The Experts below are selected from a list of 33270 Experts worldwide ranked by ideXlab platform
Christophe Grova - One of the best experts on this subject based on the ideXlab platform.
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8 source localization of the seizure onset zone from Ictal eeg and meg data
Clinical Neurophysiology, 2016Co-Authors: Giovanni Pellegrino, Tanguy Hedrich, Rasheda Arman Chowdhury, Jeffrey Hall, J M Lina, Francois Dubeau, Eliane Kobayashi, Christophe GrovaAbstract:Introduction Surgical treatment of drug-resistant epilepsy relies on the identification of the seizure onset zone (SOZ) and often requires intracranial EEG (iEEG). We have developed a new approach for non-invasive electric and magnetic source imaging of the SOZ from Ictal electroencephalography (EEG) and magnetoencephalography (MEG) recordings, using the wavelet-based Maximum Entropy on the Mean (wMEM) method. Taking as reference the clinical localization of the SOZ defined on the basis of iEEG or lesion topography and considering seizures recorded during simultaneous EEG-MEG scans, we compared: (1) Ictal EEG source imaging vs Ictal MEG source imaging; (2) Ictal source imaging vs interIctal source imaging. Methods Among the patients undergoing simultaneous EEG-MEG (56 EEG channels and 275 MEG sensors), 13 had at least one seizure. A total of 46 MEG or EEG seizures were analyzed. wMEM was applied around seizure onset, centered on the frequency band showing the strongest power change. Principal component analysis applied to spatio-temporal reconstructed wMEM sources (0.4–1 s around seizure onset) identified the main spatial pattern of Ictal oscillations. Qualitative sublobar concordance and quantitative measures of distance and spatial overlaps were estimated to compare EEG and MEG, Ictal and interIctal source imaging. Results Both Ictal EEG and Ictal MEG source imaging showed a good concordance with the clinical Seizure Onset Zone, ranging between 64% for EEG to 90% for MEG. Ictal MEG performed slightly better than Ictal EEG, localizing sources closer to the clinical-SOZ ( p = 0.012) and to interIctal MEG source imaging ( p = 0.040). The concordance and distance from the clinical-SOZ was not significantly different between interIctal and Ictal source imaging. Conclusions wMEM allows non-invasive localization of the SOZ from Ictal EEG and MEG. EEG Ictal source imaging might be sufficient in the daily clinical practice, but for the most challenging cases Ictal MEG can provide more accurate results. Ictal source imaging can be a useful tool during presurgical evaluation of drug-resistant epilepsy patients and can guide iEEG implantation and brain surgery.
Giovanni Pellegrino - One of the best experts on this subject based on the ideXlab platform.
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8 source localization of the seizure onset zone from Ictal eeg and meg data
Clinical Neurophysiology, 2016Co-Authors: Giovanni Pellegrino, Tanguy Hedrich, Rasheda Arman Chowdhury, Jeffrey Hall, J M Lina, Francois Dubeau, Eliane Kobayashi, Christophe GrovaAbstract:Introduction Surgical treatment of drug-resistant epilepsy relies on the identification of the seizure onset zone (SOZ) and often requires intracranial EEG (iEEG). We have developed a new approach for non-invasive electric and magnetic source imaging of the SOZ from Ictal electroencephalography (EEG) and magnetoencephalography (MEG) recordings, using the wavelet-based Maximum Entropy on the Mean (wMEM) method. Taking as reference the clinical localization of the SOZ defined on the basis of iEEG or lesion topography and considering seizures recorded during simultaneous EEG-MEG scans, we compared: (1) Ictal EEG source imaging vs Ictal MEG source imaging; (2) Ictal source imaging vs interIctal source imaging. Methods Among the patients undergoing simultaneous EEG-MEG (56 EEG channels and 275 MEG sensors), 13 had at least one seizure. A total of 46 MEG or EEG seizures were analyzed. wMEM was applied around seizure onset, centered on the frequency band showing the strongest power change. Principal component analysis applied to spatio-temporal reconstructed wMEM sources (0.4–1 s around seizure onset) identified the main spatial pattern of Ictal oscillations. Qualitative sublobar concordance and quantitative measures of distance and spatial overlaps were estimated to compare EEG and MEG, Ictal and interIctal source imaging. Results Both Ictal EEG and Ictal MEG source imaging showed a good concordance with the clinical Seizure Onset Zone, ranging between 64% for EEG to 90% for MEG. Ictal MEG performed slightly better than Ictal EEG, localizing sources closer to the clinical-SOZ ( p = 0.012) and to interIctal MEG source imaging ( p = 0.040). The concordance and distance from the clinical-SOZ was not significantly different between interIctal and Ictal source imaging. Conclusions wMEM allows non-invasive localization of the SOZ from Ictal EEG and MEG. EEG Ictal source imaging might be sufficient in the daily clinical practice, but for the most challenging cases Ictal MEG can provide more accurate results. Ictal source imaging can be a useful tool during presurgical evaluation of drug-resistant epilepsy patients and can guide iEEG implantation and brain surgery.
