将脑电图带回大脑:多个离散源的力量。

Taking the EEG Back Into the Brain: The Power of Multiple Discrete Sources.

作者信息

Scherg Michael, Berg Patrick, Nakasato Nobukazu, Beniczky Sándor

机构信息

Research Department, BESA GmbH, Gräfelfing, Germany.

Department of Epileptology, Tohoku University, Sendai, Japan.

出版信息

Front Neurol. 2019 Aug 20;10:855. doi: 10.3389/fneur.2019.00855. eCollection 2019.

Abstract

In contrast to many neuroimaging modalities, clinical interpretation of EEG does not take advantage of post-processing and digital signal analysis. In most centers, EEG is still interpreted at sensor level, exactly as half a century ago. A major task in clinical EEG interpretation is the identification of interictal epileptiform discharges (IEDs). However, due to the overlap of background activity, IEDs can be hard to detect in the scalp EEG. Since traditional montages, like bipolar and average reference, are linear transformations of the recorded channels, the question is whether we can provide linear transformations of the digital EEG to take it back into the brain, at least on a macroscopic level. The goal is to improve visibility of epileptiform activities and to separate out most of the overlap. Multiple discrete sources provide a stable linear inverse to transform the EEG into source space with little cross-talk between source regions. The model can be based on a few dipoles or regional sources, adapted to the individual EEG and MRI data, or on selected standard sources evenly distributed throughout the brain, e.g. below the 25 EEG standard electrodes. Auditory and somatosensory evoked potentials serve as teaching examples to show how various source spaces can reveal the underlying source components including their loss or alteration due to lesions. Source spaces were able to reveal the propagation of source activities in frontal IEDs and the sequential activation of the major nodes of the underlying epileptic network in myoclonic epilepsy. The power of multiple discrete sources in separating the activities of different brain regions was also evident in the ongoing EEG of cases with frontal cortical dysplasia and bitemporal lobe epilepsy. The new source space 25 made IEDs more clearly visible over the EEG background signals. The more focal nature of source vs. scalp space was quantitatively confirmed using a new measurement of focality. Multiple discrete sources have the power to transform the EEG back into the brain by defining new EEG traces in source space. Using standard source space 25, these can provide for improved clinical interpretation of EEG.

摘要

与许多神经成像模态不同,脑电图(EEG)的临床解读并未利用后处理和数字信号分析技术。在大多数中心,EEG仍像半个世纪前那样在传感器层面进行解读。临床EEG解读的一项主要任务是识别发作间期癫痫样放电(IEDs)。然而,由于背景活动的重叠,IEDs在头皮EEG中可能很难被检测到。由于传统的导联方式,如双极导联和平均参考导联,是对记录通道的线性变换,问题在于我们是否能够提供数字EEG的线性变换,以便至少在宏观层面将其还原到大脑中。目标是提高癫痫样活动的可见性,并分离出大部分重叠部分。多个离散源提供了一个稳定的线性逆变换,可将EEG转换为源空间,且源区域之间的串扰很小。该模型可以基于几个偶极子或区域源,根据个体的EEG和MRI数据进行调整,也可以基于均匀分布在整个大脑中的选定标准源,例如在25个EEG标准电极下方。听觉和体感诱发电位作为教学示例,展示了各种源空间如何揭示潜在的源成分,包括由于病变导致的成分缺失或改变。源空间能够揭示额叶IEDs中源活动的传播以及肌阵挛性癫痫中潜在癫痫网络主要节点的顺序激活。在额叶皮质发育异常和双侧颞叶癫痫病例的持续EEG中,多个离散源在分离不同脑区活动方面的能力也很明显。新的源空间25使IEDs在EEG背景信号上更清晰可见。使用一种新的聚焦度测量方法,定量地证实了源空间与头皮空间相比更具局灶性。多个离散源有能力通过在源空间中定义新的EEG轨迹将EEG还原到大脑中。使用标准源空间25,这些可以改善EEG的临床解读。

https://cdn.ncbi.nlm.nih.gov/pmc/blobs/162b/6710389/791e729a0c7e/fneur-10-00855-g0001.jpg

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