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Tong X, Wang J, Qin L, Zhou J, Guan Y, Zhai F, Teng P, Wang M, Li T, Wang X, Luan G. Analysis of power spectrum and phase lag index changes following deep brain stimulation of the anterior nucleus of the thalamus in patients with drug-resistant epilepsy: A retrospective study. Seizure 2022; 96:6-12. [PMID: 35042005 DOI: 10.1016/j.seizure.2022.01.004] [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: 08/03/2021] [Revised: 12/18/2021] [Accepted: 01/07/2022] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVES The mechanisms underlying the anterior nucleus of the thalamus (ANT) deep brain stimulation (DBS) for the treatment of drug-resistant epilepsy (DRE) have not been fully explored. The present study aimed to measure the changes in whole-brain activity generated by ANT DBS using interictal electroencephalography (EEG). MATERIALS AND METHODS Interictal EEG signals were retrospectively collected in 20 DRE patients who underwent ANT DBS surgery. Patients were classified as responders or non-responders depending on their response to ANT DBS treatment. The power spectrum (PS) and Phase Lag Index (PLI) were determined and data analyzed using a paired sample t-test to evaluate activity differences between pre-and-post-treatment on different frequency categories. Student's t-test, Mann-Whitney test (non-parametric test) and Fisher exact test were used to compare groups in terms of clinical variables and EEG metrics. P values < 0.05 were considered statistically significant, and FDR-corrected values were used for multiple testing. RESULTS PS analysis revealed that whole-brain spectral power had a significant decrease in the beta (p = 0.005) and gamma (p = 0.037) bands following ANT DBS treatment in responders. The analysis of scalp topographic images of all patients showed that ANT DBS decreases PS in the beta band at the F3, F7 and Cz electrode sites. The findings indicated a decrease in PS in the gamma band at the Fp2, F3, Cz, T3, T5 and Oz electrode sites. After ANT DBS treatment, PLI analysis showed a significant decrease in PLI between Fp1 and T3 in the gamma band in responders. CONCLUSION The findings showed that ANT DBS induces a decrease in power in the left frontal lobe, left temporal lobe and midline areas in the beta and gamma bands. Lower whole-brain power in the beta and gamma bands can be used as biomarkers for a favorable therapeutic response to ANT DBS, and decreased synchronization between the left frontal pole and temporal lobe in the gamma band can also be used as a biomarker for effective clinical stimulation to guide postoperative programming.
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Affiliation(s)
- Xuezhi Tong
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China
| | - Jing Wang
- Department of Neurology, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China
| | - Lang Qin
- McGovern Institute for Brain Research, Peking University, Beijing 100093, China; Center for MRI Research, Peking University, Beijing 100093, China
| | - Jian Zhou
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China
| | - Yuguang Guan
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China
| | - Feng Zhai
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China
| | - Pengfei Teng
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China
| | - Mengyang Wang
- Department of Neurology, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China
| | - Tianfu Li
- Department of Neurology, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China; Beijing Key Laboratory of Epilepsy, Beijing 100093, China
| | - Xiongfei Wang
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China; Beijing Key Laboratory of Epilepsy, Beijing 100093, China; Epilepsy Institute, Beijing Institute for Brain Disorders, Beijing 100093, China
| | - Guoming Luan
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China; Beijing Key Laboratory of Epilepsy, Beijing 100093, China; Epilepsy Institute, Beijing Institute for Brain Disorders, Beijing 100093, China
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Yeom HG, Jeong H. F-Value Time-Frequency Analysis: Between-Within Variance Analysis. Front Neurosci 2021; 15:729449. [PMID: 34955709 PMCID: PMC8697975 DOI: 10.3389/fnins.2021.729449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 11/22/2021] [Indexed: 11/23/2022] Open
Abstract
Studies on brain mechanisms enable us to treat various brain diseases and develop diverse technologies for daily life. Therefore, an analysis method of neural signals is critical, as it provides the basis for many brain studies. In many cases, researchers want to understand how neural signals change according to different conditions. However, it is challenging to find distinguishing characteristics, and doing so requires complex statistical analysis. In this study, we propose a novel analysis method, FTF (F-value time-frequency) analysis, that applies the F-value of ANOVA to time-frequency analysis. The proposed method shows the statistical differences among conditions in time and frequency. To evaluate the proposed method, electroencephalography (EEG) signals were analyzed using the proposed FTF method. The EEG signals were measured during imagined movement of the left hand, right hand, foot, and tongue. The analysis revealed the important characteristics which were different among different conditions and similar within the same condition. The FTF analysis method will be useful in various fields, as it allows researchers to analyze how frequency characteristics vary according to different conditions.
