and frontal regions. Moreover, BMTLE and left MTLE patients also showed significant mild deficits in episodic autobiographical memory performance measured with the AMI test. The right temporal and extra-temporal fMRI activation, along with the impairment in autobiographical memory retrieval found in left MTLE and BMTLE patients suggest that alternate brain areas-other than the hippocampus-may also support this process, possibly due to neuroplastic effects.
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Affiliation(s)
- Júlia Miró
- Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute-IDIBELL, Biomedical Campus Bellvitge, Feixa Llarga s/n, 08907 L'Hospitalet de Llobregat,, Barcelona, Spain.,Epilepsy Unit, Neurology Department, Universtiy Hospital of Bellvitge, 08907 L'fHospitalet de LLobregat,, Barcelona, Spain
| | - Pablo Ripollés
- Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute-IDIBELL, Biomedical Campus Bellvitge, Feixa Llarga s/n, 08907 L'Hospitalet de Llobregat,, Barcelona, Spain.,Department of Psychology, New York University, New York, 10003, USA
| | - Joanna Sierpowska
- Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute-IDIBELL, Biomedical Campus Bellvitge, Feixa Llarga s/n, 08907 L'Hospitalet de Llobregat,, Barcelona, Spain.,Department of Cognition, Development and Education Psychology, University of Barcelona, 08035, Barcelona, Spain
| | - Mila Santurino
- Epilepsy Unit, Neurology Department, Universtiy Hospital of Bellvitge, 08907 L'fHospitalet de LLobregat,, Barcelona, Spain
| | - Montserrat Juncadella
- Epilepsy Unit, Neurology Department, Universtiy Hospital of Bellvitge, 08907 L'fHospitalet de LLobregat,, Barcelona, Spain
| | - Mercè Falip
- Epilepsy Unit, Neurology Department, Universtiy Hospital of Bellvitge, 08907 L'fHospitalet de LLobregat,, Barcelona, Spain
| | - Antoni Rodríguez-Fornells
- Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute-IDIBELL, Biomedical Campus Bellvitge, Feixa Llarga s/n, 08907 L'Hospitalet de Llobregat,, Barcelona, Spain. .,Department of Cognition, Development and Education Psychology, University of Barcelona, 08035, Barcelona, Spain. .,Catalan Institution for Research and Advanced Studies, ICREA, 08010 Barcelona, Spain.
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Guo Z, Zhao B, Hu W, Zhang C, Wang X, Wang Y, Liu C, Mo J, Sang L, Ma Y, Shao X, Zhang J, Zhang K. Effective connectivity among the hippocampus, amygdala, and temporal neocortex in epilepsy patients: A cortico-cortical evoked potential study. Epilepsy Behav 2021; 115:107661. [PMID: 33434884 DOI: 10.1016/j.yebeh.2020.107661] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 08/08/2020] [Accepted: 11/21/2020] [Indexed: 10/22/2022]
Abstract
OBJECTIVE Mesial temporal lobe epilepsy (MTLE) is one of the most common types of intractable epilepsy. The hippocampus and amygdala are two crucial structures of the mesial temporal lobe and play important roles in the epileptogenic network of MTLE. This study aimed to explore the effective connectivity among the hippocampus, amygdala, and temporal neocortex and to determine whether differences in effective connectivity exist between MTLE patients and non-MTLE patients. METHODS This study recruited 20 patients from a large cohort of drug-resistant epilepsy patients, of whom 14 were MTLE patients. Single-pulse electrical stimulation (SPES) was performed to acquire cortico-cortical evoked potentials (CCEPs). The root mean square (RMS) was used as the metric of the magnitude of CCEP to represent the effective connectivity. We then conducted paired and independent sample t-tests to assess the directionality of the effective connectivity. RESULTS In both MTLE patients and non-MTLE patients, the directional connectivity from the amygdala to the hippocampus was stronger than that from the hippocampus to the amygdala (P < 0.01); the outward connectivity from the amygdala to the cortex was stronger than the inward connectivity from the cortex to the amygdala (P < 0.01); the amygdala had stronger connectivity to the neocortex than the hippocampus (P < 0.01). In MTLE patients, the neocortex had stronger connectivity to the hippocampus than to the amygdala (P < 0.01). No significant differences in directional connectivity were noted between the two groups. CONCLUSIONS A unique effective connectivity pattern among the hippocampus, amygdala, and temporal neocortex was identified through CCEPs analysis. This study may aid in our understanding of physiological and pathological networks in the brain and inspire neurostimulation protocols for neurological and psychiatric disorders.
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Affiliation(s)
- Zhihao Guo
- Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, Beijing, China
| | - Baotian Zhao
- Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, Beijing, China
| | - Wenhan Hu
- Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, Beijing, China; Stereotactic and Functional Neurosurgery Laboratory, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China; Beijing Key Laboratory of Neurostimulation, Beijing, China
| | - Chao Zhang
- Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, Beijing, China
| | - Xiu Wang
- Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, Beijing, China
| | - Yao Wang
- Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, Beijing, China
| | - Chang Liu
- Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, Beijing, China
| | - Jiajie Mo
- Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, Beijing, China
| | - Lin Sang
- Department of Neurosurgery, Beijing Fengtai Hospital, Beijing, China
| | - Yanshan Ma
- Department of Neurosurgery, Beijing Fengtai Hospital, Beijing, China
| | - Xiaoqiu Shao
- Department of Neurology, Beijing Tian Tan Hospital, Capital Medical University, Beijing, China
| | - Jianguo Zhang
- Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, Beijing, China; Stereotactic and Functional Neurosurgery Laboratory, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China; Beijing Key Laboratory of Neurostimulation, Beijing, China.
| | - Kai Zhang
- Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, Beijing, China; Stereotactic and Functional Neurosurgery Laboratory, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China; Beijing Key Laboratory of Neurostimulation, Beijing, China.
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10
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Stereotactic electroencephalography. Clin Neurol Neurosurg 2020; 189:105640. [DOI: 10.1016/j.clineuro.2019.105640] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 12/12/2019] [Accepted: 12/15/2019] [Indexed: 11/23/2022]
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11
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Rajkalyan C, Tewari A, Rao S, Avitsian R. Anesthetic considerations for stereotactic electroencephalography implantation. J Anaesthesiol Clin Pharmacol 2019; 35:434-440. [PMID: 31920225 PMCID: PMC6939570 DOI: 10.4103/joacp.joacp_342_18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The refractory seizures have significant impact on the quality of life and increase long term neurologic and non-neurologic complications. Implantation of Stereotactic Electroencephalography (SEEG) leads is one of the newer surgical techniques intended to localize seizure foci with higher accuracy than the conventional methods. Most of the commonly utilized anesthetic agents depress EEG waveforms affecting intra operative monitoring during these surgeries. Hence, the anesthetic goals include a stable induction and maintenance with agents which have minimal effect on EEG. This article discusses the peri-operative considerations of multiple anti-epileptic medications, recent advances in anesthetic management, and important post-operative concerns.
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Affiliation(s)
- Chakrabarti Rajkalyan
- Department of Anesthesiology, Newham University Hospital, Barts Health NHS Trust, London
| | | | - Shilpa Rao
- Department of Neuro-Anesthesiology, Yale School of Medicine and Yale-New Haven Hospital, CT, USA
| | - Rafi Avitsian
- Department of of Anesthesiology, Cleveland Clinic Foundation, Cleveland, Ohio, USA
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Liu S, Gurses C, Sha Z, Quach MM, Sencer A, Bebek N, Curry DJ, Prabhu S, Tummala S, Henry TR, Ince NF. Stereotyped high-frequency oscillations discriminate seizure onset zones and critical functional cortex in focal epilepsy. Brain 2019; 141:713-730. [PMID: 29394328 DOI: 10.1093/brain/awx374] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 11/12/2017] [Indexed: 01/25/2023] Open
Abstract
High-frequency oscillations in local field potentials recorded with intracranial EEG are putative biomarkers of seizure onset zones in epileptic brain. However, localized 80-500 Hz oscillations can also be recorded from normal and non-epileptic cerebral structures. When defined only by rate or frequency, physiological high-frequency oscillations are indistinguishable from pathological ones, which limit their application in epilepsy presurgical planning. We hypothesized that pathological high-frequency oscillations occur in a repetitive fashion with a similar waveform morphology that specifically indicates seizure onset zones. We investigated the waveform patterns of automatically detected high-frequency oscillations in 13 epilepsy patients and five control subjects, with an average of 73 subdural and intracerebral electrodes recorded per patient. The repetitive oscillatory waveforms were identified by using a pipeline of unsupervised machine learning techniques and were then correlated with independently clinician-defined seizure onset zones. Consistently in all patients, the stereotypical high-frequency oscillations with the highest degree of waveform similarity were localized within the seizure onset zones only, whereas the channels generating high-frequency oscillations embedded in random waveforms were found in the functional regions independent from the epileptogenic locations. The repetitive waveform pattern was more evident in fast ripples compared to ripples, suggesting a potential association between waveform repetition and the underlying pathological network. Our findings provided a new tool for the interpretation of pathological high-frequency oscillations that can be efficiently applied to distinguish seizure onset zones from functionally important sites, which is a critical step towards the translation of these signature events into valid clinical biomarkers.awx374media15721572971001.
