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Ishida M, Kakisaka Y, Jin K, Kanno A, Nakasato N. Somatosensory evoked spikes in normal adults detected by magnetoencephalography. Clin Neurophysiol 2024; 164:19-23. [PMID: 38820667 DOI: 10.1016/j.clinph.2024.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 05/08/2024] [Accepted: 05/11/2024] [Indexed: 06/02/2024]
Abstract
OBJECTIVE Somatosensory evoked spikes (SESs) have been reported only in children aged under 14 years and are considered as an age-dependent phenomenon. However, we detected SESs in adult patients with epilepsy using magnetoencephalography (MEG). The present study investigated whether MEG can detect SESs in normal adults. METHODS Spontaneous MEG was recorded during measurement of somatosensory evoked fields (SEFs) for bilateral electrical median nerve stimuli in 30 healthy adults. RESULTS Bilateral SESs were observed in 10 adults but none in the other 20 subjects. SESs consisted of one or two peaks, and the first peak latency corresponded to that of the second peak (M2) of SEFs. The first SES peak was identical to the M2 in isofield map pattern, as well as location and orientation of the equivalent current dipole (ECD). M2 ECD strength in the 10 subjects with SESs was larger (p <0.0001) than in 20 without SESs. CONCLUSIONS All-or-nothing detection of bilateral SESs by MEG in normal adults must depend on the signal-to-noise issue of symmetrical SEFs and background brain activity. SIGNIFICANCE Our results further confirm the higher sensitivity of MEG compared to scalp EEG for the detection of focal cortical sources tangential to the scalp such as SESs.
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Affiliation(s)
- Makoto Ishida
- Department of Epileptology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
| | - Yosuke Kakisaka
- Department of Epileptology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Kazutaka Jin
- Department of Epileptology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Akitake Kanno
- Department of Epileptology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Nobukazu Nakasato
- Department of Epileptology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
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Anatomo-functional evaluation for management and surgical treatment of insular cavernous malformation: a case series. Acta Neurochir (Wien) 2022; 164:1675-1684. [PMID: 35066681 DOI: 10.1007/s00701-021-05089-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 12/14/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND Insular cavernous malformations (iCMs) are very rare vascular lesions. Their surgical management is challenging, due to their complex functional and vascular relationship. The continuous improvement of intra-operative tools and neuroimaging techniques has progressively enhanced the safety of iCM surgery. Nevertheless, the best surgical approach remains controversial. OBJECTIVE To analyze the potential role of an anatomo-functional classification to guide the iCMs' management. METHODS The study included patients affected by iCMs and referred to the Senior Author (FA). All cases were divided in 2 groups, according to a mainly pial growth pattern (exophytic group) or a subcortical one (endophytic group). Endophytic iCM was further subdivided in 3 subgroups, based on the insular gyri involved. According to this classification, each patient underwent a specific additional neuroimaging investigation and surgical evaluation. RESULTS A total of 24 patients were included. In the surgical group, trans-sylvian (TS) approach was used in 6 patients with exophytic or Zone I endophytic iCMs. The transcortical (TC) approach with awake monitoring was used in 6 cases of Zone II endophytic vascular lesions. Both TS and trans-intraparietal sulcal (TIS) approach were used for 3 cases of Zone III endophytic iCM. At follow-up, 3 patients were fully recovered from a transient speech impairment while a permanent morbidity was observed in one case. CONCLUSIONS ICMs represent a single entity with peculiar clinical and surgical aspects. The proposed iCM classification focuses on anatomical and functional concerns, aiming to suggest the best pre-operative work-up and the surgical evaluation.
