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Pan R, Yang C, Li Z, Ren J, Duan Y. Magnetoencephalography-based approaches to epilepsy classification. Front Neurosci 2023; 17:1183391. [PMID: 37502686 PMCID: PMC10368885 DOI: 10.3389/fnins.2023.1183391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 06/12/2023] [Indexed: 07/29/2023] Open
Abstract
Epilepsy is a chronic central nervous system disorder characterized by recurrent seizures. Not only does epilepsy severely affect the daily life of the patient, but the risk of premature death in patients with epilepsy is three times higher than that of the normal population. Magnetoencephalography (MEG) is a non-invasive, high temporal and spatial resolution electrophysiological data that provides a valid basis for epilepsy diagnosis, and used in clinical practice to locate epileptic foci in patients with epilepsy. It has been shown that MEG helps to identify MRI-negative epilepsy, contributes to clinical decision-making in recurrent seizures after previous epilepsy surgery, that interictal MEG can provide additional localization information than scalp EEG, and complete excision of the stimulation area defined by the MEG has prognostic significance for postoperative seizure control. However, due to the complexity of the MEG signal, it is often difficult to identify subtle but critical changes in MEG through visual inspection, opening up an important area of research for biomedical engineers to investigate and implement intelligent algorithms for epilepsy recognition. At the same time, the use of manual markers requires significant time and labor costs, necessitating the development and use of computer-aided diagnosis (CAD) systems that use classifiers to automatically identify abnormal activity. In this review, we discuss in detail the results of applying various different feature extraction methods on MEG signals with different classifiers for epilepsy detection, subtype determination, and laterality classification. Finally, we also briefly look at the prospects of using MEG for epilepsy-assisted localization (spike detection, high-frequency oscillation detection) due to the unique advantages of MEG for functional area localization in epilepsy, and discuss the limitation of current research status and suggestions for future research. Overall, it is hoped that our review will facilitate the reader to quickly gain a general understanding of the problem of MEG-based epilepsy classification and provide ideas and directions for subsequent research.
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Affiliation(s)
- Ruoyao Pan
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Chunlan Yang
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Zhimei Li
- Department of Internal Neurology, Tiantan Hospital, Beijing, China
| | - Jiechuan Ren
- Department of Internal Neurology, Tiantan Hospital, Beijing, China
| | - Ying Duan
- Beijing Universal Medical Imaging Diagnostic Center, Beijing, China
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2
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Feys O, Corvilain P, Van Hecke A, Sculier C, Rikir E, Legros B, Gaspard N, Leurquin-Sterk G, Holmes N, Brookes M, Goldman S, Wens V, De Tiège X. Recording of Ictal Epileptic Activity Using on-Scalp Magnetoencephalography. Ann Neurol 2023; 93:419-421. [PMID: 36480016 DOI: 10.1002/ana.26562] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/23/2022] [Accepted: 11/25/2022] [Indexed: 12/13/2022]
Affiliation(s)
- Odile Feys
- Université libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (HUB), CUB Hôpital Erasme, Department of Neurology, Brussels, Belgium.,Université libre de Bruxelles (ULB), ULB Neuroscience Institute (UNI), Laboratoire de Neuroimagerie et Neuroanatomie translationnelles (LN2T), Brussels, Belgium
| | - Pierre Corvilain
- Université libre de Bruxelles (ULB), ULB Neuroscience Institute (UNI), Laboratoire de Neuroimagerie et Neuroanatomie translationnelles (LN2T), Brussels, Belgium
| | - Audrey Van Hecke
- Université libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (HUB), Hôpital Universitaire des Enfants Reine Fabiola (HUDERF), Department of Pediatric Neurology, Brussels, Belgium
| | - Claudine Sculier
- Université libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (HUB), CUB Hôpital Erasme, Department of Pediatric Neurology, Brussels, Belgium
| | - Estelle Rikir
- Université libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (HUB), CUB Hôpital Erasme, Department of Neurology, Brussels, Belgium
| | - Benjamin Legros
- Université libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (HUB), CUB Hôpital Erasme, Department of Neurology, Brussels, Belgium
| | - Nicolas Gaspard
- Université libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (HUB), CUB Hôpital Erasme, Department of Neurology, Brussels, Belgium
| | - Gil Leurquin-Sterk
- Université libre de Bruxelles (ULB), ULB Neuroscience Institute (UNI), Laboratoire de Neuroimagerie et Neuroanatomie translationnelles (LN2T), Brussels, Belgium.,University of Nottingham, School of Physics and Astronomy, Sir Peter Mansfield Imaging Centre, Nottingham, United Kingdom
| | - Niall Holmes
- Université libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (HUB), CUB Hôpital Erasme, Department of Nuclear Medicine, Brussels, Belgium
| | - Matthew Brookes
- Université libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (HUB), CUB Hôpital Erasme, Department of Nuclear Medicine, Brussels, Belgium
| | - Serge Goldman
- Université libre de Bruxelles (ULB), ULB Neuroscience Institute (UNI), Laboratoire de Neuroimagerie et Neuroanatomie translationnelles (LN2T), Brussels, Belgium.,University of Nottingham, School of Physics and Astronomy, Sir Peter Mansfield Imaging Centre, Nottingham, United Kingdom
| | - Vincent Wens
- Université libre de Bruxelles (ULB), ULB Neuroscience Institute (UNI), Laboratoire de Neuroimagerie et Neuroanatomie translationnelles (LN2T), Brussels, Belgium.,Université libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (HUB), CUB Hôpital Erasme, Department of Translational Neuroimaging, Brussels, Belgium
| | - Xavier De Tiège
- Université libre de Bruxelles (ULB), ULB Neuroscience Institute (UNI), Laboratoire de Neuroimagerie et Neuroanatomie translationnelles (LN2T), Brussels, Belgium.,Université libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (HUB), CUB Hôpital Erasme, Department of Translational Neuroimaging, Brussels, Belgium
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3
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Kannan MA, Ab Aziz NA, Ab Rani NS, Abdullah MW, Mohd Rashid MH, Shab MS, Ismail NI, Ab Ghani MA, Reza F, Muzaimi M. A review of the holy Quran listening and its neural correlation for its potential as a psycho-spiritual therapy. Heliyon 2022; 8:e12308. [PMID: 36578419 PMCID: PMC9791337 DOI: 10.1016/j.heliyon.2022.e12308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 07/26/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022] Open
Abstract
Since its revelation over 14 centuries ago, the Holy Quran is considered as scriptural divine words of Islam, and it is believed to promote psycho-spiritual therapeutic benefits to its reciter and/or listener. In this context, the listening of rhythmic Quranic verses among Muslims is often viewed as a form of unconventional melodic vocals, with accompanied anecdotal claims of the 'Quranic chills' pleasing effect. However, compared to music, rhythm, and meditation therapy, information on the neural basis of the anecdotal healing effects of the Quran remain largely unexplored. Current studies in this area took the leads from the low-frequency neuronal oscillations (i.e., alpha and theta) as the neural correlates, mainly using electroencephalography (EEG) and/or magnetoencephalography (MEG). In this narrative review, we present and discuss recent work related to these neural correlates and highlight several methodical issues and propose recommendations to progress this emerging transdisciplinary research. Collectively, evidence suggests that listening to rhythmic Quranic verses activates similar brain regions and elicits comparable therapeutic effects reported in music and rhythmic therapy. Notwithstanding, further research are warranted with more concise and standardized study designs to substantiate these findings, and opens avenue for the listening to Quranic verses as an effective complementary psycho-spiritual therapy.
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Affiliation(s)
- Mohammed Abdalla Kannan
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kubang Kerian, Kelantan, 16150, Malaysia,Department of Anatomy, Faculty of Medicine, Al Neelain University, Khartoum, 11111, Sudan
| | - Nurfaizatul Aisyah Ab Aziz
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kubang Kerian, Kelantan, 16150, Malaysia
| | - Nur Syairah Ab Rani
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kubang Kerian, Kelantan, 16150, Malaysia
| | - Mohd Waqiyuddin Abdullah
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kubang Kerian, Kelantan, 16150, Malaysia
| | - Muhammad Hakimi Mohd Rashid
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kubang Kerian, Kelantan, 16150, Malaysia,Department of Basic Medical Sciences, Kuliyyah of Pharmacy, International Islamic University Malaysia, 25200, Kuantan, Pahang, Malaysia
| | - Mas Syazwanee Shab
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kubang Kerian, Kelantan, 16150, Malaysia
| | - Nurul Iman Ismail
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kubang Kerian, Kelantan, 16150, Malaysia
| | - Muhammad Amiri Ab Ghani
- Department of Quran and Hadith, Sultan Ismail Petra International College, Nilam Puri, Kelantan, 15730, Malaysia
| | - Faruque Reza
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kubang Kerian, Kelantan, 16150, Malaysia
| | - Mustapha Muzaimi
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kubang Kerian, Kelantan, 16150, Malaysia,Corresponding author.
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4
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Ntolkeras G, Tamilia E, AlHilani M, Bolton J, Ellen Grant P, Prabhu SP, Madsen JR, Stufflebeam SM, Pearl PL, Papadelis C. Presurgical accuracy of dipole clustering in MRI-negative pediatric patients with epilepsy: Validation against intracranial EEG and resection. Clin Neurophysiol 2022; 141:126-138. [PMID: 33875376 PMCID: PMC8803140 DOI: 10.1016/j.clinph.2021.01.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 01/21/2021] [Accepted: 01/27/2021] [Indexed: 01/24/2023]
Abstract
OBJECTIVE To assess the utility of interictal magnetic and electric source imaging (MSI and ESI) using dipole clustering in magnetic resonance imaging (MRI)-negative patients with drug resistant epilepsy (DRE). METHODS We localized spikes in low-density (LD-EEG) and high-density (HD-EEG) electroencephalography as well as magnetoencephalography (MEG) recordings using dipoles from 11 pediatric patients. We computed each dipole's level of clustering and used it to discriminate between clustered and scattered dipoles. For each dipole, we computed the distance from seizure onset zone (SOZ) and irritative zone (IZ) defined by intracranial EEG. Finally, we assessed whether dipoles proximity to resection was predictive of outcome. RESULTS LD-EEG had lower clusterness compared to HD-EEG and MEG (p < 0.05). For all modalities, clustered dipoles showed higher proximity to SOZ and IZ than scattered (p < 0.001). Resection percentage was higher in optimal vs. suboptimal outcome patients (p < 0.001); their proximity to resection was correlated to outcome (p < 0.001). No difference in resection percentage was seen for scattered dipoles between groups. CONCLUSION MSI and ESI dipole clustering helps to localize the SOZ and IZ and facilitate the prognostic assessment of MRI-negative patients with DRE. SIGNIFICANCE Assessing the MSI and ESI clustering allows recognizing epileptogenic areas whose removal is associated with optimal outcome.
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Affiliation(s)
- Georgios Ntolkeras
- Laboratory of Children's Brain Dynamics, Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Fetal-Neonatal Neuroimaging and Developmental Science Center, Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Eleonora Tamilia
- Laboratory of Children's Brain Dynamics, Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Fetal-Neonatal Neuroimaging and Developmental Science Center, Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Michel AlHilani
- Laboratory of Children's Brain Dynamics, Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Fetal-Neonatal Neuroimaging and Developmental Science Center, Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; The Hillingdon Hospital NHS Foundation Trust, London, United Kingdom
| | - Jeffrey Bolton
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - P Ellen Grant
- Fetal-Neonatal Neuroimaging and Developmental Science Center, Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Division of Neuroradiology, Department of Radiology, Boston Children's Hospital, Harvard Medical School, MA, USA
| | - Sanjay P Prabhu
- Division of Neuroradiology, Department of Radiology, Boston Children's Hospital, Harvard Medical School, MA, USA
| | - Joseph R Madsen
- Division of Epilepsy Surgery, Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Steven M Stufflebeam
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Phillip L Pearl
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Christos Papadelis
- Laboratory of Children's Brain Dynamics, Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Jane and John Justin Neurosciences Center, Cook Children's Health Care System, Fort Worth, TX, USA; School of Medicine, Texas Christian University and University of North Texas Health Science Center, Fort Worth, TX, USA; Department of Bioengineering, University of Texas at Arlington, Arlington, TX, USA.
