1
|
Talami F, Lemieux L, Avanzini P, Ballerini A, Cantalupo G, Laufs H, Meletti S, Vaudano AE. The influence of wakefulness fluctuations on brain networks involved in centrotemporal spike occurrence. Clin Neurophysiol 2024; 164:47-56. [PMID: 38848666 DOI: 10.1016/j.clinph.2024.05.005] [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: 12/10/2023] [Revised: 04/18/2024] [Accepted: 05/11/2024] [Indexed: 06/09/2024]
Abstract
OBJECTIVE Drowsiness has been implicated in the modulation of centro-temporal spikes (CTS) in Self-limited epilepsy with Centro-Temporal Spikes (SeLECTS). Here, we explore this relationship and whether fluctuations in wakefulness influence the brain networks involved in CTS generation. METHODS Functional MRI (fMRI) and electroencephalography (EEG) was simultaneously acquired in 25 SeLECTS. A multispectral EEG index quantified drowsiness ('EWI': EEG Wakefulness Index). EEG (Pearson Correlation, Cross Correlation, Trend Estimation, Granger Causality) and fMRI (PPI: psychophysiological interactions) analytic approaches were adopted to explore respectively: (a) the relationship between EWI and changes in CTS frequency and (b) the functional connectivity of the networks involved in CTS generation and wakefulness oscillations. EEG analyses were repeated on a sample of routine EEG from the same patient's cohort. RESULTS No correlation was found between EWI fluctuations and CTS density during the EEG-fMRI recordings, while they showed an anticorrelated trend when drowsiness was followed by proper sleep in routine EEG traces. According to PPI findings, EWI fluctuations modulate the connectivity between the brain networks engaged by CTS and the left frontal operculum. CONCLUSIONS While CTS frequency per se seems unrelated to drowsiness, wakefulness oscillations modulate the connectivity between CTS generators and key regions of the language circuitry, a cognitive function often impaired in SeLECTS. SIGNIFICANCE This work advances our understanding of (a) interaction between CTS occurrence and vigilance fluctuations and (b) possible mechanisms responsible for language disruption in SeLECTS.
Collapse
Affiliation(s)
- Francesca Talami
- Institute of Neuroscience, National Research Council of Italy, Parma, Italy; Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Louis Lemieux
- Department of Clinical and Experimental and Experimental Epilepsy, UCL Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, United Kingdom
| | - Pietro Avanzini
- Institute of Neuroscience, National Research Council of Italy, Parma, Italy
| | - Alice Ballerini
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Gaetano Cantalupo
- Innovation Biomedicine Section, Department of Engineering for Innovation Medicine, University of Verona, Verona, Italy; Child Neuropsychiatry Unit and Center for Research on Epilepsies in Pediatric age (CREP), University Hospital of Verona (full member of the European Reference Network EpiCARE), Verona, Italy
| | - Helmut Laufs
- University Medical Center Schleswig-Holstein, Christian-Albrechts-Universität zu Kiel, Germany
| | - Stefano Meletti
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy; Neurophysiology Unit and Epilepsy Centre, Neuroscience Department, AOU Modena, Italy.
| | - Anna Elisabetta Vaudano
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy; Neurophysiology Unit and Epilepsy Centre, Neuroscience Department, AOU Modena, Italy.
| |
Collapse
|
2
|
Lee YJ, Bae H, Byun JC, Kwon S, Oh SS, Kim S. Clinical Usefulness of Simultaneous Electroencephalography and Functional Magnetic Resonance Imaging in Children With Focal Epilepsy. J Clin Neurol 2022; 18:535-546. [PMID: 36062771 PMCID: PMC9444567 DOI: 10.3988/jcn.2022.18.5.535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 04/04/2022] [Accepted: 04/04/2022] [Indexed: 11/17/2022] Open
Abstract
Background and Purpose The current study analyzed the interictal epileptiform discharge (IED)-related hemodynamic response and aimed to determine the clinical usefulness of simultaneous electroencephalography and functional magnetic resonance imaging (EEG-fMRI) in defining the epileptogenic zone (EZ) in children with focal epilepsy. Methods Patients with focal epilepsy showing IEDs on conventional EEG were evaluated using EEG-fMRI. Statistical analyses were performed using the times of spike as events modeled with multiple hemodynamic response functions. The area showing the most significant t-value for blood-oxygen-level-dependent (BOLD) changes was compared with the presumed EZ. Moreover, BOLD responses between -9 and +9 s around the spike times were analyzed to track the hemodynamic response patterns over time. Results Half (n=13) of 26 EEG-fMRI investigations of 19 patients were successful. Two patients showed 2 different types of spikes, resulting in 15 analyses. The maximum BOLD response was concordant with the EZ in 11 (73.3%) of the 15 analyses. In 10 (66.7%) analyses, the BOLD response localized the EZs more specifically. Focal BOLD responses in the EZs occurred before IEDs in 11 analyses and were often widespread after IEDs. Hemodynamic response patterns were consistent in the same epilepsy syndrome or when repeating the investigation in the same patients. Conclusions EEG-fMRI can provide additional information for localizing the EZ in children with focal epilepsy, and also reveal the pathogenesis of pediatric epilepsy by evaluating the patterns in the hemodynamic response across time windows of IEDs.
Collapse
Affiliation(s)
- Yun Jeong Lee
- Department of Pediatrics, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, Korea
| | - Hyunwoo Bae
- Department of Pediatrics, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, Korea
| | - Jun Chul Byun
- Department of Pediatrics, Keimyung University Dongsan Hospital, Keimyung University School of Medicine, Daegu, Korea
| | - Soonhak Kwon
- Department of Pediatrics, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, Korea
| | - Sung Suk Oh
- Medical Device Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (K-MEDI hub), Daegu, Korea.
| | - Saeyoon Kim
- Department of Pediatrics, Yeungnam University Medical Center, Yeungnam University College of Medicine, Daegu, Korea.
| |
Collapse
|
3
|
Dai XJ, Yang Y, Wang N, Tao W, Fan J, Wang Y. Reliability and availability of granger causality density in localization of Rolandic focus in BECTS. Brain Imaging Behav 2021; 15:1542-1552. [PMID: 32737823 DOI: 10.1007/s11682-020-00352-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A new method, called granger causality density (GCD), could reflect the directed information flow of the epileptiform activity, which is much closely match with excitatory and inhibitory imbalance theory of epilepsy. Here, we investigated if GCD could effectively localize the Rolandic focus in 50 patients with benign childhood epilepsy with central-temporal spikes (BECTS) from 27 normal children. The BECTS were classified into ictal epileptiform discharges (IEDs; 12 females, 15 males;age, 8.15 ± 1.68 years) and non-IEDs (10 females, 13 males; age, 9.09 ± 1.98 years) subgroups depending on the presence of central-temporal spikes. Multiple correlation-modality analyses (Pearson, across-voxel and across-subject correlations) were used to calculate the couplings between the GCD maps and IEDs-related brain activation map. The individual lateralization coefficient of localize IEDs and multiple regression analysis were used to identify the reliability of the GCD method in localizing the Rolandic focus. In this study, multiple correlation-modality analyses showed that the IEDs-related brain activation map and the GCD maps had highly temporal (coefficient ׀r\= 0.56 ~ 0.65) and spatial (\r\=0.53~0.91) (r\=~ couplings. The proposed GCD method and multiple regression analyses showed consistent findings with the clinical EEG recordings in lateralization of Rolandic focus. Furthermore, the GCD method could reflect the epilepsy-related brain activity during non-IEDs substate. Therefore, the proposed GCD method has the potential to be served as an effective and reliable neuroimaging biomarker to localize the Rolandic focus of BECTS. These findings are critical for clinical early diagnosis, and may promote the progression of treatment and management of pediatric epilepsy.