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Affiliation(s)
- Su Liu
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Candan Gurses
- Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Zhiyi Sha
- Department of Neurology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Michael M Quach
- Department of Neurology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas, USA
| | - Altay Sencer
- Department of Neurosurgery, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey, USA
| | - Nerses Bebek
- Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Daniel J Curry
- Department of Neurosurgery, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas, USA
| | - Sujit Prabhu
- Department of Neurosurgery, MD Anderson Cancer Center, University of Texas, Houston, Texas, USA
| | - Sudhakar Tummala
- Department of Neurosurgery, MD Anderson Cancer Center, University of Texas, Houston, Texas, USA
| | - Thomas R Henry
- Department of Neurology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Nuri F Ince
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
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Abstract
Electroencephalographic (EEG) investigations are crucial in the diagnosis and management of patients with focal epilepsies. EEG may reveal different interictal epileptiform discharges (IEDs: abnormal spikes, sharp waves). The EEG visibility of a spike depends on the surface area of cortex involved (>10cm2) and the brain localization of cortical generators. Regions generating IEDs (defining the "irritative zone") are not necessarily equivalent to the seizure onset zone. Focal seizures are dynamic processes originating from one or several brain regions (that generate fast oscillations and are called the epileptogenic zone) before spreading to other structures (that generate lower frequency oscillations and are called the propagation zone). Several factors limit the expression of seizures on scalp EEG, such as the area involved, degree of synchronization, and depth of the cortical generators. Different scalp EEG seizure onset patterns may be observed: fast discharge, background flattening, rhythmic spikes, sinusoidal discharge, or sharp activity. However, to a large extent EEG changes are linked to seizure propagation. Finally, in the context of presurgical evaluation, the combination of interictal and ictal EEG features is crucial to provide an optimal hypothesis concerning the epileptogenic zone.
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Affiliation(s)
- Stanislas Lagarde
- Institut de Neurosciences des Systèmes, Aix Marseille Université, Marseille, France; Department of Clinical Neurophysiology, Timone Hospital, Marseille, France
| | - Fabrice Bartolomei
- Institut de Neurosciences des Systèmes, Aix Marseille Université, Marseille, France; Department of Clinical Neurophysiology, Timone Hospital, Marseille, France.
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Multiphasic Side-Switching Seizures Are Easily Misdiagnosed as Unilateral Seizures During a Single EEG Monitoring Session: A Specific Subtype of Bitemporal Epilepsy. World Neurosurg 2018; 122:656-660. [PMID: 30481627 DOI: 10.1016/j.wneu.2018.11.138] [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: 10/16/2018] [Revised: 11/14/2018] [Accepted: 11/16/2018] [Indexed: 11/21/2022]
Abstract
BACKGROUND Bitemporal epilepsy (BTLE) is a specific anatomoelectroclinical phenotype in the spectrum of temporal lobe epilepsy. The diagnosis of BTLE and the evaluation of the degree of seizure lateralization in BTLE patients are greatly influenced by the duration of EEG recording and the number of recorded habitual seizures. CASE DESCRIPTION A 25-year-old woman had a 5-year history of seizures. Her habitual seizures were described as sudden behavioral arrest, staring, unresponsiveness, and oral automatisms, with auras of fear and palpitation. Intermittent scalp electroencephalography (EEG) and intracranial EEG monitoring over 3 years showed multiphasic side-switching seizures. The seizures were limited to 1 temporal lobe within 1 phase and switched sides between phases. Despite antiepileptic drugs and vagus nerve stimulation, her seizures remained uncontrolled. The patient finally underwent unilateral anteromedial temporal lobectomy, mainly based on >60% of seizures recorded originating from the left side. The patient has been seizure free for more than 1 year at last follow-up. CONCLUSIONS This patient presented 1 specific subtype of BTLE that is prone to be misdiagnosed as unilateral temporal lobe epilepsy if the patient is recorded for a relatively short term, e.g., over a common EEG monitoring duration of 1 to 2 weeks.
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Garcia-Lorenzo B, del Pino-Sedeño T, Rocamora R, López JE, Serrano-Aguilar P, Trujillo-Martín MM. Stereoelectroencephalography for Refractory Epileptic Patients Considered for Surgery: Systematic Review, Meta-Analysis, and Economic Evaluation. Neurosurgery 2018; 84:326-338. [DOI: 10.1093/neuros/nyy261] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 05/16/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Borja Garcia-Lorenzo
- Bordeaux Population Health, Team EMOS, Université de Bordeaux, Inserm U1219, Bordeaux, France
- Fundación Canaria de Investigación Sanitaria (FUNCANIS), Santa Cruz de Tenerife, Spain
- Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Tasmania del Pino-Sedeño
- Fundación Canaria de Investigación Sanitaria (FUNCANIS), Santa Cruz de Tenerife, Spain
- Departamento de Psicología Clínica, Psicobiología y Metodología, Universidad de La Laguna, Santa Cruz de Tenerife, Spain
| | - Rodrigo Rocamora
- Epilepsy Unit, Department of Neurology, Hospital del Mar, Parc de Salut Mar, Barcelona, Spain
- Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain
- Department of Experimental and Health Sciences, Pompeu Fabra University (UPF), Barcelona, Spain
| | - Juan Erviti López
- Red de Investigación en Servicios de Salud en Enfermedades Crónicas (REDISSEC), Madrid, Spain
- Servicio de Prestaciones Farmacéuticas, Dirección Atención Primaria, Servicio Navarro de Salud, Pamplona, Spain
| | - Pedro Serrano-Aguilar
- Red de Investigación en Servicios de Salud en Enfermedades Crónicas (REDISSEC), Madrid, Spain
- Servicio de Evaluación y Planificación (SESCS), Servicio Canario de la Salud, Santa Cruz de Tenerife, Spain
| | - María M Trujillo-Martín
- Fundación Canaria de Investigación Sanitaria (FUNCANIS), Santa Cruz de Tenerife, Spain
- Red de Investigación en Servicios de Salud en Enfermedades Crónicas (REDISSEC), Madrid, Spain
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Tatum W, Rubboli G, Kaplan P, Mirsatari S, Radhakrishnan K, Gloss D, Caboclo L, Drislane F, Koutroumanidis M, Schomer D, Kasteleijn-Nolst Trenite D, Cook M, Beniczky S. Clinical utility of EEG in diagnosing and monitoring epilepsy in adults. Clin Neurophysiol 2018; 129:1056-1082. [DOI: 10.1016/j.clinph.2018.01.019] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 12/28/2017] [Accepted: 01/09/2018] [Indexed: 12/20/2022]
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Surgical Considerations of Intractable Mesial Temporal Lobe Epilepsy. Brain Sci 2018; 8:brainsci8020035. [PMID: 29461485 PMCID: PMC5836054 DOI: 10.3390/brainsci8020035] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 02/14/2018] [Accepted: 02/15/2018] [Indexed: 11/30/2022] Open
Abstract
Surgery of temporal lobe epilepsy is the best opportunity for seizure freedom in medically intractable patients. The surgical approach has evolved to recognize the paramount importance of the mesial temporal structures in the majority of patients with temporal lobe epilepsy who have a seizure origin in the mesial temporal structures. For those individuals with medically intractable mesial temporal lobe epilepsy, a selective amygdalohippocampectomy surgery can be done that provides an excellent opportunity for seizure freedom and limits the resection to temporal lobe structures primarily involved in seizure genesis.
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Schmeiser B, Zentner J, Steinhoff B, Brandt A, Schulze-Bonhage A, Kogias E, Hammen T. The role of presurgical EEG parameters and of reoperation for seizure outcome in temporal lobe epilepsy. Seizure 2017; 51:174-179. [DOI: 10.1016/j.seizure.2017.08.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 08/13/2017] [Accepted: 08/31/2017] [Indexed: 10/18/2022] Open
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Pitkänen A, Löscher W, Vezzani A, Becker AJ, Simonato M, Lukasiuk K, Gröhn O, Bankstahl JP, Friedman A, Aronica E, Gorter JA, Ravizza T, Sisodiya SM, Kokaia M, Beck H. Advances in the development of biomarkers for epilepsy. Lancet Neurol 2017; 15:843-856. [PMID: 27302363 DOI: 10.1016/s1474-4422(16)00112-5] [Citation(s) in RCA: 229] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 02/16/2016] [Accepted: 03/02/2016] [Indexed: 12/13/2022]
Abstract
Over 50 million people worldwide have epilepsy. In nearly 30% of these cases, epilepsy remains unsatisfactorily controlled despite the availability of over 20 antiepileptic drugs. Moreover, no treatments exist to prevent the development of epilepsy in those at risk, despite an increasing understanding of the underlying molecular and cellular pathways. One of the major factors that have impeded rapid progress in these areas is the complex and multifactorial nature of epilepsy, and its heterogeneity. Therefore, the vision of developing targeted treatments for epilepsy relies upon the development of biomarkers that allow individually tailored treatment. Biomarkers for epilepsy typically fall into two broad categories: diagnostic biomarkers, which provide information on the clinical status of, and potentially the sensitivity to, specific treatments, and prognostic biomarkers, which allow prediction of future clinical features, such as the speed of progression, severity of epilepsy, development of comorbidities, or prediction of remission or cure. Prognostic biomarkers are of particular importance because they could be used to identify which patients will develop epilepsy and which might benefit from preventive treatments. Biomarker research faces several challenges; however, biomarkers could substantially improve the management of people with epilepsy and could lead to prevention in the right person at the right time, rather than just symptomatic treatment.