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Insular Involvement in Cases of Epilepsy Surgery Failure. Brain Sci 2022; 12:brainsci12020125. [PMID: 35203889 PMCID: PMC8870364 DOI: 10.3390/brainsci12020125] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/14/2022] [Accepted: 01/16/2022] [Indexed: 02/01/2023] Open
Abstract
Background: Epilepsy surgery failure is not uncommon, with several explanations having been proposed. In this series, we detail cases of epilepsy surgery failure subsequently attributed to insular involvement. Methods: We retrospectively identified patients investigated at the epilepsy monitoring units of two Canadian tertiary care centers (2004–2020). Included patients were adults who had undergone epilepsy surgeries with recurrence of seizures post-operatively and who were subsequently determined to have an insular epileptogenic focus. Clinical, electrophysiological, neuroimaging, and surgical data were synthesized. Results: We present 14 patients who demonstrated insular epileptic activity post-surgery-failure as detected by intracranial EEG, MEG, or seizure improvement after insular resection. Seven patients had manifestations evoking possible insular involvement prior to their first surgery. Most patients (8/14) had initial surgeries targeting the temporal lobe. Seizure recurrence ranged from the immediate post-operative period to one year. The main modality used to determine insular involvement was MEG (8/14). Nine patients underwent re-operations that included insular resection; seven achieved a favorable post-operative outcome (Engel I or II). Conclusions: Our series suggests that lowering the threshold for suspecting insular epilepsy may be necessary to improve epilepsy surgery outcomes. Detecting insular epilepsy post-surgery-failure may allow for re-operations which may lead to good outcomes.
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Iachim E, Vespa S, Baroumand AG, Danthine V, Vrielynck P, de Tourtchaninoff M, Fierain A, Ribeiro Vaz JG, Raftopoulos C, Ferrao Santos S, van Mierlo P, El Tahry R. Automated electrical source imaging with scalp EEG to define the insular irritative zone: Comparison with simultaneous intracranial EEG. Clin Neurophysiol 2021; 132:2965-2978. [PMID: 34715421 DOI: 10.1016/j.clinph.2021.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 08/13/2021] [Accepted: 09/16/2021] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To evaluate the accuracy of automatedinterictallow-density electrical source imaging (LD-ESI) to define the insular irritative zone (IZ) by comparing the simultaneous interictal ESI localization with the SEEG interictal activity. METHODS Long-term simultaneous scalp electroencephalography (EEG) and stereo-EEG (SEEG) with at least one depth electrode exploring the operculo-insular region(s) were analyzed. Automated interictal ESI was performed on the scalp EEG using standardized low-resolution brain electromagnetic tomography (sLORETA) and individual head models. A two-step analysis was performed: i) sublobar concordance betweencluster-based ESI localization and SEEG-based IZ; ii) time-locked ESI-/SEEG analysis. Diagnostic accuracy values were calculated using SEEG as reference standard. Subgroup analysis wascarried out, based onthe involvement of insular contacts in the seizure onset and patterns of insular interictal activity. RESULTS Thirty patients were included in the study. ESI showed an overall accuracy of 53% (C.I. 29-76%). Sensitivity and specificity were calculated as 53% (C.I. 29-76%), 55% (C.I. 23-83%) respectively. Higher accuracy was found in patients with frequent and dominant interictal insular spikes. CONCLUSIONS LD-ESI defines with good accuracy the insular implication in the IZ, which is not possible with classical interictalscalpEEG interpretation. SIGNIFICANCE Automated LD-ESI may be a valuable additional tool to characterize the epileptogenic zone in epilepsies with suspected insular involvement.
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Affiliation(s)
- Evelina Iachim
- Carol Davila University of Medicine and Pharmacy, Bucharest, Romania; Centre for Refractory Epilepsy, Department of Neurology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Simone Vespa
- Institute of Neuroscience (IoNS), Université Catholique de Louvain, Brussels, Belgium.