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5
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Validating EEG, MEG and Combined MEG and EEG Beamforming for an Estimation of the Epileptogenic Zone in Focal Cortical Dysplasia. Brain Sci 2022; 12:brainsci12010114. [PMID: 35053857 PMCID: PMC8796031 DOI: 10.3390/brainsci12010114] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/04/2022] [Accepted: 01/06/2022] [Indexed: 02/04/2023] Open
Abstract
MEG and EEG source analysis is frequently used for the presurgical evaluation of pharmacoresistant epilepsy patients. The source localization of the epileptogenic zone depends, among other aspects, on the selected inverse and forward approaches and their respective parameter choices. In this validation study, we compare the standard dipole scanning method with two beamformer approaches for the inverse problem, and we investigate the influence of the covariance estimation method and the strength of regularization on the localization performance for EEG, MEG, and combined EEG and MEG. For forward modelling, we investigate the difference between calibrated six-compartment and standard three-compartment head modelling. In a retrospective study, two patients with focal epilepsy due to focal cortical dysplasia type IIb and seizure freedom following lesionectomy or radiofrequency-guided thermocoagulation (RFTC) used the distance of the localization of interictal epileptic spikes to the resection cavity resp. RFTC lesion as reference for good localization. We found that beamformer localization can be sensitive to the choice of the regularization parameter, which has to be individually optimized. Estimation of the covariance matrix with averaged spike data yielded more robust results across the modalities. MEG was the dominant modality and provided a good localization in one case, while it was EEG for the other. When combining the modalities, the good results of the dominant modality were mostly not spoiled by the weaker modality. For appropriate regularization parameter choices, the beamformer localized better than the standard dipole scan. Compared to the importance of an appropriate regularization, the sensitivity of the localization to the head modelling was smaller, due to similar skull conductivity modelling and the fixed source space without orientation constraint.
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6
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Laohathai C, Ebersole JS, Mosher JC, Bagić AI, Sumida A, Von Allmen G, Funke ME. Practical Fundamentals of Clinical MEG Interpretation in Epilepsy. Front Neurol 2021; 12:722986. [PMID: 34721261 PMCID: PMC8551575 DOI: 10.3389/fneur.2021.722986] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 09/06/2021] [Indexed: 11/29/2022] Open
Abstract
Magnetoencephalography (MEG) is a neurophysiologic test that offers a functional localization of epileptic sources in patients considered for epilepsy surgery. The understanding of clinical MEG concepts, and the interpretation of these clinical studies, are very involving processes that demand both clinical and procedural expertise. One of the major obstacles in acquiring necessary proficiency is the scarcity of fundamental clinical literature. To fill this knowledge gap, this review aims to explain the basic practical concepts of clinical MEG relevant to epilepsy with an emphasis on single equivalent dipole (sECD), which is one the most clinically validated and ubiquitously used source localization method, and illustrate and explain the regional topology and source dynamics relevant for clinical interpretation of MEG-EEG.
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Affiliation(s)
- Christopher Laohathai
- Division of Child Neurology, Department of Pediatrics, McGovern Medical School at UTHealth, Houston, TX, United States
- Department of Neurology, Saint Louis University, Saint Louis, MO, United States
| | - John S. Ebersole
- Northeast Regional Epilepsy Group, Atlantic Health Neuroscience Institute, Summit, NJ, United States
| | - John C. Mosher
- Department of Neurology, McGovern Medical School at UTHealth, Houston, TX, United States
| | - Anto I. Bagić
- University of Pittsburgh Comprehensive Epilepsy Center (UPCEC), Department of Neurology, University of Pittsburgh Medical Center, Pittsburg, PA, United States
| | - Ai Sumida
- Department of Neurology, McGovern Medical School at UTHealth, Houston, TX, United States
| | - Gretchen Von Allmen
- Division of Child Neurology, Department of Pediatrics, McGovern Medical School at UTHealth, Houston, TX, United States
| | - Michael E. Funke
- Division of Child Neurology, Department of Pediatrics, McGovern Medical School at UTHealth, Houston, TX, United States
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7
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Bagić AI, Funke ME, Kirsch HE, Tenney JR, Zillgitt AJ, Burgess RC. The 10 Common Evidence-Supported Indications for MEG in Epilepsy Surgery: An Illustrated Compendium. J Clin Neurophysiol 2021; 37:483-497. [PMID: 33165222 DOI: 10.1097/wnp.0000000000000726] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Unfamiliarity with the indications for and benefits of magnetoencephalography (MEG) persists, even in the epilepsy community, and hinders its acceptance to clinical practice, despite the evidence. The wide treatment gap for patients with drug-resistant epilepsy and immense underutilization of epilepsy surgery had similar effects. Thus, educating referring physicians (epileptologists, neurologists, and neurosurgeons) both about the value of epilepsy surgery and about the potential benefits of MEG can achieve synergy and greatly improve the process of selecting surgical candidates. As a practical step toward a comprehensive educational process to benefit potential MEG users, current MEG referrers, and newcomers to MEG, the authors have elected to provide an illustrated guide to 10 everyday situations where MEG can help in the evaluation of people with drug-resistant epilepsy. They are as follows: (1) lacking or imprecise hypothesis regarding a seizure onset; (2) negative MRI with a mesial temporal onset suspected; (3) multiple lesions on MRI; (4) large lesion on MRI; (5) diagnostic or therapeutic reoperation; (6) ambiguous EEG findings suggestive of "bilateral" or "generalized" pattern; (7) intrasylvian onset suspected; (8) interhemispheric onset suspected; (9) insular onset suspected; and (10) negative (i.e., spikeless) EEG. Only their practical implementation and furtherance of personal and collective education will lead to the potentially impactful synergy of the two-MEG and epilepsy surgery. Thus, while fulfilling our mission as physicians, we must not forget that ignoring the wealth of evidence about the vast underutilization of epilepsy surgery - and about the usefulness and value of MEG in selecting surgical candidates - is far from benign neglect.
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Affiliation(s)
- Anto I Bagić
- University of Pittsburgh Comprehensive Epilepsy Center (UPCEC), Department of Neurology, University of Pittsburgh Medical Center (UPMC), Pittsburgh, Pennsylvania, U.S.A
| | - Michael E Funke
- MEG Center, McGovern Medical School, UT Houston, Houston, Texas, U.S.A
| | - Heidi E Kirsch
- UCSF Biomagnetic Imaging Laboratory, UCSF, San Francisco, California, U.S.A
| | - Jeffrey R Tenney
- MEG Center, Cincinnati Children's Hospital Medical Center , Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
| | - Andrew J Zillgitt
- Department of Neurology, Beaumont Health Adult Comprehensive Epilepsy Center, Neurosicence Center, Royal Oak, Michigan, U.S.A.; and
| | - Richard C Burgess
- Magnetoencephalography Laboratory, Cleveland Clinic Epilepsy Center, Cleveland, Ohio, U.S.A
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8
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Rampp S, Kakisaka Y, Shibata S, Wu X, Rössler K, Buchfelder M, Burgess RC. Normal Variants in Magnetoencephalography. J Clin Neurophysiol 2020; 37:518-536. [PMID: 33165225 DOI: 10.1097/wnp.0000000000000484] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Normal variants, although not occurring frequently, may appear similar to epileptic activity. Misinterpretation may lead to false diagnoses. In the context of presurgical evaluation, normal variants may lead to mislocalizations with severe impact on the viability and success of surgical therapy. While the different variants are well known in EEG, little has been published in regard to their appearance in magnetoencephalography. Furthermore, there are some magnetoencephalography normal variants that have no counterparts in EEG. This article reviews benign epileptiform variants and provides examples in EEG and magnetoencephalography. In addition, the potential of oscillatory configurations in different frequency bands to appear as epileptic activity is discussed.
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Affiliation(s)
- Stefan Rampp
- Department of Neurosurgery, University Hospital, Erlangen, Germany.,Department of Neurosurgery, University Hospital, Halle (Saale), Germany
| | - Yosuke Kakisaka
- Department of Epileptology, Tohoku University School of Medicine, Sendai, Japan
| | - Sumiya Shibata
- Department of Neurosurgery and Human Brain Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Xingtong Wu
- Department of Neurosurgery, University Hospital, Erlangen, Germany.,Department of Neurology, West China Hospital, Sichuan University, Sichuan, China; and
| | - Karl Rössler
- Department of Neurosurgery, University Hospital, Erlangen, Germany
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9
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Melikyan AG, Vorobiev AN, Shishkina LV, Kozlova AB, Vlasov PA, Ayvazyan SO, Shults EI, Korsakova MB, Koptelova AM, Buklina SB, Demin MO, Agrba SB, Shevchenko AM. [Surgical treatment of epilepsy in children with focal cortical dysplasia]. ZHURNAL VOPROSY NEĬROKHIRURGII IMENI N. N. BURDENKO 2020; 84:5-20. [PMID: 33095529 DOI: 10.17116/neiro2020840515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Surgery is the first-line treatment option in children with FCD and refractory epilepsy, but the rate of success and patient numbers who became free of seizures vary widely from series to series. STUDY AIMS To elicit variables affecting the outcome and predicting achievement of the long-term seizure-free status. MATERIAL AND METHODS One hundred sixty-nine children with cortical dysplasia and DR-epilepsy underwent surgery Preoperative evaluation included prolonged video-EEG and MRI (in all patients) and neuropsychological testing when possible. Fourteen patients underwent invasive EEG, fMRI and MEG were used also in some cases. Including 27 repeat procedures the list of overall 196 surgeries performed consists of: cortectomy (lesionectomy with or without adjacent epileptogenic cortices) – in 116 cases; lobectomy – in 46; and various disconnective procedures – in 34 patients. Almost routinely employed intraoperative ECOG (134 surgeries) was combined with stimulation and/or SSEP in 47 cases to map eloquent cortex (with CST-tracking in some). A new permanent and not anticipated neurological deficit developed post-surgery in 5 cases (2,5%). Patients were follow-upped using video-EEG and MRI and FU which lasts more than 2 years (median – 3 years) is known in 56 cases. Thirty-two children were free of seizures at the last check (57,2% rate of Engel IA). A list of variables regarding patients’ demography, seizure type, lesion pathology and localization, and those related to surgery and its extent were evaluated to figure out anyone associated with favorable outcome. RESULTS Both Type II FCDs and their anatomically complete excision are positive predictors for favorable outcome and achievement of SF-status (p<0,05). Residual epileptic activity on immediate post-resection ECOG do not affect the outcome. CONCLUSION Patients with Type II FCD, particularly with Type IIb malformations are the best candidates for curative surgery, including cases with lesions in brain eloquent areas. Kids with Type I FCD have much less chances to become free of seizures when attempting focal cortectomy. However, some of them with early onset catastrophic epilepsies may benefit from larger surgeries using lobectomy or various disconnections.
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Affiliation(s)
| | | | | | - A B Kozlova
- Burdenko Neurosurgical Center, Moscow, Russia
| | - P A Vlasov
- Burdenko Neurosurgical Center, Moscow, Russia
| | | | - E I Shults
- Burdenko Neurosurgical Center, Moscow, Russia
| | | | - A M Koptelova
- Center for Neurocognitive research (MEG-center), MSUPE, Moscow, Russia
| | - S B Buklina
- Burdenko Neurosurgical Center, Moscow, Russia
| | - M O Demin
- Burdenko Neurosurgical Center, Moscow, Russia
| | - S B Agrba
- Burdenko Neurosurgical Center, Moscow, Russia
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10
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Zheng L, Liao P, Luo S, Sheng J, Teng P, Luan G, Gao JH. EMS-Net: A Deep Learning Method for Autodetecting Epileptic Magnetoencephalography Spikes. IEEE TRANSACTIONS ON MEDICAL IMAGING 2020; 39:1833-1844. [PMID: 31831410 DOI: 10.1109/tmi.2019.2958699] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Epilepsy is a neurological disorder characterized by sudden and unpredictable epileptic seizures, which incurs significant negative impacts on patients' physical, psychological and social health. A practical approach to assist with the clinical assessment and treatment planning for patients is to process magnetoencephalography (MEG) data to identify epileptogenic zones. As a widely accepted biomarker of epileptic foci, epileptic MEG spikes need to be precisely detected. Given that the visual inspection of spikes is time consuming, an automatic and efficient system with adequate accuracy for spike detection is valuable in clinical practice. However, current approaches for MEG spike autodetection are dependent on hand-engineered features. Here, we propose a novel multiview Epileptic MEG Spikes detection algorithm based on a deep learning Network (EMS-Net) to accurately and efficiently recognize the spike events from MEG raw data. The results of the leave-k-subject-out validation tests for multiple datasets (i.e., balanced and realistic datasets) showed that EMS-Net achieved state-of-the-art classification performance (i.e., accuracy: 91.82% - 99.89%; precision: 91.90% - 99.45%; sensitivity: 91.61% - 99.53%; specificity: 91.60% - 99.96%; f1 score: 91.70% - 99.48%; and area under the curve: 0.9688 - 0.9998).
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11
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Abstract
Magnetoencephalography is the noninvasive measurement of miniscule magnetic fields produced by brain electrical currents, and is used most fruitfully to evaluate epilepsy patients. While other modalities infer brain function indirectly by measuring changes in blood flow, metabolism, and oxygenation, magnetoencephalography measures neuronal and synaptic function directly with submillisecond temporal resolution. The brain's magnetic field is recorded by neuromagnetometers surrounding the head in a helmet-shaped sensor array. Because magnetic signals are not distorted by anatomy, magnetoencephalography allows for a more accurate measurement and localization of brain activities than electroencephalography. Magnetoencephalography has become an indispensable part of the armamentarium at epilepsy centers.