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Affiliation(s)
- Asla Pitkänen
- Department of Neurobiology, A I Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine, Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Annamaria Vezzani
- Department of Neuroscience, Experimental Neurology, IRCCS-Istituto di Recerche Farmacologiche "Mario Negri", Milan, Italy
| | - Albert J Becker
- Section for Translational Epilepsy Research, Department of Neuropathology, University of Bonn Medical Center, University of Bonn, Bonn, Germany
| | - Michele Simonato
- Department of Medical Sciences, Section of Pharmacology, University of Ferrara, Ferrara, Italy; Unit of Gene Therapy of Neurodegenerative Diseases, Division of Neuroscience, University Vita-Salute San Raffaele, Milan, Italy
| | - Katarzyna Lukasiuk
- The Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Olli Gröhn
- Department of Neurobiology, A I Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Jens P Bankstahl
- Preclinical Molecular Imaging, Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany
| | - Alon Friedman
- Department of Brain and Cognitive Sciences, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Israel; Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Eleonora Aronica
- Department of Neuropathology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands; Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, Netherlands; Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, Netherlands
| | - Jan A Gorter
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | - Teresa Ravizza
- Department of Neuroscience, Experimental Neurology, IRCCS-Istituto di Recerche Farmacologiche "Mario Negri", Milan, Italy
| | - Sanjay M Sisodiya
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK; Epilepsy Society, Chalfont St Peter, Buckinghamshire, UK
| | - Merab Kokaia
- Epilepsy Center, Experimental Epilepsy Group, Division of Neurology, Department of Clinical Sciences, Lund University Hospital, Lund, Sweden
| | - Heinz Beck
- Laboratory for Experimental Epileptology and Cognition Research, Department of Epileptology, University of Bonn, Bonn, Germany; German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
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Stereotactic Electroencephalography Is a Safe Procedure, Including for Insular Implantations. World Neurosurg 2016; 99:353-361. [PMID: 28003163 DOI: 10.1016/j.wneu.2016.12.025] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 12/05/2016] [Accepted: 12/08/2016] [Indexed: 11/20/2022]
Abstract
BACKGROUND In some cases of drug-resistant focal epilepsy, noninvasive presurgical investigation may be insufficient to identify the ictal onset zone and the eloquent cortical areas. In such situations, invasive investigations are proposed using either stereotactic electroencephalography (SEEG) or subdural grid electrodes. Meta-analysis suggests that SEEG is safer than subdural grid electrodes, but insular implantation of SEEG electrodes has been thought to carry an additional risk of intraparenchymal hemorrhagic complications. Our objectives were to determine whether an insular SEEG trajectory is a risk factor for intracranial hematoma and to report the global safety of the procedure and provide some guidelines to prevent and detect complications. METHODS In a retrospective analysis of a surgical series of 525 consecutive procedures between 1995 and 2015, all electrodes were classified according to their insular or extrainsular trajectory. All complications were classified as major or minor according to their potential consequences regarding patient neurologic status. RESULTS Four intraparenchymal hematomas, all related to extrainsular electrodes (4/4974; 0.08%) were reported; no hematoma was found along insular electrodes (0/1042; 0%). There were 8 major complications (1.52%): 7 intracranial hematomas (1.33%) and 1 case of meningitis. Two patients had long-term neurologic impairment (0.38%), and 1 death (not directly related to the procedure) occurred (0.19%). Eleven minor complications (2.09%) were encountered, including broken electrode (1.52%), acute pneumocephalus (0.38%), and local cutaneous infection (0.19%). CONCLUSIONS SEEG is a safe procedure. Insular trajectories cannot be considered an additional risk of intracranial bleeding.
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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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Mullin JP, Shriver M, Alomar S, Najm I, Bulacio J, Chauvel P, Gonzalez-Martinez J. Is SEEG safe? A systematic review and meta-analysis of stereo-electroencephalography-related complications. Epilepsia 2016; 57:386-401. [DOI: 10.1111/epi.13298] [Citation(s) in RCA: 250] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2015] [Indexed: 12/18/2022]
Affiliation(s)
- Jeffrey P. Mullin
- Department of Neurosurgery; Neurological Institute; Cleveland Clinic; Cleveland Ohio U.S.A
| | - Michael Shriver
- Case Western Reserve University School of Medicine; Cleveland Ohio U.S.A
| | - Soha Alomar
- Department of Neurosurgery; Neurological Institute; Cleveland Clinic; Cleveland Ohio U.S.A
| | - Imad Najm
- Case Western Reserve University School of Medicine; Cleveland Ohio U.S.A
| | - Juan Bulacio
- Case Western Reserve University School of Medicine; Cleveland Ohio U.S.A
| | - Patrick Chauvel
- Case Western Reserve University School of Medicine; Cleveland Ohio U.S.A
| | - Jorge Gonzalez-Martinez
- Department of Neurosurgery; Neurological Institute; Cleveland Clinic; Cleveland Ohio U.S.A
- Epilepsy Center; Neurological Institute; Cleveland Clinic; Cleveland Ohio U.S.A
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McDonald AJ, Mott DD. Functional neuroanatomy of amygdalohippocampal interconnections and their role in learning and memory. J Neurosci Res 2016; 95:797-820. [PMID: 26876924 DOI: 10.1002/jnr.23709] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 12/01/2015] [Accepted: 12/14/2015] [Indexed: 01/31/2023]
Abstract
The amygdalar nuclear complex and hippocampal/parahippocampal region are key components of the limbic system that play a critical role in emotional learning and memory. This Review discusses what is currently known about the neuroanatomy and neurotransmitters involved in amygdalo-hippocampal interconnections, their functional roles in learning and memory, and their involvement in mnemonic dysfunctions associated with neuropsychiatric and neurological diseases. Tract tracing studies have shown that the interconnections between discrete amygdalar nuclei and distinct layers of individual hippocampal/parahippocampal regions are robust and complex. Although it is well established that glutamatergic pyramidal cells in the amygdala and hippocampal region are the major players mediating interconnections between these regions, recent studies suggest that long-range GABAergic projection neurons are also involved. Whereas neuroanatomical studies indicate that the amygdala only has direct interconnections with the ventral hippocampal region, electrophysiological studies and behavioral studies investigating fear conditioning and extinction, as well as amygdalar modulation of hippocampal-dependent mnemonic functions, suggest that the amygdala interacts with dorsal hippocampal regions via relays in the parahippocampal cortices. Possible pathways for these indirect interconnections, based on evidence from previous tract tracing studies, are discussed in this Review. Finally, memory disorders associated with dysfunction or damage to the amygdala, hippocampal region, and/or their interconnections are discussed in relation to Alzheimer's disease, posttraumatic stress disorder (PTSD), and temporal lobe epilepsy. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Alexander J McDonald
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina
| | - David D Mott
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina
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Chiang S, Levin HS, Wilde E, Haneef Z. White matter structural connectivity changes correlate with epilepsy duration in temporal lobe epilepsy. Epilepsy Res 2015; 120:37-46. [PMID: 26709881 DOI: 10.1016/j.eplepsyres.2015.12.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Revised: 10/29/2015] [Accepted: 12/04/2015] [Indexed: 11/27/2022]
Abstract
PURPOSE Temporal lobe epilepsy (TLE) is thought to be a network disease and structural changes using diffusion tensor imaging (DTI) have been shown. However, lateralized differences in the structural integrity of TLE, as well as changes in structural integrity with longer disease duration, have not been well defined. METHODS We examined the fractional anisotropy (FA) and mean diffusivity (MD) in the hippocampus, as well as its primary (cingulum and fornix) and remote (uncinate and external capsule) connections in both right and left TLE. Changes in diffusion measures over the disease course were examined by correlating FA and MD in the various structures with epilepsy duration. The potential for each measure of anisotropy and diffusivity as a marker of TLE laterality was investigated using random forest (RF) analysis. RESULTS MD was increased in the bilateral hippocampus, cingulum, fornix and the right external capsule in both left and right TLE compared to controls. In addition, left TLE exhibited an increased MD in the ipsilateral uncinate fasciculus and bilateral external capsules. A decrease in FA was seen in the left cingulum in left TLE. RF analysis demonstrated that MD of the right hippocampus and FA of the left external capsule were important predictors of TLE laterality. An association of increased MD with epilepsy duration was seen in the left hippocampus in left TLE. CONCLUSION Evidence of disrupted white matter architecture in the hippocampus and its primary and remote connections were demonstrated in TLE. While changes in the hippocampus and cingulum were more prominent in right TLE, remote changes were more prominent in left TLE. MD of the right hippocampus and FA of the left external capsule were found to be the strongest structural predictors of TLE laterality. Changes associated with duration of epilepsy indicated that changes in structural integrity may be progressive over the disease course. This study illustrates the potential of structural diffusion tensor imaging in elucidating pathophysiology, enhancing diagnosis and assisting prognostication.
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Affiliation(s)
- Sharon Chiang
- Department of Statistics, Rice University, Houston, TX, United States.
| | - Harvey S Levin
- Department of Physical Medicine, Baylor College of Medicine, Houston, TX, United States; Michael E. De Bakey Veterans Affairs Medical Center, Houston, TX, United States.
| | - Elisabeth Wilde
- Department of Physical Medicine, Baylor College of Medicine, Houston, TX, United States.
| | - Zulfi Haneef
- Department of Neurology, Baylor College of Medicine, Houston, TX, United States; Neurology Care Line, Michael E. DeBakey VA Medical Center, Houston, TX, United States.
