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Epilepsy surgery, MEG

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https://www.readbyqxmd.com/read/27912111/can-ictal-meg-obviate-the-need-for-phase-ii-monitoring-in-people-with-drug-refractory-epilepsy-a-prospective-observational-study
#1
Bhargavi Ramanujam, Kamal Bharti, Vibhin Viswanathan, Ajay Garg, Madhavi Tripathi, Chandrashekhar Bal, P Sarat Chandra, Manjari Tripathi
PURPOSE: To determine if ictal-magnetoencephalography (ictal-MEG) source localization (SL) added information towards delineating the ictal-onset zone (IOZ), whether and how it helped final decision-making in epilepsy-surgery. METHODS: Definite focal clusters on ictal-MEG were available for 32 DRE-patients, data was analyzed (single equivalent current dipole (ECD) model), SL done. Clinical history, long-term video-EEG (VEEG) monitoring, epilepsy-protocol MRI, FDG-PET, ictal-SPECT and interictal-MEG were discussed at the multispeciality Epilepsy Surgery Case-conference (ESC)...
October 31, 2016: Seizure: the Journal of the British Epilepsy Association
https://www.readbyqxmd.com/read/27889333/magnetoencephalography-meg-past-current-and-future-perspectives-for-improved-differentiation-and-treatment-of-epilepsies
#2
Hermann Stefan, Eugen Trinka
In addition to visual analysis digital computerized recording of electrical and magnetic fields by using EEG and MEG opened a new window for research concerning improved understanding of pathophysiology, diagnosis and treatment of epilepsies. In the last 25 years MEG was used more and more in clinical studies concerning localization of focal epileptic activity, functional cortex and network analysis. Simultaneous MEG/EEG recording and analysis offer the use of complimentary information increasing the sensitivity for tracing primary epileptic activity...
November 15, 2016: Seizure: the Journal of the British Epilepsy Association
https://www.readbyqxmd.com/read/27888520/identifying-the-epileptogenic-zone-in-interictal-resting-state-meg-source-space-networks
#3
Ida A Nissen, Cornelis J Stam, Jaap C Reijneveld, Ilse E C W van Straaten, Eef J Hendriks, Johannes C Baayen, Philip C De Witt Hamer, Sander Idema, Arjan Hillebrand
OBJECTIVE: In one third of patients, seizures remain after epilepsy surgery, meaning that improved preoperative evaluation methods are needed to identify the epileptogenic zone. A potential framework for such a method is network theory, as it can be applied to noninvasive recordings, even in the absence of epileptiform activity. Our aim was to identify the epileptogenic zone on the basis of hub status of local brain areas in interictal magnetoencephalography (MEG) networks. METHODS: Preoperative eyes-closed resting-state MEG recordings were retrospectively analyzed in 22 patients with refractory epilepsy, of whom 14 were seizure-free 1 year after surgery...
November 26, 2016: Epilepsia
https://www.readbyqxmd.com/read/27693985/accuracy-of-meg-in-localizing-irritative-zone-and-seizure-onset-zone-quantitative-comparison-between-meg-and-intracranial-eeg
#4
Daeyoung Kim, Eun Yeon Joo, Dae-Won Seo, Min-Young Kim, Yong-Ho Lee, Hyuk Chan Kwon, Jae-Moon Kim, Seung Bong Hong
BACKGROUND: We conducted the study to examine accuracy of the magnetoencephalography (MEG) spike source localization in presurgical evaluation of patients with medically refractory focal epilepsy. METHODS: Ten consecutive patients with refractory focal epilepsy who were candidates for two-stage surgery with long-term intracranial electroencephalography (ICEEG) monitoring were enrolled. Interictal MEG recordings with simultaneous scalp EEG were obtained within 7days before the ICEEG electrode implantation...
August 16, 2016: Epilepsy Research
https://www.readbyqxmd.com/read/27445705/from-structure-to-circuits-the-contribution-of-meg-connectivity-studies-to-functional-neurosurgery
#5
REVIEW
Elizabeth W Pang, O C Snead Iii
New advances in structural neuroimaging have revealed the intricate and extensive connections within the brain, data which have informed a number of ambitious projects such as the mapping of the human connectome. Elucidation of the structural connections of the brain, at both the macro and micro levels, promises new perspectives on brain structure and function that could translate into improved outcomes in functional neurosurgery. The understanding of neuronal structural connectivity afforded by these data now offers a vista on the brain, in both healthy and diseased states, that could not be seen with traditional neuroimaging...