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Affiliation(s)
- Hong Gi Yeom
- Department of Electronics Engineering, Chosun University, Gwangju, South Korea
| | - Hyundoo Jeong
- Department of Mechatronics Engineering, Incheon National University, Incheon, South Korea
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Champagne PO, Sanon NT, Carmant L, Nguyen DK, Deschênes S, Pouliot P, Bouthillier A, Sawan M. Superparamagnetic iron oxide nanoparticles-based detection of neuronal activity. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2021; 40:102478. [PMID: 34743018 DOI: 10.1016/j.nano.2021.102478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 09/25/2021] [Accepted: 10/06/2021] [Indexed: 10/19/2022]
Abstract
Precise detection of brain regions harboring heightened electrical activity plays a central role in the understanding and treatment of diseases such as epilepsy. Superparamagnetic iron oxide nanoparticles (SPIONs) react to magnetic fields by aggregating and represent interesting candidates as new sensors for neuronal magnetic activity. We hypothesized that SPIONs in aqueous solution close to active brain tissue would aggregate proportionally to neuronal activity. We tested this hypothesis using an in vitro model of rat brain slice with different levels of activity. Aggregation was assessed with dynamic light scattering (DLS) and magnetic resonance imaging (MRI). We found that increasing brain slice activity was associated with higher levels of aggregation as measured by DLS and MRI, suggesting that the magnetic fields from neuronal tissue could induce aggregation in nearby SPIONs in solution. MRI signal change induced by SPIONs aggregation could serve as a powerful new tool for detection of brain electrical activity.
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Affiliation(s)
- Pierre-Olivier Champagne
- Polystim Neurotech Laboratory, Electrical Engineering Department, Polytechnique Montreal, Montreal, Canada; CHU Sainte-Justine Research Center, Montreal, Canada; Neurosurgery department, University of Montreal Medical Center, Montreal, Canada.
| | | | - Lionel Carmant
- CHU Sainte-Justine Research Center, Montreal, Canada; Neurology department, CHU Sainte-Justine, Montréal, Canada
| | - Dang Khoa Nguyen
- Neurology department, University of Montreal Medical Center, Montreal, Canada
| | | | - Philippe Pouliot
- Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, Canada; Research Center, Montreal Heart Institute, Montreal, Canada
| | - Alain Bouthillier
- Neurosurgery department, University of Montreal Medical Center, Montreal, Canada
| | - Mohamad Sawan
- Polystim Neurotech Laboratory, Electrical Engineering Department, Polytechnique Montreal, Montreal, Canada; Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, Canada
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Stefan H, Rampp S. Interictal and Ictal MEG in presurgical evaluation for epilepsy surgery. ACTA EPILEPTOLOGICA 2020. [DOI: 10.1186/s42494-020-00020-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
AbstractAlthough presurgical evaluation of patients with pharamacoresistent focal epilepsies provides essential information for successful epilepsy surgery, there is still a need for further improvement. Developments of noninvasive electrophysiological recording and analysis techniques offer additional information based on interictal and ictal epileptic activities. In this review, we provide an overview on the application of ictal magnetoencephalography (MEG). The results of a literature research for published interictal/ictal MEG findings and experiences with own cases are demonstrated and discussed. Ictal MEG may provide added value in comparison to interictal recordings. The results may be more focal and closer to the invasively determined seizure onset zone. In some patients without clear interictal findings, ictal MEG could provide correct localization. Novel recording and analysis techniques facilitate ictal recordings. However, extended recording durations, movement and artifacts still represent practical limitations. Ictal MEG may provide added value regarding the localization of the seizure onset zone but depends on the selection of patients and the application of optimal analysis techniques.
