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Frauscher B, Mansilla D, Abdallah C, Astner-Rohracher A, Beniczky S, Brazdil M, Gnatkovsky V, Jacobs J, Kalamangalam G, Perucca P, Ryvlin P, Schuele S, Tao J, Wang Y, Zijlmans M, McGonigal A. Learn how to interpret and use intracranial EEG findings. Epileptic Disord 2024; 26:1-59. [PMID: 38116690 DOI: 10.1002/epd2.20190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/21/2023] [Accepted: 11/29/2023] [Indexed: 12/21/2023]
Abstract
Epilepsy surgery is the therapy of choice for many patients with drug-resistant focal epilepsy. Recognizing and describing ictal and interictal patterns with intracranial electroencephalography (EEG) recordings is important in order to most efficiently leverage advantages of this technique to accurately delineate the seizure-onset zone before undergoing surgery. In this seminar in epileptology, we address learning objective "1.4.11 Recognize and describe ictal and interictal patterns with intracranial recordings" of the International League against Epilepsy curriculum for epileptologists. We will review principal considerations of the implantation planning, summarize the literature for the most relevant ictal and interictal EEG patterns within and beyond the Berger frequency spectrum, review invasive stimulation for seizure and functional mapping, discuss caveats in the interpretation of intracranial EEG findings, provide an overview on special considerations in children and in subdural grids/strips, and review available quantitative/signal analysis approaches. To be as practically oriented as possible, we will provide a mini atlas of the most frequent EEG patterns, highlight pearls for its not infrequently challenging interpretation, and conclude with two illustrative case examples. This article shall serve as a useful learning resource for trainees in clinical neurophysiology/epileptology by providing a basic understanding on the concepts of invasive intracranial EEG.
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Affiliation(s)
- B Frauscher
- Department of Neurology, Duke University Medical Center and Department of Biomedical Engineering, Duke Pratt School of Engineering, Durham, North Carolina, USA
- Analytical Neurophysiology Lab, Montreal Neurological Institute and Hospital, Montreal, Québec, Canada
| | - D Mansilla
- Analytical Neurophysiology Lab, Montreal Neurological Institute and Hospital, Montreal, Québec, Canada
- Neurophysiology Unit, Institute of Neurosurgery Dr. Asenjo, Santiago, Chile
| | - C Abdallah
- Analytical Neurophysiology Lab, Montreal Neurological Institute and Hospital, Montreal, Québec, Canada
| | - A Astner-Rohracher
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - S Beniczky
- Danish Epilepsy Centre, Dianalund, Denmark
- Aarhus University, Aarhus, Denmark
| | - M Brazdil
- Brno Epilepsy Center, Department of Neurology, St. Anne's University Hospital and Medical Faculty of Masaryk University, Member of the ERN-EpiCARE, Brno, Czechia
- Behavioral and Social Neuroscience Research Group, Central European Institute of Technology, Masaryk University, Brno, Czechia
| | - V Gnatkovsky
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - J Jacobs
- Department of Paediatrics and Department of Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - G Kalamangalam
- Department of Neurology, University of Florida, Gainesville, Florida, USA
- Wilder Center for Epilepsy Research, University of Florida, Gainesville, Florida, USA
| | - P Perucca
- Epilepsy Research Centre, Department of Medicine (Austin Health), University of Melbourne, Melbourne, Victoria, Australia
- Bladin-Berkovic Comprehensive Epilepsy Program, Department of Neurology, Austin Health, Melbourne, Victoria, Australia
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Department of Neurology, Alfred Health, Melbourne, Victoria, Australia
- Department of Neurology, Royal Melbourne Hospital, Melbourne, Victoria, Australia
| | - P Ryvlin
- Department of Clinical Neurosciences, CHUV, Lausanne University Hospital, Lausanne, Switzerland
| | - S Schuele
- Department of Neurology, Feinberg School of Medicine, Northwestern Memorial Hospital, Chicago, Illinois, USA
| | - J Tao
- Department of Neurology, The University of Chicago, Chicago, Illinois, USA
| | - Y Wang
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
- Wilder Center for Epilepsy Research, University of Florida, Gainesville, Florida, USA
| | - M Zijlmans
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht, the Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands
| | - A McGonigal
- Department of Neurosciences, Mater Misericordiae Hospital, Brisbane, Queensland, Australia
- Mater Research Institute, Faculty of Medicine, University of Queensland, St Lucia, Queensland, Australia
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Fitzgerald Z, Morita-Sherman M, Hogue O, Joseph B, Alvim MKM, Yasuda CL, Vegh D, Nair D, Burgess R, Bingaman W, Najm I, Kattan MW, Blumcke I, Worrell G, Brinkmann BH, Cendes F, Jehi L. Improving the prediction of epilepsy surgery outcomes using basic scalp EEG findings. Epilepsia 2021; 62:2439-2450. [PMID: 34338324 PMCID: PMC8488002 DOI: 10.1111/epi.17024] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 06/15/2021] [Accepted: 07/15/2021] [Indexed: 12/23/2022]
Abstract
OBJECTIVE This study aims to evaluate the role of scalp electroencephalography (EEG; ictal and interictal patterns) in predicting resective epilepsy surgery outcomes. We use the data to further develop a nomogram to predict seizure freedom. METHODS We retrospectively reviewed the scalp EEG findings and clinical data of patients who underwent surgical resection at three epilepsy centers. Using both EEG and clinical variables categorized into 13 isolated candidate predictors and 6 interaction terms, we built a multivariable Cox proportional hazards model to predict seizure freedom 2 years after surgery. Harrell's step-down procedure was used to sequentially eliminate the least-informative variables from the model until the change in the concordance index (c-index) with variable removal was less than 0.01. We created a separate model using only clinical variables. Discrimination of the two models was compared to evaluate the role of scalp EEG in seizure-freedom prediction. RESULTS Four hundred seventy patient records were analyzed. Following internal validation, the full Clinical + EEG model achieved an optimism-corrected c-index of 0.65, whereas the c-index of the model without EEG data was 0.59. The presence of focal to bilateral tonic-clonic seizures (FBTCS), high preoperative seizure frequency, absence of hippocampal sclerosis, and presence of nonlocalizable seizures predicted worse outcome. The presence of FBTCS had the largest impact for predicting outcome. The analysis of the models' interactions showed that in patients with unilateral interictal epileptiform discharges (IEDs), temporal lobe surgery cases had a better outcome. In cases with bilateral IEDs, abnormal magnetic resonance imaging (MRI) predicted worse outcomes, and in cases without IEDs, patients with extratemporal epilepsy and abnormal MRI had better outcomes. SIGNIFICANCE This study highlights the value of scalp EEG, particularly the significance of IEDs, in predicting surgical outcome. The nomogram delivers an individualized prediction of postoperative outcome, and provides a unique assessment of the relationship between the outcome and preoperative findings.