Collapse
Affiliation(s)
- Xi-Jian Dai
- Shenzhen Mental Health Centre, Shenzhen Kangning Hospital, Shenzhen, 518003, China.
| | - Yang Yang
- Department of Radiology, the Affiliated Hospital of Zunyi Medical University, Medical Imaging Center of Guizhou Province, Zunyi, 563000, China
| | - Na Wang
- Shenzhen Mental Health Centre, Shenzhen Kangning Hospital, Shenzhen, 518003, China
| | - Weiqun Tao
- Shenzhen Mental Health Centre, Shenzhen Kangning Hospital, Shenzhen, 518003, China
| | - Jingyi Fan
- Shenzhen Mental Health Centre, Shenzhen Kangning Hospital, Shenzhen, 518003, China
| | - Yongjun Wang
- Shenzhen Mental Health Centre, Shenzhen Kangning Hospital, Shenzhen, 518003, China.
| |
Collapse
|
4
|
Fu C, Aisikaer A, Chen Z, Yu Q, Yin J, Yang W. Different Functional Network Connectivity Patterns in Epilepsy: A Rest-State fMRI Study on Mesial Temporal Lobe Epilepsy and Benign Epilepsy With Centrotemporal Spike. Front Neurol 2021; 12:668856. [PMID: 34122313 PMCID: PMC8193721 DOI: 10.3389/fneur.2021.668856] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 05/06/2021] [Indexed: 11/13/2022] Open
Abstract
The stark discrepancy in the prognosis of epilepsy is closely related to brain damage features and underlying mechanisms, which have not yet been unraveled. In this study, differences in the epileptic brain functional connectivity states were explored through a network-based connectivity analysis between intractable mesial temporal lobe epilepsy (MTLE) patients and benign epilepsy with centrotemporal spikes (BECT). Resting state fMRI imaging data were collected for 14 MTLE patients, 12 BECT patients and 16 healthy controls (HCs). Independent component analysis (ICA) was performed to identify the cortical functional networks. Subcortical nuclei of interest were extracted from the Harvard-Oxford probability atlas. Network-based statistics were used to detect functional connectivity (FC) alterations across intranetworks and internetworks, including the connectivity between cortical networks and subcortical nuclei. Compared with HCs, MTLE patients showed significant lower activity between the connectivity of cortical networks and subcortical nuclei (especially hippocampus) and lower internetwork FC involving the lateral temporal lobe; BECT patients showed normal cortical-subcortical FC with hyperconnectivity between cortical networks. Together, cortical-subcortical hypoconnectivity in MTLE suggested a low efficiency and collaborative network pattern, and this might be relevant to the final decompensatory state and the intractable prognosis. Conversely, cortical-subcortical region with normal connectivity remained well in global cooperativity, and compensatory internetwork hyperconnectivity caused by widespread cortical abnormal discharge, which might account for the self-limited clinical outcome in BECT. Based on the fMRI functional network study, different brain network patterns might provide a better explanation of mechanisms in different types of epilepsy.
Collapse
Affiliation(s)
- Cong Fu
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China
| | - Aikedan Aisikaer
- Department of Radiology, Tianjin First Central Hospital, Tianjin, China
| | - Zhijuan Chen
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China
| | - Qing Yu
- Department of Neurology, Tianjin Medical University General Hospital, Tianjin, China
| | - Jianzhong Yin
- Department of Radiology, Tianjin First Central Hospital, Tianjin, China
| | - Weidong Yang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China
| |
Collapse
|
5
|
Epilepsy syndromes of childhood with sleep activation: Insights from functional imaging. Eur J Paediatr Neurol 2020; 24:58-60. [PMID: 31875835 DOI: 10.1016/j.ejpn.2019.12.006] [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] [Received: 11/15/2019] [Accepted: 12/06/2019] [Indexed: 11/21/2022]
Abstract
In epilepsy syndromes of childhood with sleep activation, defined as the spectrum of epileptic conditions going from classical benign childhood epilepsy with centrotemporal spikes (BECTS) to epileptic encephalopathy (EE) with continuous spike and waves during slow-wave sleep (CSWS) including Landau-Kleffner syndrome (LKS), a lot of functional imaging studies have been performed so far, leading to results that are not always consistent, related to the technique of neuroimaging performed and to the variability of the clinical phenotype. Most consistent findings are, depending of the method used, activations or increased regional glucose metabolism in the epileptogenic regions, and deactivations, hypometabolism or decreased functional connectivity in cortical regions that belong to the default mode network. Functional changes are either transitory, temporally related to the occurrence of interictal epileptiform discharges (IED), or permanent, persisting across IED-free periods. Some studies have shown that the more severe phenotype, i.e. EE with CSWS, displays the more profound functional disturbances. Taken together, functional imaging studies support the concept that IED impact cognition in epilepsy syndromes of childhood with sleep activation. However, the precise chronology between the occurrence of IED and the functional disturbances, the neuropsychological correlates of the functional disturbances, and the effects of the anti-epileptic treatments on IED, functional disturbances and cognition need to be further studied.
Collapse
|
6
|
Dai XJ, Xu Q, Hu J, Zhang Q, Xu Y, Zhang Z, Lu G. BECTS Substate Classification by Granger Causality Density Based Support Vector Machine Model. Front Neurol 2019; 10:1201. [PMID: 31798523 PMCID: PMC6868120 DOI: 10.3389/fneur.2019.01201] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 10/28/2019] [Indexed: 12/30/2022] Open
Abstract
Objectives: To investigate the performance of substate classification of children with benign epilepsy with centrotemporal spikes (BECTS) by granger causality density (GCD) based support vector machine (SVM) model. Methods: Forty-two children with BECTS (21 females, 21 males; mean age, 8.6 ± 1.96 years) were classified into interictal epileptic discharges (IEDs; 11 females, 10 males) and non-IEDs (10 females, 11 males) substates depending on presence of central-temporal spikes or not. GCD was calculated on four metrics, including inflow, outflow, total-flow (inflow + outflow) and int-flow (inflow – outflow) connectivity. SVM classifier was applied to discriminate the two substates. Results: The Rolandic area, caudate, dorsal attention network, visual cortex, language networks, and cerebellum had discriminative effect on distinguishing the two substates. Relative to each of the four GCD metrics, using combined metrics could reach up the classification performance (best value; AUC, 0.928; accuracy rate, 90.83%; sensitivity, 90%; specificity, 95%), especially for the combinations with more than three GCD metrics. Specially, combined the inflow, outflow and int-flow metric received the best classification performance with the highest AUC value, classification accuracy and specificity. Furthermore, the GCD-SVM model received good and stable classification performance across 14 dimension reduced data sets. Conclusions: The GCD-SVM model could be used for BECTS substate classification, which might have the potential to provide a promising model for IEDs detection. This may help assist clinicians for administer drugs and prognosis evaluation.
Collapse
Affiliation(s)
- Xi-Jian Dai
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China.,Shenzhen Mental Health Centre, Shenzhen Kangning Hospital, Shenzhen, China.,Sleep Assessment Unit, Department of Psychiatry, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, China
| | - Qiang Xu
- Shenzhen Mental Health Centre, Shenzhen Kangning Hospital, Shenzhen, China
| | - Jianping Hu
- Shenzhen Mental Health Centre, Shenzhen Kangning Hospital, Shenzhen, China
| | - QiRui Zhang
- Shenzhen Mental Health Centre, Shenzhen Kangning Hospital, Shenzhen, China
| | - Yin Xu
- Shenzhen Mental Health Centre, Shenzhen Kangning Hospital, Shenzhen, China
| | - Zhiqiang Zhang
- Shenzhen Mental Health Centre, Shenzhen Kangning Hospital, Shenzhen, China
| | - Guangming Lu
- Shenzhen Mental Health Centre, Shenzhen Kangning Hospital, Shenzhen, China
| |
Collapse
|
7
|
Bourel-Ponchel E, Mahmoudzadeh M, Adebimpe A, Wallois F. Functional and Structural Network Disorganizations in Typical Epilepsy With Centro-Temporal Spikes and Impact on Cognitive Neurodevelopment. Front Neurol 2019; 10:809. [PMID: 31555191 PMCID: PMC6727184 DOI: 10.3389/fneur.2019.00809] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 07/15/2019] [Indexed: 12/20/2022] Open
Abstract
Epilepsy with Centrotemporal Spikes (ECTS) is the most common form of self-limited focal epilepsy. The pathophysiological mechanisms by which ECTS induces neuropsychological impairment in 15-30% of affected children remain unclear. The objective of this study is to review the current state of knowledge concerning the brain structural and functional changes that may be involved in cognitive dysfunctions in ECTS. Structural brain imaging suggests the presence of subtle neurodevelopmental changes over the epileptogenic zone and over distant regions in ECTS. This structural remodeling likely occurs prior to the diagnosis and evolves over time, especially in patients with cognitive impairment, suggesting that the epileptogenic processes might interfere with the dynamics of the brain development and/or the normal maturation processes. Functional brain imaging demonstrates profound disorganization accentuated by interictal epileptic spikes (IES) in the epileptogenic zone and in remote networks in ECTS. Over the epileptogenic zone, the literature demonstrates changes in term of neuronal activity and synchronization, which are effective several hundred milliseconds before the IES. In the same time window, functional changes are also observed in bilateral distant networks, notably in the frontal and temporal lobes. Effective connectivity demonstrates that the epileptogenic zone constitutes the key area at the origin of IES propagation toward distant cortical regions, including frontal areas. Altogether, structural and functional network disorganizations, in terms of: (i) power spectral values, (ii) functional and effective connectivity, are likely to participate in the cognitive impairment commonly reported in children with ECTS. These results suggest a central and causal role of network disorganizations related to IES in the neuropsychological impairment described in ECTS children.