2016: Frontiers in Neuroanatomy
https://www.readbyqxmd.com/read/27423016/magnetoencephalography-guided-surgery-in-frontal-lobe-epilepsy-using-neuronavigation-and-intraoperative-mr-imaging
#6
Björn Sommer, Karl Roessler, Stefan Rampp, Hajo M Hamer, Ingmar Blumcke, Hermann Stefan, Michael Buchfelder
BACKGROUND: Especially in hidden lesions causing drug-resistant frontal lobe epilepsy (FLE), the localization of the epileptic zone EZ can be a challenge. Magnetoencephalography (MEG) can raise the chances for localization of the (EZ) in combination with electroencephalography (EEG). We investigated the impact of MEG-guided epilepsy surgery with the aid of neuronavigation and intraoperative MR imaging (iopMRI) on seizure outcome of FLE patients. METHODS: Twenty-eight patients (15 females, 13 males; mean age 31...
October 2016: Epilepsy Research
https://www.readbyqxmd.com/read/27399486/207%C3%A2-aberrant-preoperative-hippocampal-interconnectivity-predicts-verbal-memory-improvement-following-anterior-temporal-lobectomy
#7
Philip Lee, Ahmad Alhourani, Robert Mark Richardson
INTRODUCTION: Changes in connectivity have been found surrounding epileptic foci during resting state magnetoencephalography (MEG). One manifestation of these changes is disorganization manifested by increased interconnectivity within a region. This abnormal interconnectivity indicates a decrease in efficiency, because efficient function within a system requires communication across brain regions. Surgical resection of seizure foci may attenuate these aberrant patterns of connectivity...
August 2016: Neurosurgery
https://www.readbyqxmd.com/read/27399485/206%C3%A2-spikes-slowing-and-functional-connectivity-multimodal-magnetoencephalography-in-epilepsy-surgery
#8
Dario J Englot, John David Rolston, Doris D Wang, Heidi E Kirsch, Srikantan S Nagarajan, Edward F Chang
INTRODUCTION: Potential uses of magnetoencephalography (MEG) to help noninvasively identify the epileptogenic zone (EZ) in epilepsy surgery and predict seizure outcome include: (1) epileptic spike localization, (2) slow-wave lateralization, and (3) measurements of resting-state functional connectivity. This is the first study to evaluate multimodal MEG techniques to aid the presurgical evaluation of patients with intractable focal epilepsy. METHODS: We studied 132 focal epilepsy patients who received MEG followed by resection at our institution (follow-up mean = 3...
August 2016: Neurosurgery
https://www.readbyqxmd.com/read/27291877/brain-areas-with-epileptic-high-frequency-oscillations-are-functionally-isolated-in-meg-virtual-electrode-networks
#9
Ida A Nissen, Nicole E C van Klink, Maeike Zijlmans, Cornelis J Stam, Arjan Hillebrand
OBJECTIVE: Previous studies have associated network hubs and epileptiform activity, such as spikes and high frequency oscillations (HFOs), with the epileptogenic zone. The epileptogenic zone is approximated by the area that generates interictal epileptiform activity: the irritative zone. Our aim was to determine the relation between network hubs and the irritative zone. METHODS: Interictal resting-state MEG recordings of 12 patients with refractory epilepsy were analysed...
July 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/27254541/remote-meg-dipoles-in-focal-cortical-dysplasia-at-bottom-of-sulcus
#10
Midori Nakajima, Elysa Widjaja, Shiro Baba, Yosuke Sato, Ryuhei Yoshida, Maya Tabei, Ayaka Okazaki, Satoru Sakuma, Stephanie A Holowka, Ayako Ochi, O Carter Snead, James T Rutka, James M Drake, Hideaki Shiraishi, Sam Doesburg, Hiroshi Otsubo
OBJECTIVE: To investigate whether the magnetoencephalography (MEG) single moving dipole (SMD) method could delineate the epileptic zone of focal cortical dysplasia (FCD) at the bottom of sulcus (FCDB). METHODS: We retrospectively analyzed 17 children (11 male; mean age 8.8 years, range 3-17 years) with FCD type II who underwent epilepsy surgery. We compared spatial congruence between the following: (1) MEG cluster and FCDB and (2) MEG cluster and FCD at the brain surface (FCDS)...