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Brændholt M, Jensen M. Evidence From Meta-Analysis Supports Ictal Magnetoencephalographic Source Imaging as an Accurate Method in Presurgery Evaluation of Patients With Drug-Resistant Epilepsy. Clin EEG Neurosci 2020; 51:403-411. [PMID: 32437218 DOI: 10.1177/1550059420921534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND. Successful epilepsy surgery relies on localization and removal of the brain area responsible for initializing the seizures called the epileptogenic zone (EZ). Intracranial EEG (icEEG) is gold standard of this localization but has several limitations like invasiveness and limited covered area. A noninvasive method with accurate localization precision is therefore desirable. The aim of this article is to investigate the following hypotheses: (1) Ictal onset zone as localized by magnetic source imaging (iMSI) can reliably localize the EZ in focal epilepsy and (2) this localization is as good as that of icEEG. METHODS. Six original studies and a total of 59 unique patients were included in a meta-analysis. RESULTS. Sensitivity and specificity of iMSI based on surgery outcome were 77% (95% CI 60%-90%) and 75% (95% CI 53%-90%), respectively. Specificity of iMSI was statistically higher than that of icEEG. There was no significant difference between sensitivity of iMSI and icEEG. CONCLUSION. The meta-analysis supports that iMSI is an accurate method, achieving similar sensitivity and higher specificity than icEEG. However, at present the use of the method is limited by short recording times. A limitation that might be overcome in the future using technical advances.
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Affiliation(s)
- Malthe Brændholt
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.,Embodied Computation Group, Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Mads Jensen
- NedComm Lab-Laboratory of NeuroDynamics of Human Communication and Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
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The Value of Source Localization for Clinical Magnetoencephalography: Beyond the Equivalent Current Dipole. J Clin Neurophysiol 2020; 37:537-544. [DOI: 10.1097/wnp.0000000000000487] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Baumgartner C, Koren JP, Britto-Arias M, Zoche L, Pirker S. Presurgical epilepsy evaluation and epilepsy surgery. F1000Res 2019; 8. [PMID: 31700611 PMCID: PMC6820825 DOI: 10.12688/f1000research.17714.1] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/14/2019] [Indexed: 12/21/2022] Open
Abstract
With a prevalence of 0.8 to 1.2%, epilepsy represents one of the most frequent chronic neurological disorders; 30 to 40% of patients suffer from drug-resistant epilepsy (that is, seizures cannot be controlled adequately with antiepileptic drugs). Epilepsy surgery represents a valuable treatment option for 10 to 50% of these patients. Epilepsy surgery aims to control seizures by resection of the epileptogenic tissue while avoiding neuropsychological and other neurological deficits by sparing essential brain areas. The most common histopathological findings in epilepsy surgery specimens are hippocampal sclerosis in adults and focal cortical dysplasia in children. Whereas presurgical evaluations and surgeries in patients with mesial temporal sclerosis and benign tumors recently decreased in most centers, non-lesional patients, patients requiring intracranial recordings, and neocortical resections increased. Recent developments in neurophysiological techniques (high-density electroencephalography [EEG], magnetoencephalography, electrical and magnetic source imaging, EEG-functional magnetic resonance imaging [EEG-fMRI], and recording of pathological high-frequency oscillations), structural magnetic resonance imaging (MRI) (ultra-high-field imaging at 7 Tesla, novel imaging acquisition protocols, and advanced image analysis [post-processing] techniques), functional imaging (positron emission tomography and single-photon emission computed tomography co-registered to MRI), and fMRI significantly improved non-invasive presurgical evaluation and have opened the option of epilepsy surgery to patients previously not considered surgical candidates. Technical improvements of resective surgery techniques facilitate successful and safe operations in highly delicate brain areas like the perisylvian area in operculoinsular epilepsy. Novel less-invasive surgical techniques include stereotactic radiosurgery, MR-guided laser interstitial thermal therapy, and stereotactic intracerebral EEG-guided radiofrequency thermocoagulation.