Collapse
Affiliation(s)
- Emilie Bourel-Ponchel
- INSERM UMR 1105, Research Group on Multimodal Analysis of Brain Function, University of Picardie Jules Verne, Amiens, France
- INSERM UMR 1105, EFSN Pediatric, Amiens University Hospital, Amiens, France
| | - Mahdi Mahmoudzadeh
- INSERM UMR 1105, Research Group on Multimodal Analysis of Brain Function, University of Picardie Jules Verne, Amiens, France
- INSERM UMR 1105, EFSN Pediatric, Amiens University Hospital, Amiens, France
| | - Azeez Adebimpe
- INSERM UMR 1105, Research Group on Multimodal Analysis of Brain Function, University of Picardie Jules Verne, Amiens, France
| | - Fabrice Wallois
- INSERM UMR 1105, Research Group on Multimodal Analysis of Brain Function, University of Picardie Jules Verne, Amiens, France
- INSERM UMR 1105, EFSN Pediatric, Amiens University Hospital, Amiens, France
| |
Collapse
|
8
|
Zhang Q, Yang F, Hu Z, Zhang Z, Xu Q, Dante M, Wu H, Li Z, Li Q, Li K, Lu G. Resting-state fMRI revealed different brain activities responding to valproic acid and levetiracetam in benign epilepsy with central-temporal spikes. Eur Radiol 2016; 27:2137-2145. [DOI: 10.1007/s00330-016-4531-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 07/12/2016] [Accepted: 07/21/2016] [Indexed: 02/04/2023]
|
9
|
Zhu Y, Yu Y, Shinkareva SV, Ji GJ, Wang J, Wang ZJ, Zang YF, Liao W, Tang YL. Intrinsic brain activity as a diagnostic biomarker in children with benign epilepsy with centrotemporal spikes. Hum Brain Mapp 2015; 36:3878-89. [PMID: 26173095 DOI: 10.1002/hbm.22884] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Revised: 05/21/2015] [Accepted: 06/11/2015] [Indexed: 12/11/2022] Open
Abstract
Benign epilepsy with centrotemporal spikes (BECTS) is often associated with neural circuit dysfunction, particularly during the transient active state characterized by interictal epileptiform discharges (IEDs). Little is known, however, about the functional neural circuit abnormalities in BECTS without IEDs, or if such abnormalities could be used to differentiate BECTS patients without IEDs from healthy controls (HCs) for early diagnosis. To this end, we conducted resting-state functional magnetic resonance imaging (RS-fMRI) and simultaneous Electroencephalogram (EEG) in children with BECTS (n = 43) and age-matched HC (n = 28). The simultaneous EEG recordings distinguished BECTS with IEDs (n = 20) from without IEDs (n = 23). Intrinsic brain activity was measured in all three groups using the amplitude of low frequency fluctuation at rest. Compared to HC, BECTS patients with IEDs exhibited an intrinsic activity abnormality in the thalamus, suggesting that thalamic dysfunction could contribute to IED emergence while patients without IEDs exhibited intrinsic activity abnormalities in middle frontal gyrus and superior parietal gyrus. Using multivariate pattern classification analysis, we were able to differentiate BECTS without IEDs from HCs with 88.23% accuracy. BECTS without epileptic transients can be distinguished from HC and BECTS with IEDs by unique regional abnormalities in resting brain activity. Both transient abnormalities as reflected by IEDs and chronic abnormalities as reflected by RS-fMRI may contribute to BECTS development and expression. Intrinsic brain activity and multivariate pattern classification techniques are promising tools to diagnose and differentiate BECTS syndromes. Hum Brain Mapp 36:3878-3889, 2015. © 2015 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Yihong Zhu
- Mental Health Education and Counseling Center, Zhejiang University, Zhejiang, China.,School of Public Health, Zhejiang University, Zhejiang, China
| | - Yang Yu
- Mental Health Education and Counseling Center, Zhejiang University, Zhejiang, China.,School of Public Health, Zhejiang University, Zhejiang, China.,Center for Cognition and Brain Disorders and the Affiliated Hospital, Hangzhou Normal University, Zhejiang, China.,Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Zhejiang, China.,Department of Psychiatry, the Second Affiliated Hospital of Medial College, Zhejiang University, Zhejiang, China
| | | | - Gong-Jun Ji
- Center for Cognition and Brain Disorders and the Affiliated Hospital, Hangzhou Normal University, Zhejiang, China.,Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Zhejiang, China
| | - Jue Wang
- Center for Cognition and Brain Disorders and the Affiliated Hospital, Hangzhou Normal University, Zhejiang, China.,Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Zhejiang, China
| | - Zhong-Jin Wang
- Department of Neurology, the Second Affiliated Hospital of Medial College, Zhejiang University, Zhejiang, China
| | - Yu-Feng Zang
- Center for Cognition and Brain Disorders and the Affiliated Hospital, Hangzhou Normal University, Zhejiang, China.,Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Zhejiang, China
| | - Wei Liao
- Center for Cognition and Brain Disorders and the Affiliated Hospital, Hangzhou Normal University, Zhejiang, China.,Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Zhejiang, China
| | - Ye-Lei Tang
- Department of Neurology, the Second Affiliated Hospital of Medial College, Zhejiang University, Zhejiang, China
| |
Collapse
|
10
|
Abstract
Electroencephalography (EEG) has been used to study and characterize epilepsy for decades, but has a limited ability to localize epileptiform activity to a specific brain region. With recent technological advances, high-quality EEG can now be recorded during functional magnetic resonance imaging (fMRI), which characterizes brain activity through local changes in blood oxygenation. By combining these techniques, the specific timing of interictal events can be identified on the EEG at millisecond resolution and spatially localized with fMRI at millimeter resolution. As a result, simultaneous EEG-fMRI provides the opportunity to better investigate the spatiotemporal mechanisms of the generation of epileptiform activity in the brain. This article discusses the technical considerations and their solutions for recording simultaneous EEG-fMRI and the results of studies to date. It also addresses the application of EEG-fMRI to epilepsy in humans, including clinical applications and ongoing challenges.
Collapse
|
11
|
Pittau F, Mégevand P, Sheybani L, Abela E, Grouiller F, Spinelli L, Michel CM, Seeck M, Vulliemoz S. Mapping epileptic activity: sources or networks for the clinicians? Front Neurol 2014; 5:218. [PMID: 25414692 PMCID: PMC4220689 DOI: 10.3389/fneur.2014.00218] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 10/08/2014] [Indexed: 01/03/2023] Open
Abstract
Epileptic seizures of focal origin are classically considered to arise from a focal epileptogenic zone and then spread to other brain regions. This is a key concept for semiological electro-clinical correlations, localization of relevant structural lesions, and selection of patients for epilepsy surgery. Recent development in neuro-imaging and electro-physiology and combinations, thereof, have been validated as contributory tools for focus localization. In parallel, these techniques have revealed that widespread networks of brain regions, rather than a single epileptogenic region, are implicated in focal epileptic activity. Sophisticated multimodal imaging and analysis strategies of brain connectivity patterns have been developed to characterize the spatio-temporal relationships within these networks by combining the strength of both techniques to optimize spatial and temporal resolution with whole-brain coverage and directional connectivity. In this paper, we review the potential clinical contribution of these functional mapping techniques as well as invasive electrophysiology in human beings and animal models for characterizing network connectivity.