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Bröer S, Löscher W. Novel combinations of phenotypic biomarkers predict development of epilepsy in the lithium-pilocarpine model of temporal lobe epilepsy in rats. Epilepsy Behav 2015; 53:98-107. [PMID: 26539702 DOI: 10.1016/j.yebeh.2015.09.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 09/22/2015] [Indexed: 10/22/2022]
Abstract
The discovery and validation of biomarkers in neurological and neurodegenerative diseases is an important challenge for early diagnosis of disease and for the development of therapeutics. Epilepsy is often a consequence of brain insults such as traumatic brain injury or stroke, but as yet no biomarker exists to predict the development of epilepsy in patients at risk. Given the complexity of epilepsy, it is unlikely that a single biomarker is sufficient for this purpose, but a combinatorial approach may be needed to overcome the challenge of individual variability and disease heterogeneity. The goal of the present prospective study in the lithium-pilocarpine model of epilepsy in rats was to determine the discriminative utility of combinations of phenotypic biomarkers by examining their ability to predict epilepsy. For this purpose, we used a recent model refinement that allows comparing rats that will or will not develop spontaneous recurrent seizures (SRS) after pilocarpine-induced status epilepticus (SE). Potential biomarkers included in our study were seizure threshold and seizure severity in response to timed i.v. infusion of pentylenetetrazole (PTZ) and behavioral alterations determined by a battery of tests during the three weeks following SE. Three months after SE, video/EEG monitoring was used to determine which rats had developed SRS. To determine whether a biomarker or combination of biomarkers performed better than chance at predicting epilepsy after SE, derived data underwent receiver operating characteristic (ROC) curve analyses. When comparing rats with and without SRS and sham controls, the best intergroup discrimination was obtained by combining all measurements, resulting in a ROC area under curve (AUC) of 0.9592 (P<0.01), indicating an almost perfect discrimination or accuracy to predict development of SRS. These data indicate that a combinatorial biomarker approach may overcome the challenge of individual variability in the prediction of epilepsy.
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Affiliation(s)
- Sonja Bröer
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany.
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Nazem-Zadeh MR, Elisevich K, Air EL, Schwalb JM, Divine G, Kaur M, Wasade VS, Mahmoudi F, Shokri S, Bagher-Ebadian H, Soltanian-Zadeh H. DTI-based response-driven modeling of mTLE laterality. NEUROIMAGE-CLINICAL 2015; 11:694-706. [PMID: 27330966 PMCID: PMC4900487 DOI: 10.1016/j.nicl.2015.10.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 10/25/2015] [Accepted: 10/27/2015] [Indexed: 12/30/2022]
Abstract
Purpose To develop lateralization models for distinguishing between unilateral and bilateral mesial temporal lobe epilepsy (mTLE) and determining laterality in cases of unilateral mTLE. Background mTLE is the most common form of medically refractory focal epilepsy. Many mTLE patients fail to demonstrate an unambiguous unilateral ictal onset. Intracranial EEG (icEEG) monitoring can be performed to establish whether the ictal origin is unilateral or truly bilateral with independent bitemporal ictal origin. However, because of the expense and risk of intracranial electrode placement, much research has been done to determine if the need for icEEG can be obviated with noninvasive neuroimaging methods, such as diffusion tensor imaging (DTI). Methods Fractional anisotropy (FA) was used to quantify microstructural changes reflected in the diffusivity properties of the corpus callosum, cingulum, and fornix, in a retrospective cohort of 31 patients confirmed to have unilateral (n = 24) or bilateral (n = 7) mTLE. All unilateral mTLE patients underwent resection with an Engel class I outcome. Eleven were reported to have hippocampal sclerosis on pathological analysis; nine had undergone prior icEEG. The bilateral mTLE patients had undergone icEEG demonstrating independent epileptiform activity in both right and left hemispheres. Twenty-three nonepileptic subjects were included as controls. Results In cases of right mTLE, FA showed significant differences from control in all callosal subregions, in both left and right superior cingulate subregions, and in forniceal crura. Comparison of right and left mTLE cases showed significant differences in FA of callosal genu, rostral body, and splenium and the right posteroinferior and superior cingulate subregions. In cases of left mTLE, FA showed significant differences from control only in the callosal isthmus. Significant differences in FA were identified when cases of right mTLE were compared with bilateral mTLE cases in the rostral and midbody callosal subregions and isthmus. Based on 11 FA measurements in the cingulate, callosal and forniceal subregions, a response-driven lateralization model successfully differentiated all cases (n = 54) into groups of unilateral right (n = 12), unilateral left (n = 12), and bilateral mTLE (n = 7), and nonepileptic control (23). Conclusion The proposed response-driven DTI biomarker is intended to lessen diagnostic ambiguity of laterality in cases of mTLE and help optimize selection of surgical candidates. Application of this model shows promise in reducing the need for invasive icEEG in prospective cases. Develop response-driven lateralization model using diffusion tensor imaging Distinguish between unilateral and bilateral mesial temporal lobe epilepsy (mTLE) Determine or lessen diagnostic ambiguity of laterality in cases of unilateral mTLE Optimize selection of surgical candidates Reduction of the need for intracranial EEG
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Affiliation(s)
| | - Kost Elisevich
- Department of Clinical Neurosciences, Spectrum Health Medical Group, Division of Neurosurgery, Michigan State University, Grand Rapids, MI 49503, USA
| | - Ellen L Air
- Neurosurgery Department, Henry Ford Health System, Detroit, MI 48202, USA.
| | - Jason M Schwalb
- Neurosurgery Department, Henry Ford Health System, Detroit, MI 48202, USA.
| | - George Divine
- Public Health Sciences Department, Henry Ford Health System, Detroit, MI 48202, USA.
| | - Manpreet Kaur
- Neurosurgery Department, Henry Ford Health System, Detroit, MI 48202, USA.
| | | | - Fariborz Mahmoudi
- Radiology and Research Administration Department, Henry Ford Health System, Detroit, MI 48202, USA; Computer and IT engineering Faculty, Islamic Azad University, Qazvin Branch, Iran.
| | - Saeed Shokri
- Radiology and Research Administration Department, Henry Ford Health System, Detroit, MI 48202, USA; School of Computer Science, Wayne State University, Detroit, MI 48202, USA.
| | - Hassan Bagher-Ebadian
- Radiology and Research Administration Department, Henry Ford Health System, Detroit, MI 48202, USA; Neurology Department, Henry Ford Health System, Detroit, MI 48202, USA.
| | - Hamid Soltanian-Zadeh
- Radiology and Research Administration Department, Henry Ford Health System, Detroit, MI 48202, USA; Control and Intelligent Processing Center of Excellence (CIPCE), School of Electrical and Computer, University of Tehran, Tehran, Iran.
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Surgical outcomes with non-invasive presurgical evaluation in MRI determined bilateral mesial temporal sclerosis: A retrospective cohort study. Int J Surg 2015; 36:429-435. [PMID: 26407830 DOI: 10.1016/j.ijsu.2015.09.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 08/25/2015] [Accepted: 09/06/2015] [Indexed: 11/20/2022]
Abstract
BACKGROUND & OBJECTIVE Epilepsy surgery for bilateral hippocampal sclerosis continues to pose a challenge and outcomes even with invasive evaluations have not been very promising. Very few studies have analyzed surgery outcomes for patients with MRI determined, bilateral mesial temporal sclerosis (MTS) after non-invasive pre-surgical evaluation. MATERIAL AND METHODS We studied 35 patients with bilateral MTS who underwent anterior temporal lobectomy (ATL) after non-invasive pre-surgical evaluation. Clinical history, EEG, neuropsychology profile and symmetry of MTS on MRI were reviewed in the groups of 'seizure free' and 'not seizure free' patients. RESULTS At an average follow up of 44 months (range 12-110 months), 26 out of 35 patients (74%) were seizure free. Unilateral interictal discharges were seen in 57% patients. 94% patients had unilateral ictal EEG onset. Bilateral interictal discharges were significantly associated with 'not seizure free' outcome (p = 0.02). Pre-operatively, 24 (71%) patients had bilateral (verbal and visual) memory impairment while 10 (28%) patients had unilateral (verbal or visual) memory impairment and 1 patient had a normal memory profile. Overall, no significant decline in memory was seen in left or right surgery groups post-operatively. There was significant improvement in Quality of Life scores in all patients (p = <0.0005). CONCLUSION Patients with bilateral MTS on MRI can be unilateral on electro physiology and neuropsychology, and can have a very good surgical outcome. In a setting of limited resources, a noninvasive pre-surgical protocol can be used. With proper patient selection, the outcomes may be comparable to those reported with invasive pre-surgical protocols. Patients with unilateral interictal and ictal EEG have the best outcome. Up to 50% patients with bilateral interictal discharges can have a seizure free outcome. Patients with bilateral independent seizure onset have a less favourable prognosis. Patients who are not seizure free can still attain worthwhile improvement in seizure frequency without significant decline in memory and some improvement in quality of life.