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Affiliation(s)
- Richard C Burgess
- Epilepsy Center, Neurological Institute, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
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12
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A novel method for extracting interictal epileptiform discharges in multi-channel MEG: Use of fractional type of blind source separation. Clin Neurophysiol 2019; 131:425-436. [PMID: 31887614 DOI: 10.1016/j.clinph.2019.11.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 10/28/2019] [Accepted: 11/15/2019] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Visual inspection of interictal epileptiform discharges (IEDs) in multi-channel MEG requires a time-consuming evaluation process and often leads to inconsistent results due to variability of IED waveforms. Here, we propose a novel extraction method for IEDs using a T/k type of blind source separation (BSST/k). METHODS We applied BSST/k with seven patients with focal epilepsy to test the accuracy of identification of IEDs. We conducted comparisons of the results of BSS components with those obtained by visual inspection in sensor-space analysis. RESULTS BSST/k provided better signal estimation of IEDs compared with sensor-space analysis. Importantly, BSST/k was able to uncover IEDs that could not be detected by visual inspection. Furthermore, IED components were clearly extracted while preserving spike and wave morphology. Variable IED waveforms were decomposed into one dominant component. CONCLUSIONS BSST/k was able to visualize the spreading signals over multiple channels into a single component from a single epileptogenic zone. BSST/k can be applied to focal epilepsy with a simple parameter setting. SIGNIFICANCE Our novel method was able to highlight IEDs with increased accuracy for identification of IEDs from multi-channel MEG data.
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13
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Plummer C, Vogrin SJ, Woods WP, Murphy MA, Cook MJ, Liley DTJ. Interictal and ictal source localization for epilepsy surgery using high-density EEG with MEG: a prospective long-term study. Brain 2019; 142:932-951. [PMID: 30805596 PMCID: PMC6459284 DOI: 10.1093/brain/awz015] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 10/07/2018] [Accepted: 12/05/2018] [Indexed: 11/17/2022] Open
Abstract
Drug-resistant focal epilepsy is a major clinical problem and surgery is under-used. Better non-invasive techniques for epileptogenic zone localization are needed when MRI shows no lesion or an extensive lesion. The problem is interictal and ictal localization before propagation from the epileptogenic zone. High-density EEG (HDEEG) and magnetoencephalography (MEG) offer millisecond-order temporal resolution to address this but co-acquisition is challenging, ictal MEG studies are rare, long-term prospective studies are lacking, and fundamental questions remain. Should HDEEG-MEG discharges be assessed independently [electroencephalographic source localization (ESL), magnetoencephalographic source localization (MSL)] or combined (EMSL) for source localization? Which phase of the discharge best characterizes the epileptogenic zone (defined by intracranial EEG and surgical resection relative to outcome)? Does this differ for interictal and ictal discharges? Does MEG detect mesial temporal lobe discharges? Thirteen patients (10 non-lesional, three extensive-lesional) underwent synchronized HDEEG-MEG (72–94 channel EEG, 306-sensor MEG). Source localization (standardized low-resolution tomographic analysis with MRI patient-individualized boundary-element method) was applied to averaged interictal epileptiform discharges (IED) and ictal discharges at three phases: ‘early-phase’ (first latency 90% explained variance), ‘mid-phase’ (first of 50% rising-phase, 50% mean global field power), ‘late-phase’ (negative peak). ‘Earliest-solution’ was the first of the three early-phase solutions (ESL, MSL, EMSL). Prospective follow-up was 3–21 (median 12) months before surgery, 14–39 (median 21) months after surgery. IEDs (n = 1474) were recorded, seen in: HDEEG only, 626 (42%); MEG only, 232 (16%); and both 616 (42%). Thirty-three seizures were captured, seen in: HDEEG only, seven (21%); MEG only, one (3%); and both 25 (76%). Intracranial EEG was done in nine patients. Engel scores were I (9/13, 69%), II (2/13,15%), and III (2/13). MEG detected baso-mesial temporal lobe epileptogenic zone sources. Epileptogenic zone OR [odds ratio(s)] were significantly higher for earliest-solution versus early-phase IED-surgical resection and earliest-solution versus all mid-phase and late-phase solutions. ESL outperformed EMSL for ictal-surgical resection [OR 3.54, 95% confidence interval (CI) 1.09–11.55, P = 0.036]. MSL outperformed EMSL for IED-intracranial EEG (OR 4.67, 95% CI 1.19–18.34, P = 0.027). ESL outperformed MSL for ictal-surgical resection (OR 3.73, 95% CI 1.16–12.03, P = 0.028) but was outperformed by MSL for IED-intracranial EEG (OR 0.18, 95% CI 0.05–0.73, P = 0.017). Thus, (i) HDEEG and MEG source solutions more accurately localize the epileptogenic zone at the earliest resolvable phase of interictal and ictal discharges, not mid-phase (as is common practice) or late peak-phase (when signal-to-noise ratios are maximal); (ii) from empirical observation of the differential timing of HDEEG and MEG discharges and based on the superiority of ESL plus MSL over either modality alone and over EMSL, concurrent HDEEG-MEG signals should be assessed independently, not combined; (iii) baso-mesial temporal lobe sources are detectable by MEG; and (iv) MEG is not ‘more accurate’ than HDEEG—emphasis is best placed on the earliest signal (whether HDEEG or MEG) amenable to source localization. Our findings challenge current practice and our reliance on invasive monitoring in these patients.
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Affiliation(s)
- Chris Plummer
- Department of Neurology, St Vincent's Hospital, Fitzroy, Australia.,School of Health Sciences, Swinburne University of Technology, Hawthorn, Australia.,Department of Medicine, University of Melbourne, Parkville, Australia
| | - Simon J Vogrin
- Department of Neurology, St Vincent's Hospital, Fitzroy, Australia.,School of Health Sciences, Swinburne University of Technology, Hawthorn, Australia.,Department of Medicine, University of Melbourne, Parkville, Australia
| | - William P Woods
- School of Health Sciences, Swinburne University of Technology, Hawthorn, Australia
| | - Michael A Murphy
- Department of Neurology, St Vincent's Hospital, Fitzroy, Australia.,Department of Medicine, University of Melbourne, Parkville, Australia
| | - Mark J Cook
- Department of Neurology, St Vincent's Hospital, Fitzroy, Australia.,Department of Medicine, University of Melbourne, Parkville, Australia.,Graeme Clark Institute of Biomedical Engineering, University of Melbourne, Parkville, Australia
| | - David T J Liley
- School of Health Sciences, Swinburne University of Technology, Hawthorn, Australia.,Department of Medicine, University of Melbourne, Parkville, Australia.,Centre for Human Psychopharmacology, Swinburne University of Technology, Hawthorn, Australia
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14
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He X, Zhou J, Teng P, Wang X, Guan Y, Zhai F, Li T, Luan G. The impact of MEG results on surgical outcomes in patients with drug-resistant epilepsy associated with focal encephalomalacia: a single-center experience. J Neurol 2019; 267:812-822. [PMID: 31773245 DOI: 10.1007/s00415-019-09638-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 11/12/2019] [Accepted: 11/13/2019] [Indexed: 11/27/2022]
Abstract
PURPOSE To analyze the impact of magnetoencephalography (MEG) results on surgical outcomes in patients with drug-resistant epilepsy secondary to encephalomalacia. METHODS We retrospectively reviewed 121 patients with drug-resistant epilepsy associated with encephalomalacia who underwent MEG followed by resection surgery. Patients were subdivided into concordant MEG group and dis-concordant MEG group for analysis based on whether the MEG results were in concordance with epileptogenic zones or not. RESULTS 121 patients were included in the present study. The MEG spike sources of 73 (60.33%) patients were in concordance with epileptogenic zones while the MEG spike sources of the other 48 (39.67%) were in dis-concordance with epileptogenic zones. Favorable seizure outcomes were achieved in 79.45% (58 of 73) of patients with concordant MEG results while only 62.50% (30 of 48) of patients with dis-concordant MEG results were seizure free with a follow-up of 2-10 years. The differences of seizure-free rate between patients with concordant MEG results and dis-concordant MEG results were statistically significant. For patients with concordant MEG results, bilateral lesions on MRI are the only independent predictor of unfavorable seizure outcomes. For patients with discordant MEG results, duration of seizures is the only independent predictor of unfavorable seizure outcomes. CONCLUSIONS Concordant MEG results are associated with favorable seizure outcomes. Bilateral lesions on MRI independently predict unfavorable seizure outcomes in patients with concordant MEG results while longer seizure durations independently predict unfavorable seizure outcomes in patients with dis-concordant MEG results.
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Affiliation(s)
- Xinghui He
- Beijing Key Laboratory of Epilepsy, Sanbo Brain Hospital, Capital Medical University, Beijing, China.,Department of Neurosurgery, Epilepsy Center, Beijing Sanbo Brain Hospital, Capital Medical University, Xiangshan Yikesong 50, Haidian District, Beijing, 100093, China
| | - Jian Zhou
- Beijing Key Laboratory of Epilepsy, Sanbo Brain Hospital, Capital Medical University, Beijing, China.,Department of Neurosurgery, Epilepsy Center, Beijing Sanbo Brain Hospital, Capital Medical University, Xiangshan Yikesong 50, Haidian District, Beijing, 100093, China
| | - Pengfei Teng
- Beijing Key Laboratory of Epilepsy, Sanbo Brain Hospital, Capital Medical University, Beijing, China.,Department of Neurosurgery, Epilepsy Center, Beijing Sanbo Brain Hospital, Capital Medical University, Xiangshan Yikesong 50, Haidian District, Beijing, 100093, China
| | - Xiongfei Wang
- Beijing Key Laboratory of Epilepsy, Sanbo Brain Hospital, Capital Medical University, Beijing, China.,Department of Neurosurgery, Epilepsy Center, Beijing Sanbo Brain Hospital, Capital Medical University, Xiangshan Yikesong 50, Haidian District, Beijing, 100093, China
| | - Yuguang Guan
- Beijing Key Laboratory of Epilepsy, Sanbo Brain Hospital, Capital Medical University, Beijing, China.,Department of Neurosurgery, Epilepsy Center, Beijing Sanbo Brain Hospital, Capital Medical University, Xiangshan Yikesong 50, Haidian District, Beijing, 100093, China
| | - Feng Zhai
- Beijing Key Laboratory of Epilepsy, Sanbo Brain Hospital, Capital Medical University, Beijing, China.,Department of Neurosurgery, Epilepsy Center, Beijing Sanbo Brain Hospital, Capital Medical University, Xiangshan Yikesong 50, Haidian District, Beijing, 100093, China
| | - Tianfu Li
- Beijing Key Laboratory of Epilepsy, Sanbo Brain Hospital, Capital Medical University, Beijing, China.,Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Guoming Luan
- Beijing Key Laboratory of Epilepsy, Sanbo Brain Hospital, Capital Medical University, Beijing, China. .,Department of Neurosurgery, Epilepsy Center, Beijing Sanbo Brain Hospital, Capital Medical University, Xiangshan Yikesong 50, Haidian District, Beijing, 100093, China. .,Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.
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15
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Carrette E, Stefan H. Evidence for the Role of Magnetic Source Imaging in the Presurgical Evaluation of Refractory Epilepsy Patients. Front Neurol 2019; 10:933. [PMID: 31551904 PMCID: PMC6746885 DOI: 10.3389/fneur.2019.00933] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 08/12/2019] [Indexed: 12/03/2022] Open
Abstract
Magnetoencephalography (MEG) in the field of epilepsy has multiple advantages; just like electroencephalography (EEG), MEG is able to measure the epilepsy specific information (i.e., the brain activity reflecting seizures and/or interictal epileptiform discharges) directly, non-invasively and with a very high temporal resolution (millisecond-range). In addition MEG has a unique sensitivity for tangential sources, resulting in a full picture of the brain activity when combined with EEG. It accurately allows to perform source imaging of focal epileptic activity and functional cortex and shows a specific high sensitivity for a source in the neocortex. In this paper the current evidence and practice for using magnetic source imaging of focal interictal and ictal epileptic activity during the presurgical evaluation of drug resistant patients is being reviewed.