Collapse
Affiliation(s)
- Francesca Pittau
- EEG and Epilepsy Unit, Neurology Department, University Hospitals and Faculty of Medicine of Geneva , Geneva , Switzerland
| | - Pierre Mégevand
- Laboratory for Multimodal Human Brain Mapping, Hofstra North Shore LIJ School of Medicine , Manhasset, NY , USA
| | - Laurent Sheybani
- Functional Brain Mapping Laboratory, Department of Fundamental Neurosciences, University of Geneva , Geneva , Switzerland
| | - Eugenio Abela
- Support Center of Advanced Neuroimaging (SCAN), Institute for Diagnostic and Interventional Neuroradiology, University Hospital Inselspital , Bern , Switzerland
| | - Frédéric Grouiller
- Radiology Department, University Hospitals and Faculty of Medicine of Geneva , Geneva , Switzerland
| | - Laurent Spinelli
- EEG and Epilepsy Unit, Neurology Department, University Hospitals and Faculty of Medicine of Geneva , Geneva , Switzerland
| | - Christoph M Michel
- Functional Brain Mapping Laboratory, Department of Fundamental Neurosciences, University of Geneva , Geneva , Switzerland
| | - Margitta Seeck
- EEG and Epilepsy Unit, Neurology Department, University Hospitals and Faculty of Medicine of Geneva , Geneva , Switzerland
| | - Serge Vulliemoz
- EEG and Epilepsy Unit, Neurology Department, University Hospitals and Faculty of Medicine of Geneva , Geneva , Switzerland
| |
Collapse
|
12
|
Ruggieri A, Vaudano AE, Benuzzi F, Serafini M, Gessaroli G, Farinelli V, Nichelli PF, Meletti S. Mapping (and modeling) physiological movements during EEG-fMRI recordings: the added value of the video acquired simultaneously. J Neurosci Methods 2014; 239:223-37. [PMID: 25455344 DOI: 10.1016/j.jneumeth.2014.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 10/06/2014] [Accepted: 10/09/2014] [Indexed: 11/27/2022]
Abstract
BACKGROUND During resting-state EEG-fMRI studies in epilepsy, patients' spontaneous head-face movements occur frequently. We tested the usefulness of synchronous video recording to identify and model the fMRI changes associated with non-epileptic movements to improve sensitivity and specificity of fMRI maps related to interictal epileptiform discharges (IED). NEW METHODS Categorization of different facial/cranial movements during EEG-fMRI was obtained for 38 patients [with benign epilepsy with centro-temporal spikes (BECTS, n=16); with idiopathic generalized epilepsy (IGE, n=17); focal symptomatic/cryptogenic epilepsy (n=5)]. We compared at single subject- and at group-level the IED-related fMRI maps obtained with and without additional regressors related to spontaneous movements. As secondary aim, we considered facial movements as events of interest to test the usefulness of video information to obtain fMRI maps of the following face movements: swallowing, mouth-tongue movements, and blinking. RESULTS Video information substantially improved the identification and classification of the artifacts with respect to the EEG observation alone (mean gain of 28 events per exam). COMPARISON WITH EXISTING METHOD Inclusion of physiological activities as additional regressors in the GLM model demonstrated an increased Z-score and number of voxels of the global maxima and/or new BOLD clusters in around three quarters of the patients. Video-related fMRI maps for swallowing, mouth-tongue movements, and blinking were comparable to the ones obtained in previous task-based fMRI studies. CONCLUSIONS Video acquisition during EEG-fMRI is a useful source of information. Modeling physiological movements in EEG-fMRI studies for epilepsy will lead to more informative IED-related fMRI maps in different epileptic conditions.
Collapse
Affiliation(s)
- Andrea Ruggieri
- Department of Biomedical, Metabolic, and Neural Science, University of Modena and Reggio Emilia, NOCSAE Hospital, ASL Modena, Italy
| | - Anna Elisabetta Vaudano
- Department of Biomedical, Metabolic, and Neural Science, University of Modena and Reggio Emilia, NOCSAE Hospital, ASL Modena, Italy
| | - Francesca Benuzzi
- Department of Biomedical, Metabolic, and Neural Science, University of Modena and Reggio Emilia, NOCSAE Hospital, ASL Modena, Italy
| | | | - Giuliana Gessaroli
- Department of Biomedical, Metabolic, and Neural Science, University of Modena and Reggio Emilia, NOCSAE Hospital, ASL Modena, Italy
| | - Valentina Farinelli
- Department of Biomedical, Metabolic, and Neural Science, University of Modena and Reggio Emilia, NOCSAE Hospital, ASL Modena, Italy
| | - Paolo Frigio Nichelli
- Department of Biomedical, Metabolic, and Neural Science, University of Modena and Reggio Emilia, NOCSAE Hospital, ASL Modena, Italy
| | - Stefano Meletti
- Department of Biomedical, Metabolic, and Neural Science, University of Modena and Reggio Emilia, NOCSAE Hospital, ASL Modena, Italy.
| |
Collapse
|
13
|
Altered regional homogeneity in rolandic epilepsy: a resting-state FMRI study. BIOMED RESEARCH INTERNATIONAL 2014; 2014:960395. [PMID: 25247197 PMCID: PMC4163434 DOI: 10.1155/2014/960395] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 08/13/2014] [Indexed: 01/17/2023]
Abstract
Children with rolandic epilepsy (RE) are often associated with cognitive deficits and behavioral problems. Findings from neurophysiological and neuroimaging studies in RE have now demonstrated dysfunction not only in rolandic focus, but also in distant neuronal circuits. Little is known, however, about whether there is distributed abnormal spontaneous brain activity in RE. Using resting-state functional magnetic resonance imaging (RS-fMRI), the present study aimed to determine whether children with RE show abnormal local synchronization during resting state and, if so, whether these changes could be associated with the behavioral/clinical characteristics of RE. Regional homogeneity (ReHo) in children with RE (n = 30) and healthy children (n = 20) was computed on resting-state functional MRI data. In comparison with healthy children, children with RE showed increased ReHo in the central, premotor, and prefrontal regions, while they showed decreased ReHo in bilateral orbitofrontal cortex and temporal pole. In addition, the ReHo value in the left orbitofrontal cortex negatively was corrected with performance intelligence quotient in the children with RE. The aberrant local synchronization, not strictly related to primary site of the typical rolandic focus, indicates the neuropathophysiological mechanism of RE. The study findings may shed new light on the understanding of neural correlation of neuropsychological deficiencies in the children with RE.
Collapse
|
14
|
Mirandola L, Cantalupo G, Vaudano AE, Avanzini P, Ruggieri A, Pisani F, Cossu G, Tassinari CA, Nichelli PF, Benuzzi F, Meletti S. Centrotemporal spikes during NREM sleep: The promoting action of thalamus revealed by simultaneous EEG and fMRI coregistration. EPILEPSY & BEHAVIOR CASE REPORTS 2013; 1:106-9. [PMID: 25667840 PMCID: PMC4150635 DOI: 10.1016/j.ebcr.2013.06.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Revised: 06/18/2013] [Accepted: 06/21/2013] [Indexed: 11/21/2022]
Abstract
Benign childhood epilepsy with centrotemporal spikes (BECTS) has been investigated through EEG-fMRI with the aim of localizing the generators of the epileptic activity, revealing, in most cases, the activation of the sensory-motor cortex ipsilateral to the centrotemporal spikes (CTS). In this case report, we investigated the brain circuits hemodynamically involved by CTS recorded during wakefulness and sleep in one boy with CTS and a language disorder but without epilepsy. For this purpose, the patient underwent EEG-fMRI coregistration. During the "awake session", fMRI analysis of right-sided CTS showed increments of BOLD signal in the bilateral sensory-motor cortex. During the "sleep session", BOLD increments related to right-sided CTS were observed in a widespread bilateral cortical-subcortical network involving the thalamus, basal ganglia, sensory-motor cortex, perisylvian cortex, and cerebellum. In this patient, who fulfilled neither the diagnostic criteria for BECTS nor that for electrical status epilepticus in sleep (ESES), the transition from wakefulness to sleep was related to the involvement of a widespread cortical-subcortical network related to CTS. In particular, the involvement of a thalamic-perisylvian neural network similar to the one previously observed in patients with ESES suggests a common sleep-related network dysfunction even in cases with milder phenotypes without seizures. This finding, if confirmed in a larger cohort of patients, could have relevant therapeutic implication.
Collapse
Affiliation(s)
- Laura Mirandola
- Department of Biomedical Sciences, Metabolism, and Neuroscience, University of Modena and Reggio Emilia, Italy
| | - Gaetano Cantalupo
- Child Neuropsychiatry Unit, Department of Neuroscience, University-Hospital of Parma, Italy
- Department of Life and Reproduction Sciences, University of Verona, Italy
| | - Anna Elisabetta Vaudano
- Department of Biomedical Sciences, Metabolism, and Neuroscience, University of Modena and Reggio Emilia, Italy
| | - Pietro Avanzini
- Department of Biomedical Sciences, Metabolism, and Neuroscience, University of Modena and Reggio Emilia, Italy
- Department of Neuroscience, University of Parma, Italy
| | - Andrea Ruggieri
- Department of Biomedical Sciences, Metabolism, and Neuroscience, University of Modena and Reggio Emilia, Italy
| | - Francesco Pisani
- Child Neuropsychiatry Unit, Department of Neuroscience, University-Hospital of Parma, Italy
| | - Giuseppe Cossu
- Child Neuropsychiatry Unit, Department of Neuroscience, University-Hospital of Parma, Italy
- Department of Neuroscience, University of Parma, Italy
| | | | - Paolo Frigio Nichelli
- Department of Biomedical Sciences, Metabolism, and Neuroscience, University of Modena and Reggio Emilia, Italy
| | - Francesca Benuzzi
- Department of Biomedical Sciences, Metabolism, and Neuroscience, University of Modena and Reggio Emilia, Italy
| | - Stefano Meletti
- Department of Biomedical Sciences, Metabolism, and Neuroscience, University of Modena and Reggio Emilia, Italy
| |
Collapse
|
15
|
Moeller F, Moehring J, Ick I, Steinmann E, Wolff S, Jansen O, Boor R, Stephani U, Siniatchkin M. EEG-fMRI in atypical benign partial epilepsy. Epilepsia 2013; 54:e103-8. [PMID: 23758518 DOI: 10.1111/epi.12243] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2013] [Indexed: 11/30/2022]
Abstract
Atypical benign partial epilepsy (ABPE) is a subgroup among the idiopathic focal epilepsies of childhood. Aim of this study was to investigate neuronal networks underlying ABPE and compare the results with previous electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) studies of related epilepsy syndromes. Ten patients with ABPE underwent simultaneous EEG-fMRI recording. In all 10 patients several types of interictal epileptiform discharges (IEDs) were recorded. Individual IED-associated blood oxygen level-dependent (BOLD) signal changes were analyzed in a single subject analysis for each IED type (33 studies). A group analysis was also performed to determine common BOLD signal changes across the patients. IED-associated BOLD signal changes were found in 31 studies. Focal BOLD signal changes concordant with the spike field (21 studies) and distant cortical and subcortical BOLD signal changes (31 studies) were detected. The group analysis revealed a thalamic activation. This study demonstrated that ABPE is characterized by patterns similar to studies in rolandic epilepsy (focal BOLD signal changes in the spike field) as well as patterns observed in continuous spikes and waves during slow sleep (CSWS) (distant BOLD signal changes in cortical and subcortical structures), thereby underscoring that idiopathic focal epilepsies of childhood form a spectrum of overlapping syndromes.