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Loesch AM, Feddersen B, Tezer FI, Hartl E, Rémi J, Vollmar C, Noachtar S. Seizure semiology identifies patients with bilateral temporal lobe epilepsy. Epilepsy Res 2015; 109:197-202. [DOI: 10.1016/j.eplepsyres.2014.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 10/14/2014] [Accepted: 11/11/2014] [Indexed: 10/24/2022]
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Brandt C, Töllner K, Klee R, Bröer S, Löscher W. Effective termination of status epilepticus by rational polypharmacy in the lithium-pilocarpine model in rats: Window of opportunity to prevent epilepsy and prediction of epilepsy by biomarkers. Neurobiol Dis 2014; 75:78-90. [PMID: 25549873 DOI: 10.1016/j.nbd.2014.12.015] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 12/12/2014] [Accepted: 12/17/2014] [Indexed: 11/30/2022] Open
Abstract
The pilocarpine rat model, in which status epilepticus (SE) leads to epilepsy with spontaneous recurrent seizures (SRS), is widely used to study the mechanisms of epileptogenesis and develop strategies for epilepsy prevention. SE is commonly interrupted after 30-90min by high-dose diazepam or other anticonvulsants to reduce mortality. It is widely believed that SE duration of 30-60min is sufficient to induce hippocampal damage and epilepsy. However, resistance to diazepam develops during SE, so that an SE that is longer than 30min is difficult to terminate, and SE typically recurs several hours after diazepam, thus forming a bias for studies on epileptogenesis or antiepileptogenesis. We developed a drug cocktail, consisting of diazepam, phenobarbital, and scopolamine that allows complete and persistent SE termination in the lithium-pilocarpine model. A number of novel findings were obtained with this cocktail. (a) In contrast to previous reports with incomplete SE suppression, a SE of 60min duration did not induce epilepsy, whereas epilepsy with SRS developed after 90 or 120min SE; (b) by comparing groups of rats with 60 and 90min of SE, development of epilepsy could be predicted by behavioral hyperexcitability and decrease in seizure threshold, indicating that these read-outs are suited as biomarkers of epileptogenesis; (c) CA1 damage was prevented by the cocktail, but rats exhibited cell loss in the dentate hilus, which was related to development of epilepsy. These data demonstrate that the duration of SE needed for induction of epileptogenesis in this model is longer than previously thought.
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Affiliation(s)
- Claudia Brandt
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Kathrin Töllner
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Rebecca Klee
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Sonja Bröer
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany.
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Řehulka P, Doležalová I, Janoušová E, Tomášek M, Marusič P, Brázdil M, Kuba R. Ictal and postictal semiology in patients with bilateral temporal lobe epilepsy. Epilepsy Behav 2014; 41:40-6. [PMID: 25282104 DOI: 10.1016/j.yebeh.2014.09.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 09/07/2014] [Accepted: 09/10/2014] [Indexed: 11/28/2022]
Abstract
Bilateral temporal lobe epilepsy is characterized by evidence of seizure onset independently in both temporal lobes. The main aim of the present study was to determine whether patients with evidence of independent bilateral temporal lobe epilepsy (biTLE) can be identified noninvasively on the basis of seizure semiology analysis. Thirteen patients with biTLE, as defined by invasive EEG, were matched with 13 patients with unilateral temporal lobe epilepsy (uniTLE). In all 26 patients, the frequency of predefined clusters of ictal and periictal signs were evaluated: ictal motor signs (IMSs), periictal motor signs (PIMSs), periictal vegetative signs (PIVSs), the frequency of early oroalimentary automatisms (EOAs), and the duration of postictal unresponsiveness (PU). Some other noninvasive and clinical data were also evaluated. A lower frequency of IMSs was noted in the group with biTLE (patients = 46.2%, seizures = 20.7%) than in the group with uniTLE (patients = 92.3%, seizures = 61.0%) (p = 0.030; p < 0.001, respectively). The individual IMS average per seizure was significantly lower in the group with biTLE (0.14; range = 0-1.0) than in the group with uniTLE (0.80; range = 0-2.6) (p = 0.003). Postictal unresponsiveness was longer than 5 min in more patients (75.0%) and seizures (42.9%) in the group with biTLE than in the group with uniTLE (patients = 30.8%, seizures = 18.6%) (p = 0.047; p = 0.002). The frequency of EOAs, PIMSs, PIVSs, and other clinical data did not differ significantly. There is a lower frequency of ictal motor signs and longer duration of postictal unresponsiveness in patients with biTLE.
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Affiliation(s)
- Pavel Řehulka
- Brno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic; Behavioural and Social Neuroscience Research Group, Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic.
| | - Irena Doležalová
- Brno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic; Behavioural and Social Neuroscience Research Group, Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Eva Janoušová
- Institute of Biostatistics and Analyses, Masaryk University, Brno, Czech Republic
| | - Martin Tomášek
- Department of Neurology, Charles University in Prague, Second Faculty of Medicine, Motol University Hospital, Prague, Czech Republic
| | - Petr Marusič
- Department of Neurology, Charles University in Prague, Second Faculty of Medicine, Motol University Hospital, Prague, Czech Republic
| | - Milan Brázdil
- Brno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic; Behavioural and Social Neuroscience Research Group, Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Robert Kuba
- Brno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic; Behavioural and Social Neuroscience Research Group, Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
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Aghakhani Y, Liu X, Jette N, Wiebe S. Epilepsy surgery in patients with bilateral temporal lobe seizures: A systematic review. Epilepsia 2014; 55:1892-901. [DOI: 10.1111/epi.12856] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Yahya Aghakhani
- Department of Clinical Neurosciences; University of Calgary; Calgary Alberta Canada
| | - Xiaorong Liu
- Institute of Neuroscience and the Second Affiliated Hospital; Guangzhou Medical University; Guangzhou China
| | - Nathalie Jette
- Department of Clinical Neurosciences; University of Calgary; Calgary Alberta Canada
- Department of Community Health Sciences; Institute of Public Health and Hotchkiss Brain Institute; University of Calgary; Calgary Alberta Canada
| | - Samuel Wiebe
- Department of Clinical Neurosciences; University of Calgary; Calgary Alberta Canada
- Department of Community Health Sciences; Institute of Public Health and Hotchkiss Brain Institute; University of Calgary; Calgary Alberta Canada
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Kalamangalam GP, Cara L, Tandon N, Slater JD. An interictal EEG spectral metric for temporal lobe epilepsy lateralization. Epilepsy Res 2014; 108:1748-57. [PMID: 25270401 DOI: 10.1016/j.eplepsyres.2014.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 08/23/2014] [Accepted: 09/06/2014] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Visually-obvious abnormalities in the resting baseline EEG--slowing, spiking and high-frequency oscillations (HFOs)--are cardinal, though incompletely understood, features of the seizure onset zone in focal epilepsy. We hypothesized that evidence of cortical network dysfunction in temporal lobe epilepsy (TLE) would persist in the absence of visually-classifiable abnormalities in the baseline EEG recorded within the conventional passband, and that metrics of such dysfunction could serve as a lateralizing diagnostic in TLE. METHODS Epochs of resting EEG without significant abnormalities in light sleep over several days were compared between a group of 10 patients with proven TLE and 10 subjects without epilepsy. A novel laterality metric computed from the line length of normalized power spectra from the temporal channels was compared between the two groups. RESULTS Significant group differences in spectral line length laterality metric were found between the TLE and control group. At the individual level, seven of 10 TLE patients had highly significant laterality metrics, all concordant with the known laterality of their disease. SIGNIFICANCE Detailed spectral analysis offers novel insight into TLE network behavior, independent of the orthodox abnormalities of EEG slowing, spikes or HFOs. The results may be deployed in a practical diagnostic manner, offer insight into the EEG manifestations of disordered cellular network architecture in TLE, and maybe understood through simple analogy with the theory of linear time-invariant physical systems.
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Affiliation(s)
| | - Lukas Cara
- Department of Neurology, University of Texas Health Science Center, Houston, TX, USA
| | - Nitin Tandon
- Department of Neurosurgery, University of Texas Health Science Center, Houston, TX, USA
| | - Jeremy D Slater
- Department of Neurology, University of Texas Health Science Center, Houston, TX, USA
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Laxer KD, Trinka E, Hirsch LJ, Cendes F, Langfitt J, Delanty N, Resnick T, Benbadis SR. The consequences of refractory epilepsy and its treatment. Epilepsy Behav 2014; 37:59-70. [PMID: 24980390 DOI: 10.1016/j.yebeh.2014.05.031] [Citation(s) in RCA: 441] [Impact Index Per Article: 44.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/27/2014] [Accepted: 05/29/2014] [Indexed: 12/12/2022]
Abstract
Seizures in some 30% to 40% of patients with epilepsy fail to respond to antiepileptic drugs or other treatments. While much has been made of the risks of new drug therapies, not enough attention has been given to the risks of uncontrolled and progressive epilepsy. This critical review summarizes known risks associated with refractory epilepsy, provides practical clinical recommendations, and indicates areas for future research. Eight international epilepsy experts from Europe, the United States, and South America met on May 4, 2013, to present, review, and discuss relevant concepts, data, and literature on the consequences of refractory epilepsy. While patients with refractory epilepsy represent the minority of the population with epilepsy, they require the overwhelming majority of time, effort, and focus from treating physicians. They also represent the greatest economic and psychosocial burdens. Diagnostic procedures and medical/surgical treatments are not without risks. Overlooked, however, is that these risks are usually smaller than the risks of long-term, uncontrolled seizures. Refractory epilepsy may be progressive, carrying risks of structural damage to the brain and nervous system, comorbidities (osteoporosis, fractures), and increased mortality (from suicide, accidents, sudden unexpected death in epilepsy, pneumonia, vascular disease), as well as psychological (depression, anxiety), educational, social (stigma, driving), and vocational consequences. Adding to this burden is neuropsychiatric impairment caused by underlying epileptogenic processes ("essential comorbidities"), which appears to be independent of the effects of ongoing seizures themselves. Tolerating persistent seizures or chronic medicinal adverse effects has risks and consequences that often outweigh risks of seemingly "more aggressive" treatments. Future research should focus not only on controlling seizures but also on preventing these consequences.