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Affiliation(s)
| | | | - Olivia Hogue
- Quantitative Health Sciences, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - Boney Joseph
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
| | | | | | - Deborah Vegh
- Epilepsy Center, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - Dileep Nair
- Epilepsy Center, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - Richard Burgess
- Epilepsy Center, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - William Bingaman
- Epilepsy Center, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - Imad Najm
- Epilepsy Center, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - Michael W. Kattan
- Quantitative Health Sciences, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - Ingmar Blumcke
- Institute of Neuropathology, University Hospitals Erlangen, Erlangen, Germany
| | - Gregory Worrell
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Fernando Cendes
- Department of Neurology, University of Campinas, Campinas, Brazil
| | - Lara Jehi
- Epilepsy Center, Cleveland Clinic Foundation, Cleveland, Ohio, USA
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Tanaka H, Gotman J, Khoo HM, Olivier A, Hall J, Dubeau F. Neurophysiological seizure-onset predictors of epilepsy surgery outcome: a multivariable analysis. J Neurosurg 2020; 133:1863-1872. [PMID: 31783358 DOI: 10.3171/2019.9.jns19527] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 09/18/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The authors sought to determine which neurophysiological seizure-onset features seen during scalp electroencephalography (EEG) and intracerebral EEG (iEEG) monitoring are predictors of postoperative outcome in a large series of patients with drug-resistant focal epilepsy who underwent resective surgery. METHODS The authors retrospectively analyzed the records of 75 consecutive patients with focal epilepsy, who first underwent scalp EEG and then iEEG (stereo-EEG) for presurgical assessment and who went on to undergo resective surgery between 2004 and 2015. To determine the independent prognostic factors from the neurophysiological scalp EEG and iEEG seizure-onset information, univariate and standard multivariable logistic regression analyses were used. Since scalp EEG and iEEG data were recorded at different times, the authors matched scalp seizures with intracerebral seizures for each patient using strict criteria. RESULTS A total of 3057 seizures were assessed. Forty-eight percent (36/75) of patients had a favorable outcome (Engel class I-II) after a minimum follow-up of at least 1 year. According to univariate analysis, a localized scalp EEG seizure onset (p < 0.001), a multilobar intracerebral seizure-onset zone (SOZ) (p < 0.001), and an extended SOZ (p = 0.001) were significantly associated with surgical outcome. According to multivariable analysis, the following two independent factors were found: 1) the ability of scalp EEG to localize the seizure onset was a predictor of a favorable postoperative outcome (OR 6.073, 95% CI 2.011-18.339, p = 0.001), and 2) a multilobar SOZ was a predictor of an unfavorable outcome (OR 0.076, 95% CI 0.009-0.663, p = 0.020). CONCLUSIONS The study findings show that localization at scalp seizure onset and a multilobar SOZ were strong predictors of surgical outcome. These predictors can help to select the better candidates for resective surgery.
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Affiliation(s)
- Hideaki Tanaka
- 1Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
- 2Department of Neurosurgery, Fukuoka University Hospital
- 3Fukuoka Sanno Hospital, Epilepsy and Sleep Center, Fukuoka; and
| | - Jean Gotman
- 1Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Hui Ming Khoo
- 1Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
- 4Department of Neurosurgery, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - André Olivier
- 1Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Jeffery Hall
- 1Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - François Dubeau
- 1Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
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Andrews JP, Ammanuel S, Kleen J, Khambhati AN, Knowlton R, Chang EF. Early seizure spread and epilepsy surgery: A systematic review. Epilepsia 2020; 61:2163-2172. [PMID: 32944952 DOI: 10.1111/epi.16668] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 08/03/2020] [Accepted: 08/04/2020] [Indexed: 01/03/2023]
Abstract
OBJECTIVE A fundamental question in epilepsy surgery is how to delineate the margins of cortex that must be resected to result in seizure freedom. Whether and which areas showing seizure activity early in ictus must be removed to avoid postoperative recurrence of seizures is an area of ongoing research. Seizure spread dynamics in the initial seconds of ictus are often correlated with postoperative outcome; there is neither a consensus definition of early spread nor a concise summary of the existing literature linking seizure spread to postsurgical seizure outcomes. The present study is intended to summarize the literature that links seizure spread to postoperative seizure outcome and to provide a framework for quantitative assessment of early seizure spread. METHODS A systematic review was carried out according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A Medline search identified clinical studies reporting data on seizure spread measured by intracranial electrodes, having at least 10 subjects and reporting at least 1-year postoperative outcome in the English literature from 1990 to 2019. Studies were evaluated regarding support for a primary hypothesis: Areas of early seizure spread represent cortex with seizure-generating potential. RESULTS The search yielded 4562 studies: 15 studies met inclusion criteria and 7 studies supported the primary hypothesis. The methods and metrics used to describe seizure spread were heterogenous. The timeframe of seizure spread associated with seizure outcome ranged from 1-14 seconds, with large, well-designed, retrospective studies pointing to 3-10 seconds as most likely to provide meaningful correlates of postoperative seizure freedom. SIGNIFICANCE The complex correlation between electrophysiologic seizure spread and the potential for seizure generation needs further elucidation. Prospective cohort studies or trials are needed to evaluate epilepsy surgery targeting cortex involved in the first 3-10 seconds of ictus.