Collapse
Affiliation(s)
- Friederike Moeller
- Department of Neuropediatrics, Christian-Albrechts-University, Kiel, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Moeller F, Stephani U, Siniatchkin M. Simultaneous EEG and fMRI recordings (EEG-fMRI) in children with epilepsy. Epilepsia 2013; 54:971-82. [PMID: 23647021 DOI: 10.1111/epi.12197] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2013] [Indexed: 11/27/2022]
Abstract
By combining electroencephalography (EEG) with functional magnetic resonance imaging (fMRI) it is possible to describe blood oxygenation level-dependent (BOLD) signal changes related to EEG patterns. This way, EEG-pattern-associated networks of hemodynamic changes can be detected anywhere in the brain with good spatial resolution. This review summarizes EEG-fMRI studies that have been performed in children with epilepsy. EEG-fMRI studies in focal epilepsy (structural and nonlesional cases, benign epilepsy with centrotemporal spikes), generalized epilepsy (especially absence epilepsy), and epileptic encephalopathies (West syndrome, Lennox-Gastaut syndrome, continuous spike and waves during slow sleep, and Dravet syndrome) are presented. Although EEG-fMRI was applied mainly to localize the region presumably generating focal interictal discharges in focal epilepsies, EEG-fMRI identified underlying networks in patients with generalized epilepsies and thereby contributed to a better understanding of these epilepsies. In epileptic encephalopathies a specific fingerprint of hemodynamic changes associated with the particular syndrome was detected. The value of the EEG-fMRI technique for diagnosis and investigation of pathogenetic mechanisms of different forms of epilepsy is discussed.
Collapse
Affiliation(s)
- Friederike Moeller
- Department of Neuropediatrics, Christian-Albrechts-University, Kiel, Germany.
| | | | | |
Collapse
|
17
|
Moehring J, von Spiczak S, Moeller F, Helbig I, Wolff S, Jansen O, Muhle H, Boor R, Stephani U, Siniatchkin M. Variability of EEG-fMRI findings in patients withSCN1A-positive Dravet syndrome. Epilepsia 2013; 54:918-26. [DOI: 10.1111/epi.12119] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2013] [Indexed: 01/18/2023]
Affiliation(s)
- Jan Moehring
- Department of Neuropediatrics; Christian-Albrechts-University; Kiel; Germany
| | - Sarah von Spiczak
- Department of Neuropediatrics; Christian-Albrechts-University; Kiel; Germany
| | - Friederike Moeller
- Department of Neuropediatrics; Christian-Albrechts-University; Kiel; Germany
| | - Ingo Helbig
- Department of Neuropediatrics; Christian-Albrechts-University; Kiel; Germany
| | | | - Olav Jansen
- Institute of Neuroradiology; Christian-Albrechts-University; Kiel; Germany
| | - Hiltrud Muhle
- Department of Neuropediatrics; Christian-Albrechts-University; Kiel; Germany
| | - Rainer Boor
- Northern German Epilepsy Center; Schwentinental-Raisdorf; Germany
| | | | - Michael Siniatchkin
- Department of Neuropediatrics; Christian-Albrechts-University; Kiel; Germany
| |
Collapse
|
18
|
Mapping brain activity using event-related independent components analysis (eICA): specific advantages for EEG-fMRI. Neuroimage 2012; 70:164-74. [PMID: 23266745 DOI: 10.1016/j.neuroimage.2012.12.025] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 12/01/2012] [Accepted: 12/13/2012] [Indexed: 11/22/2022] Open
Abstract
Event-related analyses of functional MRI (fMRI) typically assume that the onset and offset of neuronal activity match stimuli onset and offset, and that evoked fMRI signal changes follow the canonical haemodynamic response function (HRF). Some event types, however, may be unsuited to this approach: brief stimuli might elicit an extended neuronal response; anticipatory effects might result in activity preceding the event; or altered neurovascular coupling may result in a non-canonical HRF. An example is interictal epileptiform discharges (IEDs), which may show a non-canonical HRF and fMRI signal changes preceding their onset as detected on EEG. In such cases, less constrained analyses - capable of detecting early, non-canonical responses - may be necessary. A consequence of less constrained analyses, however, is that artefactual sources of signal change - motion or physiological noise for example - may also be detected and mixed with the neuronally-generated signals. In this paper, to address this issue, we describe an event-related independent components analysis (eICA) that identifies different sources of event-related signal change that can then be separately assessed to identify likely artefacts and separate primary from propagated activity. We also describe a group analysis that identifies eICA components that are spatially and temporally consistent across subjects and provides an objective approach for selecting group-specific components likely to be of neural origin. We apply eICA to patients with rolandic epilepsy - with stereotypical IEDs arising from a focus in the rolandic fissure - and demonstrate that a single event-related component, concordant with this source location, is detected.
Collapse
|
19
|
Elshoff L, Groening K, Grouiller F, Wiegand G, Wolff S, Michel C, Stephani U, Siniatchkin M. The value of EEG-fMRI and EEG source analysis in the presurgical setup of children with refractory focal epilepsy. Epilepsia 2012; 53:1597-606. [DOI: 10.1111/j.1528-1167.2012.03587.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
20
|
Rosa MJ, Daunizeau J, Friston KJ. EEG-fMRI integration: a critical review of biophysical modeling and data analysis approaches. J Integr Neurosci 2011; 9:453-76. [PMID: 21213414 DOI: 10.1142/s0219635210002512] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2010] [Accepted: 09/17/2010] [Indexed: 11/18/2022] Open
Abstract
The diverse nature of cerebral activity, as measured using neuroimaging techniques, has been recognised long ago. It seems obvious that using single modality recordings can be limited when it comes to capturing its complex nature. Thus, it has been argued that moving to a multimodal approach will allow neuroscientists to better understand the dynamics and structure of this activity. This means that integrating information from different techniques, such as electroencephalography (EEG) and the blood oxygenated level dependent (BOLD) signal recorded with functional magnetic resonance imaging (fMRI), represents an important methodological challenge. In this work, we review the work that has been done thus far to derive EEG/fMRI integration approaches. This leads us to inspect the conditions under which such an integration approach could work or fail, and to disclose the types of scientific questions one could (and could not) hope to answer with it.
Collapse
Affiliation(s)
- M J Rosa
- Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, United Kingdom
| | | | | |
Collapse
|
21
|
Moehring J, Coropceanu D, Galka A, Moeller F, Wolff S, Boor R, Jansen O, Stephani U, Siniatchkin M. Improving sensitivity of EEG-fMRI studies in epilepsy: the role of sleep-specific activity. Neurosci Lett 2011; 505:211-5. [PMID: 22027175 DOI: 10.1016/j.neulet.2011.10.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Revised: 09/19/2011] [Accepted: 10/13/2011] [Indexed: 10/16/2022]
Abstract
Using simultaneous recordings of EEG and functional MRI (EEG-fMRI) in patients with focal epilepsy, recent studies have revealed insufficient sensitivity and a lack of correspondence between epileptic EEG foci and activation patterns in some patients. In this study of children with focal epilepsy, we explore whether sleep-specific activity (sleep spindles, k-complexes and vertex sharp waves) may increase the sensitivity of EEG-fMRI of interictal epileptiform discharges (IED). When considering the sleep-specific activity in a statistical model, it was possible to increase the statistical significance of the activated voxels inside of the expected source of the IED and to reduce the number of activated voxels outside of it. According to this study, it could be worthwhile to include sleep-specific activity into the model by analyzing EEG-fMRI data in epilepsy.