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Affiliation(s)
- Kenneth D Laxer
- Sutter Pacific Epilepsy Program, California Pacific Medical Center, San Francisco, CA, USA.
| | - Eugen Trinka
- Department of Neurology, Christian Doppler Medical Centre, Paracelsus Medical University, Salzburg, Austria; Centre for Cognitive Neuroscience, Salzburg, Austria
| | - Lawrence J Hirsch
- Division of Epilepsy and EEG, Department of Neurology, Yale Comprehensive Epilepsy Center, New Haven, CT, USA
| | - Fernando Cendes
- Department of Neurology, University of Campinas (UNICAMP), Campinas, Brazil
| | - John Langfitt
- Department of Neurology, University of Rochester School of Medicine, Rochester, NY, USA; Department Psychiatry, University of Rochester School of Medicine, Rochester, NY, USA; Strong Epilepsy Center, University of Rochester School of Medicine, Rochester, NY, USA
| | - Norman Delanty
- Epilepsy Service and National Epilepsy Surgery Programme, Beaumont Hospital, Dublin, Ireland
| | - Trevor Resnick
- Comprehensive Epilepsy Program, Miami Children's Hospital, Miami, FL, USA
| | - Selim R Benbadis
- Comprehensive Epilepsy Program, University of South Florida, Tampa, FL, USA
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Mani J. Video electroencephalogram telemetry in temporal lobe epilepsy. Ann Indian Acad Neurol 2014; 17:S45-9. [PMID: 24791089 PMCID: PMC4001214 DOI: 10.4103/0972-2327.128653] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/02/2013] [Accepted: 10/02/2013] [Indexed: 11/15/2022] Open
Abstract
Temporal lobe epilepsy (TLE) is the most commonly encountered medically refractory epilepsy. It is also the substrate of refractory epilepsy that gives the most gratifying results in any epilepsy surgery program, with a minimum use of resources. Correlation of clinical behavior and the ictal patterns during ictal behavior is mandatory for success at epilepsy surgery. Video electroencephalogram (EEG) telemetry achieves this goal and hence plays a pivotal role in pre-surgical assessment. The role of telemetry is continuously evolving with the advent of digital EEG technology, of high-resolution volumetric magnetic resonance imaging and other functional imaging techniques. Most of surgical selection in patients with TLE can be done with a scalp video EEG monitoring. However, the limitations of the scalp EEG technique demand invasive recordings in a selected group of TLE patients. This subset of the patients can be a challenge to the epileptologist.
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Affiliation(s)
- Jayanti Mani
- Department of Brain and Nervous System, Kokilaben Dhirubhai Ambani Hospital, Andheri West, Mumbai, Maharashtra, India, Department of Medicine Lokmanya Tilak Memorial Medical College and Municipal Hospital, Mumbai, Maharashtra, India
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Valentín A, Alarcón G, Barrington SF, García Seoane JJ, Martín-Miguel MC, Selway RP, Koutroumanidis M. Interictal estimation of intracranial seizure onset in temporal lobe epilepsy. Clin Neurophysiol 2014; 125:231-8. [DOI: 10.1016/j.clinph.2013.07.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 06/06/2013] [Accepted: 07/11/2013] [Indexed: 01/01/2023]
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Mesial temporal lobe epilepsy with no specific histological abnormality: a distinct surgically remediable syndrome. Epilepsy Behav 2013; 29:542-7. [PMID: 24207132 DOI: 10.1016/j.yebeh.2013.09.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 09/07/2013] [Accepted: 09/17/2013] [Indexed: 11/20/2022]
Abstract
PURPOSE The purposes of the study were twofold: to clarify the clinical features and surgical outcome of mesial temporal lobe epilepsy (MTLE) with no specific histological abnormality and to determine the optimal surgical strategy. METHODS Twelve patients who met the following criteria were included: (1) normal preoperative MRI; (2) intracranial EEG findings consistent with mesial temporal onset of seizures; (3) selective amygdalohippocampectomy (AHE) was performed, and the patient was followed for more than 2years postoperatively; and (4) hippocampal histopathology was nonspecific. Clinical characteristics, intracranial EEG findings, and postoperative seizure outcome were examined. These twelve patients were compared with twenty-one patients with MTLE with unilateral hippocampal sclerosis (HS) on MRI who underwent intracranial EEG before resection (control group). RESULTS In patients with MTLE with no specific histological abnormality, the age at onset was significantly higher, the history of febrile seizures was significantly less frequent, and preoperative IQ score was significantly higher than that in the control group. The proportion of patients with bitemporal independent and/or nonlateralizing seizure onset on intracranial EEG was 50% in patients with MTLE with nonspecific histopathology and was significantly higher than that in the control group. Seizure outcome was classified as Engel class I in seven patients, class II in three, class III in one, and class IV in one. Seizure outcome was favorable even in three patients with seizures originating more frequently from the side contralateral to the resected side. CONCLUSIONS Mesial temporal lobe epilepsy with no specific histological abnormality is a clinical entity distinctly different from MTLE with HS. Bitemporal independent and/or nonlateralizing seizure onset on intracranial EEG is very common. Although the presence of lateral temporal and/or extratemporal epileptogenicity should always be kept in mind, postoperative seizure outcome after AHE is favorable even in cases with bitemporal independent and/or nonlateralizing seizure onset.
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Elshoff L, Muthuraman M, Anwar AR, Deuschl G, Stephani U, Raethjen J, Siniatchkin M. Dynamic imaging of coherent sources reveals different network connectivity underlying the generation and perpetuation of epileptic seizures. PLoS One 2013; 8:e78422. [PMID: 24194931 PMCID: PMC3806832 DOI: 10.1371/journal.pone.0078422] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 09/20/2013] [Indexed: 12/31/2022] Open
Abstract
The concept of focal epilepsies includes a seizure origin in brain regions with hyper synchronous activity (epileptogenic zone and seizure onset zone) and a complex epileptic network of different brain areas involved in the generation, propagation, and modulation of seizures. The purpose of this work was to study functional and effective connectivity between regions involved in networks of epileptic seizures. The beginning and middle part of focal seizures from ictal surface EEG data were analyzed using dynamic imaging of coherent sources (DICS), an inverse solution in the frequency domain which describes neuronal networks and coherences of oscillatory brain activities. The information flow (effective connectivity) between coherent sources was investigated using the renormalized partial directed coherence (RPDC) method. In 8/11 patients, the first and second source of epileptic activity as found by DICS were concordant with the operative resection site; these patients became seizure free after epilepsy surgery. In the remaining 3 patients, the results of DICS / RPDC calculations and the resection site were discordant; these patients had a poorer post-operative outcome. The first sources as found by DICS were located predominantly in cortical structures; subsequent sources included some subcortical structures: thalamus, Nucl. Subthalamicus and cerebellum. DICS seems to be a powerful tool to define the seizure onset zone and the epileptic networks involved. Seizure generation seems to be related to the propagation of epileptic activity from the primary source in the seizure onset zone, and maintenance of seizures is attributed to the perpetuation of epileptic activity between nodes in the epileptic network. Despite of these promising results, this proof of principle study needs further confirmation prior to the use of the described methods in the clinical praxis.
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Affiliation(s)
- Lydia Elshoff
- Department of Neuropediatrics, Christian-Albrechts-University, Kiel, Germany
| | | | - Abdul Rauf Anwar
- Department of Neurology, Christian-Albrechts-University, Kiel, Germany
- Digital Signal Processing and System Theory, Technical Faculty, Christian-Albrechts-University, Kiel, Germany
| | - Günther Deuschl
- Department of Neurology, Christian-Albrechts-University, Kiel, Germany
| | - Ulrich Stephani
- Department of Neuropediatrics, Christian-Albrechts-University, Kiel, Germany
| | - Jan Raethjen
- Department of Neurology, Christian-Albrechts-University, Kiel, Germany
| | - Michael Siniatchkin
- Department of Neuropediatrics, Christian-Albrechts-University, Kiel, Germany
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Goethe-University of Frankfurt am Main, Frankfurt, Germany
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Beniczky S, Lantz G, Rosenzweig I, Åkeson P, Pedersen B, Pinborg LH, Ziebell M, Jespersen B, Fuglsang-Frederiksen A. Source localization of rhythmic ictal EEG activity: a study of diagnostic accuracy following STARD criteria. Epilepsia 2013; 54:1743-52. [PMID: 23944234 DOI: 10.1111/epi.12339] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2013] [Indexed: 11/28/2022]
Abstract
PURPOSE Although precise identification of the seizure-onset zone is an essential element of presurgical evaluation, source localization of ictal electroencephalography (EEG) signals has received little attention. The aim of our study was to estimate the accuracy of source localization of rhythmic ictal EEG activity using a distributed source model. METHODS Source localization of rhythmic ictal scalp EEG activity was performed in 42 consecutive cases fulfilling inclusion criteria. The study was designed according to recommendations for studies on diagnostic accuracy (STARD). The initial ictal EEG signals were selected using a standardized method, based on frequency analysis and voltage distribution of the ictal activity. A distributed source model-local autoregressive average (LAURA)-was used for the source localization. Sensitivity, specificity, and measurement of agreement (kappa) were determined based on the reference standard-the consensus conclusion of the multidisciplinary epilepsy surgery team. Predictive values were calculated from the surgical outcome of the operated patients. To estimate the clinical value of the ictal source analysis, we compared the likelihood ratios of concordant and discordant results. Source localization was performed blinded to the clinical data, and before the surgical decision. KEY FINDINGS Reference standard was available for 33 patients. The ictal source localization had a sensitivity of 70% and a specificity of 76%. The mean measurement of agreement (kappa) was 0.61, corresponding to substantial agreement (95% confidence interval (CI) 0.38-0.84). Twenty patients underwent resective surgery. The positive predictive value (PPV) for seizure freedom was 92% and the negative predictive value (NPV) was 43%. The likelihood ratio was nine times higher for the concordant results, as compared with the discordant ones. SIGNIFICANCE Source localization of rhythmic ictal activity using a distributed source model (LAURA) for the ictal EEG signals selected with a standardized method is feasible in clinical practice and has a good diagnostic accuracy. Our findings encourage clinical neurophysiologists assessing ictal EEGs to include this method in their armamentarium.