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Affiliation(s)
- John P Andrews
- Department of Neurological Surgery, School of Medicine, University of California-San Francisco, San Francisco, California, USA
| | - Simon Ammanuel
- Department of Neurological Surgery, School of Medicine, University of California-San Francisco, San Francisco, California, USA
| | - Jonathan Kleen
- Department of Neurology, School of Medicine, University of California-San Francisco, San Francisco, California, USA
| | - Ankit N Khambhati
- Department of Neurological Surgery, School of Medicine, University of California-San Francisco, San Francisco, California, USA
| | - Robert Knowlton
- Department of Neurology, School of Medicine, University of California-San Francisco, San Francisco, California, USA
| | - Edward F Chang
- Department of Neurological Surgery, School of Medicine, University of California-San Francisco, San Francisco, California, USA
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Di Giacomo R, Uribe-San-Martin R, Mai R, Francione S, Nobili L, Sartori I, Gozzo F, Pelliccia V, Onofrj M, Lo Russo G, de Curtis M, Tassi L. Stereo-EEG ictal/interictal patterns and underlying pathologies. Seizure 2019; 72:54-60. [DOI: 10.1016/j.seizure.2019.10.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 09/24/2019] [Accepted: 10/01/2019] [Indexed: 11/24/2022] Open
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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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Kasper BS, Rössler K, Hamer HM, Dörfler A, Blümcke I, Coras R, Roesch J, Mennecke A, Wellmer J, Sommer B, Lorber B, Lang JD, Graf W, Stefan H, Schwab S, Buchfelder M, Rampp S. Coregistrating magnetic source and magnetic resonance imaging for epilepsy surgery in focal cortical dysplasia. Neuroimage Clin 2018; 19:487-496. [PMID: 29984157 PMCID: PMC6029564 DOI: 10.1016/j.nicl.2018.04.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 04/18/2018] [Accepted: 04/28/2018] [Indexed: 11/29/2022]
Abstract
Background Epilepsy surgery for focal cortical dysplasia type II (FCD II) offers good chances for seizure freedom, but remains a challenge with respect to lesion detection, defining the epileptogenic zone and the optimal resection strategy. Integrating results from magnetic source imaging from magnetoencephalography (MEG) with magnetic resonance imaging (MRI) including MRI postprocessing may be useful for optimizing these goals. Methods We here present data from 21 adult FCD II patients, investigated during a 10 year period and evaluated including magnetic source imaging. 16 patients had epilepsy surgery, i.e. histopathologically verified FCD II, and a long follow up. We present our analysis of epileptogenic zones including MEG in relation to structural data according to MRI data and relate these results to surgical outcomes. Results FCD II in our cohort was characterized by high MEG yield and localization accuracy and MEG showed impact on surgical success-rates. MEG source localizations were detected in 95.2% of patients and were as close as 12.3 ± 8,1 mm to the MRI-lesion. After a mean follow up of >3 years, we saw >80% Engel I outcomes, with more favourable outcomes when the MEG source was completely resected (Fishers exact test 0,033). Conclusion We argue for a high value of conducting a combined MEG-MRI approach in the presurgical workup and the resection strategy in patients with FCD II related epilepsy.
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Affiliation(s)
- Burkhard S Kasper
- Epilepsy Center, Department of Neurology, Friedrich Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Karl Rössler
- Department of Neurosurgery, Friedrich Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Hajo M Hamer
- Epilepsy Center, Department of Neurology, Friedrich Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Arnd Dörfler
- Department of Neuroradiology, Friedrich Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Ingmar Blümcke
- Department of Neuropathology, Friedrich Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Roland Coras
- Department of Neuropathology, Friedrich Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Julie Roesch
- Department of Neuroradiology, Friedrich Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Angelika Mennecke
- Department of Neuroradiology, Friedrich Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Jörg Wellmer
- Ruhr-Epileptology, University Hospital Knappschaftskrankenhaus, Ruhr-University Bochum, In der Schornau 23-25, Germany.
| | - Björn Sommer
- Department of Neurosurgery, Friedrich Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Bogdan Lorber
- Department of Neurology, University Medical Centre Ljubljana, Zaloška cesta 2, 1000 Ljubljana, Slovenia.