| | - Amir G Baroumand
- Medical Image and Signal Processing Group (MEDISIP), Department of Electronics and Information Systems, Ghent University, Ghent, Belgium; Epilog NV, Ghent, Belgium
| | - Venethia Danthine
- Institute of Neuroscience (IoNS), Université Catholique de Louvain, Brussels, Belgium
| | - Pascal Vrielynck
- Epileptology and Clinical Neurophysiology, Centre Neurologique William Lennox, Ottignies, Belgium
| | - Marianne de Tourtchaninoff
- Centre for Refractory Epilepsy, Department of Neurology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Alexane Fierain
- Epileptology and Clinical Neurophysiology, Centre Neurologique William Lennox, Ottignies, Belgium
| | - Jose Geraldo Ribeiro Vaz
- Centre for Refractory Epilepsy, Department of Neurology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | | | - Susana Ferrao Santos
- Institute of Neuroscience (IoNS), Université Catholique de Louvain, Brussels, Belgium; Centre for Refractory Epilepsy, Department of Neurology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Pieter van Mierlo
- Medical Image and Signal Processing Group (MEDISIP), Department of Electronics and Information Systems, Ghent University, Ghent, Belgium; Epilog NV, Ghent, Belgium
| | - Riëm El Tahry
- Institute of Neuroscience (IoNS), Université Catholique de Louvain, Brussels, Belgium; Centre for Refractory Epilepsy, Department of Neurology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
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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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Otsubo H, Ogawa H, Pang E, Wong SM, Ibrahim GM, Widjaja E. A review of magnetoencephalography use in pediatric epilepsy: an update on best practice. Expert Rev Neurother 2021; 21:1225-1240. [PMID: 33780318 DOI: 10.1080/14737175.2021.1910024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Introduction: Magnetoencephalography (MEG) is a noninvasive technique that is used for presurgical evaluation of children with drug-resistant epilepsy (DRE).Areas covered: The contributions of MEG for localizing the epileptogenic zone are discussed, in particular in extra-temporal lobe epilepsy and focal cortical dysplasia, which are common in children, as well as in difficult to localize epilepsy such as operculo-insular epilepsy. Further, the authors review current evidence on MEG for mapping eloquent cortex, its performance, application in clinical practice, and potential challenges.Expert opinion: MEG could change the clinical management of children with DRE by directing placement of intracranial electrodes thereby enhancing their yield. With improved identification of a circumscribed epileptogenic zone, MEG could render more patients as suitable candidates for epilepsy surgery and increase utilization of surgery.
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Affiliation(s)
- Hiroshi Otsubo
- Diagnostic Imaging, Hospital for Sick Children, Toronto, Canada
| | - Hiroshi Ogawa
- Diagnostic Imaging, Hospital for Sick Children, Toronto, Canada
| | - Elizabeth Pang
- Diagnostic Imaging, Hospital for Sick Children, Toronto, Canada.,Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Canada
| | - Simeon M Wong
- Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Canada
| | - George M Ibrahim
- Division of Neurosurgery, Hospital for Sick Children, Toronto, Canada.,Diagnostic Imaging, Hospital for Sick Children, Toronto, Canada
| | - Elysa Widjaja
- Diagnostic Imaging, Hospital for Sick Children, Toronto, Canada.,Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Canada.,Diagnostic Imaging, Hospital for Sick Children, Toronto, Canada
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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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Yin C, Zhang X, Xiang J, Chen Z, Li X, Wu S, Lv P, Wang Y. Altered effective connectivity network in patients with insular epilepsy: A high-frequency oscillations magnetoencephalography study. Clin Neurophysiol 2019; 131:377-384. [PMID: 31865139 DOI: 10.1016/j.clinph.2019.11.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 11/03/2019] [Accepted: 11/08/2019] [Indexed: 01/05/2023]
Abstract
OBJECTIVE The project aimed to determine the alterations in the effective connectivity (EC) neural network in patients with insular epilepsy based on interictal high-frequency oscillations (HFOs) from magnetoencephalography (MEG) data. METHODS We studied MEG data from 22 insular epilepsy patients and 20 normal subjects. Alterations in spatial pattern and connection properties of the patients with insular epilepsy were investigated in the entire brain network and insula-based network. RESULTS Analyses of the parameters of graph theory revealed the over-connectivity and small-world configuration of the global connectivity patterns observed in the patients. In the insula-based network, the insular cortex ipsilateral to the seizure onset displayed increased efferent and afferentEC. Left insular epilepsy featured strong connectivity with the bilateral hemispheres, whereas right insular epilepsy featured increased connectivity with only the ipsilateral hemisphere. CONCLUSIONS Patients with insular epilepsy display alterations in the EC network in terms of both whole-brain connectivity and the insula-based network during interictal HFOs. SIGNIFICANCE Alterations of interictal HFO-based networks provide evidence that epilepsy networks, instead of epileptic foci, play a key role in the complex pathophysiological mechanisms of insular epilepsy. The dysfunction of HFO networks may prove to be a novel promising biomarker and the cause of interictal brain dysfunctions in insular epilepsy.