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Affiliation(s)
- Sándor Beniczky
- Department of Clinical Neurophysiology, Danish Epilepsy Center, Dianalund, Denmark; Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
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Scholl EA, Dudek FE, Ekstrand JJ. Neuronal degeneration is observed in multiple regions outside the hippocampus after lithium pilocarpine-induced status epilepticus in the immature rat. Neuroscience 2013; 252:45-59. [PMID: 23896573 DOI: 10.1016/j.neuroscience.2013.07.045] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 07/17/2013] [Accepted: 07/18/2013] [Indexed: 01/25/2023]
Abstract
Although hippocampal sclerosis is frequently identified as a possible epileptic focus in patients with temporal lobe epilepsy, neuronal loss has also been observed in additional structures, including areas outside the temporal lobe. The claim from several researchers using animal models of acquired epilepsy that the immature brain can develop epilepsy without evidence of hippocampal neuronal death raises the possibility that neuronal death in some of these other regions may also be important for epileptogenesis. The present study used the lithium pilocarpine model of acquired epilepsy in immature animals to assess which structures outside the hippocampus are injured acutely after status epilepticus. Sprague-Dawley rat pups were implanted with surface EEG electrodes, and status epilepticus was induced at 20 days of age with lithium pilocarpine. After 72 h, brain tissue from 12 animals was examined with Fluoro-Jade B, a histochemical marker for degenerating neurons. All animals that had confirmed status epilepticus demonstrated Fluoro-Jade B staining in areas outside the hippocampus. The most prominent staining was seen in the thalamus (mediodorsal, paratenial, reuniens, and ventral lateral geniculate nuclei), amygdala (ventral lateral, posteromedial, and basomedial nuclei), ventral premammillary nuclei of hypothalamus, and paralimbic cortices (perirhinal, entorhinal, and piriform) as well as parasubiculum and dorsal endopiriform nuclei. These results demonstrate that lithium pilocarpine-induced status epilepticus in the immature rat brain consistently results in neuronal injury in several distinct areas outside of the hippocampus. Many of these regions are similar to areas damaged in patients with temporal lobe epilepsy, thus suggesting a possible role in epileptogenesis.
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Key Words
- AA
- ACH
- ACo
- AD
- AHC
- AI
- AM
- AO
- APir
- AStr
- AV
- Acb
- AcbSh
- BAOT
- BLA
- BLP
- BLV
- BMA
- BMP
- BSTIA
- BSTM
- CA
- CL
- CM
- CPu
- CeL
- CeM
- Cg1-3
- DEn
- DG
- DI
- DLG
- DP
- EEG
- Ent
- Fluoro-jade B
- Fr1-3
- GABA
- GI
- GP
- HC
- Hil
- I
- IL
- LDDM
- LDVL
- LHb
- LM
- LO
- LOT
- LPLR
- LPMR
- LSD
- LSI
- LSV
- LaD
- LaV
- MD
- MGD
- MGM
- MGP
- MGV
- MHb
- MO
- MS
- MTu
- MeA
- MePD
- MePV
- NAc
- Oc2L
- P
- PC
- PF
- PLCo
- PMCo
- PMD
- PMV
- PRh
- PT
- PVA
- PVP
- PaS
- Par1
- Pir
- Po
- PrS
- RSA
- RSG
- Re
- Rh
- Rt
- S
- SG
- SI
- SNR
- STh
- TLE
- Te1,3
- VL
- VLG
- VLO
- VM
- VP
- VPL
- VPM
- VTR
- ZI
- accumbens
- accumbens shell
- agranular insular cortex
- amygdalopiriform transition area
- amygdalostriatal transition area
- anterior amygdaloid area
- anterior cingulate
- anterior cortical nucleus
- anterior hypothalamic area
- anterior hypothalamic area, central
- anterior olfactory nucleus
- anterodorsal nucleus
- anteromedial
- anteroventral nucleus
- basolateral nucleus, anterior
- basolateral nucleus, posterior
- basolateral nucleus, ventral
- basomedial nucleus, anterior
- basomedial nucleus, posterior
- bed nucleus accessory olfactory tract
- bed nucleus stria terminalis, intraamygdaloid division
- bed stria terminalis nuclei
- caudate putamen
- central nucleus, lateral
- central nucleus, medial
- centrolateral nucleus
- centromedial nucleus
- cornu ammonis
- dentate gyrus
- dorsal endopiriform nucleus
- dorsal peduncular
- dorsolateral geniculate nucleus
- dysgranular insular cortex
- electroencephalogram
- entorhinal cortex
- frontal cortex
- globus pallidus
- granular insular cortex
- hilus
- hippocampus
- immature brain
- infralimbic
- intercalated masses
- lateral habenula
- lateral mammillary
- lateral nucleus, dorsal
- lateral nucleus, ventral
- lateral orbital cortex
- lateral septal, dorsal
- lateral septal, intermediate
- lateral septal, ventral
- laterodorsal nucleus, dorsomedial
- laterodorsal nucleus, ventrolateral
- lateroposterior nucleus, lateral rostral
- lateroposterior nucleus, medial rostral
- lithium pilocarpine
- medial geniculate nucleus, dorsal
- medial geniculate nucleus, medial
- medial geniculate nucleus, ventral
- medial globus pallidus
- medial habenula
- medial nucleus, anterior
- medial nucleus, posterodorsal
- medial nucleus, posteroventral
- medial orbital cortex
- medial septal
- medial tuberal
- mediodorsal nucleus
- nucleus accumbens
- nucleus lateral olfactory tract
- occipital cortex
- paracentral
- parafasicular
- parasubiculum
- paratenial
- paraventricular nucleus, anterior
- paraventricular nucleus, posterior
- parietal cortex
- perirhinal cortex
- piriform cortex
- post-natal day
- posterior nucleus
- posterolateral cortical nucleus
- posteromedial cortical nucleus
- premammillary nucleus, dorsal
- premammillary nucleus, ventral
- presubiculum
- reticular nucleus
- retrosplenial agranular cortex
- retrosplenial granular cortex
- reuniens nucleus
- rhomboid nucleus
- status epilepticus
- subiculum
- substantia innominate
- substantia nigra pars reticulate
- subthalamic nucleus
- suprageniculate nucleus
- temporal cortex
- temporal lobe epilepsy
- vRe
- ventral pallidum
- ventral posterolateral nucleus
- ventral posteromedial nucleus
- ventral reuniens nucleus
- ventral tegmental area
- ventrolateral geniculate nucleus
- ventrolateral nucleus
- ventrolateral orbital cortex
- ventromedial nucleus
- zona incerta
- γ-aminobutyric acid
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Affiliation(s)
- E A Scholl
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, United States
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Abstract
BACKGROUND The surgical removal of the epileptogenic zone in medically intractable seizures depends on accurate localization to minimize the neurological sequelae and prevent future seizures. To date, few studies have demonstrated the use of depth electrodes in a pediatric epilepsy population. Here, we report our study of pediatric epilepsy patients at our epilepsy center who were successfully operated for medically intractable seizures following the use of intracranial depth electrodes. In addition, we detail three individuals with distinct clinical scenarios in which depth electrodes were helpful and describe our technical approach to implantation and surgery. METHODS We retrospectively reviewed 18 pediatric epilepsy patients requiring depth electrode studies who presented at the University of Alberta Comprehensive Epilepsy Program between 1999 and 2010 with medically intractable epilepsy. Patients underwent cortical resection following depth electrode placement according to the Comprehensive Epilepsy Program surgical protocols after failure of surface electroencephalogram and magnetic resonance imaging to localize ictal onset zone. RESULT The ictal onset zone was successfully identified in all 18 patients. Treatment of all surgical patients resulted in successful seizure freedom (Engel class I) without neurological complications. CONCLUSION Intracranial depth electrode use is safe and able to provide sufficient information for the identification of the epileptogenic zone in pediatric epilepsy patients previously not considered for epilepsy surgery.