| | - Johannes D Lang
- Epilepsy Center, Department of Neurology, Friedrich Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Wolfgang Graf
- Epilepsy Center, Department of Neurology, Friedrich Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Hermann Stefan
- Epilepsy Center, Department of Neurology, Friedrich Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Stefan Schwab
- Department of Neurology, Friedrich Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Michael Buchfelder
- Department of Neurosurgery, Friedrich Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Stefan Rampp
- Department of Neurosurgery, Friedrich Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
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Tanaka H, Khoo HM, Dubeau F, Gotman J. Association between scalp and intracerebral electroencephalographic seizure-onset patterns: A study in different lesional pathological substrates. Epilepsia 2017; 59:420-430. [PMID: 29226305 DOI: 10.1111/epi.13979] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2017] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Our purpose was to determine the correlation between scalp electroencephalography (EEG) and intracerebral EEG (iEEG) seizure-onset patterns in patients with focal lesional epilepsy to determine whether scalp seizure-onset patterns can be specific to intracerebral seizure-onset patterns and to lesion type. METHODS We retrospectively analyzed 61 patients with focal epilepsy and a structural magnetic resonance imaging (MRI)-visible lesion, who first underwent extensive scalp recordings and then iEEG studies (stereo-EEG) for presurgical evaluation, and who showed an iEEG seizure onset in the lesional/perilesional area. Five seizure-onset patterns were recognized on scalp EEG, and 7 on iEEG, and in each patient, only the predominant scalp and iEEG seizure-onset patterns were compared. Because scalp and iEEG recordings were acquired at different times, we followed strict criteria based on semiology and topography to match scalp with intracerebral seizures. RESULTS Seventy-one pairs of seizure-onset patterns matched between scalp and iEEG were identified. Each scalp pattern did not correspond to a single intracerebral pattern, but there were significant associations: (1) paroxysmal fast activity (≥13 Hz) at scalp onset was associated with low-voltage fast activity at iEEG onset (P < .001), with malformations of cortical development (P < .001), and with superficial seizure-onset zone based on iEEG (P < .001); (2) rhythmic slow activity (<13 Hz) at scalp onset was associated with low-frequency high-amplitude periodic spikes at iEEG onset (P = .0014), with medial temporal atrophy/sclerosis (P < .001), and with deep seizure-onset zone (P < .001); and (3) repetitive epileptiform discharge at scalp onset was associated with a burst of high-amplitude polyspikes at iEEG onset (P = .0002). SIGNIFICANCE Our results disclosed that in focal epilepsy patients with seizures generated in an MRI-visible lesion, some scalp seizure-onset patterns are highly associated with a specific intracerebral pattern, with specific pathologies, and with the depth of seizure-onset zone. These findings allow the interpretation of scalp seizure-onset patterns to be significantly more informative.
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Affiliation(s)
- Hideaki Tanaka
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada.,Department of Neurosurgery, Fukuoka University Hospital, Fukuoka City, Japan
| | - Hui Ming Khoo
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada.,Department of Neurosurgery, Osaka University Graduate School of Medicine, Suita, Japan
| | - François Dubeau
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Jean Gotman
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
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Davis KA, Devries SP, Krieger A, Mihaylova T, Minecan D, Litt B, Wagenaar JB, Stacey WC. The effect of increased intracranial EEG sampling rates in clinical practice. Clin Neurophysiol 2017; 129:360-367. [PMID: 29288992 DOI: 10.1016/j.clinph.2017.10.039] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 10/09/2017] [Accepted: 10/22/2017] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Recent research suggests that high frequency intracranial EEG (iEEG) may improve localization of epileptic networks. This study aims to determine whether recording macroelectrode iEEG with higher sampling rates improves seizure localization in clinical practice. METHODS 14 iEEG seizures from 10 patients recorded with >2000 Hz sampling rate were downsampled to four sampling rates: 100, 200, 500, 1000 Hz. In the 56 seizures, seizure onset time and location was marked by 5 independent, blinded EEG experts. RESULTS When reading iEEG under clinical conditions, there was no consistent difference in time or localization of seizure onset or number of electrodes involved in the seizure onset zone with sampling rates varying from 100 to 1000 Hz. Stratification of patients by outcome did not improve with higher sampling rate. CONCLUSION When utilizing standard clinical protocols, there was no benefit to acquiring iEEGs with sampling rate >100 Hz. Significant variability was noted in EEG marking both within and between individual expert EEG readers. SIGNIFICANCE Although commercial equipment is capable of sampling much faster than 100 Hz, tools allowing visualization of subtle high frequency activity such as HFOs will be required to improve patient care. Quantitative methods may decrease reader variability, and potentially improve patient outcomes.
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Affiliation(s)
| | - Seth P Devries
- Dept of Pediatric Neurology, Helen DeVos Children's Hospital, USA
| | - Abba Krieger
- Dept of Statistics, The Wharton School of the University of Pennsylvania, USA
| | | | | | - Brian Litt
- Department of Neurology, University of Pennsylvania, USA
| | - Joost B Wagenaar
- Department of Neurology, University of Pennsylvania, USA; Blackfynn, Inc, USA
| | - William C Stacey
- Dept of Neurology, University of Michigan, USA; Dept of Biomedical Engineering, University of Michigan, USA
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10
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Mehvari-Habibabadi J, Basiratnia R, Moein H, Zare M, Barakatain M, Aghakhani Y, Tabrizi N. Prognostic value of ictal onset patterns in postsurgical outcome of temporal lobe epilepsy. IRANIAN JOURNAL OF NEUROLOGY 2017; 16:185-191. [PMID: 29736224 PMCID: PMC5937004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Background: To investigate ictal onset patterns (IOP) in scalp electroencephalography (EEG) of patients with temporal lobe epilepsy (TLE) and their prognostic effect on the postoperative outcome. Methods: We conducted a retrospective cohort study between 2011 and 2015 in our referral Epilepsy Surgery Center enrolling adult patients with refractory TLE and a visible epileptogenic lesion in magnetic resonance imaging (MRI), who underwent epilepsy surgery. Demographic, clinical and MRI findings were collected and ictal findings during video-EEG monitoring were reviewed in detail. The correlation between preoperative findings and the postsurgical outcome was analyzed. Results: We reviewed 303 seizures in 93 patients. Rhythmic theta and rhythmic spike/sharp and wave were respectively the most common initial ictal pattern and late significant discharges. Engel class I outcome was observed in 88.2% of patients. Female sex, aura, the absence of secondary generalization, rhythmic theta as initial ictal pattern and concordance of ictal-interictal EEG findings were correlated with favorable 1-year postsurgical outcome. Conclusion: Preoperative clinical and EEG findings can provide valuable information regarding postsurgical prognosis in TLE patients.
