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Viateur Tuyisenge Lena Trebaul Manik Bhattacharjee Blandine Chanteloup-Forêt Carole Saubat-Guigui Ioana Mîndruţă Sylvain Rheims Louis Maillard Philippe Kahane Delphine Taussig Olivier David 《Clinical neurophysiology》2018,129(3):548-554
Objective
Intracranial electroencephalographic (iEEG) recordings contain “bad channels”, which show non-neuronal signals. Here, we developed a new method that automatically detects iEEG bad channels using machine learning of seven signal features.Methods
The features quantified signals’ variance, spatial–temporal correlation and nonlinear properties. Because the number of bad channels is usually much lower than the number of good channels, we implemented an ensemble bagging classifier known to be optimal in terms of stability and predictive accuracy for datasets with imbalanced class distributions. This method was applied on stereo-electroencephalographic (SEEG) signals recording during low frequency stimulations performed in 206 patients from 5 clinical centers.Results
We found that the classification accuracy was extremely good: It increased with the number of subjects used to train the classifier and reached a plateau at 99.77% for 110 subjects. The classification performance was thus not impacted by the multicentric nature of data.Conclusions
The proposed method to automatically detect bad channels demonstrated convincing results and can be envisaged to be used on larger datasets for automatic quality control of iEEG data.Significance
This is the first method proposed to classify bad channels in iEEG and should allow to improve the data selection when reviewing iEEG signals. 相似文献2.
《Clinical neurophysiology》2021,132(2):487-497
ObjectiveThe classical homunculus of the human primary somatosensory cortex (S1) established by Penfield has mainly portrayed the functional organization of convexial cortex, namely Brodmann area (BA) 1. However, little is known about the functions in fissural cortex including BA2 and BA3. We aim at drawing a refined and detailed somatosensory homunculus of the entire S1.MethodsWe recruited 20 patients with drug-resistant focal epilepsy who underwent stereo-electroencephalography for preoperative assessments. Direct electrical stimulation was performed for functional mapping. Montreal Neurological Institute coordinates of the stimulation sites lying in S1 were acquired.ResultsStimulation of 177 sites in S1 yielded 149 positive sites (84%), most of which were located in the sulcal cortex. The spatial distribution of different body-part representations across the S1 surface revealed that the gross medial-to-lateral sequence of body representations within the entire S1 was consistent with the classical “homunculus”. And we identified several unreported body-part representations from the sulcal cortex, such as forehead, deep elbow and wrist joints, and some dorsal body regions.ConclusionsOur results reveal general somatotopical characteristics of the entire S1 cortex and differences with the previous works of Penfield.SignificanceThe classical S1 homunculus was extended by providing further refinement and additional detail. 相似文献
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《Clinical neurophysiology》2021,132(12):2965-2978
Objective To evaluate the accuracy of automated interictal low-density electrical source imaging (LD-ESI) to define the insular irritative zone (IZ) by comparing the simultaneous interictal ESI localization with the SEEG interictal activity.Methods Long-term simultaneous scalp electroencephalography (EEG) and stereo-EEG (SEEG) with at least one depth electrode exploring the operculo-insular region(s) were analyzed. Automated interictal ESI was performed on the scalp EEG using standardized low-resolution brain electromagnetic tomography (sLORETA) and individual head models. A two-step analysis was performed: i) sublobar concordance between cluster-based ESI localization and SEEG-based IZ; ii) time-locked ESI-/SEEG analysis. Diagnostic accuracy values were calculated using SEEG as reference standard. Subgroup analysis was carried out, based on the involvement of insular contacts in the seizure onset and patterns of insular interictal activity.Results Thirty patients were included in the study. ESI showed an overall accuracy of 53% (C.I. 29–76%). Sensitivity and specificity were calculated as 53% (C.I. 29–76%), 55% (C.I. 23–83%) respectively. Higher accuracy was found in patients with frequent and dominant interictal insular spikes.Conclusions LD-ESI defines with good accuracy the insular implication in the IZ, which is not possible with classical interictal scalp EEG interpretation.SignificanceAutomated LD-ESI may be a valuable additional tool to characterize the epileptogenic zone in epilepsies with suspected insular involvement. 相似文献
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Curtis M Tassi L Lo Russo G Mai R Cossu M Francione S 《The European journal of neuroscience》2005,22(11):2971-2976
It is commonly assumed that interictal spikes (ISs) in focal epilepsies set off a period of inhibition that transiently reduces tissue excitability. Post-spike inhibition was described in experimental models but was never demonstrated in the human epileptic cortex. In the present study post-spike excitability was retrospectively evaluated on intracerebral stereo-electroencephalographic recordings performed in the epileptogenic cortex of five patients suffering from drug-resistant focal epilepsy secondary to Taylor-type neocortical dysplasias. Patients typically presented with highly periodic interictal spiking activity at 2.33 +/- 0.87 Hz (mean +/- SD) in the dysplastic region. During the stereo-electroencephalographic procedure, low-frequency stimulation at 1 Hz was systematically performed for diagnostic purposes to identify the epileptogenic zone. The probability of evoking an IS during the interspike period in response to 1-Hz stimuli delivered close to the ictal-onset zone was examined. Stimuli that occurred early after a spontaneous IS (within 70% of the inter-IS period) had a very low probability of generating a further IS. On the contrary, stimuli delivered during the late inter-IS period had the highest probability of evoking a further IS. The generation of stimulus-evoked ISs is occluded for several hundred milliseconds after the occurrence of a preceding spike discharge. As previously shown in animal models, these findings suggest that, during focal, periodic interictal spiking, human neocortical excitability is phasically controlled by post-spike inhibition. 相似文献