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Affiliation(s)
- Evelien Carrette
- Reference Centre for Refractory Epilepsy, Ghent University Hospital, Ghent, Belgium
| | - Hermann Stefan
- Department of Neurology-Biomagnetism, University Hospital Erlangen, Erlangen, Germany
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16
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Rampp S, Stefan H, Wu X, Kaltenhäuser M, Maess B, Schmitt FC, Wolters CH, Hamer H, Kasper BS, Schwab S, Doerfler A, Blümcke I, Rössler K, Buchfelder M. Magnetoencephalography for epileptic focus localization in a series of 1000 cases. Brain 2019; 142:3059-3071. [PMID: 31373622 DOI: 10.1093/brain/awz231] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 05/29/2019] [Accepted: 06/02/2019] [Indexed: 02/05/2023] Open
Abstract
Abstract
The aim of epilepsy surgery in patients with focal, pharmacoresistant epilepsies is to remove the complete epileptogenic zone to achieve long-term seizure freedom. In addition to a spectrum of diagnostic methods, magnetoencephalography focus localization is used for planning of epilepsy surgery. We present results from a retrospective observational cohort study of 1000 patients, evaluated using magnetoencephalography at the University Hospital Erlangen over the time span of 28 years. One thousand consecutive cases were included in the study, evaluated at the University Hospital Erlangen between 1990 and 2018. All patients underwent magnetoencephalography as part of clinical workup for epilepsy surgery. Of these, 405 underwent epilepsy surgery after magnetoencephalography, with postsurgical follow-ups of up to 20 years. Sensitivity for interictal epileptic activity was evaluated, in addition to concordance of localization with the consensus of presurgical workup on a lobar level. We evaluate magnetoencephalography characteristics of patients who underwent epilepsy surgery versus patients who did not proceed to surgery. In operated patients, resection of magnetoencephalography localizations were related to postsurgical seizure outcomes, including long-term results after several years. In comparison, association of lesionectomy with seizure outcomes was analysed. Measures of diagnostic accuracy were calculated for magnetoencephalography resection and lesionectomy. Sensitivity for interictal epileptic activity was 72% with significant differences between temporal and extra-temporal lobe epilepsy. Magnetoencephalography was concordant with the presurgical consensus in 51% and showed additional or more focal involvement in an additional 32%. Patients who proceeded to surgery showed a significantly higher percentage of monofocal magnetoencephalography results. Complete magnetoencephalography resection was associated with significantly higher chances to achieve seizure freedom in the short and long-term. Diagnostic accuracy was significant in temporal and extra-temporal lobe cases, but was significantly higher in extra-temporal lobe epilepsy (diagnostic odds ratios of 4.4 and 41.6). Odds ratios were also higher in non-lesional versus lesional cases (42.0 versus 6.2). The results show that magnetoencephalography provides non-redundant information, which significantly contributes to patient selection, focus localization and ultimately long-term seizure freedom after epilepsy surgery. Specifically in extra-temporal lobe epilepsy and non-lesional cases, magnetoencephalography provides excellent accuracy.
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Affiliation(s)
- Stefan Rampp
- Department of Neurosurgery, University Hospital Erlangen, Germany
- Department of Neurosurgery, University Hospital Halle (Saale), Germany
| | - Hermann Stefan
- Department of Neurology, University Hospital Erlangen, Germany
| | - Xintong Wu
- Department of Neurosurgery, University Hospital Erlangen, Germany
- Department of Neurology, West China Hospital, Sichuan University, Sichuan, China
| | | | - Burkhard Maess
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | | | - Carsten H Wolters
- Institute for Biomagnetism and Biosignalanalysis, University Münster, Germany
| | - Hajo Hamer
- Department of Neurology, Epilepsy Center, University Hospital Erlangen, Germany
| | - Burkhard S Kasper
- Department of Neurology, Epilepsy Center, University Hospital Erlangen, Germany
| | - Stefan Schwab
- Department of Neurology, University Hospital Erlangen, Germany
| | - Arndt Doerfler
- Department of Neuroradiology, University Hospital Erlangen, Germany
| | - Ingmar Blümcke
- Department of Neuropathology, University Hospital Erlangen, Germany
| | - Karl Rössler
- Department of Neurosurgery, University Hospital Erlangen, Germany
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17
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van Klink N, Mooij A, Huiskamp G, Ferrier C, Braun K, Hillebrand A, Zijlmans M. Simultaneous MEG and EEG to detect ripples in people with focal epilepsy. Clin Neurophysiol 2019; 130:1175-1183. [PMID: 30871799 DOI: 10.1016/j.clinph.2019.01.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 01/14/2019] [Accepted: 01/31/2019] [Indexed: 01/07/2023]
Abstract
OBJECTIVE We studied ripples (80-250 Hz) simultaneously recorded in electroencephalography (EEG) and magnetoencephalography (MEG) to evaluate the differences. METHODS Simultaneous EEG and MEG were recorded in 30 patients with drug resistant focal epilepsy. Ripples were automatically detected and visually checked in virtual channels throughout the cortex. The number and location of ripples in EEG and MEG were compared to each other and to a region of interest (ROI) defined by clinically available information. RESULTS Eleven patients showed ripples in both MEG and EEG, 11 only in EEG and one only in MEG. Twenty-four percent of the ripples occurred simultaneously in EEG and MEG, 71% only in EEG, and 5% only in MEG. Three patients without spikes in EEG showed EEG ripples. Ripple localization was concordant with the ROI in 80% of patients with MEG ripples, as opposed to 62% full or partial concordance for EEG ripples. With the optimal threshold for localizing the ROI, sensitivity and specificity were more than 80%. CONCLUSIONS Ripples in MEG are less frequent but more specific and sensitive for the region of interest than ripples in EEG. Ripples in EEG can exist without spikes in the EEG. SIGNIFICANCE Ripples in MEG and EEG provide complementary information.
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Affiliation(s)
- Nicole van Klink
- Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, UMC Utrecht, the Netherlands; SEIN - Stichting Epilepsie Instellingen Nederland, Heemstede, the Netherlands.
| | - Anne Mooij
- Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, UMC Utrecht, the Netherlands
| | - Geertjan Huiskamp
- Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, UMC Utrecht, the Netherlands
| | - Cyrille Ferrier
- Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, UMC Utrecht, the Netherlands
| | - Kees Braun
- Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, UMC Utrecht, the Netherlands
| | - Arjan Hillebrand
- Department of Clinical Neurophysiology and Magnetoencephalography Center, VU University Medical Center, Amsterdam, the Netherlands
| | - Maeike Zijlmans
- Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, UMC Utrecht, the Netherlands; SEIN - Stichting Epilepsie Instellingen Nederland, Heemstede, the Netherlands
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18
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Mouthaan BE, Rados M, Boon P, Carrette E, Diehl B, Jung J, Kimiskidis V, Kobulashvili T, Kuchukhidze G, Larsson PG, Leitinger M, Ryvlin P, Rugg-Gunn F, Seeck M, Vulliémoz S, Huiskamp G, Leijten FSS, Van Eijsden P, Trinka E, Braun KPJ. Diagnostic accuracy of interictal source imaging in presurgical epilepsy evaluation: A systematic review from the E-PILEPSY consortium. Clin Neurophysiol 2019; 130:845-855. [PMID: 30824202 DOI: 10.1016/j.clinph.2018.12.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 11/16/2018] [Accepted: 12/20/2018] [Indexed: 10/27/2022]
Abstract
OBJECTIVE Interictal high resolution (HR-) electric source imaging (ESI) and magnetic source imaging (MSI) are non-invasive tools to aid epileptogenic zone localization in epilepsy surgery candidates. We carried out a systematic review on the diagnostic accuracy and quality of evidence of these modalities. METHODS Embase, Pubmed and the Cochrane database were searched on 13 February 2017. Diagnostic accuracy studies taking post-surgical seizure outcome as reference standard were selected. Quality appraisal was based on the QUADAS-2 framework. RESULTS Eleven studies were included: eight MSI (n = 267), three HR-ESI (n = 127) studies. None was free from bias. This mostly involved: selection of operated patients only, interference of source imaging with surgical decision, and exclusion of indeterminate results. Summary sensitivity and specificity estimates were 82% (95% CI: 75-88%) and 53% (95% CI: 37-68%) for overall source imaging, with no statistical difference between MSI and HR-ESI. Specificity is higher when partially concordant results were included as non-concordant (p < 0.05). Inclusion of indeterminate test results as non-concordant lowered sensitivity (p < 0.05). CONCLUSIONS Source imaging has a relatively high sensitivity but low specificity for identification of the epileptogenic zone. SIGNIFICANCE We need higher quality studies allowing unbiased test evaluation to determine the added value and diagnostic accuracy of source imaging in the presurgical workup of refractory focal epilepsy.
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Affiliation(s)
- Brian E Mouthaan
- Department of (Child) Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, PO Box 85090, 3508 AB Utrecht, The Netherlands
| | - Matea Rados
- Department of (Child) Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, PO Box 85090, 3508 AB Utrecht, The Netherlands
| | - Paul Boon
- Reference Center for Refractory Epilepsy, Department of Neurology, Ghent University Hospital, Belgium
| | - Evelien Carrette
- Reference Center for Refractory Epilepsy, Department of Neurology, Ghent University Hospital, Belgium
| | - Beate Diehl
- National Hospital for Neurology and Neurosurgery, University College London Hospitals, London, United Kingdom; Department of Clinical and Experimental Epilepsy, University College, London, UK
| | - Julien Jung
- Department of Functional Neurology and Epileptology, Institute of Epilepsies (IDEE), Hospices Civils de Lyon, Lyon, France
| | - Vasilios Kimiskidis
- Laboratory of Clinical Neurophysiology, Medical School, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Teia Kobulashvili
- Department of Neurology, Christian-Doppler University Hospital, Paracelsus Medical University, and Centre for Cognitive Neuroscience, Salzburg, Austria
| | - Giorgi Kuchukhidze
- Department of Neurology, Christian-Doppler University Hospital, Paracelsus Medical University, and Centre for Cognitive Neuroscience, Salzburg, Austria
| | - Pål G Larsson
- Department of Neurosurgery, Clinic of Surgery and Neuroscience, Oslo University Hospital, Norway
| | - Markus Leitinger
- Department of Neurology, Christian-Doppler University Hospital, Paracelsus Medical University, and Centre for Cognitive Neuroscience, Salzburg, Austria
| | - Philippe Ryvlin
- Department of Clinical Neurosciences, Lausanne University Hospital, Lausanne, Switzerland
| | - Fergus Rugg-Gunn
- National Hospital for Neurology and Neurosurgery, University College London Hospitals, London, United Kingdom; Department of Clinical and Experimental Epilepsy, University College, London, UK
| | - Margitta Seeck
- EEG and Epilepsy Unit, Department of Clinical Neurosciences, University Hospital of Geneva, Switzerland
| | - Serge Vulliémoz
- EEG and Epilepsy Unit, Department of Clinical Neurosciences, University Hospital of Geneva, Switzerland
| | - Geertjan Huiskamp
- Department of (Child) Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, PO Box 85090, 3508 AB Utrecht, The Netherlands
| | - Frans S S Leijten
- Department of (Child) Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, PO Box 85090, 3508 AB Utrecht, The Netherlands
| | - Pieter Van Eijsden
- Department of (Child) Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, PO Box 85090, 3508 AB Utrecht, The Netherlands
| | - Eugen Trinka
- Department of Neurology, Christian-Doppler University Hospital, Paracelsus Medical University, and Centre for Cognitive Neuroscience, Salzburg, Austria; Institute of Public Health, Medical Decision Making and HTA, UMIT, Private University for Health Sciences, Medical Informatics and Technology, Hall in Tyrol, Austria
| | - Kees P J Braun
- Department of (Child) Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, PO Box 85090, 3508 AB Utrecht, The Netherlands.
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19
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Tamilia E, AlHilani M, Tanaka N, Tsuboyama M, Peters JM, Grant PE, Madsen JR, Stufflebeam SM, Pearl PL, Papadelis C. Assessing the localization accuracy and clinical utility of electric and magnetic source imaging in children with epilepsy. Clin Neurophysiol 2019; 130:491-504. [PMID: 30771726 DOI: 10.1016/j.clinph.2019.01.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 12/07/2018] [Accepted: 01/08/2019] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To evaluate the accuracy and clinical utility of conventional 21-channel EEG (conv-EEG), 72-channel high-density EEG (HD-EEG) and 306-channel MEG in localizing interictal epileptiform discharges (IEDs). METHODS Twenty-four children who underwent epilepsy surgery were studied. IEDs on conv-EEG, HD-EEG, MEG and intracranial EEG (iEEG) were localized using equivalent current dipoles and dynamical statistical parametric mapping (dSPM). We compared the localization error (ELoc) with respect to the ground-truth Irritative Zone (IZ), defined by iEEG sources, between non-invasive modalities and the distance from resection (Dres) between good- (Engel 1) and poor-outcomes. For each patient, we estimated the resection percentage of IED sources and tested whether it predicted outcome. RESULTS MEG presented lower ELoc than HD-EEG and conv-EEG. For all modalities, Dres was shorter in good-outcome than poor-outcome patients, but only the resection percentage of the ground-truth IZ and MEG-IZ predicted surgical outcome. CONCLUSIONS MEG localizes the IZ more accurately than conv-EEG and HD-EEG. MSI may help the presurgical evaluation in terms of patient's outcome prediction. The promising clinical value of ESI for both conv-EEG and HD-EEG prompts the use of higher-density EEG-systems to possibly achieve MEG performance. SIGNIFICANCE Localizing the IZ non-invasively with MSI/ESI facilitates presurgical evaluation and surgical prognosis assessment.