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Affiliation(s)
| | - Reza Basiratnia
- Isfahan Neurosciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Houshang Moein
- Isfahan Neurosciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohamad Zare
- Isfahan Neurosciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Majid Barakatain
- Isfahan Neurosciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Yahya Aghakhani
- Department of Clinical Neurosciences, University of Calgary, Calgary, Canada
| | - Nasim Tabrizi
- Isfahan University of Medical Sciences, Isfahan, Iran,Department of Neurology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
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Shi J, Lacuey N, Lhatoo S. Surgical outcome of MRI-negative refractory extratemporal lobe epilepsy. Epilepsy Res 2017; 133:103-108. [PMID: 28477458 DOI: 10.1016/j.eplepsyres.2017.04.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 04/05/2017] [Accepted: 04/14/2017] [Indexed: 12/13/2022]
Abstract
OBJECTIVE The aim of this study is to determine outcome of resective epilepsy surgery in MRI-negative extratemporal lobe epilepsy (MNETLE) patients who underwent invasive evaluations and to determine factors governing outcome. METHODS We studied 28 patients who underwent resective epilepsy surgery for MNETLE from August 2006 to November 2015, in whom complete follow-up information was available. Electro-clinical, pathological and surgical data were evaluated. 24 patients (82.8%) were explored with intracranial EEG (9 stereoelectroencephalography (SEEG), 7 subdural grids and 8 both). All patients were followed for at least 6 months. RESULTS During a mean follow up period of 32 [6-113] months, 13 (46.4%) patients became seizure-free (ILAE 1) and 18 (64.3%) had a good (ILAE 1, 2, 3) outcome. 21 (75.0%) patients had focal cortical dysplasia (FCD). Univariate analysis showed that more restricted (regional) interictal and ictal epileptiform discharges in surface EEG were significantly associated with seizure freedom (P=0.016 and P=0.024). Multivariate analysis confirmed that having ≥120 electrode contacts in the evaluation is an independent variable predicting seizure freedom (HR=4.283, 95% CI=1.342-13.676, P=0.014). CONCLUSION Invasive EEG is a powerful tool in the pre-surgical evaluation of patients with MNETLE. Invasive EEG implantation that include the irritative zone and EEG onset zone as indicated by surface EEG, as well as wider brain coverage predict seizure freedom, contingent upon a sound anatomo-electro-clinical hypothesis for implantation.
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Affiliation(s)
- Jianguo Shi
- Department of Neurosurgery, Jinan Central Hospital affiliated to Shandong University, Jinan, Shandong, 250000, China.
| | - Nuria Lacuey
- Epilepsy Center, UH Case Medical Center, 11100 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Samden Lhatoo
- Epilepsy Center, UH Case Medical Center, 11100 Euclid Avenue, Cleveland, OH, 44106, USA
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12
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Hupalo M, Wojcik R, Jaskolski DJ. Intracranial video-EEG monitoring in presurgical evaluation of patients with refractory epilepsy. Neurol Neurochir Pol 2017; 51:201-207. [PMID: 28279512 DOI: 10.1016/j.pjnns.2017.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 02/09/2017] [Indexed: 10/20/2022]
Abstract
OBJECTIVE Reviewing our experience in intracranial video-EEG monitoring in the presurgical evaluation of patients with refractory epilepsy. METHODS We report on 62 out of 202 (31%) patients with refractory epilepsy, who underwent a long term video-EEG monitoring (LTM). The epileptogenic zone (EZ) was localised either based on the results of LTM or after intracranial EEG recordings from depth, subdural or foramen ovale electrodes. The decision on the location of the electrodes was based upon semiology of the seizures, EEG findings and the lesions visualised in MRI brain scan. Intraoperative corticography was carried out before and right after the resection of the seizure onset zone. RESULTS The video-EEG monitoring could localise EZ in 43 (69%) cases based. The remaining patients underwent invasive diagnostics: 10 (53%) had intracerebral depth electrodes, 6 (31%) depth and subdural and 3 (16%) foramen ovale electrodes. Intracranial video EEG recordings showed seizure focus in all the patients. Ten of them had EZ in mesial temporal structures, 4 in accessory motor area, 3 at the base of the frontal lobe and 2 in parietal lobe. There was one case of an asymptomatic intracerebral haematoma at the electrode. All patients were subsequently operated on. In 15 (79%) cases the seizures subsided (follow-up from 2 to 5 years), in 4 (21%) they decreased. CONCLUSIONS The intracranial EEG is required in all patients with normal MRI (so-called nonlesional cases) in whom EZ is suspected to be located in the hippocampus, insula or in the basal parts of the frontal lobe.
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Affiliation(s)
- Marlena Hupalo
- Department of Neurosurgery and Oncology of Central Nervous System, Barlicki University Hospital, Medical University of Lodz, Lodz, Poland
| | - Rafal Wojcik
- Department of Neurosurgery and Oncology of Central Nervous System, Barlicki University Hospital, Medical University of Lodz, Lodz, Poland
| | - Dariusz J Jaskolski
- Department of Neurosurgery and Oncology of Central Nervous System, Barlicki University Hospital, Medical University of Lodz, Lodz, Poland.
