Celesia G G, Parmeggiani L, Brigell M
Loyola University of Chicago, Stritch School of Medicine, Department of Neurology, Maywood, IL 60153.
Electroencephalogr Clin Neurophysiol. 1994 Apr;90(4):316-9. doi: 10.1016/0013-4694(94)90151-1.
A 72-year-old woman with epilepsia partialis continua (EPC) of the right foot is presented. Rhythmic myoclonic jerks were localized to the 1st and 2nd toes of the right foot and persisted for 72 h. EEG/video monitoring did not show any epileptiform transient in association with myoclonic jerks. MRI and MRA demonstrated an arterio-venous malformation involving the left fronto-parietal parasagittal area. Using the EMG signal from the myoclonic jerk we back-averaged the EEG 640 msec before and after the onset of the twitch. A negative-positive deflection was observed preceding the myoclonic jerks by 128-188 msec. Voltage topographic mapping showed a negative maximum in the left centro-parietal region. A multiple spatio-temporal dipole model was applied to the back-averaged deflection preceding the myoclonus. The patient's MRI was used to determine the center of the best fitting sphere, and the model was corrected accordingly. The best dipole solution consisted of 3 dipoles localized in the parasagittal frontal cortex, in the location of the motor representation for the foot. The utilization of a combined technique of back-averaging from the myoclonus and dipole source localization supported the epileptogenic etiology in this case.
本文介绍了一位72岁患有右脚持续性部分性癫痫（EPC）的女性患者。节律性肌阵挛性抽搐局限于右脚的第一和第二脚趾，并持续了72小时。脑电图/视频监测未显示任何与肌阵挛性抽搐相关的癫痫样瞬变。磁共振成像（MRI）和磁共振血管造影（MRA）显示左侧额顶叶矢状旁区存在动静脉畸形。利用肌阵挛性抽搐的肌电图信号，我们对抽搐发作前后640毫秒的脑电图进行了反向平均。在肌阵挛性抽搐前128 - 188毫秒观察到一个正负偏转。电压地形图显示左侧中央顶叶区域有最大负电位。对肌阵挛前的反向平均偏转应用了多时空偶极子模型。利用患者的MRI确定最佳拟合球的中心，并相应地对模型进行校正。最佳偶极子解由3个偶极子组成，位于矢状旁额叶皮层，即足部运动代表区的位置。在这种情况下，肌阵挛反向平均和偶极子源定位相结合的技术支持了癫痫病因。
