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Chaudhari DM, . P, Renjen PN, Ahmad K. A Case of Hypermotor Seizures in Posterior Insular Cortex Epilepsy. Cureus 2023; 15:e36280. [PMID: 37075168 PMCID: PMC10105905 DOI: 10.7759/cureus.36280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/17/2023] [Indexed: 03/19/2023] Open
Abstract
Insular seizure is a rare entity. Insular spikes spread to the temporal, parietal, and frontal lobes and clinically manifest with seizure semiology specific to these areas. We report the case of a 19-year-old male patient who presented with complaints of left-sided hemimotor tonic-clonic focal seizures of the limbs occurring three times per day. Neuroimaging showed cortical-subcortical right posterior insular cortex hyperintensities on fluid-attenuated inversion recovery (FLAIR) sequence and T2-weighted MRI with no significant diffusion restriction on apparent diffusion coefficient (ADC) and no post-contrast enhancement, suggesting focal cortical dysplasia of right posterior insular cortex. Electroencephalogram (EEG) showed right frontal epileptiform activity with secondary bilateral synchrony. The patient's atypical hemimotor tonic-clonic focal seizure, the conventional video EEG showing right frontal spikes synchronizing with bilateral temporal ictal spikes, and insular cortical dysplasia on MRI led us to a diagnosis of insular epilepsy.
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Solanki C, Williams J, Andrews C, Fayed I, Wu C. Insula in epilepsy - "untying the gordian knot": A systematic review. Seizure 2023; 106:148-161. [PMID: 36878050 DOI: 10.1016/j.seizure.2023.02.019] [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: 05/16/2022] [Revised: 02/23/2023] [Accepted: 02/25/2023] [Indexed: 03/02/2023] Open
Abstract
PURPOSE Despite significant advances in epileptology, there are still many uncertainties about the role of the insula in epilepsy. Until recently, most insular onset seizures were wrongly attributed to the temporal lobe. Further, there are no standardised approaches to the diagnosis and treatment of insular onset seizures. This systematic review gathers the available information about insular epilepsy and synthesizes current knowledge as a basis for future research. METHOD Adhering to the PRISMA guidelines, studies were meticulously extracted from the PubMed database. The empirical data pertaining to the semiology of insular seizures, insular networks in epilepsy, techniques of mapping the insula, and the surgical intricacies of non-lesional insular epilepsy were reviewed from published studies. The corpus of information available was then subjected to a process of concise summarization and astute synthesis. RESULTS Out of 235 studies identified for full-text review, 86 studies were included in the systematic review. The insula emerges as a brain region with a number of functional subdivisions. The semiology of insular seizures is diverse and depends on the involvement of particular subdivisions. The semiological heterogeneity of insular seizures is explained by the extensive connectivity of the insula and its subdivisions with all four lobes of the brain, deep grey matter structures, and remote brainstem areas. The mainstay of the diagnosis of seizure onset in the insula is stereoelectroencephalography (SEEG). The surgical resection of the insular epileptogenic zone (when possible) is the most effective treatment. Open surgery on the insula is challenging but magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) also holds promise. CONCLUSION The physiological and functional roles of the insula in epilepsy have remained obfuscated. The dearth of precisely defined diagnostic and therapeutic protocols acts as an impediment to scientific advancement. This review could potentially facilitate forthcoming research endeavours by establishing a foundational framework for uniform data collection protocols, thereby enhancing the feasibility of comparing findings across future studies and promoting progress in this domain.
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Affiliation(s)
- Chirag Solanki
- Consultant Neurosurgeon, Department of Neurosurgery, Sterling Hospital, Ahmedabad, Gujarat, India.
| | - Justin Williams
- Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, United States.
| | - Carrie Andrews
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, United States.
| | - Islam Fayed
- Stereotactic and Functional Neurosurgery, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, United States.
| | - Chengyuan Wu
- Associate Professor of Neurosurgery and Radiology, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, United States.