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Moon HJ, Kim DW, Chung CK, Shin JW, Moon J, Kang BS, Lee ST, Jung KH, Chu K, Jung KY, Cho YW, Lee SK. Change of Patient Selection Strategy and Improved Surgical Outcome in MRI-negative Neocortical Epilepsy. J Epilepsy Res 2016; 6:66-74. [PMID: 28101477 PMCID: PMC5206102 DOI: 10.14581/jer.16013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 12/14/2016] [Indexed: 11/21/2022] Open
Abstract
Background and Purpose It is crucial to make selection strategy to identify surgical candidates among medically refractory MRI-negative neocortical epilepsy patients. In our previous study, we suggested two or more concordance between noninvasive studies (EEG, ictal scalp EEG, interictal FDG-PET, and SPECT) as a new patient selection strategy for MRI-negative neocortical epilepsy surgery. The objective of this study was to evaluate the surgical outcomes of MRI-negative neocortical epilepsy patients before and after the implementation of a new selection strategy. Methods From 1995 to 2011, we included 153 consecutive MRI-negative neocortical epilepsy patients who received focal resection and had a follow-up period of at least 2 years. These patients were divided into two groups according to their date of surgery (before and after July 2002). The old group consisted of 89 patients and the new one consisted of 53 patients. Clinical characteristics, presurgical evaluations, and pathology were reviewed. Results The new patient selection strategy led to a significant increase in the concordance between two or more modalities. The improvement in surgical outcome after 2002 was significant (seizure-free outcome, 47.2% vs. 75.5%; p = 0.001). Concordance between two or more presurgical evaluations and localizing PET were related to a seizure-free outcome in a multivariate analysis. Conclusions After a change in surgical strategy to select patients with two or more concordance between noninvasive studies, the seizure-free outcome improved up to 75.5%. MRI-negative neocortical epilepsy patients with two or more concordance between noninvasive studies seem to be good candidates for epilepsy surgery.
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Affiliation(s)
- Hye-Jin Moon
- Department of Neurology, Keimyung University Dongsan Medical Center, Daegu, Korea
| | - Dong Wook Kim
- Department of Neurology, Konkuk University School of Medicine, Seoul, Korea
| | - Chun-Kee Chung
- Department of Neurosurgery, Seoul National University College of Medicine, Seoul, Korea
| | - Jung-Won Shin
- Department of Neurology, Seoul National University College of Medicine, Seoul, Korea
| | - Jangsup Moon
- Department of Neurology, Seoul National University College of Medicine, Seoul, Korea
| | - Bong Su Kang
- Department of Neurology, Korea University College of Medicine, Seoul, Korea
| | - Soon-Tae Lee
- Department of Neurology, Seoul National University College of Medicine, Seoul, Korea
| | - Keun-Hwa Jung
- Department of Neurology, Seoul National University College of Medicine, Seoul, Korea
| | - Kon Chu
- Department of Neurology, Seoul National University College of Medicine, Seoul, Korea
| | - Ki-Young Jung
- Department of Neurology, Seoul National University College of Medicine, Seoul, Korea
| | - Yong Won Cho
- Department of Neurology, Keimyung University Dongsan Medical Center, Daegu, Korea
| | - Sang Kun Lee
- Department of Neurology, Seoul National University College of Medicine, Seoul, Korea
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14
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Multiscale Aspects of Generation of High-Gamma Activity during Seizures in Human Neocortex. eNeuro 2016; 3:eN-NWR-0141-15. [PMID: 27257623 PMCID: PMC4876490 DOI: 10.1523/eneuro.0141-15.2016] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 04/19/2016] [Accepted: 04/21/2016] [Indexed: 01/14/2023] Open
Abstract
High-gamma (HG; 80-150 Hz) activity in macroscopic clinical records is considered a marker for critical brain regions involved in seizure initiation; it is correlated with pathological multiunit firing during neocortical seizures in the seizure core, an area identified by correlated multiunit spiking and low frequency seizure activity. High-gamma (HG; 80-150 Hz) activity in macroscopic clinical records is considered a marker for critical brain regions involved in seizure initiation; it is correlated with pathological multiunit firing during neocortical seizures in the seizure core, an area identified by correlated multiunit spiking and low frequency seizure activity. However, the effects of the spatiotemporal dynamics of seizure on HG power generation are not well understood. Here, we studied HG generation and propagation, using a three-step, multiscale signal analysis and modeling approach. First, we analyzed concurrent neuronal and microscopic network HG activity in neocortical slices from seven intractable epilepsy patients. We found HG activity in these networks, especially when neurons displayed paroxysmal depolarization shifts and network activity was highly synchronized. Second, we examined HG activity acquired with microelectrode arrays recorded during human seizures (n = 8). We confirmed the presence of synchronized HG power across microelectrode records and the macroscale, both specifically associated with the core region of the seizure. Third, we used volume conduction-based modeling to relate HG activity and network synchrony at different network scales. We showed that local HG oscillations require high levels of synchrony to cross scales, and that this requirement is met at the microscopic scale, but not within macroscopic networks. Instead, we present evidence that HG power at the macroscale may result from harmonics of ongoing seizure activity. Ictal HG power marks the seizure core, but the generating mechanism can differ across spatial scales.