July 2016: Epilepsia
https://www.readbyqxmd.com/read/27232766/preoperative-evaluation-using-magnetoencephalography-experience-in-382-epilepsy-patients
#11
I A Nissen, C J Stam, J Citroen, J C Reijneveld, A Hillebrand
OBJECTIVE: Identifying epilepsy patients for whom clinical MEG is likely to be beneficial avoids or optimizes burdensome ancillary investigations. We determined whether it could be predicted upfront if MEG would be able to generate a hypothesis about the location of the epileptogenic zone (EZ), and in which patients MEG fails to do so. METHODS: MEG recordings of 382 epilepsy patients with inconclusive findings regarding EZ localization prior to MEG were acquired for preoperative evaluation...
August 2016: Epilepsy Research
https://www.readbyqxmd.com/read/27220112/magnetoencephalographic-signatures-of-insular-epileptic-spikes-based-on-functional-connectivity
#12
Younes Zerouali, Philippe Pouliot, Manon Robert, Ismail Mohamed, Alain Bouthillier, Frédéric Lesage, Dang K Nguyen
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...
September 2016: Human Brain Mapping
https://www.readbyqxmd.com/read/27012361/current-use-of-imaging-and-electromagnetic-source-localization-procedures-in-epilepsy-surgery-centers-across-europe
#13
Brian E Mouthaan, Matea Rados, Péter Barsi, Paul Boon, David W Carmichael, Evelien Carrette, Dana Craiu, J Helen Cross, Beate Diehl, Petia Dimova, Daniel Fabo, Stefano Francione, Vladislav Gaskin, Antonio Gil-Nagel, Elena Grigoreva, Alla Guekht, Edouard Hirsch, Hrvoje Hecimovic, Christoph Helmstaedter, Julien Jung, Reetta Kalviainen, Anna Kelemen, Vasilios Kimiskidis, Teia Kobulashvili, Pavel Krsek, Giorgi Kuchukhidze, Pål G Larsson, Markus Leitinger, Morten I Lossius, Roman Luzin, Kristina Malmgren, Ruta Mameniskiene, Petr Marusic, Baris Metin, Cigdem Özkara, Hrvoje Pecina, Carlos M Quesada, Fergus Rugg-Gunn, Bertil Rydenhag, Philippe Ryvlin, Julia Scholly, Margitta Seeck, Anke M Staack, Bernhard J Steinhoff, Valentin Stepanov, Oana Tarta-Arsene, Eugen Trinka, Mustafa Uzan, Viola L Vogt, Sjoerd B Vos, Serge Vulliémoz, Geertjan Huiskamp, Frans S S Leijten, Pieter Van Eijsden, Kees P J Braun
OBJECTIVE: In 2014 the European Union-funded E-PILEPSY project was launched to improve awareness of, and accessibility to, epilepsy surgery across Europe. We aimed to investigate the current use of neuroimaging, electromagnetic source localization, and imaging postprocessing procedures in participating centers. METHODS: A survey on the clinical use of imaging, electromagnetic source localization, and postprocessing methods in epilepsy surgery candidates was distributed among the 25 centers of the consortium...
May 2016: Epilepsia
https://www.readbyqxmd.com/read/26934426/influence-of-metallic-artifact-filtering-on-meg-signals-for-source-localization-during-interictal-epileptiform-activity
#14
Carolina Migliorelli, Joan F Alonso, Sergio Romero, Miguel A Mañanas, Rafał Nowak, Antonio Russi
OBJECTIVE: Medical intractable epilepsy is a common condition that affects 40% of epileptic patients that generally have to undergo resective surgery. Magnetoencephalography (MEG) has been increasingly used to identify the epileptogenic foci through equivalent current dipole (ECD) modeling, one of the most accepted methods to obtain an accurate localization of interictal epileptiform discharges (IEDs). Modeling requires that MEG signals are adequately preprocessed to reduce interferences, a task that has been greatly improved by the use of blind source separation (BSS) methods...
April 2016: Journal of Neural Engineering
https://www.readbyqxmd.com/read/26707266/statistical-parametric-mapping-for-analyzing-interictal-magnetoencephalography-in-patients-with-left-frontal-lobe-epilepsy
#15
Haitao Zhu, Jinlong Zhu, Forrest Sheng Bao, Hongyi Liu, Xuchuang Zhu, Ting Wu, Lu Yang, Yuanjie Zou, Rui Zhang, Gang Zheng
PURPOSE: Frontal lobe epilepsy is a common epileptic disorder and is characterized by recurring seizures that arise in the frontal lobes. The purpose of this study is to identify the epileptogenic regions and other abnormal regions in patients with left frontal lobe epilepsy (LFLE) based on the magnetoencephalogram (MEG), and to understand the effects of clinical variables on brain activities in patients with LFLE. METHOD: Fifteen patients with LFLE (23.20 ± 8...