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Affiliation(s)
- Eleonora Tamilia
- Laboratory of Children's Brain Dynamics, Division of Newborn Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Fetal-Neonatal Neuroimaging Developmental Science Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Michel AlHilani
- Laboratory of Children's Brain Dynamics, Division of Newborn Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Fetal-Neonatal Neuroimaging Developmental Science Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Naoaki Tanaka
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Sapporo Neuroimaging Research Group, Sapporo, Japan
| | - Melissa Tsuboyama
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jurriaan M Peters
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - P Ellen Grant
- Fetal-Neonatal Neuroimaging Developmental Science Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Joseph R Madsen
- Division of Epilepsy Surgery, Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, USA
| | - Steven M Stufflebeam
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Phillip L Pearl
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Christos Papadelis
- Laboratory of Children's Brain Dynamics, Division of Newborn Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Fetal-Neonatal Neuroimaging Developmental Science Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
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20
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Burgess RC. Magnetoencephalography for localizing and characterizing the epileptic focus. HANDBOOK OF CLINICAL NEUROLOGY 2019; 160:203-214. [PMID: 31277848 DOI: 10.1016/b978-0-444-64032-1.00013-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Magnetoencephalography (MEG) is the noninvasive measurement of the miniscule magnetic fields produced by electrical currents flowing in the brain-the same neuroelectric activity that produces the EEG. MEG is one of several diagnostic tests employed in the evaluation of patients with epilepsy, but without the need to expose the patient to any potentially harmful agents. MEG is especially important in those being considered for epilepsy surgery, in whom accurate localization of the epileptic focus is paramount. While other modalities infer brain function indirectly by measuring changes in blood flow, metabolism, oxygenation, etc., MEG, as well as EEG, measures neuronal and synaptic function directly and, like EEG, MEG enjoys submillisecond temporal resolution. The measurement of magnetic fields provides information not only about the amplitude of the current but also its orientation. MEG picks up the magnetic field from neuromagnetometers surrounding the head in a helmet-shaped array of sensors. Clinical whole-head systems currently have 200-300 magnetic sensors, thereby offering very high resolution. The magnetic signals are not distorted by anatomy, because magnetic susceptibility is the same for all tissues, including the skull. Hence, MEG allows for a more accurate measurement and localization of brain activities than does EEG. Because one of its primary strengths is the ability to precisely localize electromagnetic activity within brain areas, MEG results are always coregistered to the patient's MRI. When combined in this way with structural imaging, it has been called magnetic source imaging (MSI), but MEG is properly understood as a clinical neurophysiologic diagnostic test. Signal processing and clinical interpretation in magnetoencephalography require sophisticated noise reduction and computerized mathematical modeling. Technological advances in these areas have brought MEG to the point where it is now part of routine clinical practice. MEG has become an indispensable part of the armamentarium at epilepsy centers where MEG laboratories are located, especially when patients are MRI-negative or where results of other structural and functional tests are not entirely concordant.
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Affiliation(s)
- Richard C Burgess
- Department of Neurology, Cleveland Clinic Foundation, Cleveland, OH, United States.
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Hopkins SE, Chadehumbe M, Blaine Crowley T, Zackai EH, Bilaniuk LT, McDonald-McGinn DM. Neurologic challenges in 22q11.2 deletion syndrome. Am J Med Genet A 2018; 176:2140-2145. [PMID: 30365873 DOI: 10.1002/ajmg.a.38614] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 09/10/2015] [Accepted: 01/11/2016] [Indexed: 01/30/2023]
Abstract
Children with 22q11.2 deletion syndrome often come to medical attention due to signs and symptoms of neurologic dysfunction. It is imperative to understand the expected neurologic development of patients with this diagnosis in order to be alert for the potential neurologic complications, including cortical malformations, tethered cord, epilepsy, and movement disorders. We present an update of brain imaging findings from the CHOP 22q and You Center, a review of the current literature, and our current management practices for neurological issues.
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Affiliation(s)
- Sarah E Hopkins
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Madeline Chadehumbe
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | | | - Elaine H Zackai
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Larissa T Bilaniuk
- Division of Neuroradiology, Children's Hospital of Philadelphia, The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
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Hari R, Baillet S, Barnes G, Burgess R, Forss N, Gross J, Hämäläinen M, Jensen O, Kakigi R, Mauguière F, Nakasato N, Puce A, Romani GL, Schnitzler A, Taulu S. IFCN-endorsed practical guidelines for clinical magnetoencephalography (MEG). Clin Neurophysiol 2018; 129:1720-1747. [PMID: 29724661 PMCID: PMC6045462 DOI: 10.1016/j.clinph.2018.03.042] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 03/18/2018] [Accepted: 03/24/2018] [Indexed: 12/22/2022]
Abstract
Magnetoencephalography (MEG) records weak magnetic fields outside the human head and thereby provides millisecond-accurate information about neuronal currents supporting human brain function. MEG and electroencephalography (EEG) are closely related complementary methods and should be interpreted together whenever possible. This manuscript covers the basic physical and physiological principles of MEG and discusses the main aspects of state-of-the-art MEG data analysis. We provide guidelines for best practices of patient preparation, stimulus presentation, MEG data collection and analysis, as well as for MEG interpretation in routine clinical examinations. In 2017, about 200 whole-scalp MEG devices were in operation worldwide, many of them located in clinical environments. Yet, the established clinical indications for MEG examinations remain few, mainly restricted to the diagnostics of epilepsy and to preoperative functional evaluation of neurosurgical patients. We are confident that the extensive ongoing basic MEG research indicates potential for the evaluation of neurological and psychiatric syndromes, developmental disorders, and the integrity of cortical brain networks after stroke. Basic and clinical research is, thus, paving way for new clinical applications to be identified by an increasing number of practitioners of MEG.
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Affiliation(s)
- Riitta Hari
- Department of Art, Aalto University, Helsinki, Finland.
| | - Sylvain Baillet
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Gareth Barnes
- Wellcome Centre for Human Neuroimaging, University College of London, London, UK
| | - Richard Burgess
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Nina Forss
- Clinical Neuroscience, Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Joachim Gross
- Centre for Cognitive Neuroimaging, University of Glasgow, Glasgow, UK; Institute for Biomagnetism and Biosignalanalysis, University of Muenster, Germany
| | - Matti Hämäläinen
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA; NatMEG, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Ole Jensen
- Centre for Human Brain Health, University of Birmingham, Birmingham, UK
| | - Ryusuke Kakigi
- Department of Integrative Physiology, National Institute of Physiological Sciences, Okazaki, Japan
| | - François Mauguière
- Department of Functional Neurology and Epileptology, Neurological Hospital & University of Lyon, Lyon, France
| | | | - Aina Puce
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Gian-Luca Romani
- Department of Neuroscience, Imaging and Clinical Sciences, Università degli Studi G. D'Annunzio, Chieti, Italy
| | - Alfons Schnitzler
- Institute of Clinical Neuroscience and Medical Psychology, and Department of Neurology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Samu Taulu
- Institute for Learning & Brain Sciences, University of Washington, Seattle, WA, USA; Department of Physics, University of Washington, Seattle, WA, USA
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Colon A, Osch MV, Buijs M, Grond J, Hillebrand A, Schijns O, Wagner G, Ossenblok P, Hofman P, Buchem M, Boon P. MEG-guided analysis of 7T-MRI in patients with epilepsy. Seizure 2018; 60:29-38. [DOI: 10.1016/j.seizure.2018.05.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 05/22/2018] [Accepted: 05/24/2018] [Indexed: 11/26/2022] Open
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Mohamed IS, Bouthillier A, Bérubé A, Cossette P, Finet P, Saint-Hilaire JM, Robert M, Nguyen DK. The clinical impact of integration of magnetoencephalography in the presurgical workup for refractory nonlesional epilepsy. Epilepsy Behav 2018; 79:34-41. [PMID: 29253675 DOI: 10.1016/j.yebeh.2017.10.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 10/11/2017] [Accepted: 10/27/2017] [Indexed: 11/28/2022]
Abstract
OBJECTIVE For patients with nonlesional refractory focal epilepsy (NLRFE), localization of the epileptogenic zone is more arduous, and intracranial electroencephalography (EEG) (icEEG) is frequently required. Planning for icEEG is dependent on combined data from multiple noninvasive modalities. We report the negative impact of lack of integration of magnetoencephalography (MEG) in the presurgical workup in NLRFE. METHODS Observational MEG case series involving 31 consecutive patients with NLRFE in an academic epilepsy center. For various reasons, MEG data were not analyzed in a timely manner to be included in the decision-making process. The presumed impact of MEG was assessed retrospectively. RESULTS Magnetoencephalography would have changed the initial management in 21/31 (68%) had MEG results been available by reducing the number of intracranial electrodes, modifying their position, allowing for direct surgery, canceling the intracranial study, or providing enough evidence to justify one. Good surgical outcome was achieved in 11 out of 17 patients who proceeded to epilepsy surgery. Nine out of eleven had MEG clusters corresponding to the resection area, and MEG findings would have allowed for direct surgery (avoiding icEEG) in 2/11. Six patients had poor outcome including three patients where MEG would have significantly changed the outcome by modifying the resection margin. Magnetoencephalography provided superior information in 3 patients where inadequate coverage precluded accurate mapping of the epileptogenic zone. CONCLUSION In this single center retrospective study, MEG would have changed patient management, icEEG planning, and surgical outcome in a significant percentage of patients with NLRFE and should be considered in the presurgical workup in those patients.
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Affiliation(s)
- Ismail S Mohamed
- IWK Health Center, Department of Pediatrics, Division of Neurology, Halifax, Canada; University of Alabama, Department of Pediatrics, Division of Neurology, Birmingham, AL, USA
| | - Alain Bouthillier
- Division of Neurosurgery, Notre-Dame Hospital (CHUM), University of Montreal, Canada
| | - Arline Bérubé
- Division of Neurology, Notre-Dame Hospital (CHUM), University of Montréal, Canada
| | - Patrick Cossette
- Division of Neurology, Notre-Dame Hospital (CHUM), University of Montréal, Canada
| | - Patrice Finet
- Division of Neurosurgery, Notre-Dame Hospital (CHUM), University of Montreal, Canada
| | | | - Manon Robert
- Neuropsychology and Cognition Research Center, Psychology Department, University of Montreal, Canada
| | - Dang Khoa Nguyen
- Division of Neurology, Notre-Dame Hospital (CHUM), University of Montréal, Canada.
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Chowdhury RA, Pellegrino G, Aydin Ü, Lina JM, Dubeau F, Kobayashi E, Grova C. Reproducibility of EEG-MEG fusion source analysis of interictal spikes: Relevance in presurgical evaluation of epilepsy. Hum Brain Mapp 2017; 39:880-901. [PMID: 29164737 DOI: 10.1002/hbm.23889] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 11/03/2017] [Accepted: 11/07/2017] [Indexed: 11/06/2022] Open
Abstract
Fusion of electroencephalography (EEG) and magnetoencephalography (MEG) data using maximum entropy on the mean method (MEM-fusion) takes advantage of the complementarities between EEG and MEG to improve localization accuracy. Simulation studies demonstrated MEM-fusion to be robust especially in noisy conditions such as single spike source localizations (SSSL). Our objective was to assess the reliability of SSSL using MEM-fusion on clinical data. We proposed to cluster SSSL results to find the most reliable and consistent source map from the reconstructed sources, the so-called consensus map. Thirty-four types of interictal epileptic discharges (IEDs) were analyzed from 26 patients with well-defined epileptogenic focus. SSSLs were performed on EEG, MEG, and fusion data and consensus maps were estimated using hierarchical clustering. Qualitative (spike-to-spike reproducibility rate, SSR) and quantitative (localization error and spatial dispersion) assessments were performed using the epileptogenic focus as clinical reference. Fusion SSSL provided significantly better results than EEG or MEG alone. Fusion found at least one cluster concordant with the clinical reference in all cases. This concordant cluster was always the one involving the highest number of spikes. Fusion yielded highest reproducibility (SSR EEG = 55%, MEG = 71%, fusion = 90%) and lowest localization error. Also, using only few channels from either modality (21EEG + 272MEG or 54EEG + 25MEG) was sufficient to reach accurate fusion. MEM-fusion with consensus map approach provides an objective way of finding the most reliable and concordant generators of IEDs. We, therefore, suggest the pertinence of SSSL using MEM-fusion as a valuable clinical tool for presurgical evaluation of epilepsy.
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Affiliation(s)
- Rasheda Arman Chowdhury
- Multimodal Functional Imaging Lab, Biomedical Engineering Department, McGill University, Montreal, Québec, Canada
| | | | - Ümit Aydin
- Multimodal Functional Imaging Lab, Department of Physics and PERFORM Centre, Concordia University, Montreal, Québec, Canada
| | - Jean-Marc Lina
- Ecole de Technologie Supérieure, Montréal, Québec, Canada.,Centre de Recherches Mathématiques, Université de Montréal, Montréal, Québec, Canada
| | - François 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.,Centre de Recherches Mathématiques, Université de Montréal, Montréal, Québec, Canada.,Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Québec, Canada.,Multimodal Functional Imaging Lab, Department of Physics and PERFORM Centre, Concordia University, Montreal, Québec, Canada
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Epileptic MEG Spike Detection Using Statistical Features and Genetic Programming with KNN. JOURNAL OF HEALTHCARE ENGINEERING 2017; 2017:3035606. [PMID: 29118962 PMCID: PMC5651155 DOI: 10.1155/2017/3035606] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 08/06/2017] [Accepted: 09/13/2017] [Indexed: 11/18/2022]
Abstract
Epilepsy is a neurological disorder that affects millions of people worldwide. Monitoring the brain activities and identifying the seizure source which starts with spike detection are important steps for epilepsy treatment. Magnetoencephalography (MEG) is an emerging epileptic diagnostic tool with high-density sensors; this makes manual analysis a challenging task due to the vast amount of MEG data. This paper explores the use of eight statistical features and genetic programing (GP) with the K-nearest neighbor (KNN) for interictal spike detection. The proposed method is comprised of three stages: preprocessing, genetic programming-based feature generation, and classification. The effectiveness of the proposed approach has been evaluated using real MEG data obtained from 28 epileptic patients. It has achieved a 91.75% average sensitivity and 92.99% average specificity.