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Affiliation(s)
- Chunli Yin
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China; Department of Neurology, Hebei Medical University, Shijiazhuang 050017, China; Department of Neurology, Tangshan Gongren Hospital, Tangshan 063000, China
| | - Xiating Zhang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing 100053, China; Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing 100053, China
| | - Jing Xiang
- MEG Center, Division of Neurology, Cincinnati Children's Hospital, Medical Center, Cincinnati, OH 45220, USA
| | - Zheng Chen
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Xin Li
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Siqi Wu
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Peiyuan Lv
- Department of Neurology, Hebei Medical University, Shijiazhuang 050017, China; Department of Neurology, Hebei General Hospital, Shijiazhuang 050051, China
| | - Yuping Wang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing 100053, China; Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing 100053, China.
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Stefan H, Gollwitzer S. Ictal semiology, functional anatomy and multimodal diagnostic in patients with insular epilepsies. ACTA EPILEPTOLOGICA 2019. [DOI: 10.1186/s42494-019-0006-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Abstract
Background
The insula is a hidden part in the cerebral cortex. Insular epilepsy is underrecognized and it bears a special risk for misdiagnosis with regard to nonepileptic seizures or wrong localization of epileptic seizures.
Case presentations
The manuscript describes 2 cases with ictal semiology of paresthesia and pain followed by hyperkinetic movements, noninvasive findings of source localization and/or invasive SEEG exploration.
Conclusion
Magnetic source imaging, ictal SPECT as noninvasive and invasive recordings with depth electrodes (SEEG) can provide important preoperative information for the involvement of insular and periinsular regions in focal pharmacoresistant epilepsies. The optimal use of these methods presupposes extensive knowledge of ictal semiology and other clinical characteristics. The clinical localization hypothesis can be optimally proofed by SEEG exploration.
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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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Yin C, Zhang X, Chen Z, Li X, Wu S, Lv P, Wang Y. Detection and localization of interictal ripples with magnetoencephalography in the presurgical evaluation of drug-resistant insular epilepsy. Brain Res 2018; 1706:147-156. [PMID: 30408475 DOI: 10.1016/j.brainres.2018.11.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 09/29/2018] [Accepted: 11/03/2018] [Indexed: 01/15/2023]
Abstract
Precise noninvasive presurgical localization of insular epilepsy is important. The objective of the present study was to detect and localize interictal high-frequency oscillations (HFOs) in patients with insular epilepsy at the source levels using magnetoencephalography (MEG). We investigated whether HFOs can delineate epileptogenic areas. We analysed MEG data with new accumulated source imaging (HFOs, 80-250 Hz ripples during spikes) and conventional dipole modelling (spikes) methods for localizing epileptic foci. We evaluated the relationship of the resection of focal brain regions containing interictal HFOs and the spikes with the postsurgical seizure outcome. Interictal HFOs were localized in the insular epileptogenic zone (EZ) in 18 out of 21 patients undergoing surgical treatment for clinically diagnosed insular epilepsy. While dipole clusters of spikes were involved in the insular EZ in 15 patients. Both the HFOs and the dipole cluster were localized in the insula in 14 patients. The seizure-free percentage was 87% for the resection of brain regions generating HFOs, whereas 80% for the resection of brain regions generating spikes. There was a much higher chance of freedom from seizures with complete resection of the HFO-generating regions than with partial resection or no resection (P = 0.031). No such difference was seen for spike-generating regions. Our results suggest that HFOs from insular epilepsy could be noninvasively detected and quantitatively assessed with MEG technology. MEG HFOs (ripples during spikes) may be valuable for the localization of the epileptogenic zone in insular epilepsy.
