Willoughby John O, Fitzgibbon Sean P, Pope Kenneth J, Mackenzie Lorraine, Davey Matthew, Wilcox Robert A, Clark C Richard
Centre for Neuroscience and Department of Medicine (Neurology), School of Psychology School of Informatics & Engineering, Flinders University, Adelaide, South Australia, Australia.
Epilepsia. 2003 Nov;44(11):1406-12. doi: 10.1046/j.1528-1157.2003.20103.x.
We previously revealed an interictal increase in intensity of EEG rhythms during quiescent mental activity in the 30- to 100-Hz frequency (gamma) range in primary generalized epilepsy (PGE). We have evidence that there is induction of gamma EEG in normal subjects in response to controlled mental activity. Here we test whether mental tasks further augment interictal gamma oscillations in people with PGE.
We recorded interictal EEG from patients with PGE and partial epilepsy and compared EEG power spectral responses (increases over resting) during mental tasks.
In partial epilepsy, mental tasks (except for alternating checkerboard visual stimulation) induced 1.5- to 2.5-fold increases in power of gamma EEG. In generalized epilepsy, generalized increases of 1.5-fold in gamma EEG were induced by only two mental tasks (reading and subtraction), and enhancement of 1- to 1.5-fold in the remaining six (checkerboard, expectancy, music, learning, recalling, and a video).
Gamma EEG is less responsive to mental activation in PGE than in partial epilepsy, confirming an abnormality in gamma mechanisms in PGE. Our findings also provide a possible mechanistic link between mental activity and seizures in reading- and arithmetic-induced seizures.
我们之前发现，在原发性全身性癫痫（PGE）患者静息脑电活动期间，30至100赫兹频率（γ）范围内的脑电图节律强度在发作间期有所增加。我们有证据表明，正常受试者在受到可控的脑电活动刺激时会诱发γ脑电活动。在此，我们测试脑力任务是否会进一步增强PGE患者发作间期的γ振荡。
我们记录了PGE患者和部分性癫痫患者的发作间期脑电图，并比较了脑力任务期间脑电图功率谱响应（相对于静息状态的增加）。
在部分性癫痫中，脑力任务（除交替棋盘视觉刺激外）使γ脑电功率增加了1.5至2.5倍。在全身性癫痫中，只有两项脑力任务（阅读和减法）使γ脑电普遍增加了1.5倍，其余六项任务（棋盘、预期、音乐、学习、回忆和视频）使γ脑电增强了1至1.5倍。
与部分性癫痫相比，PGE患者的γ脑电对脑力激活的反应较弱，这证实了PGE患者γ机制存在异常。我们的研究结果还为阅读和算术诱发癫痫发作时的脑力活动与癫痫发作之间提供了可能的机制联系。