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Jayapaul P, Gopinath S, Pillai A. Outcome following surgery for insulo-opercular epilepsies. J Neurosurg 2022; 137:1226-1236. [PMID: 35276652 DOI: 10.3171/2021.12.jns212220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/20/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The purpose of this study was to evaluate the clinical outcome in patients with medically refractory epilepsy who had undergone resective or ablative surgery for suspected insulo-opercular epileptogenic foci. METHODS The prospectively maintained database of patients undergoing epilepsy surgery was reviewed, and all patients who underwent insulo-opercular surgery for medically refractory epilepsy with a minimum of 12 months of postoperative follow-up were identified, excluding those who had insulo-opercular resection in combination with temporal lobectomy. The presurgical electroclinicoradiological data, stereo-EEG (SEEG) findings, resection/ablation patterns, surgical pathology, postoperative seizure outcome, and neurological complications were analyzed. RESULTS Of 407 patients undergoing epilepsy surgery in a 5-year period at the Amrita Advanced Centre for Epilepsy, 24 patients (5.9%) who underwent exclusive insulo-opercular interventions were included in the study. Eleven (46%) underwent surgery on the right side, 12 (50%) on the left side, and the operation was bilateral in 1 (4%). The mean age at surgery was 24.5 ± 12.75 years. Onset of seizures occurred on average at 10.6 ± 9.7 years of life. Characteristic auras were identified in 66% and predominant seizure type was hypermotor (15.4%), automotor (15.4%), hypomotor (11.5%), or a mixed pattern. Seventy-five percent of the seizures recorded on scalp video-EEG occurred during sleep. The 3T MRI results were normal in 12 patients (50%). Direct single-stage surgery was undertaken in 5 patients, and SEEG followed by intervention in 19. Eighteen patients (75%) underwent exclusive resective surgery, 4 (16.7%) underwent exclusive volumetric radiofrequency ablation, and 2 (8.3%) underwent staged radiofrequency ablation and resective surgery. Immediate postoperative neurological deficits occurred in 10/24 (42%), which persisted beyond 12 postoperative months in 3 (12.5%). With a mean follow-up of 25.9 ± 14.6 months, 18 patients (75%) had Engel class I outcome, 3 (12.5%) had Engel class II, and 3 (12.5%) had Engel class III or IV. There was no statistically significant difference in outcomes between MRI-positive versus MRI-negative cases. CONCLUSIONS Surgery for medically refractory epilepsy in insulo-opercular foci is less common and remains a challenge to epilepsy surgery centers. Localization is aided significantly by a careful study of auras and semiology followed by EEG and imaging. The requirement for SEEG is generally high. Satisfactory rates of seizure freedom were achievable independent of the MRI lesional/nonlesional status. Morbidity is higher for insulo-opercular epilepsy surgery compared to other focal epilepsies; hence, the practice and development of minimally invasive strategies for this subgroup of patients undergoing epilepsy surgery is perhaps most important.
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Affiliation(s)
| | - Siby Gopinath
- 2Department of Neurology, Amrita Advanced Centre for Epilepsy, Amrita Institute of Medical Sciences & Research Centre, Kochi, India
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Fujiwara H, Kadis DS, Greiner HM, Holland KD, Arya R, Aungaroon G, Fong SL, Arthur TM, Kremer KM, Lin N, Liu W, Mangano DO FT, Skoch J, Horn PS, Tenney JR. Clinical validation of magnetoencephalography network analysis for presurgical epilepsy evaluation. Clin Neurophysiol 2022; 142:199-208. [DOI: 10.1016/j.clinph.2022.07.506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 06/29/2022] [Accepted: 07/20/2022] [Indexed: 11/27/2022]
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Prognostic value of high-frequency oscillations combined with multimodal imaging methods for epilepsy surgery. Chin Med J (Engl) 2021; 135:1087-1095. [PMID: 35773966 PMCID: PMC9276102 DOI: 10.1097/cm9.0000000000001909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Background: The combination of high-frequency oscillations (HFOs) with single-mode imaging methods has been proved useful in identifying epileptogenic zones, whereas few studies have examined HFOs combined with multimodal imaging methods. The aim of this study was to evaluate the prognostic value of ripples, an HFO subtype with a frequency of 80 to 200 Hz is combined with multimodal imaging methods in predicting epilepsy surgery outcome. Methods: HFOs were analyzed in 21 consecutive medically refractory epilepsy patients who underwent epilepsy surgery. All patients underwent positron emission tomography (PET) and deep electrode implantation for stereo-electroencephalography (SEEG); 11 patients underwent magnetoencephalography (MEG). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in predicting surgical outcome were calculated for ripples combined with PET, MEG, both PET and MEG, and PET combined with MEG. Kaplan-Meier survival analyses were conducted in each group to estimate prognostic value. Results: The study included 13 men and 8 women. Accuracy for ripples, PET, and MEG alone in predicting surgical outcome was 42.9%, 42.9%, and 81.8%, respectively. Accuracy for ripples combined with PET and MEG was the highest. Resection of regions identified by ripples, MEG dipoles, and combined PET findings was significantly associated with better surgical outcome (P < 0.05). Conclusions: Intracranial electrodes are essential to detect regions which generate ripples and to remove these areas which indicate good surgical outcome for medically intractable epilepsy. With the assistance of presurgical noninvasive imaging examinations, PET and MEG, for example, the SEEG electrodes would identify epileptogenic regions more effectively.