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Affiliation(s)
- Christoph Baumgartner
- Department of Neurology, General Hospital Hietzing with Neurological Center Rosenhügel, Vienna, Austria.,Karl Landsteiner Institute for Clinical Epilepsy Research and Cognitive Neurology, Vienna, Austria.,Medical Faculty, Sigmund Freud University, Vienna, Austria
| | - Johannes P Koren
- Department of Neurology, General Hospital Hietzing with Neurological Center Rosenhügel, Vienna, Austria.,Karl Landsteiner Institute for Clinical Epilepsy Research and Cognitive Neurology, Vienna, Austria
| | - Martha Britto-Arias
- Department of Neurology, General Hospital Hietzing with Neurological Center Rosenhügel, Vienna, Austria.,Karl Landsteiner Institute for Clinical Epilepsy Research and Cognitive Neurology, Vienna, Austria
| | - Lea Zoche
- Department of Neurology, General Hospital Hietzing with Neurological Center Rosenhügel, Vienna, Austria.,Karl Landsteiner Institute for Clinical Epilepsy Research and Cognitive Neurology, Vienna, Austria
| | - Susanne Pirker
- Department of Neurology, General Hospital Hietzing with Neurological Center Rosenhügel, Vienna, Austria.,Karl Landsteiner Institute for Clinical Epilepsy Research and Cognitive Neurology, Vienna, Austria
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Alkawadri R, Burgess RC, Kakisaka Y, Mosher JC, Alexopoulos AV. Assessment of the Utility of Ictal Magnetoencephalography in the Localization of the Epileptic Seizure Onset Zone. JAMA Neurol 2019; 75:1264-1272. [PMID: 29889930 DOI: 10.1001/jamaneurol.2018.1430] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Importance Literature on ictal magnetoencephalography (MEG) in clinical practice and the relationship to other modalities is limited because of the brevity of routine studies. Objective To investigate the utility and reliability of ictal MEG in the localization of the epileptogenic zone. Design, Setting, and Participants A retrospective medical record review and prospective analysis of a novel ictal rhythm analysis method was conducted at a tertiary epilepsy center with a wide base of referrals for epilepsy surgery evaluation and included consecutive cases of patients who experienced epileptic seizures during routine MEG studies from March 2008 to February 2012. A total of 377 studies screened. Data were analyzed from November 2011 to October 2015. Main Outcomes and Measures Presurgical workup and interictal and ictal MEG data were reviewed. The localizing value of using extended-source localization of a narrow band identified visually at onset was analyzed. Results Of the 44 included patients, the mean (SD) age at the time of recording was 19.3 (14.9) years, and 25 (57%) were male. The mean duration of recording was 51.2 minutes. Seizures were provoked by known triggers in 3 patients and were spontaneous otherwise. Twenty-five patients (57%) had 1 seizure, 6 (14%) had 2, and 13 (30%) had 3 or more. Magnetoencephalography single equivalent current dipole analysis was possible in 29 patients (66%), of whom 8 (28%) had no clear interictal discharges. Sublobar concordance between ictal and interictal dipoles was seen in 18 of 21 patients (86%). Three patients (7%) showed clear ictal MEG patterns without electroencephalography changes. Ictal MEG dipoles correlated with the lobe of onset in 7 of 8 patients (88%) who underwent intracranial electroencephalography evaluations. Reasons for failure to identify ictal dipoles included diffuse or poor dipolar ictal patterns, no MEG changes, and movement artifact. Resection of areas containing a minimum-norm estimate of a narrow band at onset, not single equivalent current dipole, was associated with sustained seizure freedom. Conclusions and Significance Ictal MEG data can provide reliable localization, including in cases that are difficult to localize by other modalities. These findings support the use of extended-source localization for seizures recorded during MEG.
