Ochi A, Otsubo H, Chitoku S, Hunjan A, Sharma R, Rutka J T, Chuang S H, Kamijo K, Yamazaki T, Snead O C
Bloorview Epilepsy Research Program, Department of Pediatrics, The Hospital for Sick Children and the University of Toronto, Ontario, Canada.
Epilepsia. 2001 Apr;42(4):483-90. doi: 10.1046/j.1528-1157.2001.27000.x.
We evaluated dipole localizations of independent neighboring interictal spike foci using scalp electroencephalogram (EEG) to identify neuronal generators of epileptic discharges.
Three pediatric patients with extratemporal lobe epilepsy who had two independent neighboring interictal spike foci on scalp EEG were studied. Prolonged video EEG was digitally recorded from 19 scalp electrodes, whose positions were registered using a three-dimensional digitizer. Interictal spikes were visually selected based on negative phase reversals on bipolar montages. We analyzed the dipole position and moment of each spike using a single moving dipole and three-shell spherical head model. The dipoles were overlaid onto magnetic resonance (MR) images and divided into two groups based on two spike foci.
The dipoles of the two groups were oriented either tangentially or radially to the scalp in close proximity to each other. The dipoles oriented radially were located underneath the electrode with a negative peak; those oriented tangentially were between electrodes with a negative and positive peak. The positions of tangential dipoles were more concentrated than those of radial dipoles. The epileptogenic regions corresponded to the dipole localizations. Surgical excisions were performed based on the results of electrocorticography. After surgery, two patients were seizure free, and one had rare seizures (follow-up period, 13-31 months).
We showed that dipoles in close proximity but with different orientations projected two negative maxima on scalp EEG in three patients with extratemporal localization-related epilepsy. Equivalent current dipole analysis of individual interictal spikes can provide useful information about the epileptogenic zone in these patients.
我们利用头皮脑电图（EEG）评估独立相邻发作间期棘波灶的偶极定位，以确定癫痫放电的神经元起源。
研究了3例颞叶外癫痫患儿，他们的头皮EEG上有两个独立相邻的发作间期棘波灶。通过19个头皮电极进行长时间视频EEG数字记录，电极位置使用三维数字化仪进行定位。根据双极导联上的负相反转在视觉上选择发作间期棘波。我们使用单个移动偶极和三层球头模型分析每个棘波的偶极位置和矩。将偶极叠加到磁共振（MR）图像上，并根据两个棘波灶分为两组。
两组偶极彼此紧邻，分别沿头皮切线方向或径向排列。径向排列的偶极位于负峰电极下方；切线排列的偶极位于正负峰电极之间。切线偶极的位置比径向偶极更集中。致痫区域与偶极定位相对应。根据皮质脑电图结果进行手术切除。术后，2例患者无癫痫发作，1例患者有罕见发作（随访期13 - 31个月）。
我们发现，在3例颞叶外定位相关癫痫患者中，紧邻但方向不同的偶极在头皮EEG上投射出两个负最大值。对单个发作间期棘波进行等效电流偶极分析可为这些患者的致痫区提供有用信息。