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Ioannides AA, Liu L, Poghosyan V, Kostopoulos GK. Using MEG to Understand the Progression of Light Sleep and the Emergence and Functional Roles of Spindles and K-Complexes. Front Hum Neurosci 2017; 11:313. [PMID: 28670270 PMCID: PMC5472839 DOI: 10.3389/fnhum.2017.00313] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 05/31/2017] [Indexed: 12/20/2022] Open
Abstract
We used tomographic analysis of MEG signals to characterize regional spectral changes in the brain at sleep onset and during light sleep. We identified two key processes that may causally link to loss of consciousness during the quiet or "core" periods of NREM1. First, active inhibition in the frontal lobe leads to delta and theta spectral power increases. Second, activation suppression leads to sharp drop of spectral power in alpha and higher frequencies in posterior parietal cortex. During NREM2 core periods, the changes identified in NREM1 become more widespread, but focal increases also emerge in alpha and low sigma band power in frontal midline cortical structures, suggesting reemergence of some monitoring of internal and external environment. Just before spindles and K-complexes (KCs), the hallmarks of NREM2, we identified focal spectral power changes in pre-frontal cortex, mid cingulate, and areas involved in environmental and internal monitoring, i.e., the rostral and sub-genual anterior cingulate. During both spindles and KCs, alpha and low sigma bands increases. Spindles emerge after further active inhibition (increase in delta power) of the frontal areas responsible for environmental monitoring, while in posterior parietal cortex, power increases in low and high sigma bands. KCs are correlated with increase in alpha power in the monitoring areas. These specific regional changes suggest strong and varied vigilance changes for KCs, but vigilance suppression and sharpening of cognitive processing for spindles. This is consistent with processes designed to ensure accurate and uncorrupted memory consolidation. The changes during KCs suggest a sentinel role: evaluation of the salience of provoking events to decide whether to increase processing and possibly wake up, or to actively inhibit further processing of intruding influences. The regional spectral patterns of NREM1, NREM2, and their dynamic changes just before spindles and KCs reveal an edge effect facilitating the emergence of spindles and KCs and defining the precise loci where they might emerge. In the time domain, the spindles are seen in widespread areas of the cortex just as reported from analysis of intracranial data, consistent with the emerging consensus of a differential topography that depends on the kind of memory stored.
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Affiliation(s)
- Andreas A. Ioannides
- Laboratory for Human Brain Dynamics, AAI Scientific Cultural Services Ltd.Nicosia, Cyprus
| | - Lichan Liu
- Laboratory for Human Brain Dynamics, AAI Scientific Cultural Services Ltd.Nicosia, Cyprus
| | - Vahe Poghosyan
- Laboratory for Human Brain Dynamics, AAI Scientific Cultural Services Ltd.Nicosia, Cyprus
- MEG Unit, Department of Neurophysiology, King Fahad Medical CityRiyadh, Saudi Arabia
| | - George K. Kostopoulos
- Neurophysiology Unit, Department of Physiology, Medical School, University of PatrasRion, Greece
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Colon AJ, Ronner HE, Boon P, Ossenblok P. Evaluation of MEG vs EEG after sleep deprivation in epilepsy. Acta Neurol Scand 2017; 135:247-251. [PMID: 26957488 DOI: 10.1111/ane.12586] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2016] [Indexed: 11/28/2022]
Abstract
OBJECTIVE MEG and EEG after sleep deprivation (EEG-SD) are applied as diagnostic tools in the evaluation of patients with possible epilepsy. There is no gold standard to check whether the diagnosis based on these two modalities is correct. The best standard available is the long-term follow-up of patients. As follow-up of an earlier study in which the additional value of MEG vs EEG-SD diagnosis was evaluated, we investigated the long-term validity of MEG-based and EEG-SD-based diagnosis. MATERIALS AND METHODS Data collected from 46 patients were used in a comparative study of the last known diagnosis against the original one of 8 years ago. RESULTS Long-term (3-8 years) sensitivity of sharp phenomena (combining spikes and sharp waves) in routine MEG and in EEG-SD for the diagnosis epilepsy is 71% and 62%, respectively. When compared to the original study, this hardly changed. Over time, uncertainty on diagnosis diminishes. CONCLUSION MEG as well as EEG-SD are robust long-term predictors for epilepsy.
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Affiliation(s)
- A. J. Colon
- Department of Clinical Neurophysiology; ACE, location Kempenhaeghe; Heeze The Netherlands
- Department of R&D; ACE; Heeze The Netherlands
- Department of Neurology; Ghent University Hospital; Ghent Belgium
| | - H. E. Ronner
- Department of Clinical Neurophysiology; VUmc; Amsterdam The Netherlands
| | - P. Boon
- Department of R&D; ACE; Heeze The Netherlands
- Department of Neurology; Ghent University Hospital; Ghent Belgium
| | - P. Ossenblok
- Department of R&D; ACE; Heeze The Netherlands
- Department of Clinical Physics; ACE, location Kempenhaeghe; Heeze The Netherlands
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Abstract
Magnetoencephalography (MEG) is a method to study electrical activity in the human brain by recording the neuromagnetic field outside the head. MEG, like electroencephalography (EEG), provides an excellent, millisecond-scale time resolution, and allows the estimation of the spatial distribution of the underlying activity, in favorable cases with a localization accuracy of a few millimeters. To detect the weak neuromagnetic signals, superconducting sensors, magnetically shielded rooms, and advanced signal processing techniques are used. The analysis and interpretation of MEG data typically involves comparisons between subject groups and experimental conditions using various spatial, temporal, and spectral measures of cortical activity and connectivity. The application of MEG to cognitive neuroscience studies is illustrated with studies of spoken language processing in subjects with normal and impaired reading ability. The mapping of spatiotemporal patterns of activity within networks of cortical areas can provide useful information about the functional architecture of the brain related to sensory and cognitive processing, including language, memory, attention, and perception.
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Affiliation(s)
- Seppo P Ahlfors
- MGH/HST Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 149 13th St., Mailcode 149-2301, Charlestown, MA 02129; U.S.A. Tel. +1-617-726-0663
| | - Maria Mody
- MGH/HST Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 149 13th St., Mailcode 149-2301, Charlestown, MA 02129; U.S.A. Tel. +1-617-726-0663
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30
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Magnetoencephalography-guided surgery in frontal lobe epilepsy using neuronavigation and intraoperative MR imaging. Epilepsy Res 2016; 126:26-36. [DOI: 10.1016/j.eplepsyres.2016.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 06/01/2016] [Accepted: 06/24/2016] [Indexed: 11/17/2022]
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Kim D, Joo EY, Seo DW, Kim MY, Lee YH, Kwon HC, Kim JM, Hong SB. Accuracy of MEG in localizing irritative zone and seizure onset zone: Quantitative comparison between MEG and intracranial EEG. Epilepsy Res 2016; 127:291-301. [PMID: 27693985 DOI: 10.1016/j.eplepsyres.2016.08.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 07/25/2016] [Accepted: 08/14/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND We conducted the study to examine accuracy of the magnetoencephalography (MEG) spike source localization in presurgical evaluation of patients with medically refractory focal epilepsy. METHODS Ten consecutive patients with refractory focal epilepsy who were candidates for two-stage surgery with long-term intracranial electroencephalography (ICEEG) monitoring were enrolled. Interictal MEG recordings with simultaneous scalp EEG were obtained within 7days before the ICEEG electrode implantation. The location of each MEG spike source was quantitatively compared with ICEEG spike foci (focal area of interictal spikes) and ICEEG ictal foci (earliest cortical origin of seizures). Gyral-width concordance and sublobar concordance were also determined for all MEG spike sources. Gyral-width concordance was defined by distance of 15mm or less between MEG spike sources and ICEEG spike foci or ICEEG ictal foci. RESULTS Visual analyses of the MEG traces of all 10 patients revealed 292 spikes (29.2±24.0 per patient). Spike yield of the MEG was similar to the simultaneously recorded scalp EEG. MEG spike sources were closely located with ICEEG spike foci (distance: 9.3±10.8mm). Clustered MEG spike sources were even closer to ICEEG spike foci (distance: 7.3±6.4mm). MEG spike sources, even clustered ones, were less concordant with ICEEG ictal foci and had significant longer distance from ICEEG ictal foci (distance: 21.5±15.6mm for all sources, 19.7±13.7mm for clustered sources). Gyral-width concordance rate and sublobar concordance rate were also higher with ICEEG interictal spike foci than with ICEEG ictal foci. On the other hand, 53.4% of interictal spike foci from ICEEG were not detected by interictal MEG recordings. CONCLUSIONS MEG spike sources, especially clustered ones, from interictal recording could localize the irritative zone of ICEEG with a high accuracy. However, MEG spike sources have relatively poor correlation with seizure onset zone and lower sensitivity in identifying all irritative zones of ICEEG. This limitation should be considered in the interpretation of MEG results.
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Affiliation(s)
- Daeyoung Kim
- Department of Neurology, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, Republic of Korea
| | - Eun Yeon Joo
- Department of Neurology, Samsung Medical Center, Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Dae-Won Seo
- Department of Neurology, Samsung Medical Center, Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Min-Young Kim
- Center for Biosignals, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea
| | - Yong-Ho Lee
- Center for Biosignals, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea
| | - Hyuk Chan Kwon
- Center for Biosignals, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea
| | - Jae-Moon Kim
- Department of Neurology, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, Republic of Korea.
| | - Seung Bong Hong
- Department of Neurology, Samsung Medical Center, Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; Samsung Biomedical Research Institute, Seoul, Republic of Korea.
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Duez L, Beniczky S, Tankisi H, Hansen PO, Sidenius P, Sabers A, Fuglsang-Frederiksen A. Added diagnostic value of magnetoencephalography (MEG) in patients suspected for epilepsy, where previous, extensive EEG workup was unrevealing. Clin Neurophysiol 2016; 127:3301-5. [PMID: 27573996 DOI: 10.1016/j.clinph.2016.08.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 08/04/2016] [Accepted: 08/07/2016] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To elucidate the possible additional diagnostic yield of MEG in the workup of patients with suspected epilepsy, where repeated EEGs, including sleep-recordings failed to identify abnormalities. METHODS Fifty-two consecutive patients with clinical suspicion of epilepsy and at least three normal EEGs, including sleep-EEG, were prospectively analyzed. The reference standard was inferred from the diagnosis obtained from the medical charts, after at least one-year follow-up. MEG (306-channel, whole-head) and simultaneous EEG (MEG-EEG) was recorded for one hour. The added sensitivity of MEG was calculated from the cases where abnormalities were seen in MEG but not EEG. RESULTS Twenty-two patients had the diagnosis epilepsy according to the reference standard. MEG-EEG detected abnormalities, and supported the diagnosis in nine of the 22 patients with the diagnosis epilepsy at one-year follow-up. Sensitivity of MEG-EEG was 41%. The added sensitivity of MEG was 18%. MEG-EEG was normal in 28 of the 30 patients categorized as 'not epilepsy' at one year follow-up, yielding a specificity of 93%. CONCLUSIONS MEG provides additional diagnostic information in patients suspected for epilepsy, where repeated EEG recordings fail to demonstrate abnormality. SIGNIFICANCE MEG should be included in the diagnostic workup of patients where the conventional, widely available methods are unrevealing.
