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  • 1
    Online-Ressource
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    Subject‐level reliability analysis of fast fMRI with application to epilepsy
    Wiley ; 2017
    In:  Magnetic Resonance in Medicine Vol. 78, No. 1 ( 2017-07)
    Details
    In: Magnetic Resonance in Medicine, Wiley, Vol. 78, No. 1 ( 2017-07)
    Kurzfassung: Recent studies have applied the new magnetic resonance encephalography (MREG) sequence to the study of interictal epileptic discharges (IEDs) in the electroencephalogram (EEG) of epileptic patients. However, there are no criteria to quantitatively evaluate different processing methods, to properly use the new sequence. Methods We evaluated different processing steps of this new sequence under the common generalized linear model (GLM) framework by assessing the reliability of results. A bootstrap sampling technique was first used to generate multiple replicated data sets; a GLM with different processing steps was then applied to obtain activation maps, and the reliability of these maps was assessed. Results We applied our analysis in an event‐related GLM related to IEDs. A higher reliability was achieved by using a GLM with head motion confound regressor with 24 components rather than the usual 6, with an autoregressive model of order 5 and with a canonical hemodynamic response function (HRF) rather than variable latency or patient‐specific HRFs. Comparison of activation with IED field also favored the canonical HRF, consistent with the reliability analysis. Conclusion The reliability analysis helps to optimize the processing methods for this fast fMRI sequence, in a context in which we do not know the ground truth of activation areas. Magn Reson Med 78:1–1, 2017. © 2016 International Society for Magnetic Resonance in Medicine
    Materialart: Online-Ressource
    ISSN: 0740-3194 , 1522-2594
    URL: Issue
    URL: Article
    DOI: 10.1002/mrm.v78.1
    DOI: 10.1002/mrm.26792
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2017
    ZDB Id: 1493786-4
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  • 2
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    Epileptic networks in action: Synchrony between distant hemodynamic responses
    Wiley ; 2017
    In:  Annals of Neurology Vol. 82, No. 1 ( 2017-07), p. 57-66
    Details
    In: Annals of Neurology, Wiley, Vol. 82, No. 1 ( 2017-07), p. 57-66
    Kurzfassung: Structural and functional imaging studies in focal epilepsy often reveal distributed regions of abnormality. These are interpreted as representing the existence of epileptic networks, but the presence of actual neuronal interactions between these regions has not been demonstrated. We sought to determine whether the distributed hemodynamic responses often seen in functional magnetic resonance imaging (fMRI) studies of scalp interictal epileptic discharges (IEDs) actually correspond to synchronized neuronal activities when examining the intracerebral electroencephalogram (iEEG) at distant nodes of the network. Methods We studied 28 patients who underwent first EEG‐fMRI and then iEEG, and had significant hemodynamic responses in the gray matter. We coregistered the hemodynamic responses to the iEEG electrode contact positions and analyzed synchrony, measured by correlation, between IEDs recorded by iEEG in regions with and without hemodynamic responses. Results The synchrony of intracerebral IED activity between pairs of regions showing a hemodynamic response was higher compared to that between pairs of regions without ( p   〈  0.0001) and between pairs of regions, one with and one without hemodynamic response ( p   〈  0.0001). These differences were found during the interictal periods with IEDs but were absent during the interictal periods without IEDs. Higher synchrony was also observed between regions involved at seizure onset ( p   〈  0.0001). Interpretation EEG‐fMRI studies are unique in their ability to reveal hemodynamic concomitants of IEDs anywhere in the brain. This study proves that iEEG activity is synchronized between these regions of hemodynamic response, thus demonstrating the existence of an actual neuronally based interictal epileptic network. This also validates the EEG‐fMRI approach to reveal this network noninvasively. Ann Neurol 2017;82:57–66
    Materialart: Online-Ressource
    ISSN: 0364-5134 , 1531-8249
    URL: Issue
    URL: Article
    DOI: 10.1002/ana.v82.1
    DOI: 10.1002/ana.24973
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2017
    ZDB Id: 2037912-2
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  • 3
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    WONOEP appraisal: Network concept from an imaging perspective
    Wiley ; 2019
    In:  Epilepsia Vol. 60, No. 7 ( 2019-07), p. 1293-1305
    Details
    In: Epilepsia, Wiley, Vol. 60, No. 7 ( 2019-07), p. 1293-1305
    Kurzfassung: Neuroimaging techniques applied to a variety of organisms—from zebrafish, to rodents to humans—can offer valuable insights into neuronal network properties and their dysfunction in epilepsy. A wide range of imaging methods used to monitor neuronal circuits and networks during evoked seizures in animal models and advances in functional magnetic resonance imaging (fMRI) applied to patients with epilepsy were discussed during the XIV Workshop on Neurobiology of Epilepsy (XIV WONOEP) organized in 2017 by the Neurobiology Commission of the International League Against Epilepsy (ILAE). We review the growing number of technological approaches developed, as well as the current state of knowledge gained from studies applying these advanced imaging approaches to epilepsy research.