January 2016: Seizure: the Journal of the British Epilepsy Association
https://www.readbyqxmd.com/read/26693401/magnetoencephalographic-study-of-hand-and-foot-sensorimotor-organization-in-325-consecutive-patients-evaluated-for-tumor-or-epilepsy-surgery
#16
Ronald B Willemse, Arjan Hillebrand, Hanneke E Ronner, W Peter Vandertop, Cornelis J Stam
OBJECTIVES: The presence of intracranial lesions or epilepsy may lead to functional reorganization and hemispheric lateralization. We applied a clinical magnetoencephalography (MEG) protocol for the localization of the contralateral and ipsilateral S1 and M1 of the foot and hand in patients with non-lesional epilepsy, stroke, developmental brain injury, traumatic brain injury and brain tumors. We investigated whether differences in activation patterns could be related to underlying pathology...
2016: NeuroImage: Clinical
https://www.readbyqxmd.com/read/26656177/verbal-memory-and-verbal-fluency-tasks-used-for-language-localization-and-lateralization-during-magnetoencephalography
#17
Mona Pirmoradi, Boutheina Jemel, Anne Gallagher, Julie Tremblay, Fabien D'Hondt, Dang Khoa Nguyen, Renée Béland, Maryse Lassonde
OBJECTIVE: The aim of this study was to develop a presurgical magnetoencephalography (MEG) protocol to localize and lateralize expressive and receptive language function as well as verbal memory in patients with epilepsy. Two simple language tasks and a different analytical procedure were developed. METHODS: Ten healthy participants and 13 epileptic patients completed two language tasks during MEG recording: a verbal memory task and a verbal fluency task. As a first step, principal component analyses (PCA) were performed on source data from the group of healthy participants to identify spatiotemporal factors that were relevant to these paradigms...
January 2016: Epilepsy Research
https://www.readbyqxmd.com/read/26642968/non-invasive-brain-mapping-in-epilepsy-applications-from-magnetoencephalography
#18
REVIEW
Khalid Hamandi, Bethany C Routley, Loes Koelewijn, Krish D Singh
BACKGROUND: Non-invasive in vivo neurophysiological recordings with EEG/MEG are key to the diagnosis, classification, and further understanding of epilepsy. Historically the emphasis of these recordings has been the localisation of the putative sources of epileptic discharges. More recent developments see new techniques studying oscillatory dynamics, connectivity and network properties. NEW METHOD: New analysis strategies for whole head MEG include the development of spatial filters or beamformers for source localisation, time-frequency analysis for cortical dynamics and graph theory applications for connectivity...
February 15, 2016: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/26519893/reliability-for-non-invasive-somatosensory-cortex-localization-implications-for-pre-surgical-mapping
#19
Jack Solomon, Shaun Boe, Timothy Bardouille
OBJECTIVES: In patients with epilepsy or space occupying tumors in cortical regions, surgical resection is often considered as the primary treatment. Pre-surgical neuroimaging can provide a detailed map of pathological and functional cortex, leading to safer surgery. Mapping can be achieved non-invasively using magnetoencephalography (MEG), and is concordant with invasive findings. However, the reliability of MEG mapping between sessions is not well established. The inter-session reliability is an important property in pre-surgical mapping to establish resection margins, but repeated scans are impracticable...
December 2015: Clinical Neurology and Neurosurgery
https://www.readbyqxmd.com/read/26181952/106%C3%A2-functional-network-analysis-in-surgical-epilepsy-patients-using-magnetoencephalography
#20
Dario J Englot, Robert C Knowlton, Edward F Chang, Heidi E Kirsch, Srikantan S Nagarajan
INTRODUCTION: Intractable focal epilepsy is a devastating disorder with profound effects on cognition and quality of life. Epilepsy surgery can lead to seizure freedom in patients with focal epilepsy; however, sometimes it fails owing to an incomplete delineation of the epileptogenic zone (EZ). Brain networks in epilepsy can be studied with resting-state functional connectivity (RSFC) analysis, yet previous investigations using functional MRI or electrocorticography have produced inconsistent results...
August 2015: Neurosurgery
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