皮层电刺激功能定位与后发放阈值测定的初步研究

目的通过皮层电刺激进行皮层功能定位,比较大脑皮层不同部位后发放(ADs)的阈值及其对致痫区定位的意义。方法对7例难治性癫痫患者,综合分析其长程头皮视频脑电图(VEEG)、MRI及SPECT和PET资料,放置硬膜下条状或栅状电极,通过恒流电刺激对大脑皮层进行功能定位,并测定大脑皮层不同部位ADs的阈值,探讨ADs阈值与致痫区之间的关系。结果致痫区位于额叶者3例,颞叶者2例,顶叶者1例,枕叶者1例;在额叶、顶枕叶和颞叶内,相邻电极之间功能变化的阈值之差分别为11、4.5和3 mA,不同功能区之间的阈值无统计学差异(P=0.685);颞叶ADs的阈值显著低于额及顶枕叶(P=0.015);刺激致痫区时,ADs主要出现在致痫区周围2～3 cm的范围内,且节律性强,波幅高;而刺激非致痫区时,ADs出现的部位较为弥散,节律性差,波幅低;当致痫区位于或靠近皮层功能区时,选择性点状切除阈值较低的区域,不会造成明显的或永久性的神经功能障碍,疗效较好。结论皮层电刺激测定大脑皮层不同部位的ADs阈值,并进行大脑皮层功能定位,有助于致痫区定位,提高手术疗效,减少致残率。

Primary study on electrical cortical stimulation mapping and threshold for afterdischarges

Objective To perform cortical functional mapping by means of electrical cortical stimulation,and to compare the differences of threshold for afterdischarges(ADs) among anatomical lobes as well as to correlate its threshold with epileptogenic zone localizaiton.Methods To implant subdural electrode strips or grids over the most possible areas of epileptogenic zone(EZ) determined by the integral information analysis of scalp vedio-electroencephalography(VEEG),MRI,SPECT and PET in 7 patients with intractable epilepsy.To accomplish the cortical functional mapping using electrical cortical stimulation with constan current stimulus,and to compare the differences of threshold for afterdischarge among fronal,parietal-occipital and temporal lobes as well as to explore its value for EZ localizaiton.Results EZ was located in the frontal lobe in 3 cases,parietal lobe in 1 cases,occipital lobe in 1 case and temporal lobe in 2 case.Differences of threshold for cortical mapping between adjacent electrods within the frontal,parietal-occipital and temporal lobes were 11,4 and 4.5 mA,respectively.No significant difference was found among the these cortical areas(P=0.685).AD threshold in temporal lobe was statistically lower than those in frontal and parietal-occipital regions(P=0.015).ADs mostly occurred within the areas 2-3 cm around the EZ with strong rhythm and high amplitude when EZ were stimulated.However,ADs scatterd among the different places with relatively weak rhythm and low amplitude when non-EZ were stimulated.When EZ was located or closed to the eloquent cortex,the cortex with relatively lower AD threshold were selectively operated.No obvious or permanent neurological deficit was remained,the outcome for seizure control was good according Engel’classification scale.Conclusion ADs and electrical cortical stimulation would help to localize the EZ focu,improve the surgical outcome,and decrease the postoperative disability.