    Materialart: Online-Ressource
    ISSN: 0013-9580 , 1528-1167
    URL: Issue
    URL: Article
    DOI: 10.1111/epi.2019.60.issue-7
    DOI: 10.1111/epi.16067
    RVK:
    XA 10000
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2019
    ZDB Id: 2002194-X
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  • 4
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    Swallowing‐related neural oscillation: an intracranial EEG study
    Wiley ; 2021
    In:  Annals of Clinical and Translational Neurology Vol. 8, No. 6 ( 2021-06), p. 1224-1238
    Details
    In: Annals of Clinical and Translational Neurology, Wiley, Vol. 8, No. 6 ( 2021-06), p. 1224-1238
    Kurzfassung: Swallowing is a unique movement due to the indispensable orchestration of voluntary and involuntary movements. The transition from voluntary to involuntary swallowing is executed within milliseconds. We hypothesized that the underlying neural mechanism of swallowing would be revealed by high‐frequency cortical activities. Methods Eight epileptic participants fitted with intracranial electrodes over the orofacial cortex were asked to swallow a water bolus and cortical oscillatory changes, including the high γ band (75–150 Hz) and β band (13–30 Hz), were investigated at the time of mouth opening, water injection, and swallowing. Results Increases in high γ power associated with mouth opening were observed in the ventrolateral prefrontal cortex (VLPFC) with water injection in the lateral central sulcus and with swallowing in the region along the Sylvian fissure. Mouth opening induced a decrease in β power, which continued until the completion of swallowing. The high γ burst of activity was focal and specific to swallowing; however, the β activities were extensive and not specific to swallowing. In the interim between voluntary and involuntary swallowing, swallowing‐related high γ power achieved its peak, and subsequently, the power decreased. Interpretation We demonstrated three distinct activities related to mouth opening, water injection, and swallowing induced at different timings using high γ activities. The peak of high γ power related to swallowing suggests that during voluntary swallowing phases, the cortex is the main driving force for swallowing as opposed to the brain stem.