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15
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Jirsa VK, Stacey WC, Quilichini PP, Ivanov AI, Bernard C. On the nature of seizure dynamics. ACTA ACUST UNITED AC 2014; 137:2210-30. [PMID: 24919973 DOI: 10.1093/brain/awu133] [Citation(s) in RCA: 384] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Seizures can occur spontaneously and in a recurrent manner, which defines epilepsy; or they can be induced in a normal brain under a variety of conditions in most neuronal networks and species from flies to humans. Such universality raises the possibility that invariant properties exist that characterize seizures under different physiological and pathological conditions. Here, we analysed seizure dynamics mathematically and established a taxonomy of seizures based on first principles. For the predominant seizure class we developed a generic model called Epileptor. As an experimental model system, we used ictal-like discharges induced in vitro in mouse hippocampi. We show that only five state variables linked by integral-differential equations are sufficient to describe the onset, time course and offset of ictal-like discharges as well as their recurrence. Two state variables are responsible for generating rapid discharges (fast time scale), two for spike and wave events (intermediate time scale) and one for the control of time course, including the alternation between 'normal' and ictal periods (slow time scale). We propose that normal and ictal activities coexist: a separatrix acts as a barrier (or seizure threshold) between these states. Seizure onset is reached upon the collision of normal brain trajectories with the separatrix. We show theoretically and experimentally how a system can be pushed toward seizure under a wide variety of conditions. Within our experimental model, the onset and offset of ictal-like discharges are well-defined mathematical events: a saddle-node and homoclinic bifurcation, respectively. These bifurcations necessitate a baseline shift at onset and a logarithmic scaling of interspike intervals at offset. These predictions were not only confirmed in our in vitro experiments, but also for focal seizures recorded in different syndromes, brain regions and species (humans and zebrafish). Finally, we identified several possible biophysical parameters contributing to the five state variables in our model system. We show that these parameters apply to specific experimental conditions and propose that there exists a wide array of possible biophysical mechanisms for seizure genesis, while preserving central invariant properties. Epileptor and the seizure taxonomy will guide future modeling and translational research by identifying universal rules governing the initiation and termination of seizures and predicting the conditions necessary for those transitions.
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Affiliation(s)
- Viktor K Jirsa
- 1 Aix Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France2 Inserm, UMR_S 1106, 27 Bd Jean Moulin, 13385 Marseille Cedex 5, France
| | - William C Stacey
- 3 Department of Neurology, Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Pascale P Quilichini
- 1 Aix Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France2 Inserm, UMR_S 1106, 27 Bd Jean Moulin, 13385 Marseille Cedex 5, France
| | - Anton I Ivanov
- 1 Aix Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France2 Inserm, UMR_S 1106, 27 Bd Jean Moulin, 13385 Marseille Cedex 5, France
| | - Christophe Bernard
- 1 Aix Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France2 Inserm, UMR_S 1106, 27 Bd Jean Moulin, 13385 Marseille Cedex 5, France
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16
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Wang ZI, Alexopoulos AV, Jones SE, Najm IM, Ristic A, Wong C, Prayson R, Schneider F, Kakisaka Y, Wang S, Bingaman W, Gonzalez-Martinez JA, Burgess RC. Linking MRI postprocessing with magnetic source imaging in MRI-negative epilepsy. Ann Neurol 2014; 75:759-70. [PMID: 24777960 DOI: 10.1002/ana.24169] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 04/25/2014] [Accepted: 04/26/2014] [Indexed: 11/08/2022]
Abstract
OBJECTIVE MRI-negative (MRI-) pharmacoresistant focal epilepsy (PFE) patients are most challenging for epilepsy surgical management. This study utilizes a voxel-based MRI postprocessing technique, implemented using a morphometric analysis program (MAP), aiming to facilitate detection of subtle focal cortical dysplasia (FCD) in MRI- patients. Furthermore, the study examines the concordance between MAP-identified regions and localization from magnetic source imaging (MSI). METHODS Included in this retrospective study were 25 MRI- surgical patients. MAP was performed on T1-weighted MRI, with comparison to a normal database. The pertinence of MAP+ areas was confirmed by MSI, surgical outcome and pathology. Analyses of MAP and MSI were performed blindly from patients' clinical information and independently from each other. RESULTS The detection rate of subtle changes by MAP was 48% (12/25). Once MAP+ areas were resected, patients were more likely to be seizure-free (p=0.02). There were no false positives in the 25 age-matched normal controls. Seven patients had a concordant MSI correlate. Patients in whom a concordant area was identified by both MAP and MSI had a significantly higher chance of achieving a seizure-free outcome following complete resection of this area (p=0.008). In the 9 resected MAP+ areas, pathology revealed FCD type IA in 7 and type IIB in 2. INTERPRETATION MAP shows promise in identifying subtle FCD abnormalities and increasing the diagnostic yield of conventional MRI visual analysis in presurgical evaluation of PFE. Concordant MRI postprocessing and MSI analyses may lead to the noninvasive identification of a structurally and electrically abnormal subtle lesion that can be surgically targeted.
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Affiliation(s)
- Zhong I Wang
- Epilepsy Center, Cleveland Clinic, Cleveland, OH
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Noe K, Sulc V, Wong-Kisiel L, Wirrell E, Van Gompel JJ, Wetjen N, Britton J, So E, Cascino GD, Marsh WR, Meyer F, Horinek D, Giannini C, Watson R, Brinkmann BH, Stead M, Worrell GA. Long-term outcomes after nonlesional extratemporal lobe epilepsy surgery. JAMA Neurol 2013; 70:1003-8. [PMID: 23732844 DOI: 10.1001/jamaneurol.2013.209] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
IMPORTANCE A focal lesion detected by use of magnetic resonance imaging (MRI) is a favorable prognostic finding for epilepsy surgery. Patients with normal MRI findings and extratemporal lobe epilepsy have less favorable outcomes. Most studies investigating the outcomes of patients with normal MRI findings who underwent (nonlesional) extratemporal epilepsy surgery are confined to a highly select group of patients with limited follow-up. OBJECTIVE To evaluate noninvasive diagnostic test results and their association with excellent surgical outcomes (defined using Engel classes I-IIA of surgical outcomes) in a group of patients with medically resistant nonlesional extratemporal epilepsy. DESIGN A retrospective study. SETTING Mayo Clinic, Rochester, Minnesota. PARTICIPANTS From 1997 through 2002, we identified 85 patients with medically resistant extratemporal lobe epilepsy who had normal MRI findings. Based on a standardized presurgical evaluation and review at a multidisciplinary epilepsy surgery conference, some of these patients were selected for intracranial electroencephalographic (EEG) monitoring and epilepsy surgery. EXPOSURE Nonlesional extratemporal lobe epilepsy surgery. MAIN OUTCOMES AND MEASURES The results of noninvasive diagnostic tests and the clinical variables potentially associated with excellent surgical outcome were examined in patients with a minimum follow-up of 1 year (mean follow-up, 9 years). RESULTS Based on the noninvasive diagnostic test results, a clear hypothesis for seizure origin was possible for 47 of the 85 patients (55%), and 31 of these 47 patients (66%) proceeded to intracranial EEG monitoring. For 24 of these 31 patients undergoing long-term intracranial EEG (77%), a seizure focus was identified and surgically resected. Of these 24 patients, 9 (38%) had an excellent outcome after resective epilepsy surgery. All patients with an excellent surgical outcome had at least 10 years of follow-up. Univariate analysis showed that localized interictal epileptiform discharges on scalp EEGs were associated with an excellent surgical outcome. CONCLUSIONS AND RELEVANCE Scalp EEG was the most useful test for identifying patients with normal MRI findings and extratemporal lobe epilepsy who were likely to have excellent outcomes after epilepsy surgery. Extending outcome analysis beyond the resective surgery group to the entire group of patients who were evaluated further highlights the challenge that these patients pose. Although 9 of 24 patients undergoing resective surgery (38%) had excellent outcomes, only 9 of 31 patients undergoing intracranial EEG (29%) and only 9 of 85 patient with nonlesional extratemporal lobe epilepsy (11%) had long-term excellent outcomes.