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Affiliation(s)
- Chunli Yin
- Department of Neurology, Hebei Medical University, Shijiazhuang 050017, China
| | - Xiating Zhang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing 100053, China; Center of Epilepsy, Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100053, China
| | - Zheng Chen
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing 100053, China; Center of Epilepsy, Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100053, China
| | - Xin Li
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing 100053, China; Center of Epilepsy, Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100053, China
| | - Siqi Wu
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing 100053, China; Center of Epilepsy, Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100053, China
| | - Peiyuan Lv
- Department of Neurology, Hebei Medical University, Shijiazhuang 050017, China; Department of Neurology, Hebei General Hospital, Shijiazhuang 050051, China.
| | - Yuping Wang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing 100053, China; Center of Epilepsy, Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100053, China.
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Diagnostic evaluation and surgical management of pediatric insular epilepsy utilizing magnetoencephalography and invasive EEG monitoring. Epilepsy Res 2018; 140:72-81. [DOI: 10.1016/j.eplepsyres.2017.12.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 11/28/2017] [Accepted: 12/11/2017] [Indexed: 11/21/2022]
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13
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Zerouali Y, Ghaziri J, Nguyen DK. Multimodal investigation of epileptic networks: The case of insular cortex epilepsy. PROGRESS IN BRAIN RESEARCH 2017; 226:1-33. [PMID: 27323937 DOI: 10.1016/bs.pbr.2016.04.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The insula is a deep cortical structure sharing extensive synaptic connections with a variety of brain regions, including several frontal, temporal, and parietal structures. The identification of the insular connectivity network is obviously valuable for understanding a number of cognitive processes, but also for understanding epilepsy since insular seizures involve a number of remote brain regions. Ultimately, knowledge of the structure and causal relationships within the epileptic networks associated with insular cortex epilepsy can offer deeper insights into this relatively neglected type of epilepsy enabling the refining of the clinical approach in managing patients affected by it. In the present chapter, we first review the multimodal noninvasive tests performed during the presurgical evaluation of epileptic patients with drug refractory focal epilepsy, with particular emphasis on their value for the detection of insular cortex epilepsy. Second, we review the emerging multimodal investigation techniques in the field of epilepsy, that aim to (1) enhance the detection of insular cortex epilepsy and (2) unveil the architecture and causal relationships within epileptic networks. We summarize the results of these approaches with emphasis on the specific case of insular cortex epilepsy.
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Affiliation(s)
- Y Zerouali
- Research Centre, Centre hospitalier de l'Université de Montréal, Montreal, QC, Canada; Ecole Polytechnique de Montréal, Montreal, QC, Canada
| | - J Ghaziri
- Research Centre, Centre hospitalier de l'Université de Montréal, Montreal, QC, Canada
| | - D K Nguyen
- Research Centre, Centre hospitalier de l'Université de Montréal, Montreal, QC, Canada; CHUM-Hôpital Notre-Dame, Montreal, QC, Canada.
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Ducis K, Guan J, Karsy M, Bollo RJ. Preoperative evaluation and surgical decision-making in pediatric epilepsy surgery. Transl Pediatr 2016; 5:169-179. [PMID: 27709099 PMCID: PMC5035764 DOI: 10.21037/tp.2016.06.02] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Epilepsy is a common disease in the pediatric population, and the majority of cases are controlled with medications and lifestyle modification. For the children whose seizures are pharmacoresistant, continued epileptic activity can have a severely detrimental impact on cognitive development. Early referral of children with drug-resistant seizures to a pediatric epilepsy surgery center for evaluation is critical to achieving optimal patient outcomes. There are several components to a thorough presurgical evaluation, including a detailed medical history and physical examination, noninvasive testing including electroencephalogram, magnetic resonance imaging (MRI) of the brain, and often metabolic imaging. When necessary, invasive diagnostic testing using intracranial monitoring can be used. The identification of an epileptic focus may allow resection or disconnection from normal brain structures, with the ultimate goal of complete seizure remission. Additional operative measures can decrease seizure frequency and/or intensity if a clear epileptic focus cannot be identified. In this review, we will discuss the nuances of presurgical evaluation and decision-making in the management of children with drug-resistant epilepsy (DRE).