    Materialart: Online-Ressource
    ISSN: 2328-9503 , 2328-9503
    URL: Issue
    URL: Article
    DOI: 10.1002/acn3.v8.6
    DOI: 10.1002/acn3.51344
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2021
    ZDB Id: 2740696-9
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  • 5
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    Internodular functional connectivity in heterotopia‐related epilepsy
    Wiley ; 2019
    In:  Annals of Clinical and Translational Neurology Vol. 6, No. 6 ( 2019-06), p. 1010-1023
    Details
    In: Annals of Clinical and Translational Neurology, Wiley, Vol. 6, No. 6 ( 2019-06), p. 1010-1023
    Kurzfassung: A vast network involving the nodules and overlying cortices is believed to be responsible for the epileptogenicity in gray matter heterotopia with multiple nodules, which often associated with difficult‐to‐treat epilepsy. We sought to determine if functional magnetic resonance imaging (fMRI) could detect internodular functional connectivity (FC), and if this connectivity reflects an actual synchronized neuronal activity and partakes in epileptogenicity. Methods We studied 16 epilepsy patients with multiple heterotopic nodules; eight underwent subsequent intracerebral EEG. We examined the internodular FC using fMRI and its correspondence with internodular synchrony of intracerebral interictal activity. We then compared the spreading speed of ictal activity between connected and unconnected nodules; and the FC among possible combinations of nodule pairs in terms of their involvement at seizure onset. Results Seventy nodules were studied: 83% have significant connection to at least one other nodule. Among the 49 pairs studied with intracerebral EEG, (1) synchronized interictal activity is more prevalent in fMRI‐connected pairs ( P   〈  0.05), (2) ictal activity spreads faster between connected pairs ( P   〈  0.0001), and (3) stronger FC was observed between pairs in which both nodules were involved at seizure onset ( P   〈  0.01). Interpretation fMRI could reliably and noninvasively detect the FC between heterotopic nodules. These functional connections correspond to the synchrony of interictal epileptic activity between the nodules and to the ability of nodules to generate synchronous seizure onsets or rapid seizure spread. These findings may help in understanding the complexity of the epileptogenic network in multiple heterotopic nodules and better targeting the likely epileptogenic nodules.
    Materialart: Online-Ressource
    ISSN: 2328-9503 , 2328-9503
    URL: Issue
    URL: Article
    DOI: 10.1002/acn3.2019.6.issue-6
    DOI: 10.1002/acn3.769
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2019
    ZDB Id: 2740696-9
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  • 6
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    Coupling between infraslow activities and high‐frequency oscillations precedes seizure onset
    Wiley ; 2020
    In:  Epilepsia Open Vol. 5, No. 3 ( 2020-09), p. 501-506
    Details
    In: Epilepsia Open, Wiley, Vol. 5, No. 3 ( 2020-09), p. 501-506
    Kurzfassung: Infraslow activities and high‐frequency oscillations (HFOs) are observed in seizure‐onset zones. However, the relation between them remains unclear. In this study, we investigated phase‐amplitude coupling between infraslow phase (0.016‐1 Hz) and HFOs' amplitude of focal impaired awareness seizures followed by focal to bilateral tonic‐clonic seizures, in a 28‐year‐old right‐handed man with a dysembryoplastic neuroepithelial tumor. We recorded five habitual seizures. After the time of seizure onset, a significant increase in the power of HFOs was observed, and the power was significantly coupled with θ (4‐8 Hz) phase. In contrast, coupling of infraslow activities and HFOs surged a few minutes before the seizure‐onset time, and ictal HFOs discharged after that. Collectively, our results show that coupling of infraslow activities and HFOs precedes the seizure‐onset time. We infer that such coupling may be a potential biomarker for seizure prediction.
