Yasuda K, Takanashi J, Sugita K, Niimi H, Iwasa H, Nakajima Y
Department of Pediatrics, Faculty of Medicine, University of Chiba.
No To Hattatsu. 1998 Sep;30(5):377-82.
We studied the location of the electric generator of photoparoxysmal discharges using a scalp-skull-brain dipole tracing (DT) method. By this method, the location of epileptic discharges on each scalp EEG was calculated as an equivalent current dipole (ECD) in 8 cases of epilepsy who had photoparoxysmal discharges. We divided these cases into groups A and B (4 cases each), comprising of patients with and without visually-induced seizures, respectively. The ECDs of the 3 cases in group A corresponded to the small area adjacent to the lateral geniculate nucleus on MRI superimposed. On the other hand, the ECDs of all cases in group B located at the corpus callosum. This study suggests the pathways of epileptic discharges from the epileptic focus are different between two groups. It is supposed that neural activity of the lateral geniculate nucleus might be responsible for the generator mechanism of photoparoxysmal discharges which evokes photosensitive epilepsy.
我们采用头皮-颅骨-脑偶极子追踪（DT）方法研究了光阵发性放电的发电部位。通过该方法，计算了8例有光阵发性放电的癫痫患者每次头皮脑电图上癫痫放电的位置，将其作为等效电流偶极子（ECD）。我们将这些病例分为A组和B组（每组4例），分别包括有和无视觉诱发性癫痫发作的患者。A组3例的ECD对应于MRI叠加时外侧膝状体附近的小区域。另一方面，B组所有病例的ECD位于胼胝体。本研究提示两组癫痫灶的癫痫放电路径不同。推测外侧膝状体的神经活动可能是诱发光敏性癫痫的光阵发性放电发生机制的原因。