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Affiliation(s)
- Rafeed Alkawadri
- The Epilepsy Center at Cleveland Clinic Foundation, Cleveland, Ohio.,Yale Comprehensive Epilepsy Center, School of Medicine, Yale University, New Haven, Connecticut.,Yale Human Brain Mapping Program, School of Medicine, Yale University, New Haven, Connecticut
| | | | - Yosuke Kakisaka
- The Epilepsy Center at Cleveland Clinic Foundation, Cleveland, Ohio.,The Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - John C Mosher
- The Epilepsy Center at Cleveland Clinic Foundation, Cleveland, Ohio
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Electroencephalography, magnetoencephalography and source localization: their value in epilepsy. Curr Opin Neurol 2019; 31:176-183. [PMID: 29432218 DOI: 10.1097/wco.0000000000000545] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
PURPOSE OF REVIEW Source localization of cerebral activity using electroencephalography (EEG) or magnetoencephalography (MEG) can reveal noninvasively the generators of the abnormal signals recorded in epilepsy, such as interictal epileptic discharges (IEDs) and seizures. Here, we review recent progress showcasing the usefulness of these techniques in treating patients with drug-resistant epilepsy. RECENT FINDINGS The source localization of IEDs by high-density EEG and MEG has now been proved in large patient cohorts to be accurate and clinically relevant, with positive and negative predictive values rivaling those of structural MRI. Localizing seizure onsets is an emerging technique that seems to perform similarly well to the localization of interictal spikes, although there remain questions regarding the processing of signals for reliable results. The localization of somatosensory cortex using EEG/MEG is well established. The localization of language cortex is less reliable, although progress has been made regarding hemispheric lateralization. Source localization is also able to reveal how epilepsy alters the dynamics of neuronal activity in the large-scale networks that underlie cerebral function. SUMMARY Given the high performance of EEG/MEG source localization, these tools should find a place similar to that of established techniques like MRI in the assessment of patients for epilepsy surgery.
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Velmurugan J, Nagarajan SS, Mariyappa N, Ravi SG, Thennarasu K, Mundlamuri RC, Raghavendra K, Bharath RD, Saini J, Arivazhagan A, Rajan J, Mahadevan A, Rao MB, Satishchandra P, Sinha S. Magnetoencephalographic imaging of ictal high-frequency oscillations (80-200 Hz) in pharmacologically resistant focal epilepsy. Epilepsia 2017; 59:190-202. [PMID: 29111591 DOI: 10.1111/epi.13940] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2017] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Specificity of ictal high-frequency oscillations (HFOs) in identifying epileptogenic abnormality is significant, compared to the spikes and interictal HFOs. The objectives of the study were to detect and to localize ictal HFOs by magnetoencephalography (MEG) for identifying the seizure onset zone (SOZ), evaluate the cortical excitability from preictal to ictal transition, and establish HFO concordance rates with other modalities and postsurgical resection. METHODS Sixty-seven patients with drug-resistant epilepsy had at least 1 spontaneous seizure each during MEG acquisition, and analysis was carried out on 20 seizures from 20 patients. Ictal MEG data were bandpass filtered (80-200 Hz) to visualize, review, and analyze the HFOs co-occurring with ictal spikes. Source montages were generated on both hemispheres, mean fast Fourier transform was computed on virtual time series for determining the preictal to ictal spectral power transition, and source reconstruction was performed with sLORETA and beamformers. The concordance rates of ictal MEG HFOs (SOZ) was estimated with 4 reference epileptogenic regions. RESULTS In each subject, transient bursts of high-frequency oscillatory cycles, distinct from the background activity, were observed in the periictal continuum. Time-frequency analysis showed significant spectral power surge (85-160 Hz) during ictal state (P < .05) compared to preictal state, but there was no variation in the peak HFO frequencies (P > .05) for each subgroup and at each source montage. HFO source localization was consistent between algorithms (k = 0.857 ± 0.138), with presumed epileptogenic zone (EZ) comparable to other modalities. In patients who underwent surgery (n = 6), MEG HFO SOZ was concordant with the presumed EZ and the surgical resection site (100%), and all were seizure-free during follow-up. SIGNIFICANCE HFOs could be detected in the MEG periictal state, and its sources were accurately localized. During preictal to ictal transition, HFOs exhibited dynamic augmentation in intrinsic epileptogenicity. Spatial overlap of ictal HFO sources was consistent with EZ determinants and the surgical resection area.