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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: 11] [Impact Index Per Article: 3.7] [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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Structural Connectivity Alterations in Operculo-Insular Epilepsy. Brain Sci 2021; 11:brainsci11081041. [PMID: 34439659 PMCID: PMC8392362 DOI: 10.3390/brainsci11081041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/27/2021] [Accepted: 08/02/2021] [Indexed: 11/17/2022] Open
Abstract
Operculo-insular epilepsy (OIE) is an under-recognized condition that can mimic temporal and extratemporal epilepsies. Previous studies have revealed structural connectivity changes in the epileptic network of focal epilepsy. However, most reports use the debated streamline-count to quantify ‘connectivity strength’ and rely on standard tracking algorithms. We propose a sophisticated cutting-edge method that is robust to crossing fibers, optimizes cortical coverage, and assigns an accurate microstructure-reflecting quantitative conectivity marker, namely the COMMIT (Convex Optimization Modeling for Microstructure Informed Tractography)-weight. Using our pipeline, we report the connectivity alterations in OIE. COMMIT-weighted matrices were created in all participants (nine patients with OIE, eight patients with temporal lobe epilepsy (TLE), and 22 healthy controls (HC)). In the OIE group, widespread increases in ‘connectivity strength’ were observed bilaterally. In OIE patients, ‘hyperconnections’ were observed between the insula and the pregenual cingulate gyrus (OIE group vs. HC group) and between insular subregions (OIE vs. TLE). Graph theoretic analyses revealed higher connectivity within insular subregions of OIE patients (OIE vs. TLE). We reveal, for the first time, the structural connectivity distribution in OIE. The observed pattern of connectivity in OIE likely reflects a diffuse epileptic network incorporating insular-connected regions and may represent a structural signature and diagnostic biomarker.
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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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10
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Bou Assi E, Zerouali Y, Robert M, Lesage F, Pouliot P, Nguyen DK. Large-Scale Desynchronization During Interictal Epileptic Discharges Recorded With Intracranial EEG. Front Neurol 2020; 11:529460. [PMID: 33424733 PMCID: PMC7785800 DOI: 10.3389/fneur.2020.529460] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 11/27/2020] [Indexed: 11/13/2022] Open
Abstract
It is increasingly recognized that deep understanding of epileptic seizures requires both localizing and characterizing the functional network of the region where they are initiated, i. e., the epileptic focus. Previous investigations of the epileptogenic focus' functional connectivity have yielded contrasting results, reporting both pathological increases and decreases during resting periods and seizures. In this study, we shifted paradigm to investigate the time course of connectivity in relation to interictal epileptiform discharges. We recruited 35 epileptic patients undergoing intracranial EEG (iEEG) investigation as part of their presurgical evaluation. For each patient, 50 interictal epileptic discharges (IEDs) were marked and iEEG signals were epoched around those markers. Signals were narrow-band filtered and time resolved phase-locking values were computed to track the dynamics of functional connectivity during IEDs. Results show that IEDs are associated with a transient decrease in global functional connectivity, time-locked to the peak of the discharge and specific to the high range of the gamma frequency band. Disruption of the long-range connectivity between the epileptic focus and other brain areas might be an important process for the generation of epileptic activity. Transient desynchronization could be a potential biomarker of the epileptogenic focus since 1) the functional connectivity involving the focus decreases significantly more than the connectivity outside the focus and 2) patients with good surgical outcome appear to have a significantly more disconnected focus than patients with bad outcomes.
