Visualization of epileptogenic phenomena using cross-correlation analysis: Localization of epileptic foci and propagation of epileptiform discharges
Visualization of epileptogenic phenomena using cross-correlation analysis: Localization of epileptic foci and propagation of epileptiform discharges
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DOI：
10.1109/10.748980
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发表时间：
1999-03-01
影响因子：
4.6
通讯作者：
Hayakawa, T
中科院分区：
文献类型：
--
作者：
Mizuno-Matsumoto, Y;Okazaki, K;Hayakawa, T
对药物难治性癫痫发作患者进行术前评估的主要目的是定位病灶和癫痫样放电的传播。采用AR模型、小波分析和互相关分析对难治性局灶性癫痫的皮层脑电图（ECoG）数据进行分析。为了得到时移，计算每单位时间内癫痫样放电的互相关。进一步的分析是通过一组等高线图的时移和连续的二维和三维可视化的时移图，以定位癫痫灶，并研究其传播过程。结果表明，两种类型的病灶和传播。在第一种类型中，癫痫样放电产生于局部病灶部位，并迅速扩散到其他部位。在第二种类型中，癫痫样放电的病灶，出现在前爆发后不久，局限于一个以上的网站，放电往往蔓延较慢。结果提示，癫痫的发生至少有两种机制：前者可能通过突触投射介导癫痫的传播，而后者则可能是兴奋因子的细胞外扩散起重要作用。此外，我们新开发的可视化技术的癫痫灶的定位和癫痫样放电的传播应证明是有用的癫痫病因学的研究。
The main objectives of the preoperative evaluation of a patient with medically intractable epileptic seizures are localization of the foci and propagation of the epileptiform discharges. Electrocorticographic (ECoG) data of intractable focal epilepsy were analyzed using an AR model, wavelet analysis, and cross-correlation analysis. In order to derive the time-shifts, the cross correlations of the epileptiform discharges were calculated beta een electrodes for every unit of time. Further analyses were made by means of a set of contour maps of the time-shifts and sequential two- and three-dimensional visualizations of the time-shift maps in order to localize the epileptic foci and study their propagation process. Two types of foci and propagation were revealed in the results. In the first type, epileptiform discharges were generated at localized focal sites and spread quickly to other sites. In the second type, the foci of epileptiform discharges, which appeared soon after the former bursts, were localized at more than one site, and the discharges tended to spread more slowly. The findings suggest that epileptic phenomena can be caused by at least two kinds of mechanisms in one patient: in the former, the propagation might be mediated through synaptic projections, while in the latter, the extracellular diffusion of an excitatory factor might play an important role. In addition, our newly developed visualization technique for the localization of epileptic foci and the propagation of epileptiform discharges should prove useful in the study of epileptogenesis etiology.