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Affiliation(s)
- Jayabal Velmurugan
- Department of Clinical Neurosciences, National Institute of Mental Health and Neurosciences, Bangalore, India.,MEG Research Center, National Institute of Mental Health and Neurosciences, Bangalore, India.,Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India.,Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA
| | - Srikantan S Nagarajan
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA
| | - Narayanan Mariyappa
- MEG Research Center, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Shankar G Ravi
- Department of Biostatistics, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Kandavel Thennarasu
- Department of Biostatistics, National Institute of Mental Health and Neurosciences, Bangalore, India
| | | | - Kenchaiah Raghavendra
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Rose Dawn Bharath
- Department of Neuroimaging & interventional radiology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Jitender Saini
- Department of Neuroimaging & interventional radiology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | | | - Jamuna Rajan
- Department of Clinical Psychology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Anita Mahadevan
- Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Malla B Rao
- Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Parthasarathy Satishchandra
- MEG Research Center, National Institute of Mental Health and Neurosciences, Bangalore, India.,Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Sanjib Sinha
- MEG Research Center, National Institute of Mental Health and Neurosciences, Bangalore, India.,Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India
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Shirozu H, Hashizume A, Masuda H, Ito Y, Nakayama Y, Higashijima T, Fukuda M, Kameyama S. Analysis of ictal magnetoencephalography using gradient magnetic-field topography (GMFT) in patients with neocortical epilepsy. Clin Neurophysiol 2017. [PMID: 28646743 DOI: 10.1016/j.clinph.2017.05.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE We aimed to validate the usefulness of gradient magnetic-field topography (GMFT) for analysis of ictal magnetoencephalography (MEG) in patients with neocortical epilepsy. METHODS We identified 13 patients presenting with an ictal event during preoperative MEG. We applied equivalent current dipole (ECD) estimation and GMFT to detect and localize the ictal MEG onset, and compared these methods with the ictal onset zone (IOZ) derived from chronic intracranial electroencephalography. The surgical resection areas and outcomes were also evaluated. RESULTS GMFT detected and localized the ictal MEG onset in all patients, whereas ECD estimation showed localized ECDs in only 2. The delineation of GMFT was concordant with the IOZ at the gyral-unit level in 10 of 12 patients (83.3%). The detectability and precision of delineation of ictal MEG activity by GMFT were significantly superior to those of ECD (p<0.05 and p<0.01, respectively). Complete resection of the IOZ in the concordant group provided seizure freedom in 3 patients, whereas seizures remained in 9 patients who had incomplete resections. CONCLUSIONS Because of its higher spatial resolution, GMFT of ictal MEG is superior to conventional ECD estimation in patients with neocortical epilepsy. SIGNIFICANCE Ictal MEG study is a useful tool to estimate the seizure onset in patients with neocortical epilepsy.
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Affiliation(s)
- Hiroshi Shirozu
- Department of Functional Neurosurgery, Nishi-Niigata Chuo National Hospital, 1-14-1, Masago, Nishi-ku, Niigata 950-2085, Japan.
| | - Akira Hashizume
- Department of Neurosurgery, Takanobashi Central Hospital, 2-4-16, Kokutaiji-chou, Naka-ku, Hiroshima 730-0042, Japan
| | - Hiroshi Masuda
- Department of Functional Neurosurgery, Nishi-Niigata Chuo National Hospital, 1-14-1, Masago, Nishi-ku, Niigata 950-2085, Japan
| | - Yosuke Ito
- Department of Functional Neurosurgery, Nishi-Niigata Chuo National Hospital, 1-14-1, Masago, Nishi-ku, Niigata 950-2085, Japan
| | - Yoko Nakayama
- Department of Functional Neurosurgery, Nishi-Niigata Chuo National Hospital, 1-14-1, Masago, Nishi-ku, Niigata 950-2085, Japan
| | - Takefumi Higashijima
- Department of Functional Neurosurgery, Nishi-Niigata Chuo National Hospital, 1-14-1, Masago, Nishi-ku, Niigata 950-2085, Japan
| | - Masafumi Fukuda
- Department of Functional Neurosurgery, Nishi-Niigata Chuo National Hospital, 1-14-1, Masago, Nishi-ku, Niigata 950-2085, Japan
| | - Shigeki Kameyama
- Department of Functional Neurosurgery, Nishi-Niigata Chuo National Hospital, 1-14-1, Masago, Nishi-ku, Niigata 950-2085, Japan
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