局灶性皮质发育不良癫癎患者头皮脑电图的特点及其定位意义

A study on the characteristics and localizing significance of the scalp electroencephalogram in patients with focal cortical dysplasia

目的:探讨头皮脑电图(EEG)在局灶性皮质发育不良(focal cortical dysplasia,FCD)癫癎中的表现特点及定位致癎灶的意义。方法:选择自2005年4月至2006年8月我研究所收治的22例术前采用长程颅内电极埋置,术后病理证实为FCD的患者为研究对象。将发作间期皮层电图(ECoG)癎样异常放电(interictal epileptiform discharge,IED)分为四种类型:A:独立棘波,B:重复棘慢波,C:多棘波,D:快波,以a、b、c、d分别表示头皮EEG与上述分类相对应的IED波形。发作期癫癎异常放电(ictal discharge,ID)被分为:Ⅰ型:节律性快波,Ⅱ型:棘波节律,Ⅲ型:小于8 Hz的节律性电活动。将22例患者术前头皮EEG与ECoG的数字资料进行分析比较。结果:22例FCD患者头皮EEG的IED分型中,a型占50%,ECoG的IED中,A型占36%,D型与C型各占23%。头皮EEGa型中,45%来自ECoG类型IED。头皮EEG表现为c和d型IED的均来自ECoG的C与D型。头皮EEG的ID中Ⅰ型有7例,Ⅱ型有4例,Ⅲ型有9例;头皮EEG的ID中的Ⅲ型明显多于ECoG的Ⅲ型(X2=7.02,P= 0.03)。头皮EEG局限型Ⅰ型与Ⅱ型ID的部位与手术部位一致性好。结论:FCD患者头皮EEG的IED以棘波、尖波波形较多见,且表现范围较ECoG上的IED广泛。头皮EEG的ID表现以Ⅲ型为主,且定位意义不如ECoG上的ID类型。经过由皮层到头皮的传导,不论是IED还是ID,异常放电形式均有可能发生改变。当头皮EEG的IED与ID同时为局限型且部位彼此相一致时,定位可靠性较高。

Objective：To discuss the characteristics and localizing significance of scalp EEG in the epilepsy patients due to focal cortical dysplasia（FCD）. Methods： Twenty-two subjects were collected, who underwent epilepsy surgeries consecutively in our institute from April 2005 to August 2006. All patients underwent intracranial electrode implantations and long-term video-EEG monitoring before the surgeries and all the postoperative pathologies were proved to be FCDs. The scalp digital EEG of the 22 patients were analysed including interictal epileptiform discharges（IED） and ictal discharges（ID）, IED were divided into four catalogs, A： isolated spikes, B： repetitive spike-wave pattern, C： repetitive spikes, D： paroxysmal fast（a, b, c, d represented scalp IED catalogs which corresponded the above cortical IED clas sification）. ID was catalogued as Type Ⅰ ：Paroxysmal fast, Type Ⅱ ：Repetitive spikes and TypeⅢ ：Slow rhythm lower than 8 Hz. The intracranial EEG was compared with scalp EEG to clarify the significance and localizing value of the scalp EEG. Results： In the scalp EEGs of 22 patients, ‘a＇ type IED was more than other types（50%） and relatively wide distributed, while intracranial EEG showed ‘A＇type IED was only36%, ‘D＇ type and ‘C＇ type was 23% respectively, About 45% of ‘a＇ type IED came from the other types on the cortical EEGs. On the contrary, no ‘D＇ type and ‘C’type changed the pattern shown on the scalp EEG. Seven cases of Type Ⅰ ,4 of Type Ⅱ and 9 of TypeⅢ on the scalp EEG. Type Ⅲ ID were more common on the scalp EEG than on the intracranial EEG（Χ^2= 7.02, P=0. 030）. The localized Type Ⅰ and Type Ⅱ ID on the scalp EEG showed more consistent with the resection than Type Ⅲ ID. Conclusions： Spike or sharp wavs are the common IED types on the scalp EEG of FCD patients and usual ly wide distributed, and had less localizing value. Type Ⅲ was the common ID type and less localizing than the other ID types in the scalp. Both the IED and ID could change their types when they came from the cortex to the scalp. When localized IED and localized ID are concordant with each other, high locali zing value could be expected.