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Chkhenkeli SA, ramka M, Rakviashvili TN, Lortkipanidze GS, Magalashvili GE, Bregvadze ES, Otarashvili A, Gagoshidze TS. Bitemporal Intractable Epilepsy: Could It Be Surgically Treatable? Stereotact Funct Neurosurg 2013; 91:104-12. [DOI: 10.1159/000343198] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Accepted: 02/12/2011] [Indexed: 11/19/2022]
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Wasade VS, Elisevich K, Schultz L, Jafari-Khouzani K, Smith BJ, Soltanian-Zadeh H, Constantinou J. Analysis of scalp EEG and quantitative MRI in cases of temporal lobe epilepsy requiring intracranial electrographic monitoring. Br J Neurosurg 2012; 27:221-7. [DOI: 10.3109/02688697.2012.724121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Bercovici E, Kumar BS, Mirsattari SM. Neocortical temporal lobe epilepsy. EPILEPSY RESEARCH AND TREATMENT 2012; 2012:103160. [PMID: 22953057 PMCID: PMC3420667 DOI: 10.1155/2012/103160] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 01/04/2012] [Accepted: 05/22/2012] [Indexed: 01/15/2023]
Abstract
Complex partial seizures (CPSs) can present with various semiologies, while mesial temporal lobe epilepsy (mTLE) is a well-recognized cause of CPS, neocortical temporal lobe epilepsy (nTLE) albeit being less common is increasingly recognized as separate disease entity. Differentiating the two remains a challenge for epileptologists as many symptoms overlap due to reciprocal connections between the neocortical and the mesial temporal regions. Various studies have attempted to correctly localize the seizure focus in nTLE as patients with this disorder may benefit from surgery. While earlier work predicted poor outcomes in this population, recent work challenges those ideas yielding good outcomes in part due to better localization using improved anatomical and functional techniques. This paper provides a comprehensive review of the diagnostic workup, particularly the application of recent advances in electroencephalography and functional brain imaging, in neocortical temporal lobe epilepsy.
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Affiliation(s)
- Eduard Bercovici
- Division of Neurology, University of Toronto, Toronto, ON, Canada
| | - Balagobal Santosh Kumar
- Department of Clinical Neurological Sciences, University of Western Ontario, London, ON, Canada
| | - Seyed M. Mirsattari
- Department of Clinical Neurological Sciences, University of Western Ontario, London, ON, Canada
- Department of Medical Imaging, University of Western Ontario, London, ON, Canada
- Department of Medical Biophysics, University of Western Ontario, London, ON, Canada
- Department of Psychology, University of Western Ontario, London, ON, Canada
- London Health Sciences Centre, B10-110, London, ON, Canada N6A 5A5
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Gritsch G, Hartmann MM, Perko H, Fürbass F, Ossenblok P, Kluge T. Automatic detection of the seizure onset zone based on ictal EEG. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2011:3901-4. [PMID: 22255192 DOI: 10.1109/iembs.2011.6090969] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this paper we show a proof of concept for novel automatic seizure onset zone detector. The proposed approach utilizes the Austrian Institute of Technology (AIT) seizure detection system EpiScan extended by a frequency domain source localization module. EpiScan was proven to detect rhythmic epileptoform seizure activity often seen during the early phase of epileptic seizures with reasonable high sensitivity and specificity. Additionally, the core module of EpiScan provides complex coefficients and fundamental frequencies representing the rhythmic activity of the ictal EEG signal. These parameters serve as input to a frequency domain version of the Minimum Variance Beamformer to estimate the most dominant source. The position of this source is the detected seizure onset zone. The results are compared to a state of the art wavelet transformation approach based on a manually chosen frequency band. Our first results are encouraging since they coincide with those obtained with the wavelet approach and furthermore show excellent accordance with the medical report for the majority of analyzed seizures. In contrast to the wavelet approach our method has the advantage that it does not rely on a manual selection of the frequency band.
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Affiliation(s)
- G Gritsch
- Austrian Institute of Technology, Donau-City-Strasse 1, 1220 Vienna, Austria
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Javidan M. Electroencephalography in mesial temporal lobe epilepsy: a review. EPILEPSY RESEARCH AND TREATMENT 2012; 2012:637430. [PMID: 22957235 PMCID: PMC3420622 DOI: 10.1155/2012/637430] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 01/17/2012] [Accepted: 02/23/2012] [Indexed: 11/17/2022]
Abstract
Electroencephalography (EEG) has an important role in the diagnosis and classification of epilepsy. It can provide information for predicting the response to antiseizure drugs and to identify the surgically remediable epilepsies. In temporal lobe epilepsy (TLE) seizures could originate in the medial or lateral neocortical temporal region, and many of these patients are refractory to medical treatment. However, majority of patients have had excellent results after surgery and this often relies on the EEG and magnetic resonance imaging (MRI) data in presurgical evaluation. If the scalp EEG data is insufficient or discordant, invasive EEG recording with placement of intracranial electrodes could identify the seizure focus prior to surgery. This paper highlights the general information regarding the use of EEG in epilepsy, EEG patterns resembling epileptiform discharges, and the interictal, ictal and postictal findings in mesial temporal lobe epilepsy using scalp and intracranial recordings prior to surgery. The utility of the automated seizure detection and computerized mathematical models for increasing yield of non-invasive localization is discussed. This paper also describes the sensitivity, specificity, and predictive value of EEG for seizure recurrence after withdrawal of medications following seizure freedom with medical and surgical therapy.
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Affiliation(s)
- Manouchehr Javidan
- Division of Neurology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada V5Z 1M9
- Neurophysiology Laboratory, Vancouver General Hospital, Vancouver, BC, Canada V5Z1M9
- Epilepsy Program, Vancouver General Hospital, Vancouver, BC, Canada V5Z 1M9
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Shih JJ, Rodin E, Gupta V, Wharen RE. Signal characteristics of intraventricular electrodes recordings in human epilepsy: a case report. Clin EEG Neurosci 2012; 43:105-11. [PMID: 22715487 DOI: 10.1177/1550059412438936] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The case of a patient with intractable temporal lobe seizures and inadvertent unilateral intraventricular depth electrode placement is presented. The resting electroencephalograph (EEG) showed marked amplitude differences between the intraventricular electrode on the left and the parenchymal electrode on the right. All recorded seizures originated on the left side and in spite of its intraventricular location, frequency power spectra during the early ictal phase showed a marked increase in power for all frequency bands in the left depth electrode, exceeding that on the right. Analysis with Brain Electrical Source Analysis (BESA) software demonstrated marked ictal baseline shifts which were initially limited to the left side but changed to the right during clinical secondary generalization. In the immediate postictal state, all, except for infraslow, frequencies were markedly reduced in power. We conclude that intraventricular depth electrode contacts placed adjacent to the hippocampal structure can record interictal and ictal activity for all frequency bands, albeit at reduced amplitudes. Furthermore, infraslow activity can provide supplementary information about the epileptogenic zone.
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Affiliation(s)
- Jerry J Shih
- Department of Neurology, Mayo Clinic, Jacksonville, FL 32224, USA.
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Gross RE, Rowland NC, Sung EK, LaBorde DV, Suleiman SL. Anchoring depth electrodes for bedside removal: a "break-away" suturing technique for intracranial monitoring. Neurosurgery 2012; 71:52-6; discussion 56-7. [PMID: 22433201 DOI: 10.1227/neu.0b013e31825569c0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Intracranial depth electrodes for epilepsy are easily dislodged during long-term monitoring unless adequately anchored, but a technique is not available that is both secure and allows easy explantation without reopening the incision. OBJECTIVE To describe a convenient and inexpensive method for anchoring depth electrodes that prevents migration and incidental pullout while allowing electrode removal at the bedside. METHODS An easily breakable suture (eg, MONOCRYL) is tied around both the depth electrode and a heavy nylon suture and anchored to a hole at the edge of the burr hole; the tails of both are tunneled together percutaneously. The "break-away" MONOCRYL suture effectively anchors the electrode for as long as needed. At the completion of the intracranial electroencephalography session, the 2 tails of the nylon suture are pulled to break their encompassing MONOCRYL anchor suture, thus freeing the depth electrode for easy removal. RESULTS The break-away depth electrode anchoring technique was used for 438 electrodes in 68 patients, followed by explantation of these and associated strip electrodes without reopening the incision. Only 1 electrode (0.2%) migrated spontaneously, and 3 depth electrodes (0.7%) fractured in 2 patients (2.9%) on explantation, necessitating open surgery to remove them in 1 of the patients (1.5%). CONCLUSION An easy and inexpensive anchoring configuration for depth electrodes is described that provides an effective and safe means of securing the electrodes while allowing easy explantation at the bedside.
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Affiliation(s)
- Robert E Gross
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
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Centeno RS, Yacubian EMT, Caboclo LOSF, Carrete Júnior H, Cavalheiro S. Intracranial depth electrodes implantation in the era of image-guided surgery. ARQUIVOS DE NEURO-PSIQUIATRIA 2011; 69:693-8. [DOI: 10.1590/s0004-282x2011000500022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 03/09/2011] [Indexed: 11/21/2022]
Abstract
The advent of modern image-guided surgery has revolutionized depth electrode implantation techniques. Stereoelectroencephalography (SEEG), introduced by Talairach in the 1950s, is an invasive method for three-dimensional analysis on the epileptogenic zone based on the technique of intracranial implantation of depth electrodes. The aim of this article is to discuss the principles of SEEG and their evolution from the Talairach era to the image-guided surgery of today, along with future prospects. Although the general principles of SEEG have remained intact over the years, the implantation of depth electrodes, i.e. the surgical technique that enables this method, has undergone tremendous evolution over the last three decades, due the advent of modern imaging techniques, computer systems and new stereotactic techniques. The use of robotic systems, the constant evolution of imaging and computing techniques and the use of depth electrodes together with microdialysis probes will open up enormous prospects for applying depth electrodes and SEEG both for investigative use and for therapeutic use. Brain stimulation of deep targets and the construction of "smart" electrodes may, in the near future, increase the need to use this method.
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