Collapse
Affiliation(s)
- Jan Moehring
- Department of Neuropediatrics, Christian-Albrechts-University, Kiel, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Combination of EEG–fMRI and EEG source analysis improves interpretation of spike-associated activation networks in paediatric pharmacoresistant focal epilepsies. Neuroimage 2009; 46:827-33. [DOI: 10.1016/j.neuroimage.2009.02.026] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 02/12/2009] [Accepted: 02/15/2009] [Indexed: 11/20/2022] Open
|
23
|
Hemodynamic changes preceding the interictal EEG spike in patients with focal epilepsy investigated using simultaneous EEG-fMRI. Neuroimage 2009; 45:1220-31. [DOI: 10.1016/j.neuroimage.2009.01.014] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2008] [Revised: 01/05/2009] [Accepted: 01/08/2009] [Indexed: 11/24/2022] Open
|
24
|
Manganotti P, Formaggio E, Gasparini A, Cerini R, Bongiovanni LG, Storti SF, Mucelli RP, Fiaschi A, Avesani M. Continuous EEG–fMRI in patients with partial epilepsy and focal interictal slow-wave discharges on EEG. Magn Reson Imaging 2008; 26:1089-100. [DOI: 10.1016/j.mri.2008.02.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Revised: 02/13/2008] [Accepted: 02/21/2008] [Indexed: 11/25/2022]
|
25
|
Liu Y, Yang T, Yang X, Liu I, Liao W, Lui S, Huang X, Chen H, Gong Q, Zhou D. EEG-fMRI study of the interictal epileptic activity in patients with partial epilepsy. J Neurol Sci 2008; 268:117-23. [PMID: 18191150 DOI: 10.1016/j.jns.2007.11.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2007] [Revised: 11/18/2007] [Accepted: 11/21/2007] [Indexed: 02/05/2023]
Abstract
PURPOSE To investigate Blood Oxygen Level Dependent (BOLD) responses to interictal epileptic discharges (IEDs) during EEG-correlated functional MRI (EEG-fMRI) in patients with partial epilepsy. METHODS We studied eight patients who had a diagnosis of partial epilepsy and active spiking on routine scalp EEG recording. Sessions of continuous EEG-fMRI were recorded, and spikes (identified after online artifact removal) were used as events in the fMRI analysis. Regions of BOLD signal change in response to interictal epileptic discharge were assessed and epileptogenic zone localization was electroclinically identified. RESULTS Eight patients with partial epilepsy were recruited (6 males, 2 females, mean age 18.5, mean onset age range 0.5-29). Two who underwent EEG-fMRI were excluded from further analysis: one due to absence of epileptic discharges, the other due to excessive head motion. Eight sessions of EEG-fMRI scanning in 6 patients were obtained: 6 with activation and deactivation, one with activation only, and one with deactivation only. Focal activations corresponding to electroclinical localization occurred in 7 sessions, 5 of which were maximal. CONCLUSIONS Maximally activated areas detected by EEG-fMRI in patients with partial epilepsy appear to be concordant with epileptogenic areas as defined by electroclinical localization data. In most patients with focal epilepsy, positive BOLD responses seem to be mainly in epileptogenic zones and the corresponding contralateral areas. Responses to deactivation seem less associated with IEDs. So EEG-fMRI is a useful tool to study the pathophysiological mechanisms of epilepsy and may assist in presurgical evaluation of epilepsy.
Collapse
Affiliation(s)
- Yonghong Liu
- Department of Neurology, West China Hospital, Si Chuan University, Chengdu, Sichuan, P. R. China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
|
27
|
Variability of the hemodynamic response as a function of age and frequency of epileptic discharge in children with epilepsy. Neuroimage 2007; 40:601-614. [PMID: 18221891 DOI: 10.1016/j.neuroimage.2007.11.056] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Revised: 10/30/2007] [Accepted: 11/28/2007] [Indexed: 11/20/2022] Open
Abstract
EEG-fMRI is a non-invasive tool to investigate epileptogenic networks in patients with epilepsy. Different patterns of BOLD responses have been observed in children as compared to adults. A high intra- and intersubject variability of the hemodynamic response function (HRF) to epileptic discharges has been observed in adults. The actual HRF to epileptic discharges in children and its dependence on age are unknown. We analyzed 64 EEG-fMRI event types in 37 children (3 months to 18 years), 92% showing a significant BOLD response. HRFs were calculated for each BOLD cluster using a Fourier basis set. After excluding HRFs with a low signal-to-noise ratio, 126 positive and 98 negative HRFs were analyzed. We evaluated age-dependent changes as well as the effect of increasing numbers of spikes. Peak time, amplitude and signal-to-noise ratio of the HRF and the t-statistic score of the cluster were used as dependent variables. We observed significantly longer peak times of the HRF in the youngest children (0 to 2 years), suggesting that the use of multiple HRFs might be important in this group. A different coupling between neuronal activity and metabolism or blood flow in young children may cause this phenomenon. Even if the t-value increased with frequent spikes, the amplitude of the HRF decreased significantly with spike frequency. This reflects a violation of the assumptions of the General Linear Model and therefore the use of alternative analysis techniques may be more appropriate with high spiking rates, a common situation in children.
Collapse
|
28
|
Jacobs J, Kobayashi E, Boor R, Muhle H, Stephan W, Hawco C, Dubeau F, Jansen O, Stephani U, Gotman J, Siniatchkin M. Hemodynamic Responses to Interictal Epileptiform Discharges in Children with Symptomatic Epilepsy. Epilepsia 2007; 48:2068-78. [PMID: 17645544 DOI: 10.1111/j.1528-1167.2007.01192.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE Simultaneous electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) (EEG-fMRI) recording is a noninvasive tool for investigating epileptogenic networks. Most EEG-fMRI studies in epilepsy have been performed in adults. Childhood epilepsies, however, differ from those in adults due to interactions between epileptogenic and developmental processes. The purpose of this study was to investigate EEG-fMRI in children with lesional epilepsies. METHODS Thirteen children with symptomatic epilepsy underwent a 20-min EEG-fMRI acquisition at 3 T under sedation-induced sleep. Statistical analysis was performed using the timing of spikes as events, modelled with hemodynamic response functions (HRFs) that peaked at 3, 5, 7, and 9 s after the spike. RESULTS Each spike type was analyzed separately, resulting in 25 studies. In 84% of the studies, blood oxygenation level-dependent (BOLD) responses were localized in the lesion or brain area presumably generating spikes. Activation (positive BOLD) corresponding with the lesion was seen in 20% and deactivation (negative BOLD) in 52% of the studies. In the area of spike generation, activation was found in 48% of studies and deactivation in 36%. CONCLUSIONS Despite the necessarily short recording times (20 min), good results could be obtained from the EEG-fMRI recordings, performed in sedated children using a high field scanner and individual HRFs. In contrast to studies in adults, deactivations in the lesion and the irritative zone were more common than activations. The impact of age, sleep, and sedation on the BOLD response might explain these findings, but future studies in children should not disregard the importance of deactivations in relation to the epileptogenic network.
Collapse
Affiliation(s)
- Julia Jacobs
- Neuropediatric Department, Christian-Albrechts-University Kiel, Schwanenweg 20, Kiel, Germany.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Plummer C, Litewka L, Farish S, Harvey AS, Cook MJ. Clinical utility of current-generation dipole modelling of scalp EEG. Clin Neurophysiol 2007; 118:2344-61. [PMID: 17889598 DOI: 10.1016/j.clinph.2007.08.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Revised: 08/14/2007] [Accepted: 08/18/2007] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To investigate the clinical utility of current-generation dipole modelling of scalp EEG in focal epilepsies seen commonly in clinical practice. METHODS Scalp EEG recordings from 10 patients with focal epilepsy, five with Benign Focal Epilepsy of Childhood (BFEC) and five with Mesial Temporal Lobe Epilepsy (MTLE), were used for interictal spike dipole modelling using Scan 4.3 and CURRY 5.0. Optimum modelling parameters for EEG source localisation (ESL) were sought by the step-wise application of various volume conductor (forward) and dipole (inverse) models. Best-fit ESL solutions (highest explained forward-fit to measured data variance) were used to characterise best-fit forward and inverse models, regularisation effect, additional electrode effect, single-to-single spike and single-to-averaged spike variability, and intra- and inter-operator concordance. Inter-parameter relationships were examined. Computation times and interface problems were recorded. RESULTS For both BFEC and MTLE, the best-fit forward model was the finite element method interpolated (FEMi) model, while the best-fit single dipole models were the rotating non-regularised and the moving regularised models. When combined, these forward-inverse models appeared to offer clinically meaningful ESL results when referenced to an averaged cortex overlay, best-fit dipoles localising to the central fissure region in BFEC and to the basolateral temporal region in MTLE. Single-to-single spike and single-to-averaged spike measures of concordance for dipole location and orientation were stronger for BFEC versus MTLE. The use of an additional pair of inferior temporal electrodes in MTLE directed best-fit dipoles towards the basomesial temporal region. Inverse correlations were noted between unexplained variance (RD) and dipole strength (Amp), RD and signal to noise ratio (SNR), and SNR and confidence ellipsoid (CE) volume. Intra- and inter-operator levels of agreement were relatively robust for dipole location and orientation. Technical problems were infrequent and modelling operations were performed within 5min. CONCLUSIONS The optimal forward-inverse single dipole modelling set-up for BFEC and MTLE interictal spike analysis is the FEMi model using the combination of rotating non-regularised and moving regularised dipoles. Dipole modelling of single spikes characterises best-fit dipole location and orientation more reliably in BFEC than in MTLE for which spike averaging is recommended. SIGNIFICANCE The clinical utility of dipole modelling in two common forms of focal epilepsy strengthens the case for its place in the routine clinical work-up of patients with localisation-related epilepsy syndromes.