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Affiliation(s)
- Elie Bou Assi
- University of Montreal Hospital Research Center (CRCHUM), University of Montreal, Montreal, QC, Canada.,Department of Neuroscience, University of Montreal, Montreal, QC, Canada
| | - Younes Zerouali
- University of Montreal Hospital Research Center (CRCHUM), University of Montreal, Montreal, QC, Canada.,Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, QC, Canada
| | - Manon Robert
- University of Montreal Hospital Research Center (CRCHUM), University of Montreal, Montreal, QC, Canada
| | - Frederic Lesage
- Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, QC, Canada.,Montreal Heart Institute, Montreal, QC, Canada
| | - Philippe Pouliot
- Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, QC, Canada.,Montreal Heart Institute, Montreal, QC, Canada
| | - Dang K Nguyen
- University of Montreal Hospital Research Center (CRCHUM), University of Montreal, Montreal, QC, Canada.,Department of Neuroscience, University of Montreal, Montreal, QC, Canada
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Siems M, Siegel M. Dissociated neuronal phase- and amplitude-coupling patterns in the human brain. Neuroimage 2020; 209:116538. [PMID: 31935522 PMCID: PMC7068703 DOI: 10.1016/j.neuroimage.2020.116538] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 01/09/2020] [Accepted: 01/10/2020] [Indexed: 02/07/2023] Open
Abstract
Coupling of neuronal oscillations may reflect and facilitate the communication between neuronal populations. Two primary neuronal coupling modes have been described: phase-coupling and amplitude-coupling. Theoretically, both coupling modes are independent, but so far, their neuronal relationship remains unclear. Here, we combined MEG, source-reconstruction and simulations to systematically compare cortical amplitude-coupling and phase-coupling patterns in the human brain. Importantly, we took into account a critical bias of amplitude-coupling measures due to phase-coupling. We found differences between both coupling modes across a broad frequency range and most of the cortex. Furthermore, by combining empirical measurements and simulations we ruled out that these results were caused by methodological biases, but instead reflected genuine neuronal amplitude coupling. Our results show that cortical phase- and amplitude-coupling patterns are non-redundant, which may reflect at least partly distinct neuronal mechanisms. Furthermore, our findings highlight and clarify the compound nature of amplitude coupling measures.
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Affiliation(s)
- Marcus Siems
- Centre for Integrative Neuroscience, University of Tübingen, Germany; Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; MEG Center, University of Tübingen, Germany; IMPRS for Cognitive and Systems Neuroscience, University of Tübingen, Germany.
| | - Markus Siegel
- Centre for Integrative Neuroscience, University of Tübingen, Germany; Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; MEG Center, University of Tübingen, Germany.
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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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13
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Bouthillier A, Weil AG, Martineau L, Létourneau-Guillon L, Nguyen DK. Operculoinsular cortectomy for refractory epilepsy. Part 1: Is it effective? J Neurosurg 2019; 133:950-959. [PMID: 31629321 DOI: 10.3171/2019.4.jns1912] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 04/19/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Patients with refractory epilepsy of operculoinsular origin are often denied potentially effective surgical treatment with operculoinsular cortectomy (also termed operculoinsulectomy) because of feared complications and the paucity of surgical series with a significant number of cases documenting seizure control outcome. The goal of this study was to document seizure control outcome after operculoinsular cortectomy in a group of patients investigated and treated by an epilepsy team with 20 years of experience with this specific technique. METHODS Clinical, imaging, surgical, and seizure control outcome data of all patients who underwent surgery for refractory epilepsy requiring an operculoinsular cortectomy were retrospectively reviewed. Tumors and progressive encephalitis cases were excluded. Descriptive and uni- and multivariate analyses were done to determine seizure control outcome and predictors. RESULTS Forty-three patients with 44 operculoinsular cortectomies were studied. Kaplan-Meier estimates of complete seizure freedom (first seizure recurrence excluding auras) for years 0.5, 1, 2, and 5 were 70.2%, 70.2%, 65.0%, and 65.0%, respectively. With patients with more than 1 year of follow-up, seizure control outcome Engel class I was achieved in 76.9% (mean follow-up duration 5.8 years; range 1.25-20 years). With multivariate analysis, unfavorable seizure outcome predictors were frontal lobe-like seizure semiology, shorter duration of epilepsy, and the use of intracranial electrodes for invasive monitoring. Suspected causes of recurrent seizures were sparing of the language cortex part of the focus, subtotal resection of cortical dysplasia/polymicrogyria, bilateral epilepsy, and residual epileptic cortex with normal preoperative MRI studies (insula, frontal lobe, posterior parieto-temporal, orbitofrontal). CONCLUSIONS The surgical treatment of operculoinsular refractory epilepsy is as effective as epilepsy surgeries in other brain areas. These patients should be referred to centers with appropriate experience. A frontal lobe-like seizure semiology should command more sampling with invasive monitoring. Recordings with intracranial electrodes are not always required if the noninvasive investigation is conclusive. The complete resection of the epileptic zone is crucial to achieve good seizure control outcome.