    Materialart: Online-Ressource
    ISSN: 2470-9239 , 2470-9239
    URL: Issue
    URL: Article
    DOI: 10.1002/epi4.v5.3
    DOI: 10.1002/epi4.12425
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2020
    ZDB Id: 2863427-5
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  • 7
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    Association between scalp and intracerebral electroencephalographic seizure‐onset patterns: A study in different lesional pathological substrates
    Wiley ; 2018
    In:  Epilepsia Vol. 59, No. 2 ( 2018-02), p. 420-430
    Details
    In: Epilepsia, Wiley, Vol. 59, No. 2 ( 2018-02), p. 420-430
    Kurzfassung: Our purpose was to determine the correlation between scalp electroencephalography ( EEG ) and intracerebral EEG ( iEEG ) seizure‐onset patterns in patients with focal lesional epilepsy to determine whether scalp seizure‐onset patterns can be specific to intracerebral seizure‐onset patterns and to lesion type. Methods We retrospectively analyzed 61 patients with focal epilepsy and a structural magnetic resonance imaging ( MRI )‐visible lesion, who first underwent extensive scalp recordings and then iEEG studies (stereo‐ EEG ) for presurgical evaluation, and who showed an iEEG seizure onset in the lesional/perilesional area. Five seizure‐onset patterns were recognized on scalp EEG , and 7 on iEEG , and in each patient, only the predominant scalp and iEEG seizure‐onset patterns were compared. Because scalp and iEEG recordings were acquired at different times, we followed strict criteria based on semiology and topography to match scalp with intracerebral seizures. Results Seventy‐one pairs of seizure‐onset patterns matched between scalp and iEEG were identified. Each scalp pattern did not correspond to a single intracerebral pattern, but there were significant associations: (1) paroxysmal fast activity (≥13 Hz) at scalp onset was associated with low‐voltage fast activity at iEEG onset ( P 〈 .001), with malformations of cortical development ( P 〈 .001), and with superficial seizure‐onset zone based on iEEG ( P 〈 .001); (2) rhythmic slow activity ( 〈 13 Hz) at scalp onset was associated with low‐frequency high‐amplitude periodic spikes at iEEG onset ( P = .0014), with medial temporal atrophy/sclerosis ( P 〈 .001), and with deep seizure‐onset zone ( P 〈 .001); and (3) repetitive epileptiform discharge at scalp onset was associated with a burst of high‐amplitude polyspikes at iEEG onset ( P = .0002). Significance Our results disclosed that in focal epilepsy patients with seizures generated in an MRI ‐visible lesion, some scalp seizure‐onset patterns are highly associated with a specific intracerebral pattern, with specific pathologies, and with the depth of seizure‐onset zone. These findings allow the interpretation of scalp seizure‐onset patterns to be significantly more informative.
    Materialart: Online-Ressource
    ISSN: 0013-9580 , 1528-1167
    URL: Issue
    URL: Article
    DOI: 10.1111/epi.2018.59.issue-2
    DOI: 10.1111/epi.13979
    RVK:
    XA 10000
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2018
    ZDB Id: 2002194-X
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  • 8
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    Estimation of fMRI responses related to epileptic discharges using Bayesian hierarchical modeling
    Wiley ; 2023
    In:  Human Brain Mapping
    Details
    In: Human Brain Mapping, Wiley
    Kurzfassung: Simultaneous electroencephalography–functional MRI (EEG‐fMRI) is a unique and noninvasive method for epilepsy presurgical evaluation. When selecting voxels by null‐hypothesis tests, the conventional analysis may overestimate fMRI response amplitudes related to interictal epileptic discharges (IEDs), especially when IEDs are rare. We aimed to estimate fMRI response amplitudes represented by blood oxygen level dependent (BOLD) percentage changes related to IEDs using a hierarchical model. It involves the local and distributed hemodynamic response homogeneity to regularize estimations. Bayesian inference was applied to fit the model. Eighty‐two epilepsy patients who underwent EEG‐fMRI and subsequent surgery were included in this study. A conventional voxel‐wise general linear model was compared to the hierarchical model on estimated fMRI response amplitudes and on the concordance between the highest response cluster and the surgical cavity. The voxel‐wise model overestimated fMRI responses compared to the hierarchical model, evidenced by a practically and statistically significant difference between the estimated BOLD percentage changes. Only the hierarchical model differentiated brief and long‐lasting IEDs with significantly different BOLD percentage changes. Overall, the hierarchical model outperformed the voxel‐wise model on presurgical evaluation, measured by higher prediction performance. When compared with a previous study, the hierarchical model showed higher performance metric values, but the same or lower sensitivity. Our results demonstrated the capability of the hierarchical model of providing more physiologically reasonable and more accurate estimations of fMRI response amplitudes induced by IEDs. To enhance the sensitivity of EEG‐fMRI for presurgical evaluation, it may be necessary to incorporate more appropriate spatial priors and bespoke decision strategies.