Collapse
Affiliation(s)
- C Plummer
- Centre for Clinical Neurosciences and Neurological Research, St. Vincent's Hospital, 5th Floor Daly Wing, 35 Victoria Parade, Fitzroy, Victoria 3065, Australia.
| | | | | | | | | |
Collapse
|
30
|
Laufs H, Duncan JS. Electroencephalography/functional MRI in human epilepsy: what it currently can and cannot do. Curr Opin Neurol 2007; 20:417-23. [PMID: 17620876 DOI: 10.1097/wco.0b013e3282202b92] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Simultaneous recording of electroencephalogram and functional MRI is being increasingly applied to the investigation of normal cerebral processes and disorders, particularly epilepsies. We will summarize recent epilepsy-related studies and appraise the clinical and scientific value of EEG/fMRI. RECENT FINDINGS Interictal and ictal EEG/fMRI can provide helpful information in the presurgical evaluation of epilepsy. At present, EEG/fMRI cannot supercede any of the current methods because validation studies are lacking, informative results are only obtained in some patients, and haemodynamic activation and deactivation patterns are not always of localizing value. EEG/fMRI data often identify distributed brain areas and can help to generate concepts of epileptogenic networks both in individual patients and groups with particular epilepsy syndromes. SUMMARY Clinically, EEG/fMRI studies may influence further investigations such as more detailed structural imaging or the planning of intracranial electrophysiological studies by generating hypotheses about the location of epileptic foci. Validation studies are underway to determine whether such clinical applications are appropriate. EEG/fMRI can also assess epileptogenic networks and changes in brain state, leading to a new dimension of understanding of dynamic cerebral processes in health and disease.
Collapse
Affiliation(s)
- Helmut Laufs
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK.
| | | |
Collapse
|
31
|
Lengler U, Kafadar I, Neubauer BA, Krakow K. fMRI correlates of interictal epileptic activity in patients with idiopathic benign focal epilepsy of childhood. Epilepsy Res 2007; 75:29-38. [PMID: 17509833 DOI: 10.1016/j.eplepsyres.2007.03.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 02/26/2007] [Accepted: 03/18/2007] [Indexed: 11/26/2022]
Abstract
EEG-correlated fMRI (EEG/fMRI) can identify alterations of brain function associated with interictal epileptiform discharges (IED). fMRI activation can localize the irritative zone and indicate functional disturbance distant from the spike focus. This might be of particular interest in paediatric epilepsy syndromes with frequent IED. Using simultaneous EEG/fMRI in a 3T MR scanner we studied blood oxygen level-dependent (BOLD) signal changes related to spontaneous IED in 10 children with typical and atypical benign focal epilepsy of childhood (BFE) or benign epileptic activity of childhood (BEAC). EEG artefacts were subtracted offline and IED were used as regressors for event-related fMRI analysis in SPM2. In four of the seven children with IED during EEG/fMRI we found IED related positive and negative signal changes (p<0.001, uncorrected). In three children we found only significant negative signal changes. At a more liberal threshold (p<0.05, uncorrected) these three children had positive signal changes congruent with the four children with significant positive signal changes. In summary, we found positive or negative signal changes in perisylvian, central, premotor and prefrontal regions. One child showed additional bilateral occipital fMRI activation. In addition to former reports our results indicated that frontal brain areas are functionally disturbed during IED corresponding to general neuropsychological findings in BFE and BEAC. We conclude that using EEG/fMRI it might be possible to localize generators of IED and functionally disturbed brain regions in children with BFE. Further studies are required to differentiate between BFE subtypes and to identify fMRI signatures of specific syndromes or corresponding neuropsychological deficits.
Collapse
Affiliation(s)
- Ulrike Lengler
- Department of Neurology, Johann Wolfgang Goethe-University and Brain Imaging Center, Frankfurt/Main, Germany.
| | | | | | | |
Collapse
|
32
|
Boor R, Jacobs J, Hinzmann A, Bauermann T, Scherg M, Boor S, Vucurevic G, Pfleiderer C, Kutschke G, Stoeter P. Combined spike-related functional MRI and multiple source analysis in the non-invasive spike localization of benign rolandic epilepsy. Clin Neurophysiol 2007; 118:901-9. [PMID: 17317297 DOI: 10.1016/j.clinph.2006.11.272] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2004] [Revised: 10/30/2006] [Accepted: 11/08/2006] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To localize the irritative zone in children by combined spike-related fMRI and EEG multiple source analysis (MSA) in children with benign rolandic epilepsy. METHODS Interictal spikes were averaged and localized using MSA, and source locations were displayed in the anatomical 3D-MRI in 11 patients (5-12 yrs, median 10). Interictal spikes were additionally recorded during the fMRI acquisition (EEG-fMRI), and the fMRI sequences were correlated off-line with the EEG spikes. RESULTS MSA revealed an initial central dipole in all patients, including the face or hand area. A second dipolar source was mostly consistent with propagated activity. BOLD activations from EEG-fMRI, consistent with the locations of the initial dipoles, were found in four patients. We found additional large areas of BOLD activations in 3 of these subjects extending into the sylvian fissure and the insula. These were identified as propagated activity by MSA using the short time differences in the source waveforms. CONCLUSIONS MSA provided reliable localization of the spike onset zone in all children with benign rolandic epilepsy. Using the combination of EEG-fMRI and MSA we were able to discriminate the spike onset zone from propagated epileptiform source activity, using the spatial resolution of the EEG-fMRI technique and the temporal resolution of the MSA. However, the sensitivity of the EEG-fMRI technique was low and further improvements of the technique are warranted. SIGNIFICANCE This study shows that a combination of EEG-fMRI and MSA may be a powerful tool to describe the irritative zone of patients with idiopathic focal epilepsies. Clinical studies in patients with non-idiopathic focal epilepsies may clarify whether both techniques can be used as complementary clinical tools to localize the onset of interictal epileptic activity in focal epilepsies.
Collapse
Affiliation(s)
- R Boor
- University Children's Hospital, Pediatric Neurology Johannes-Gutenberg University, Mainz, Germany.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Bagshaw AP, Torab L, Kobayashi E, Hawco C, Dubeau F, Pike GB, Gotman J. EEG-fMRI using z-shimming in patients with temporal lobe epilepsy. J Magn Reson Imaging 2007; 24:1025-32. [PMID: 17036359 DOI: 10.1002/jmri.20744] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To use z-shimming, a technique that reduces signal loss due to susceptibility artifacts that can result in reduced or absent activation in electroencephalography (EEG) functional MRI (fMRI) sessions in patients with temporal lobe epilepsy (TLE), to determine whether it would result in an increased ability to detect significant regions of blood oxygenation level-dependent (BOLD) signal change. MATERIALS AND METHODS Eight patients with TL EEG spikes underwent an EEG-fMRI scanning session using z-shimming. The signal intensities in the z-shimmed images were compared with those in the standard images. BOLD activation maps were created from the two sets of images using the timings of the spikes observed on the EEG. RESULTS The mean signal increase in the TLs as a result of z-shimming was 45.9%+/-4.5%. The percentage of TL voxels above a brain intensity threshold rose from 66.1%+/-7.6% to 77.6%+/-5.7%. This appreciable increase in signal did not lead to any significant differences in the statistical maps created with the two sets of functional images. CONCLUSION The results suggest that loss of signal is not the limiting factor for the detection of spike-related BOLD signal changes in patients with TLE activity.