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Affiliation(s)
| | - Alexander G Weil
- 1Divisions of Neurosurgery
- 4Division of Neurosurgery, Sainte-Justine University Hospital Center, Montreal, Quebec, Canada
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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: 21] [Impact Index Per Article: 3.5] [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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Obaid S, Tucholka A, Ghaziri J, Jodoin PM, Morency F, Descoteaux M, Bouthillier A, Nguyen DK. Cortical thickness analysis in operculo-insular epilepsy. NEUROIMAGE-CLINICAL 2018; 19:727-733. [PMID: 30003025 PMCID: PMC6040575 DOI: 10.1016/j.nicl.2018.05.033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 05/23/2018] [Accepted: 05/25/2018] [Indexed: 01/06/2023]
Abstract
Background In temporal lobe epilepsy (TLE), advanced neuroimaging techniques reveal anomalies extending beyond the temporal lobe such as thinning of fronto-central cortices. Operculo-insular epilepsy (OIE) is an under-recognized and poorly characterized condition with the potential of mimicking TLE. In this work, we investigated insular and extra-insular cortical thickness (CT) changes in OIE. Methods All participants (14 patients with refractory OIE, 9 age- and sex-matched patients with refractory TLE and 26 healthy controls) underwent a T1-weighted acquisition on a 3 T MRI. Anatomical images were processed with Advanced Normalization Tools. Between-group analysis of CT was performed using a two-sided t-test (threshold of p < 0.05 after correction for multiple comparisons; cut-off threshold of 250 voxels) between (i) patients with OIE vs TLE, and (ii) patients with OIE vs healthy controls. Results Significant widespread thinning was observed in OIE patients as compared with healthy controls mainly in the ipsilateral insula, peri-rolandic region, orbito-frontal area, mesiotemporal structures and lateral temporal neocortex. Contralateral cortical shrinkage followed a similar albeit milder and less diffuse pattern.The CT of OIE patients was equal or reduced relative to the TLE group for every cortical region analyzed. Thinning was observed diffusely in OIE patients, predominantly inboth insulae and the ipsilateral occipito-temporal area. Conclusion Our results reveal structural anomalies extending beyond the operculo-insular area in OIE.
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Affiliation(s)
- Sami Obaid
- Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada; Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada; Service de Neurochirurgie, Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
| | - Alan Tucholka
- Barcelona Beta Brain Research Center, Foundation Pasqual Maragall, Barcelona, Spain
| | - Jimmy Ghaziri
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada; Département de psychologie, Université du Québec à Montréal, Montréal, Québec, Canada
| | - Pierre-Marc Jodoin
- Sherbrooke Connectivity Imaging Lab (SCIL), Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Félix Morency
- Sherbrooke Connectivity Imaging Lab (SCIL), Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Maxime Descoteaux
- Sherbrooke Connectivity Imaging Lab (SCIL), Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Alain Bouthillier
- Service de Neurochirurgie, Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
| | - Dang K Nguyen
- Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada; Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada; Service de Neurologie, Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada.
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Wang Q, Teng P, Luan G. Magnetoencephalography in Preoperative Epileptic Foci Localization: Enlightenment from Cognitive Studies. Front Comput Neurosci 2017; 11:58. [PMID: 28701945 PMCID: PMC5487414 DOI: 10.3389/fncom.2017.00058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 06/12/2017] [Indexed: 02/02/2023] Open
Abstract
Over 30% epileptic patients are refractory to medication, who are amenable to neurosurgical treatment. Non-invasive brain imaging technologies including video-electroencephalogram (EEG), magnetic resonance imaging (MRI), and magnetoencephalography (MEG) are widely used in presurgical assessment of epileptic patients. This review mainly discussed the current development of clinical MEG imaging as a diagnose approach, and its correlations with the golden standard intracranial electroencephalogram (iEEG). More importantly, this review discussed the possible applications of functional networks in preoperative epileptic foci localization in future studies.