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Affiliation(s)
- Katherine Noe
- Department of Neurology, Mayo Clinic, Scottsdale, Arizona, USA
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Kuba R, Novák Z, Chrastina J, Pažourková M, Hermanová M, Ošlejšková H, Rektor I, Brázdil M. Comparing the effects of cortical resection and vagus nerve stimulation in patients with nonlesional extratemporal epilepsy. Epilepsy Behav 2013; 28:474-80. [PMID: 23892577 DOI: 10.1016/j.yebeh.2013.05.036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/28/2013] [Accepted: 05/31/2013] [Indexed: 10/26/2022]
Abstract
The main purpose of this retrospective study was to compare the effects of resective surgery (RESgr-26 patients) and vagus nerve stimulation (VNSgr-35 patients) on seizure frequency (2 and 5years after surgery) in patients with nonlesional extratemporal epilepsy (NLexTLE). We analyzed hospital admission costs directly associated with epilepsy (HACE) in both groups at the same follow-up. The decrease in seizure frequency from the preoperative levels, in both VNSgr and RESgr, was statistically significant (p<0.001). The seizure frequency reduction did not differ significantly between the follow-up visits for either group (p=0.221 at 2years and 0.218 at 5years). A significantly higher number of Engel I and Engel I+II patients were found in RESgr than in VNSgr at both follow-up visits (p=0.04 and 0.007, respectively). Using McHugh classification, we did not find statistically significant differences between both groups at both follow-up visits. Hospital admission costs directly associated with epilepsy/patient/year in both RESgr and VNSgr dropped significantly at 2- and 5-year follow-up visit and this reduction was not statistically different between RESgr and VNSgr (p=0.232). Both VNS and resective surgery cause comparably significant seizure reduction in NLexTLE. Resective surgery leads to a greater number of patients with excellent postoperative outcome (Engel I+II). The HACE reduction is statistically comparable between both groups.
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Affiliation(s)
- Robert Kuba
- Brno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic.
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Wang ZI, Alexopoulos AV, Jones SE, Jaisani Z, Najm IM, Prayson RA. The pathology of magnetic-resonance-imaging-negative epilepsy. Mod Pathol 2013; 26:1051-8. [PMID: 23558575 DOI: 10.1038/modpathol.2013.52] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 01/11/2013] [Indexed: 11/09/2022]
Abstract
Patients with magnetic-resonance-imaging (MRI)-negative (or 'nonlesional') pharmacoresistant focal epilepsy are the most challenging group undergoing presurgical evaluation. Few large-scale studies have systematically reviewed the pathological substrates underlying MRI-negative epilepsies. In the current study, histopathological specimens were retrospectively reviewed from MRI-negative epilepsy patients (n=95, mean age=30 years, 50% female subjects). Focal cortical dysplasia cases were classified according to the International League Against Epilepsy (ILAE) and Palmini et al classifications. The most common pathologies found in this MRI-negative cohort included: focal cortical dysplasia (n=43, 45%), gliosis (n=21, 22%), hamartia+gliosis (n=12, 13%), and hippocampal sclerosis (n=9, 9%). The majority of focal cortical dysplasia were ILAE type I (n=37) or Palmini type I (n=39). Seven patients had no identifiable pathological abnormalities. The existence of positive pathology was not significantly associated with age or temporal/extratemporal resection. Follow-up data post surgery was available in 90 patients; 63 (70%) and 57 (63%) attained seizure freedom at 6 and 12 months, respectively. The finding of positive pathology was significantly associated with seizure-free outcome at 6 months (P=0.035), but not at 12 months. In subgroup analysis, the focal cortical dysplasia group was not significantly correlated with seizure-free outcome, as compared with the negative-pathology groups at either 6 or 12 months. Of note, the finding of hippocampal sclerosis had a significant positive correlation with seizure-free outcome when compared with the negative-pathology group (P=0.009 and 0.004 for 6- and 12-month outcome, respectively). Absence of a significant histopathology in the resected surgical specimen did not preclude seizure freedom. In conclusion, our study highlights the heterogeneity of epileptic pathologies in MRI-negative epilepsies, with focal cortical dysplasia being the most common finding. The existence of positive pathology in surgical specimen may be a good indication for short-term good seizure outcome. There is a small subset of cases in which no pathological abnormalities are identified.
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Affiliation(s)
- Z Irene Wang
- Cleveland Clinic Epilepsy Center, Cleveland, OH, USA
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