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Affiliation(s)
- Katrina Ducis
- Department of Neurosurgery, University of Vermont School of Medicine, Burlington, VT, USA; ; Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Jian Guan
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Michael Karsy
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Robert J Bollo
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, UT, USA; ; Division of Pediatric Neurosurgery, Primary Children's Hospital, Salt Lake City, UT, USA
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Zerouali Y, Pouliot P, Robert M, Mohamed I, Bouthillier A, Lesage F, Nguyen DK. Magnetoencephalographic signatures of insular epileptic spikes based on functional connectivity. Hum Brain Mapp 2016; 37:3250-61. [PMID: 27220112 DOI: 10.1002/hbm.23238] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 04/19/2016] [Accepted: 04/21/2016] [Indexed: 11/10/2022] Open
Abstract
Failure to recognize insular cortex seizures has recently been identified as a cause of epilepsy surgeries targeting the temporal, parietal, or frontal lobe. Such failures are partly due to the fact that current noninvasive localization techniques fare poorly in recognizing insular epileptic foci. Our group recently demonstrated that magnetoencephalography (MEG) is sensitive to epileptiform spikes generated by the insula. In this study, we assessed the potential of distributed source imaging and functional connectivity analyses to distinguish insular networks underlying the generation of spikes. Nineteen patients with operculo-insular epilepsy were investigated. Each patient underwent MEG as well as T1-weighted magnetic resonance imaging (MRI) as part of their standard presurgical evaluation. Cortical sources of MEG spikes were reconstructed with the maximum entropy on the mean algorithm, and their time courses served to analyze source functional connectivity. The results indicate that the anterior and posterior subregions of the insula have specific patterns of functional connectivity mainly involving frontal and parietal regions, respectively. In addition, while their connectivity patterns are qualitatively similar during rest and during spikes, couplings within these networks are much stronger during spikes. These results show that MEG can establish functional connectivity-based signatures that could help in the diagnosis of different subtypes of insular cortex epilepsy. Hum Brain Mapp 37:3250-3261, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Younes Zerouali
- Département De Génie Électrique, École Polytechnique De Montréal, Montreal, Quebec, Canada.,Research Centre, Centre Hospitalier De L'Université De Montréal (CRCHUM), Montreal, Quebec, Canada
| | - Philippe Pouliot
- Département De Génie Électrique, École Polytechnique De Montréal, Montreal, Quebec, Canada.,Institut De Cardiologie De Montréal, Montreal, Quebec, Canada
| | - Manon Robert
- Research Centre, Centre Hospitalier De L'Université De Montréal (CRCHUM), Montreal, Quebec, Canada
| | - Ismail Mohamed
- Division of Neurology, Department of Pediatrics, IWK Health Centre, Halifax, Nova Scotia, Canada
| | - Alain Bouthillier
- Research Centre, Centre Hospitalier De L'Université De Montréal (CRCHUM), Montreal, Quebec, Canada
| | - Frédéric Lesage
- Département De Génie Électrique, École Polytechnique De Montréal, Montreal, Quebec, Canada.,Institut De Cardiologie De Montréal, Montreal, Quebec, Canada
| | - Dang K Nguyen
- Research Centre, Centre Hospitalier De L'Université De Montréal (CRCHUM), Montreal, Quebec, Canada.,Division of Neurology, Department of Medicine, CHUM - Hôpital Notre-Dame, Montreal, Quebec, Canada
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Mohamed IS, Gibbs SA, Robert M, Bouthillier A, Leroux JM, Khoa Nguyen D. The utility of magnetoencephalography in the presurgical evaluation of refractory insular epilepsy. Epilepsia 2013; 54:1950-9. [DOI: 10.1111/epi.12376] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Ismail S. Mohamed