Collapse
Affiliation(s)
- Andrew P Bagshaw
- School of Psychology, University of Birmingham, Birmingham, United Kingdom.
| | | | | | | | | | | | | |
Collapse
|
34
|
Matthews PM, Honey GD, Bullmore ET. Applications of fMRI in translational medicine and clinical practice. Nat Rev Neurosci 2006; 7:732-44. [PMID: 16924262 DOI: 10.1038/nrn1929] [Citation(s) in RCA: 187] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Functional MRI (fMRI) has had a major impact in cognitive neuroscience. fMRI now has a small but growing role in clinical neuroimaging, with initial applications to neurosurgical planning. Current clinical research has emphasized novel concepts for clinicians, such as the role of plasticity in recovery and the maintenance of brain functions in a broad range of diseases. There is a wider potential for clinical fMRI in applications ranging from presymptomatic diagnosis, through drug development and individualization of therapies, to understanding functional brain disorders. Realization of this potential will require changes in the way clinical neuroimaging services are planned and delivered.
Collapse
Affiliation(s)
- Paul M Matthews
- Centre for Functional Magnetic Resonance Imaging of the Brain, Dept. of Clinical Neurology, University of Oxford, UK.
| | | | | |
Collapse
|
35
|
Gotman J, Kobayashi E, Bagshaw AP, Bénar CG, Dubeau F. Combining EEG and fMRI: A multimodal tool for epilepsy research. J Magn Reson Imaging 2006; 23:906-20. [PMID: 16649203 DOI: 10.1002/jmri.20577] [Citation(s) in RCA: 207] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Patients with epilepsy often present in their electroencephalogram (EEG) short electrical potentials (spikes or spike-wave bursts) that are not accompanied by clinical manifestations but are of important diagnostic significance. They result from a population of abnormally hyperactive and hypersynchronous neurons. It is not easy to determine the location of the cerebral generators and the other brain regions that may be involved as a result of this abnormal activity. The possibility to combine EEG recording with functional MRI (fMRI) scanning opens the opportunity to uncover the regions of the brain showing changes in the fMRI signal in response to epileptic spikes seen in the EEG. These regions are presumably involved in the abnormal neuronal activity at the origin of epileptic discharges. This paper reviews the methodology involved in performing such studies, particularly the challenge of recording a good quality EEG inside the MR scanner while scanning is taking place, and the methods required for the statistical analysis of the combined EEG and fMRI time series. We review the results obtained in patients with different types of epileptic disorders and discuss the difficult theoretical problems raised by the interpretation of an increase (activation) and decrease (deactivation) in blood oxygen level dependent (BOLD) signal, both frequently seen in response to spikes.
Collapse
Affiliation(s)
- Jean Gotman
- Montreal Neurological Institute and Hospital, McGill University, Montréal, Québec, Canada.
| | | | | | | | | |
Collapse
|
36
|
Ishitobi M, Nakasato N, Yamamoto K, Iinuma K. Opercular to interhemispheric source distribution of benign rolandic spikes of childhood. Neuroimage 2005; 25:417-23. [PMID: 15784420 DOI: 10.1016/j.neuroimage.2004.11.040] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2004] [Revised: 05/21/2004] [Accepted: 11/30/2004] [Indexed: 11/28/2022] Open
Abstract
We evaluated the source distribution of benign rolandic spikes of childhood along and across the central sulcus in 15 patients, aged between 7 and 15 years, who suffered from seizure disorders. Previous routine EEG showed centrotemporal spikes, but none of them had major abnormalities on brain magnetic resonance imaging or neurological deficits. The equivalent current dipoles (ECDs) of the spikes measured by whole-head magnetoencephalography (MEG) were compared to the spike distributions detected by simultaneous scalp EEG according to the international 10-20 system. Locations and orientations of the MEG spikes corresponded to the EEG spike distribution as follows: superiorly oriented spike MEG dipoles in the opercular area corresponded to T3/4 negative peaks (8 spike groups in 6 patients); anteriorly oriented spike dipoles in the rolandic area corresponded to C3/4 or P3/4 negative peaks (17 spike groups in 13 patients); laterally oriented spike dipoles in the interhemispheric area corresponded to Cz/Pz negative peaks (4 spike groups in 3 patients); and others (4 spike groups in 4 patients). Rolandic spikes include three main types according to the ECD location from the opercular to the interhemispheric areas. The functional anatomy of benign rolandic spikes was correlated with partial seizure semiology. All three rolandic spike types can be explained by a precentral origin, assuming that the surface negative potential is continuous from the gyral to fissural cortices.
Collapse
Affiliation(s)
- Mamiko Ishitobi
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | | | | | | |
Collapse
|
37
|
Bagshaw AP, Hawco C, Bénar CG, Kobayashi E, Aghakhani Y, Dubeau F, Pike GB, Gotman J. Analysis of the EEG-fMRI response to prolonged bursts of interictal epileptiform activity. Neuroimage 2004; 24:1099-112. [PMID: 15670687 DOI: 10.1016/j.neuroimage.2004.10.010] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2004] [Revised: 07/22/2004] [Accepted: 10/07/2004] [Indexed: 11/17/2022] Open
Abstract
The use of combined EEG-fMRI to study interictal epileptiform activity is increasing and has great potential as a clinical tool, but the haemodynamic response to epileptiform activity remains incompletely characterised. To this end, 19 data sets from 14 patients with prolonged bursts of focal or generalised interictal epileptiform activity lasting up to 15 s were analysed. To determine whether the inclusion of the durations of the epileptic events in the general linear model resulted in increased statistical significance of activated regions, statistical maps were generated with and without the event durations. The mean differences when including the durations were a 14.5% increase in peak t value and a 29.5% increase in volume of activation. This suggests that when analysing EEG-fMRI data from patients with prolonged bursts of interictal epileptiform activity, it is better to include the event durations. To determine whether the amplitudes and latencies of the measured responses were consistent with the general linear model, the haemodynamic response functions for bursts of different durations were calculated and compared with the model predictions. The measured amplitude of the response to the shortest duration events was consistently larger than predicted, which is consistent with studies in normal subjects. For the two data sets with the widest range of event durations, the measured amplitudes increased with the durations of the events without evidence of the plateau that was expected from the general linear model. There were no consistent differences between the measured and modelled latencies.
Collapse
Affiliation(s)
- Andrew P Bagshaw
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Room 786, 3801 University Street, Montréal, Québec, Canada H3A 2B4.
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Abstract
PURPOSE OF REVIEW The purpose of this review is to consider the current and potential role of neuroimaging from an epilepsy perspective, and to illustrate that by combining appropriate imaging techniques, neuroimaging can contribute greatly to elucidating the basic mechanisms of the various forms of epileptic disorders. RECENT FINDINGS New magnetic resonance imaging sequences (magnetization transfer imaging) and positron emission tomography ligands (serotonergic system) were biologically validated in large groups of patients with localization-related epilepsies. Investigations in genetically determined homogenous patient populations (PAX6, juvenile myoclonic epilepsy) have strengthened the link between genetic defects and neuropathological targets (anterior commissure, thalamus). Magnetic resonance spectroscopy and electroencephalogram-triggered functional magnetic resonance imaging provided converging evidence for a key role of the thalamus in the generation of generalized seizures. The role of functional magnetic resonance imaging in identifying eloquent areas of cortex and its relationship to structural lesions, in particular malformations of cortical development, has been further elucidated. Longitudinal magnetic resonance imaging studies reported progressive volume loss after febrile convulsions and in active epilepsy. SUMMARY Neuroimaging is essential for improving the efficacy and safety of therapeutic, in particular, surgical procedures. Investigations of larger, more homogenous genetic disorders and longitudinal rather than cross-sectional neuroimaging studies have advanced our knowledge about the cause and effect of epileptic disorders, and will ultimately link defects in molecular genetics with specific neuropathological targets.
Collapse
Affiliation(s)
- Matthias J Koepp
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK.
| | | |
Collapse
|
39
|
Abstract
Pediatric neuroradiology is a fascinating and challenging field because there are normal changes associated with normal development and unique and unusual pathologies that occur in this population. The numerous new MR techniques first applied in the adult population are appropriate for use in the pediatric population, often with minimal modification of parameters. These new techniques will undoubtedly contribute significantly to use of pediatric neuroimaging, but the adult experience is not always directly transferable. The pediatric brain, particularly the immature brain is different in structure, has predilection for different types of disease processes, and may react differently to insults than the adult brain. As a result, the role of these techniques needs to be evaluated in the context of the pediatric brain and common pediatric disease processes.
Collapse
Affiliation(s)
- P Ellen Grant
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Gray Building B285, Boston, MA 02114, USA.
| | | |
Collapse
|