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Affiliation(s)
- Lene Duez
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.
| | - Sándor Beniczky
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Neurophysiology, Danish Epilepsy Centre, Dianalund, Denmark
| | - Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - Peter Orm Hansen
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - Per Sidenius
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - Anne Sabers
- Department of Neurology, Copenhagen University Hospital, Rigshospitalet-Blegdamsvej, Copenhagen, Denmark
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Hunold A, Funke ME, Eichardt R, Stenroos M, Haueisen J. EEG and MEG: sensitivity to epileptic spike activity as function of source orientation and depth. Physiol Meas 2016; 37:1146-62. [DOI: 10.1088/0967-3334/37/7/1146] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Rozendaal YJW, van Luijtelaar G, Ossenblok PPW. Spatiotemporal mapping of interictal epileptiform discharges in human absence epilepsy: A MEG study. Epilepsy Res 2015; 119:67-76. [PMID: 26681490 DOI: 10.1016/j.eplepsyres.2015.11.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 10/03/2015] [Accepted: 11/13/2015] [Indexed: 01/15/2023]
Abstract
PURPOSE Although absence epilepsy is considered to be a prototypic type of generalized epilepsy, it is still under debate whether generalized 3 Hz spike-and-wave discharges (SWDs) might have a cortical focal origin. Here it is investigated whether focal interictal epileptiform discharges (IEDs), which typically occur in the electro- (EEG) and magnetoencephalogram (MEG) in case of focal epilepsy, are present in the MEG of children with absence epilepsy. Next, the location of the sources of the IEDs is established, and it is investigated whether the location is concordant to the earlier established focal cortical regions involved in the generalized SWDs of these children. METHODS Whole head MEG recordings of seven children with absence epilepsy were reviewed with respect to the presence of IEDs (spikes and sharp waves). These IEDs were grouped into distinct clusters, in which each contribution to a cluster yields a comparable magnetic field distribution. Source localization was then performed onto the average signal of each cluster using an equivalent current dipole model and a realistic head model of the cortical surface. RESULTS IEDs were detected in 6 out of 7 patients. Source reconstruction indicated most often frontal, central or parietal origins of the IED in either the left and or right hemisphere. Spatiotemporal assessment of the IEDs indicated a stable location of the averages of these discharges, indicating a single underlying cortical source. DISCUSSION The outcome of this pilot study shows that MEG is well suited for the detection of IEDs and suggests that their estimated sources coincide rather well with the cortical regions involved during the spikes of the SWDs. It is discussed whether the presence of IEDs, classically seen as a marker of focal epilepsies, indicate that absence epilepsy should be considered as a focal type of epilepsy, in which changes in the network are evolving rapidly.
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Affiliation(s)
- Yvonne J W Rozendaal
- Department Function and Medical Technology, Academic Center of Epileptology, Kempenhaeghe & Maastricht UMC+, PO Box 61, 5590AB Heeze, The Netherlands; Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600MB Eindhoven, The Netherlands.
| | - Gilles van Luijtelaar
- Donders Centre of Cognition, Radboud University, PO Box 9104, 6500HE Nijmegen, The Netherlands.
| | - Pauly P W Ossenblok
- Department Function and Medical Technology, Academic Center of Epileptology, Kempenhaeghe & Maastricht UMC+, PO Box 61, 5590AB Heeze, The Netherlands.
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Llinás RR, Ustinin MN, Rykunov SD, Boyko AI, Sychev VV, Walton KD, Rabello GM, Garcia J. Reconstruction of human brain spontaneous activity based on frequency-pattern analysis of magnetoencephalography data. Front Neurosci 2015; 9:373. [PMID: 26528119 PMCID: PMC4608363 DOI: 10.3389/fnins.2015.00373] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/28/2015] [Indexed: 11/13/2022] Open
Abstract
A new method for the analysis and localization of brain activity has been developed, based on multichannel magnetic field recordings, over minutes, superimposed on the MRI of the individual. Here, a high resolution Fourier Transform is obtained over the entire recording period, leading to a detailed multi-frequency spectrum. Further analysis implements a total decomposition of the frequency components into functionally invariant entities, each having an invariant field pattern localizable in recording space. The method, addressed as functional tomography, makes it possible to find the distribution of magnetic field sources in space. Here, the method is applied to the analysis of simulated data, to oscillating signals activating a physical current dipoles phantom, and to recordings of spontaneous brain activity in 10 healthy adults. In the analysis of simulated data, 61 dipoles are localized with 0.7 mm precision. Concerning the physical phantom the method is able to localize three simultaneously activated current dipoles with 1 mm precision. Spatial resolution 3 mm was attained when localizing spontaneous alpha rhythm activity in 10 healthy adults, where the alpha peak was specified for each subject individually. Co-registration of the functional tomograms with each subject's head MRI localized alpha range activity to the occipital and/or posterior parietal brain region. This is the first application of this new functional tomography to human brain activity. The method successfully provides an overall view of brain electrical activity, a detailed spectral description and, combined with MRI, the localization of sources in anatomical brain space.
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Affiliation(s)
- Rodolfo R Llinás
- Department of Neuroscience and Physiology, New York University School of Medicine New York, NY, USA
| | - Mikhail N Ustinin
- Institute of Mathematical Problems of Biology, Russian Academy of Sciences Pushchino, Russia
| | - Stanislav D Rykunov
- Institute of Mathematical Problems of Biology, Russian Academy of Sciences Pushchino, Russia
| | - Anna I Boyko
- Institute of Mathematical Problems of Biology, Russian Academy of Sciences Pushchino, Russia
| | - Vyacheslav V Sychev
- Institute of Mathematical Problems of Biology, Russian Academy of Sciences Pushchino, Russia
| | - Kerry D Walton
- Department of Neuroscience and Physiology, New York University School of Medicine New York, NY, USA
| | - Guilherme M Rabello
- Department of Neuroscience and Physiology, New York University School of Medicine New York, NY, USA
| | - John Garcia
- Department of Neuroscience and Physiology, New York University School of Medicine New York, NY, USA
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Gavaret M, Maillard L, Jung J. High-resolution EEG (HR-EEG) and magnetoencephalography (MEG). Neurophysiol Clin 2015; 45:105-11. [DOI: 10.1016/j.neucli.2014.11.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 11/09/2014] [Indexed: 10/24/2022] Open
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Bagić A, Ebersole JS. Does MEG/MSI dipole variability mean unreliability? Clin Neurophysiol 2015; 126:209-11. [DOI: 10.1016/j.clinph.2014.01.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 01/20/2014] [Accepted: 01/23/2014] [Indexed: 11/28/2022]
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[French guidelines on electroencephalogram]. Neurophysiol Clin 2014; 44:515-612. [PMID: 25435392 DOI: 10.1016/j.neucli.2014.10.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Accepted: 10/07/2014] [Indexed: 12/11/2022] Open
Abstract
Electroencephalography allows the functional analysis of electrical brain cortical activity and is the gold standard for analyzing electrophysiological processes involved in epilepsy but also in several other dysfunctions of the central nervous system. Morphological imaging yields complementary data, yet it cannot replace the essential functional analysis tool that is EEG. Furthermore, EEG has the great advantage of being non-invasive, easy to perform and allows control tests when follow-up is necessary, even at the patient's bedside. Faced with the advances in knowledge, techniques and indications, the Société de Neurophysiologie Clinique de Langue Française (SNCLF) and the Ligue Française Contre l'Épilepsie (LFCE) found it necessary to provide an update on EEG recommendations. This article will review the methodology applied to this work, refine the various topics detailed in the following chapters. It will go over the summary of recommendations for each of these chapters and underline proposals for writing an EEG report. Some questions could not be answered by the review of the literature; in those cases, an expert advice was given by the working and reading groups in addition to the guidelines.
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Almubarak S, Alexopoulos A, Von-Podewils F, Wang ZI, Kakisaka Y, Mosher JC, Bulacio J, González-Martínez J, Bingaman W, Burgess RC. The correlation of magnetoencephalography to intracranial EEG in localizing the epileptogenic zone: A study of the surgical resection outcome. Epilepsy Res 2014; 108:1581-90. [DOI: 10.1016/j.eplepsyres.2014.08.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 07/20/2014] [Accepted: 08/21/2014] [Indexed: 11/27/2022]
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Mu J, Rampp S, Carrette E, Roessler K, Sommer B, Schmitt FC, De Tiège X, Hamer H, Boon P, Pauli E, Bluemcke I, Zhou D, Buchfelder M, Stefan H. Clinical relevance of source location in frontal lobe epilepsy and prediction of postoperative long-term outcome. Seizure 2014; 23:553-9. [DOI: 10.1016/j.seizure.2014.04.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 03/04/2014] [Accepted: 04/10/2014] [Indexed: 11/26/2022] Open
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Pittau F, Grouiller F, Spinelli L, Seeck M, Michel CM, Vulliemoz S. The role of functional neuroimaging in pre-surgical epilepsy evaluation. Front Neurol 2014. [PMID: 24715886 DOI: 10.3389/fneur.2014.00031.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The prevalence of epilepsy is about 1% and one-third of cases do not respond to medical treatment. In an eligible subset of patients with drug-resistant epilepsy, surgical resection of the epileptogenic zone is the only treatment that can possibly cure the disease. Non-invasive techniques provide information for the localization of the epileptic focus in the majority of cases, whereas in others invasive procedures are required. In the last years, non-invasive neuroimaging techniques, such as simultaneous recording of functional magnetic resonance imaging and electroencephalogram (EEG-fMRI), positron emission tomography (PET), single photon emission computed tomography (SPECT), electric and magnetic source imaging (MSI, ESI), spectroscopy (MRS), have proved their usefulness in defining the epileptic focus. The combination of these functional techniques can yield complementary information and their concordance is crucial for guiding clinical decision, namely the planning of invasive EEG recordings or respective surgery. The aim of this review is to present these non-invasive neuroimaging techniques, their potential combination, and their role in the pre-surgical evaluation of patients with pharmaco-resistant epilepsy.
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Affiliation(s)
- Francesca Pittau
- Presurgical Epilepsy Evaluation Unit, Neurology Department, University Hospital of Geneva , Geneva , Switzerland
| | - Frédéric Grouiller
- Department of Radiology and Medical Informatics, University Hospital of Geneva , Geneva , Switzerland
| | - Laurent Spinelli
- Presurgical Epilepsy Evaluation Unit, Neurology Department, University Hospital of Geneva , Geneva , Switzerland
| | - Margitta Seeck
- Presurgical Epilepsy Evaluation Unit, Neurology Department, University Hospital of Geneva , Geneva , Switzerland
| | - Christoph M Michel
- Functional Brain Mapping Laboratory, Department of Fundamental Neurosciences, University of Geneva , Geneva , Switzerland
| | - Serge Vulliemoz
- Presurgical Epilepsy Evaluation Unit, Neurology Department, University Hospital of Geneva , Geneva , Switzerland
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Aydin Ü, Vorwerk J, Küpper P, Heers M, Kugel H, Galka A, Hamid L, Wellmer J, Kellinghaus C, Rampp S, Wolters CH. Combining EEG and MEG for the reconstruction of epileptic activity using a calibrated realistic volume conductor model. PLoS One 2014; 9:e93154. [PMID: 24671208 PMCID: PMC3966892 DOI: 10.1371/journal.pone.0093154] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 02/28/2014] [Indexed: 11/18/2022] Open
Abstract
To increase the reliability for the non-invasive determination of the irritative zone in presurgical epilepsy diagnosis, we introduce here a new experimental and methodological source analysis pipeline that combines the complementary information in EEG and MEG, and apply it to data from a patient, suffering from refractory focal epilepsy. Skull conductivity parameters in a six compartment finite element head model with brain anisotropy, constructed from individual MRI data, are estimated in a calibration procedure using somatosensory evoked potential (SEP) and field (SEF) data. These data are measured in a single run before acquisition of further runs of spontaneous epileptic activity. Our results show that even for single interictal spikes, volume conduction effects dominate over noise and need to be taken into account for accurate source analysis. While cerebrospinal fluid and brain anisotropy influence both modalities, only EEG is sensitive to skull conductivity and conductivity calibration significantly reduces the difference in especially depth localization of both modalities, emphasizing its importance for combining EEG and MEG source analysis. On the other hand, localization differences which are due to the distinct sensitivity profiles of EEG and MEG persist. In case of a moderate error in skull conductivity, combined source analysis results can still profit from the different sensitivity profiles of EEG and MEG to accurately determine location, orientation and strength of the underlying sources. On the other side, significant errors in skull modeling are reflected in EEG reconstruction errors and could reduce the goodness of fit to combined datasets. For combined EEG and MEG source analysis, we therefore recommend calibrating skull conductivity using additionally acquired SEP/SEF data.
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Affiliation(s)
- Ümit Aydin
- Institute for Biomagnetism and Biosignalanalysis, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Johannes Vorwerk
- Institute for Biomagnetism and Biosignalanalysis, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Philipp Küpper
- Institute for Biomagnetism and Biosignalanalysis, Westfälische Wilhelms-Universität Münster, Münster, Germany
- Department of Neurology, Klinikum Osnabrück, Osnabrück, Germany
| | - Marcel Heers
- Ruhr-Epileptology Department of Neurology, Universitätsklinikum Knappschaftskrankenhaus Bochum, Bochum, Germany
| | - Harald Kugel
- Department of Clinical Radiology, Universitätsklinikum Münster, Münster, Germany
| | - Andreas Galka
- Department of Neuropediatrics, Universitätsklinikum Schleswig-Holstein, Kiel, Germany
| | - Laith Hamid
- Department of Neuropediatrics, Universitätsklinikum Schleswig-Holstein, Kiel, Germany
| | - Jörg Wellmer
- Ruhr-Epileptology Department of Neurology, Universitätsklinikum Knappschaftskrankenhaus Bochum, Bochum, Germany
| | | | - Stefan Rampp
- Epilepsy Center, Department of Neurology, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Carsten Hermann Wolters
- Institute for Biomagnetism and Biosignalanalysis, Westfälische Wilhelms-Universität Münster, Münster, Germany
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Pittau F, Grouiller F, Spinelli L, Seeck M, Michel CM, Vulliemoz S. The role of functional neuroimaging in pre-surgical epilepsy evaluation. Front Neurol 2014; 5:31. [PMID: 24715886 PMCID: PMC3970017 DOI: 10.3389/fneur.2014.00031] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 03/06/2014] [Indexed: 12/25/2022] Open
Abstract
The prevalence of epilepsy is about 1% and one-third of cases do not respond to medical treatment. In an eligible subset of patients with drug-resistant epilepsy, surgical resection of the epileptogenic zone is the only treatment that can possibly cure the disease. Non-invasive techniques provide information for the localization of the epileptic focus in the majority of cases, whereas in others invasive procedures are required. In the last years, non-invasive neuroimaging techniques, such as simultaneous recording of functional magnetic resonance imaging and electroencephalogram (EEG-fMRI), positron emission tomography (PET), single photon emission computed tomography (SPECT), electric and magnetic source imaging (MSI, ESI), spectroscopy (MRS), have proved their usefulness in defining the epileptic focus. The combination of these functional techniques can yield complementary information and their concordance is crucial for guiding clinical decision, namely the planning of invasive EEG recordings or respective surgery. The aim of this review is to present these non-invasive neuroimaging techniques, their potential combination, and their role in the pre-surgical evaluation of patients with pharmaco-resistant epilepsy.