Sándor Beniczky - One of the best experts on this subject based on the ideXlab platform.
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Ictal EEG source imaging
Zeitschrift für Epileptologie, 2018Co-Authors: Sándor Beniczky, Praveen Kumar SharmaAbstract:Background Ictal electroencephalogram (EEG) source imaging has both advantages and disadvantages compared with source imaging of interIctal epileptiform discharges. Ictal source imaging estimates the seizure onset zone directly. However, the rapid propagation of the Ictal activity and the low signal-to-noise ratio impose additional challenges on Ictal source imaging. Several methods have been developed to circumvent these challenges.
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Source imaging of Ictal patterns
Clinical Neurophysiology, 2016Co-Authors: Sándor BeniczkyAbstract:Most of the attempts for source imaging in epilepsy focused on localising the interIctal epileptiform discharges. Although localizing Ictal EEG patterns (seizure-onset zone) is crucial for decision-making in epilepsy surgery, source imaging of Ictal patterns has received surprisingly little attention until now. This is mainly because of technical and methodological difficulties. This lecture summarises the main challenges for source imaging of Ictal patterns and will present possible solutions, with main emphasis on averaging Ictal waveforms and on phase-mapping. Source imaging of Ictal patterns is feasible and provides valuable clinical information for the presurgical workup.
Sang Kun Lee - One of the best experts on this subject based on the ideXlab platform.
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Dancing with a seizure, a case report
BMC Neurology, 2017Co-Authors: Keun Tae Kim, Kon Chu, Sang Kun LeeAbstract:Background Dancing is a very rare seizure semiology, and has only few case reports so far. Moreover, no case regarded as dancing with both description and video was presented. Case presentation A 42-year-old woman with medical intractable epilepsy showed a typical semiology of right temporal lobe epilepsy: right hand automatism and Ictal speech. The following semiology, appeared during Ictal and post-Ictal stage, was complex, rhythmical and sequential movement. It was enough to be called dancing. Conclusions We hereby report the most plausible dancing in the Ictal and post-Ictal state, documented by simultaneous video and electroencephalography.
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Intracranial Ictal onset zone in nonlesional lateral temporal lobe epilepsy on scalp Ictal EEG
Neurology, 2003Co-Authors: Sang Kun Lee, Dong Soo Lee, Chang-ho Yun, Hyunwoo Nam, S. W. Jung, Jin Chul Paeng, Chun Kee Chung, Gheeyoung ChoeAbstract:Objective: To determine the Ictal focus and the role of seizure characteristics, fluorodeoxyglucose (FDG) PET, and subtraction Ictal SPECT in patients diagnosed as having nonlesional lateral temporal lobe epilepsy by long-term scalp video-EEG monitoring. Methods: The authors studied 33 consecutive patients with nonlesional neocortical epilepsy who had a scalp Ictal onset zone localized in the temporal lobe and good surgical outcome after focal neocortical resection. All patients were evaluated using intracranial recordings prior to resection. Semiology, FDG-PET, and Ictal–interIctal subtraction SPECT were used to verify the diagnostic role of these methods in the localization of epileptic foci. Results: The Ictal onset zones, confirmed by intracranial study, were the lateral temporal (22 patients), parietal (5), frontal (3), temporoparietal (2), and occipital (1) areas. FDG-PET analyzed by statistical parametric mapping correctly localized the epileptogenic lobe in 18 of 33 patients and subtraction Ictal SPECT correctly localized it in 13 of 25 patients. However, in patients with extratemporal Ictal onset zones, FDG-PET and Ictal SPECT in combination correctly localized the epileptogenic lobe in only 3 of 11 cases. Conclusions: An extratemporal Ictal onset zone was encountered in patients with nonlesional lateral temporal lobe seizures based on scalp video-EEG monitoring. FDG-PET and subtraction SPECT had localizing value in no more than half of patients.
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Functional neuroimaging in epilepsy: FDG PET and Ictal SPECT.
