Magnetoencepharographic analyses by spatial filtering for child patients with epilepsy

109例患者行脑磁图（MEG）检查。脑磁图数据由北海道大学医院的306ch头盔状梯度仪（矢量视图系统，Neuromag Oy斯德哥尔摩，瑞典）以600 Hz采样率采集。根据国际抗癫痫联盟（1987）对癫痫类型和综合征的分类，主观患者分为：症状性定位相关癫痫（SLRE） 85例，特发性定位相关癫痫（ILRE） 15例，症状性全面性癫痫（SGE） 2例，特发性全面性癫痫（IGE） 2例。常规单偶极子分析可以解决83例（SLRE 65例，ILRE 12例，SGE 3例，IGE 1例，UDE 2例）的数据集，在大脑皮层特定回中存在显著的等效电流偶极子聚类，并证实其癫痫表现和其他电临床表现。对其余16例（SLRE 10例、ILRE 3例、SGE 2例、IGE 1例）多灶性或广泛性癫痫样活动进行动态统计参数映射（dSPM）分析，可合理评价为MEG活动多灶性或广泛性。最后，我们对其余10例低幅幅节律性脑磁图癫痫样活动进行时频分析：短时傅立叶变换（SFT），显示出显著的癫痫区，因为节律性活动的分布与癫痫发作区显示有很好的相关性。通过单偶极子分析、空间滤波分析、dSPM和时频分析，SFT成功地展示了癫痫患者的癫痫区分布，MEG分析被认为对几乎所有癫痫患者的术前评估或癫痫综合征的诊断都是有用的。少

One hundred nine patients underwent magnetoencephalographic (MEG) study. MEG data were collected by 306ch helmet-shape gradiometers (Vector View System, Neuromag Oy Stockholm, Sweden) with 600 Hz sampling rate at Hokkaido University Hospital.According to classification of epileptic types and syndromes by International League against Epilepsy (1987), subjective patients were classified as following: 85 cases with symptomatic localization related epilepsy (SLRE), 15 cases with idiopathic localization related epilepsy (ILRE), 2 cases with symptomatic generalized epilepsy (SGE) and 2 cases with idiopathic generalized epilepsy (IGE).Conventional single dipole analysis could solve the data sets of 83 cases (65 cases with SLRE, 12 cases with ILRE, 3 cases with SGE, a case with IGE, 2 cases with UDE) with significant clustering of equivalent current dipoles in a specific gyrus in cerebral cortex, and with confirmation in their seizure manifestation and other electro-clinical findings.Then we u … More sed spatial filtering analysis: dynamic statistical parametric mapping (dSPM) for the rest of cases and 16 cases (10 cases with SLRE, 3 cases with ILRE, 2 cases with SGE, a case with IGE) with multi-focal or widespread epileptiform activities could be evaluated reasonably as multi-focal or widespread distribution of MEG activities.Finally we applied time frequency analysis: short time Fourier transforms (SFT) for remaining 10 cases with low amplitude rhythmic magnetoencephalographic epileptiform activities and it showed the significant epileptogenic area, since the distribution of rhythmic activities were well correlated to the demonstration of ictal onset area.By means of single dipole analysis, spatial filtering analysis: dSPM and time-frequency analysis: SFT successfully demonstrated the distribution of the epileptogenic area in patients with epilepsy MEG analysis was supposed to be useful for almost every patient with epilepsy for presurgical evaluation or the diagnosis of the epileptic syndromes. Less