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Affiliation(s)
- Qian Wang
- Beijing Key Laboratory of Epilepsy, Sanbo Brain Hospital, Capital Medical UniversityBeijing, China.,Department of Neurosurgery, Epilepsy Center, Sanbo Brain Hospital, Capital Medical UniversityBeijing, China
| | - Pengfei Teng
- Department of Neurosurgery, Epilepsy Center, Sanbo Brain Hospital, Capital Medical UniversityBeijing, China
| | - Guoming Luan
- Beijing Key Laboratory of Epilepsy, Sanbo Brain Hospital, Capital Medical UniversityBeijing, China.,Department of Neurosurgery, Epilepsy Center, Sanbo Brain Hospital, Capital Medical UniversityBeijing, China.,Beijing Institute for Brain Disorders, Capital Medical UniversityBeijing, China
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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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Hedrich T, Pellegrino G, Kobayashi E, Lina JM, Grova C. Comparison of the spatial resolution of source imaging techniques in high-density EEG and MEG. Neuroimage 2017; 157:531-544. [PMID: 28619655 DOI: 10.1016/j.neuroimage.2017.06.022] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 04/29/2017] [Accepted: 06/09/2017] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND The present study aims at evaluating and comparing electrical and magnetic distributed source imaging methods applied to high-density Electroencephalography (hdEEG) and Magnetoencephalography (MEG) data. We used resolution matrices to characterize spatial resolution properties of Minimum Norm Estimate (MNE), dynamic Statistical Parametric Mapping (dSPM), standardized Low-Resolution Electromagnetic Tomography (sLORETA) and coherent Maximum Entropy on the Mean (cMEM, an entropy-based technique). The resolution matrix provides information of the Point Spread Functions (PSF) and of the Crosstalk functions (CT), this latter being also called source leakage, as it reflects the influence of a source on its neighbors. METHODS The spatial resolution of the inverse operators was first evaluated theoretically and then with real data acquired using electrical median nerve stimulation on five healthy participants. We evaluated the Dipole Localization Error (DLE) and the Spatial Dispersion (SD) of each PSF and CT map. RESULTS cMEM showed the smallest spatial spread (SD) for both PSF and CT maps, whereas localization errors (DLE) were similar for all methods. Whereas cMEM SD values were lower in MEG compared to hdEEG, the other methods slightly favored hdEEG over MEG. In real data, cMEM provided similar localization error and significantly less spatial spread than other methods for both MEG and hdEEG. Whereas both MEG and hdEEG provided very accurate localizations, all the source imaging methods actually performed better in MEG compared to hdEEG according to all evaluation metrics, probably due to the higher signal-to-noise ratio of the data in MEG. CONCLUSION Our overall results show that all investigated methods provide similar localization errors, suggesting very accurate localization for both MEG and hdEEG when similar number of sensors are considered for both modalities. Intrinsic properties of source imaging methods as well as their behavior for well-controlled tasks, suggest an overall better performance of cMEM in regards to spatial resolution and spatial leakage for both hdEEG and MEG. This indicates that cMEM would be a good candidate for studying source localization of focal and extended generators as well as functional connectivity studies.
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Affiliation(s)
- T Hedrich
- Multimodal Functional Imaging Lab, Biomedical Engineering Dpt., McGill University, Montreal, Canada.
| | - G Pellegrino
- Multimodal Functional Imaging Lab, Biomedical Engineering Dpt., McGill University, Montreal, Canada; Neurology and Neurosurgery Department, Montreal Neurological Institute (MNI), McGill University, Montreal, Canada; San Camillo Hospital IRCCS, Venice, Italy
| | - E Kobayashi
- Neurology and Neurosurgery Department, Montreal Neurological Institute (MNI), McGill University, Montreal, Canada
| | - J M Lina
- Département de Génie Électrique, École de Technologie Supérieure, Canada; Centre de recherches mathémathiques, Université de Montréal, Montreal, Canada; Center for Advanced Research on Sleep Medecine (CEAMS), hôpital du Sacré-Coeur, Montreal, Canada
| | - C Grova
- Multimodal Functional Imaging Lab, Biomedical Engineering Dpt., McGill University, Montreal, Canada; Neurology and Neurosurgery Department, Montreal Neurological Institute (MNI), McGill University, Montreal, Canada; Physics Dpt., PERFORM Centre, Concordia University, Canada; Centre de recherches mathémathiques, Université de Montréal, Montreal, Canada
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