Journal of Korean medical science, 2001Co-Authors: Dong Soo Lee, Sang Kun Lee, Myung Chul LeeAbstract:Epileptogenic zones can be localized by F-18 fluorodeoxyglucose positron emission tomography (FDG PET) and Ictal single-photon emission computed tomography(SPECT). In medial temporal lobe epilepsy, the diagnostic sensitivity of FDG PET or Ictal SPECT is excellent, however, the sensitivity of MRI is so high that the incremental sensitivity by FDG PET or Ictal SPECT has yet to be proven. When MRI findings are ambiguous or normal, or discordant with those of Ictal EEG, FDG PET and Ictal SPECT are helpful for localization without the need for invasive Ictal EEG. In neocortical epilepsy, the sensitivities of FDG PET or Ictal SPECT are fair. However, because almost a half of the patients are normal on MRI, FDG PET and Ictal SPECT are helpful for localization or at least for lateralization in these non-lesional epilepsies in order to guide the subdural insertion of electrodes. Interpretation of FDG PET has been recently advanced by voxel-based analysis and automatic volume of interest analysis based on a population template. Both analytical methods confirmed the performance of previous visual interpretation results. Ictal SPECT was analyzed using subtraction methods(coregistered to MRI) and voxel-based analysis. Rapidity of injection of tracers, HMPAO versus ECD, and repeated Ictal SPECT, which remain the technical issues of Ictal SPECT, are detailed.
Paul A. Garcia - One of the best experts on this subject based on the ideXlab platform.
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speech preservation during language dominant left temporal lobe seizures report of a rare potentially misleading finding
Epilepsia, 2006Co-Authors: Kitti Kaiboriboon, Nicholas M. Barbaro, Jack M Parent, John A Walker, Paul A. GarciaAbstract:Summary: Purpose: To evaluate the prevalence and mechanism of Ictal speech in patients with language-dominant, left temporal lobe seizures. Methods: We retrospectively reviewed the video-EEG telemetry records for the presence of Ictal speech in 96 patients with surgically proven left temporal lobe epilepsy and studied the seizure-propagation patterns in three patients who required intracranial EEG recordings for seizure localization. Results: Ictal speech preservation was observed in five patients. One patient’s seizures demonstrated rapid propagation of the Ictal discharges to the contralateral temporal area where the seizure evolved, resembling a nondominant temporal lobe seizure. The other two patients had Ictal discharges that remained confined to the inferomesial temporal areas, sparing language cortex. Conclusions: Preservation of speech in complex partial seizures of language-dominant, left temporal lobe origin is rare. Based on intracranial EEG recordings, the likely mechanism underlying this potentially misleading clinical finding is the preservation of language areas due to limited seizure-propagation patterns. Key Words: Ictal speech—Seizure semiology— Temporal lobe epilepsy—Language.
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Ictal magnetoencephalography in temporal and extratemporal lobe epilepsy.
Epilepsia, 2003Co-Authors: Bassam A. Assaf, Kameel M. Karkar, Kenneth D. Laxer, Paul A. Garcia, Everett J. Austin, Nicholas M. Barbaro, Michael J. AminoffAbstract:Summary: Purpose: We evaluated visual patterns and source localization of Ictal magnetoencephalography (MEG) in patients with intractable temporal lobe epilepsy (TLE) and extratemporal epilepsy (ETE). Methods: We performed spike and seizure recording simultaneously with EEG and MEG on two patients with TLE and five patients with ETE. Scalp EEG was recorded from 21 channels (10-20 international system), whereas MEG was recorded from two 37-channel sensors. We compared Ictal EEG and MEG onset, frequency, and evolution and performed MEG dipole source localization of interIctal spikes and early Ictal discharges and co-registered dipoles to brain magnetic resonance imaging (MRI). We correlated dipole characteristics with intracranial EEG, surgical resection, and outcome. Results: Ictal MEG lateralized seizure onset in both TLE patients and demonstrated Ictal onset, frequency, and evolution in accordance with EEG. Ictal MEG source analysis revealed tangential vertical dipoles in the anterolateral angle in one patient, and anterior dipoles with anteroposterior orientation in the other. Intracranial EEG revealed regional entorhinal seizure onset in the first patient. Both patients became seizure free after temporal lobectomy. In ETE, Ictal MEG demonstrated visual patterns similar to Ictal EEG and had concordant localization with interIctal MEG in all five patients. Two patients underwent surgery. Ictal MEG localization was concordant with intracranial EEG in both cases. One patient had successful outcome after surgery. The second patient did not improve after limited resection and multiple subpial transections. Conclusions: Ictal MEG can demonstrate Ictal onset frequency and evolution and provide useful localizing information before epilepsy surgery.