    Materialart: Online-Ressource
    ISSN: 1065-9471 , 1097-0193
    URL: Article
    DOI: 10.1002/hbm.26490
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2023
    ZDB Id: 1492703-2
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  • 9
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    Subject‐level reliability analysis of fast fMRI with application to epilepsy
    Wiley ; 2017
    In:  Magnetic Resonance in Medicine Vol. 78, No. 1 ( 2017-07), p. 370-382
    Details
    In: Magnetic Resonance in Medicine, Wiley, Vol. 78, No. 1 ( 2017-07), p. 370-382
    Kurzfassung: Recent studies have applied the new magnetic resonance encephalography (MREG) sequence to the study of interictal epileptic discharges (IEDs) in the electroencephalogram (EEG) of epileptic patients. However, there are no criteria to quantitatively evaluate different processing methods, to properly use the new sequence. Methods We evaluated different processing steps of this new sequence under the common generalized linear model (GLM) framework by assessing the reliability of results. A bootstrap sampling technique was first used to generate multiple replicated data sets; a GLM with different processing steps was then applied to obtain activation maps, and the reliability of these maps was assessed. Results We applied our analysis in an event‐related GLM related to IEDs. A higher reliability was achieved by using a GLM with head motion confound regressor with 24 components rather than the usual 6, with an autoregressive model of order 5 and with a canonical hemodynamic response function (HRF) rather than variable latency or patient‐specific HRFs. Comparison of activation with IED field also favored the canonical HRF, consistent with the reliability analysis. Conclusion The reliability analysis helps to optimize the processing methods for this fast fMRI sequence, in a context in which we do not know the ground truth of activation areas. Magn Reson Med 78:370–382, 2017. © 2016 International Society for Magnetic Resonance in Medicine
    Materialart: Online-Ressource
    ISSN: 0740-3194 , 1522-2594
    URL: Issue
    URL: Article
    DOI: 10.1002/mrm.v78.1
    DOI: 10.1002/mrm.26365
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2017
    ZDB Id: 1493786-4
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  • 10
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    Low‐frequency subthalamic nucleus stimulation in Parkinson's disease: A randomized clinical trial
    Wiley ; 2014
    In:  Movement Disorders Vol. 29, No. 2 ( 2014-02), p. 270-274
    Details
    In: Movement Disorders, Wiley, Vol. 29, No. 2 ( 2014-02), p. 270-274
    Kurzfassung: Low‐frequency, bilateral stimulation of the subthalamic nucleus can improve axial symptoms of advanced Parkinson's disease (PD), but it is not particularly effective for segmental symptoms. Methods The optimal contacts for low‐frequency (60 Hz) and high‐frequency (130 Hz) single monopolar stimulation were determined. Then, in a randomized, double‐blind, prospective crossover manner, 60‐Hz and 130‐Hz stimulations via the respective optimal contacts were compared for immediate efficacy in improving the motor function of patients with PD. Results The optimal contacts for 60‐Hz stimulation were situated more ventrally than those for 130‐Hz stimulation ( P  = 0.038). Under the respective optimal, single monopolar stimulation, 60 Hz provided superior efficacy over 130 Hz in improving the total Unified Parkinson's Disease Rating Scale motor score ( P   〈  0.001) and the akinesia ( P  = 0.011) and axial motor signs ( P  = 0.012) subscores without compromising the therapeutic effect on tremor and rigidity. Conclusions Low‐frequency stimulation via the optimal contacts is effective in improving overall motor function of patients with PD. © 2014 International Parkinson and Movement Disorder Society
    Materialart: Online-Ressource
    ISSN: 0885-3185 , 1531-8257
    URL: Issue
    URL: Article
    DOI: 10.1002/mds.v29.2
    DOI: 10.1002/mds.25810
    RVK:
    XA 10000
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2014
    ZDB Id: 2041249-6
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