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Affiliation(s)
- Francesca Pittau
- Presurgical Epilepsy Evaluation Unit, Neurology Department, University Hospital of Geneva , Geneva , Switzerland
| | - Frédéric Grouiller
- Department of Radiology and Medical Informatics, University Hospital of Geneva , Geneva , Switzerland
| | - Laurent Spinelli
- Presurgical Epilepsy Evaluation Unit, Neurology Department, University Hospital of Geneva , Geneva , Switzerland
| | - Margitta Seeck
- Presurgical Epilepsy Evaluation Unit, Neurology Department, University Hospital of Geneva , Geneva , Switzerland
| | - Christoph M Michel
- Functional Brain Mapping Laboratory, Department of Fundamental Neurosciences, University of Geneva , Geneva , Switzerland
| | - Serge Vulliemoz
- Presurgical Epilepsy Evaluation Unit, Neurology Department, University Hospital of Geneva , Geneva , Switzerland
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Wijnen BFM, de Kinderen RJA, Colon AJ, Dirksen CD, Essers BAB, Hiligsmann M, Leijten FSS, Ossenblok PPW, Evers SMAA. Eliciting patients' preferences for epilepsy diagnostics: a discrete choice experiment. Epilepsy Behav 2014; 31:102-9. [PMID: 24389020 DOI: 10.1016/j.yebeh.2013.11.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 11/27/2013] [Accepted: 11/29/2013] [Indexed: 10/25/2022]
Abstract
BACKGROUND Diagnosing epilepsy is a lengthy and burdensome process for patients and their family. Although the need for a more patient-centered approach in clinical practice is widely acknowledged, empirical evidence regarding patient preferences for diagnostic modalities in epilepsy is missing. The objectives of this study were 1) to identify to what extent important attributes of diagnostic procedures in epilepsy affect preferences for a procedure, 2) to determine the relative importance of these attributes, and 3) to calculate overall utility scores for routine electroencephalography (EEG) and magnetoencephalography (MEG) recordings. METHODS A discrete choice experiment was performed to determine patients' preferences, which involved presentation of pairwise choice tasks regarding hypothetical scenarios. Scenarios varied along six attributes: "way of measuring brain activity", "duration", "freedom of movement", "travel time", "type of additional examination", and "chance of additional examination". Choice tasks were constructed using a statistically efficient design, and the questionnaire contained 15 unique unlabeled choice tasks. Mixed multinomial logistic regression was used to estimate patients' preferences. RESULTS A total of 289 questionnaires were included in the analysis. McFadden's pseudo R(2) showed a model fit of 0.28, and all attributes were statistically significant. Heterogeneity in preferences was present for all attributes. "Freedom of movement" and "Chance of additional examination" were perceived as the most important attributes. Overall utility scores did not substantially differ between routine EEG and MEG. CONCLUSION This study suggests that the identified attributes are important in determining patients' preference for epilepsy diagnostics. It can be concluded that MEG is not necessarily more patient-friendly than a routine EEG in primary diagnostics and, regarding additional diagnostics, patients have a strong preference for long-term 24-h EEG over EEG after sleep deprivation. Furthermore, barring substantial heterogeneity within the parameters in mind, our study suggests that it is important to take individual preferences into account in medical decision-making.
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Affiliation(s)
- B F M Wijnen
- CAPHRI, Research School for Public Health and Primary Care, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands; Department of Health Services Research, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands; Department of Research & Development, Epilepsy Centre Kempenhaeghe, PO Box 61, 5590 AB Heeze, The Netherlands.
| | - R J A de Kinderen
- CAPHRI, Research School for Public Health and Primary Care, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands; Department of Health Services Research, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands; Department of Research & Development, Epilepsy Centre Kempenhaeghe, PO Box 61, 5590 AB Heeze, The Netherlands.
| | - A J Colon
- Department of Clinical Neurophysiology, Epilepsy Centre Kempenhaeghe, PO Box 61, 5590 AB Heeze, The Netherlands; Department of Neurology, Epilepsy Centre Kempenhaeghe, PO Box 61, 5590 AB Heeze, The Netherlands.
| | - C D Dirksen
- CAPHRI, Research School for Public Health and Primary Care, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands; Department of Clinical Epidemiology and Medical Technology Assessment, University Hospital Maastricht, PO Box 5800, 6202 AZ Maastricht, The Netherlands.
| | - B A B Essers
- Department of Clinical Epidemiology and Medical Technology Assessment, University Hospital Maastricht, PO Box 5800, 6202 AZ Maastricht, The Netherlands.
| | - M Hiligsmann
- CAPHRI, Research School for Public Health and Primary Care, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands; Department of Health Services Research, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands.
| | - F S S Leijten
- Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Centre Utrecht, 3584 CG Utrecht, The Netherlands.
| | - P P W Ossenblok
- Department of Neurology, Epilepsy Centre Kempenhaeghe, PO Box 61, 5590 AB Heeze, The Netherlands.
| | - S M A A Evers
- CAPHRI, Research School for Public Health and Primary Care, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands; Department of Health Services Research, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands.
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Agirre-Arrizubieta Z, Thai NJ, Valentín A, Furlong PL, Seri S, Selway RP, Elwes RDC, Alarcón G. The value of Magnetoencephalography to guide electrode implantation in epilepsy. Brain Topogr 2013; 27:197-207. [PMID: 24249204 DOI: 10.1007/s10548-013-0330-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 11/05/2013] [Indexed: 11/28/2022]
Abstract
To investigate if Magnetoencephalography (MEG) can add non-redundant information to guide implantation sites for intracranial recordings (IR). The contribution of MEG to intracranial recording planning was evaluated in 12 consecutive patients assessed pre-surgically with MEG followed by IR. Primary outcome measures were the identification of focal seizure onset in IR and favorable surgical outcome. Outcome measures were compared to those of 12 patients matched for implantation type in whom non-invasive pre-surgical assessment suggested clear hypotheses for implantation (non-MEG group). In the MEG group, non-invasive assessment without MEG was inconclusive, and MEG was then used to further help identify implantation sites. In all MEG patients, at least one virtual MEG electrode generated suitable hypotheses for the location of implantations. No differences in outcome measures were found between non-MEG and MEG groups. Although the MEG group included more complex patients, it showed similar percentage of successful implantations as the non-MEG group. This suggests that MEG can contribute to identify implantation sites where standard methods failed.
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Malinowska U, Badier JM, Gavaret M, Bartolomei F, Chauvel P, Bénar CG. Interictal networks in magnetoencephalography. Hum Brain Mapp 2013; 35:2789-805. [PMID: 24105895 DOI: 10.1002/hbm.22367] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 06/11/2013] [Accepted: 06/17/2013] [Indexed: 11/12/2022] Open
Abstract
Epileptic networks involve complex relationships across several brain areas. Such networks have been shown on intracerebral EEG (stereotaxic EEG, SEEG), an invasive technique. Magnetoencephalography (MEG) is a noninvasive tool, which was recently proven to be efficient for localizing the generators of epileptiform discharges. However, despite the importance of characterizing non-invasively network aspects in partial epilepsies, only few studies have attempted to retrieve fine spatiotemporal dynamics of interictal discharges with MEG. Our goal was to assess the relevance of magnetoencephalography for detecting and characterizing the brain networks involved in interictal epileptic discharges. We propose here a semi-automatic method based on independent component analysis (ICA) and on co-occurrence of events across components. The method was evaluated in a series of seven patients by comparing its results with networks identified in SEEG. On both MEG and SEEG, we found that interictal discharges can involve remote regions which are acting in synchrony. More regions were identified in SEEG (38 in total) than in MEG (20). All MEG regions were confirmed by SEEG when an electrode was present in the vicinity. In all patients, at least one region could be identified as leading according to our criteria. A majority (71%) of MEG leaders were confirmed by SEEG. We have therefore shown that MEG measurements can extract a significant proportion of the networks visible in SEEG. This suggests that MEG can be a useful tool for defining noninvasively interictal epileptic networks, in terms of regions and patterns of connectivity, in search for a "primary irritative zone".
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Affiliation(s)
- Urszula Malinowska
- INSERM, UMR 1106, Marseille, France; Aix-Marseille Université, INS, Marseille, France
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Gavaret M, Badier JM, Bartolomei F, Bénar CG, Chauvel P. MEG and EEG Sensitivity in a Case of Medial Occipital Epilepsy. Brain Topogr 2013; 27:192-6. [DOI: 10.1007/s10548-013-0317-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 08/31/2013] [Indexed: 11/24/2022]
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Abstract
Mesial frontal lobe epilepsies can be divided into epilepsies arising from the anterior cingulate gyrus and those of the supplementary sensorimotor area. They provide diagnostic challenges because they often lack lateralizing or localizing features on clinical semiology and interictal and ictal scalp electroencephalographic (EEG) recordings. A number of unique semiologic features have been described over the last decade in patients with mesial frontal lobe epilepsy (FLE). There are few reports of applying advanced neurophysiologic techniques such as electrical source imaging, magnetoencephalography, EEG/functional magnetic resonance imaging, or analysis of high-frequency oscillations in patients with mesial FLE. Despite these diagnostic challenges, it seems that patients with mesial FLE benefit from epilepsy surgery to the same extent or even better than patients with FLE do, as a whole.
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Schneider F, Irene Wang Z, Alexopoulos AV, Almubarak S, Kakisaka Y, Jin K, Nair D, Mosher JC, Najm IM, Burgess RC. Magnetic source imaging and ictal SPECT in MRI-negative neocortical epilepsies: Additional value and comparison with intracranial EEG. Epilepsia 2012; 54:359-69. [DOI: 10.1111/epi.12004] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Vachhrajani S, de Ribaupierre S, Otsubo H, Ochi A, Weiss SK, Donner EJ, Widjaja E, Kerr E, Smith ML, Drake J, Snead C, Rutka JT. Neurosurgical management of frontal lobe epilepsy in children. J Neurosurg Pediatr 2012; 10:206-16. [PMID: 22838737 DOI: 10.3171/2012.6.peds11125] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECT Pediatric frontal lobe epilepsy (FLE) remains a challenging condition for neurosurgeons and epileptologists to manage. Postoperative seizure outcomes remain far inferior to those observed in temporal lobe epilepsies, possibly due to inherent difficulties in delineating and subsequently completely resecting responsible epileptogenic regions. In this study, the authors review their institutional experience with the surgical management of FLE and attempt to find predictors that may help to improve seizure outcome in this population. METHODS All surgically treated cases of intractable FLE from 1990 to 2008 were reviewed. Demographic information, preoperative and intraoperative imaging and electrophysiological investigations, and follow-up seizure outcome were assessed. Inferential statistics were performed to look for potential predictors of seizure outcome. RESULTS Forty patients (20 male, 20 female) underwent surgical management of FLE during the study period. Patients were an average of 5.6 years old at the time of FLE onset and 11.7 years at the time of surgery; patients were followed for a mean of 40.25 months. Most patients displayed typical FLE semiology. Twenty-eight patients had discrete lesions identified on MRI. Eight patients underwent 2 operations. Cortical dysplasia was the most common pathological diagnosis. Engel Class I outcome was obtained in 25 patients (62.5%), while Engel Class II outcome was observed in 5 patients (12.5%). No statistically significant predictors of outcome were found. CONCLUSIONS Control of FLE remains a challenging problem. Favorable seizure outcome, obtained in 62% of patients in this series, is still not as easily obtained in FLE as it is in temporal lobe epilepsy. While no statistically significant predictors of seizure outcome were revealed in this study, patients with FLE continue to require extensive workup and investigation to arrive at a logical and comprehensive neurosurgical treatment plan. Future studies with improved neuroimaging and advanced invasive monitoring strategies may well help define factors for success in this form of epilepsy that is difficult to control.
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Affiliation(s)
- Shobhan Vachhrajani
- Divisions of Pediatric Neurosurgery, The Hospital for Sick Children, The University of Toronto, Ontario, Canada
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