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目的:探讨立体定向技术植入的深部电极构成的立体定位脑电图对药物难治性癫(痫)致(痫)灶的定位阳性率和近期手术效果.方法:对于头皮脑电、CT、MRI难以确定致(痫)灶位置的药物难治性癫(痫)的10例患者,采用立体定向方法植入深部电极2根6例、3根4例,长程记录发作3次以上,结合发作间期和发作期深部电极脑电确定致(痫)灶,外科治疗后随访术后发作改善情况.结果:外科术前监测106例,实行手术33例,其中10例患者需要植入深部电极辅助定位.此10例中无植入电极并发症,均有发作间期局灶(痫)样放电和发作期局灶性起源位置,其中局灶性起源7例、区域性起源3例.参照深部电极脑电图结果采取外科手术治疗,术后9~20个月,癫(痫)缓解4例,2例好转90%以上,4例好转50%以上,无手术并发症.结论:立体定位脑电图可对头皮脑电难以确定致(痫)灶的患者进行定位,为外科提供定位性诊断信息,提高外科手术效果. 相似文献
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《Clinical neurophysiology》2021,132(2):520-529
ObjectiveTo visualize and validate the dynamics of interhemispheric neural propagations induced by single-pulse electrical stimulation (SPES).MethodsThis methodological study included three patients with drug-resistant focal epilepsy who underwent measurement of cortico-cortical spectral responses (CCSRs) during bilateral stereo-electroencephalography recording. We delivered SPES to 83 electrode pairs and analyzed CCSRs recorded at 268 nonepileptic electrode sites. Diffusion-weighted imaging (DWI) tractography localized the interhemispheric white matter pathways as streamlines directly connecting two electrode sites. We localized and visualized the putative SPES-related fiber activation, at each 1-ms time window, based on the propagation velocity defined as the DWI-based streamline length divided by the early CCSR peak latency.ResultsThe resulting movie, herein referred to as four-dimensional tractography, delineated the spatiotemporal dynamics of fiber activation via the corpus callosum and anterior commissure. Longer streamline length was associated with delayed peak latency and smaller amplitude of CCSRs. The cortical regions adjacent to each fiber activation site indeed exhibited CCSRs at the same time window.ConclusionsOur four-dimensional tractography successfully animated neural propagations via distinct interhemispheric pathways.SignificanceOur novel animation method has the potential to help investigators in addressing the mechanistic significance of the interhemispheric network dynamics supporting physiological function. 相似文献
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《Clinical neurophysiology》2020,131(12):2781-2792
ObjectiveTo determine the optimal depth electrode montages for the assessment of effective connectivity based on single-pulse electrical stimulation (SPES). To determine the effect of SPES locations on the extent of resulting neuronal propagations.MethodsWe studied 14 epilepsy patients who underwent invasive monitoring with depth electrodes and measurement of cortico-cortical evoked potentials (CCEPs) and cortico-cortical spectral responses (CCSRs). We determined the effects of electrode montage and stimulus sites on the CCEP/CCSR amplitudes.ResultsBipolar and Laplacian montages effectively reduced the degree of SPES-related signal deflections at extra-cortical levels, including outside the brain, while maintaining those at the cortical level. SPES of structures more proximal to the deep white matter, compared to the cortical surface, elicited greater CCEPs and CCSRs.ConclusionsOn depth electrode recording, bipolar and Laplacian montages are suitable for measurement of near-field CCEPs and CCSRs. SPES of the white matter axons may induce neuronal propagations to extensive regions of the cerebral cortex.SignificanceThis study helps to establish the practical guidelines on the diagnostic use of CCEPs/CCSRs. 相似文献
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Stephan Meesters Pauly Ossenblok Albert Colon Louis Wagner Olaf Schijns Paul Boon Luc Florack Andrea Fuster 《Clinical neurophysiology》2018,129(6):1276-1290
Objective
The interictal epileptic discharges (IEDs) occurring in stereotactic EEG (SEEG) recordings are in general abundant compared to ictal discharges, but difficult to interpret due to complex underlying network interactions. A framework is developed to model these network interactions.Methods
To identify the synchronized neuronal activity underlying the IEDs, the variation in correlation over time of the SEEG signals is related to the occurrence of IEDs using the general linear model. The interdependency is assessed of the brain areas that reflect highly synchronized neural activity by applying independent component analysis, followed by cluster analysis of the spatial distributions of the independent components. The spatiotemporal interactions of the spike clusters reveal the leading or lagging of brain areas.Results
The analysis framework was evaluated for five successfully operated patients, showing that the spike cluster that was related to the MRI-visible brain lesions coincided with the seizure onset zone. The additional value of the framework was demonstrated for two more patients, who were MRI-negative and for whom surgery was not successful.Conclusions
A network approach is promising in case of complex epilepsies.Significance
Analysis of IEDs is considered a valuable addition to routine review of SEEG recordings, with the potential to increase the success rate of epilepsy surgery. 相似文献10.
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