- Division of Neurology; Department of Pediatrics; IIWK Health Center; Halifax NS Canada
| | - Steve A. Gibbs
- Division of Neurology; Notre-Dame Hospital (CHUM); University of Montreal; Montreal QC Canada
| | - Manon Robert
- Department of Psychology; Neuropsychology and Cognition Research Center; University of Montreal, Montreal; QC Canada
| | - Alain Bouthillier
- Division of Neurosurgery; Notre-Dame Hospital (CHUM); University of Montreal, Montreal; QC Canada
| | - Jean-Maxime Leroux
- Department of Radiology; Notre-Dame Hospital (CHUM); University of Montreal, Montreal; QC Canada
| | - Dang Khoa Nguyen
- Division of Neurology; Notre-Dame Hospital (CHUM); University of Montreal; Montreal QC Canada
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Somatosensory and pharyngolaryngeal auras in temporal lobe epilepsy surgeries. ISRN NEUROLOGY 2013; 2013:148519. [PMID: 23862072 PMCID: PMC3686131 DOI: 10.1155/2013/148519] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 05/08/2013] [Indexed: 12/04/2022]
Abstract
Purpose. Somatosensory (SSA) and pharyngolaryngeal auras (PLA) may suggest an extratemporal onset (e.g., insula, second somatosensory area). We sought to determine the prognostic significance of SSA and PLA in temporal lobe epilepsy (TLE) patients undergoing epilepsy surgery. Methods. Retrospective review of all patients operated for refractory TLE at our institution between January 1980 and July 2007 comparing outcome between patients with SSA/PLA to those without. Results. 158 patients underwent surgery for pharmacoresistant TLE in our institution. Eleven (7%) experienced SSA/PLA as part of their seizures. All but one had lesional (including hippocampal atrophy/sclerosis) TLE. Compared to patients without SSA or PLA, these patients were older (P = 0.049), had a higher prevalence of early ictal motor symptoms (P = 0.022) and prior CNS infection (P = 0.022), and were less likely to have a localizing SPECT study (P = 0.025). A favorable outcome was achieved in 81.8% of patients with SSA and/or PLA and 90.4% of those without SSA or PLA (P > 0.05). Conclusion. Most patients with pharmacoresistant lesional TLE appear to have a favorable outcome following temporal lobectomy, even in the presence of SSA and PLA.
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Abstract
Although previous studies have investigated the sensitivity of electroencephalography (EEG) and magnetoencephalography (MEG) to detect spikes by comparing simultaneous recordings, there are no published reports that focus on the relationship between spike dipole orientation or sensitivity of scalp EEG/MEG and the "gold standard" of intracranial recording (stereotactic EEG). We evaluated two patients with focal epilepsy; one with lateral temporal focus and the other with insular focus. Two MEG recordings were performed for both patients, each recorded simultaneously with initially scalp EEG, based on international 10-20 electrode placement with additional electrodes for anterior temporal regions, and subsequently stereotactic EEG. Localisation of MEG spike dipoles from both studies was concordant and all MEG spikes were detected by stereotactic EEG. For the patient with lateral temporal epilepsy, spike sensitivity of MEG and scalp EEG (relative to stereotactic EEG) was 55 and 0%, respectively. Of note, in this case, MEG spike dipoles were oriented tangentially to scalp surface in a tight cluster; the angle of the spike dipole to the vertical line was 3.6 degrees. For the patient with insular epilepsy, spike sensitivity of MEG and scalp EEG (relative to stereotactic EEG) was 83 and 44%, respectively; the angle of the spike dipole to the vertical line was 45.3 degrees. For the patient with lateral temporal epilepsy, tangential spikes from the lateral temporal cortex were difficult to detect based on scalp 10-20 EEG and for the patient with insular epilepsy, it was possible to evaluate operculum insular sources using MEG. We believe that these findings may be important for the interpretation of clinical EEG and MEG.
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