局灶性癫痫患者皮层-皮层诱发电位的电生理特点

The physiological features of cortico-cortical evoked potentials obtained in patients with focal epilepsy

目的 描述局灶性癫痫患者的皮层-皮层诱发电位（cortico-cortical evoked potential,CCEP）电生理学形态特征,比较其在不同类型颅内电极中的差异.方法 选取2012-02-2013-02在北京三博脑科医院癫痫中心行颅内电极植入的局灶性癫痫患者共10例,其中7例患者行立体定向电极植入术,3例患者行硬膜下电极＋深部电极植入术.CCEP刺激参数：1 Hz双相方波、脉宽200 μs、刺激持续时间50～70 s,记录CCEP,对其波形、潜伏期、波幅、出现比例等电生理形态特征进行统计.结果 （1） CCEP的波形主要由3部分构成：正相电位P1,负相电位N1以及之后的第2个负相电位N2.共出现1749个电极次,其中N1出现率77.2％,N2出现率49.1％.N1的潜伏期中位数为19.0（范围：2.8～260.0）ms,波幅中位数为54.9（范围：3.1～1895.1）μV; N2的潜伏期中位数为91.0（范围：19.8～433.0）ms,波幅中位数为62.1（范围：1.9～1361.4）μV.（2）立体定向电极组中P1的出现率高于硬膜下电极组（P＜0.01）,N1、N2的潜伏期较硬膜下电极组延长（P＜0.01）;硬膜下电极组N1的波幅明显大于立体定向电极组（P＜0.01）.结论 CCEP的波形主要由P1、N1和N2等3个成分构成;立体定向电极和硬膜下电极所记录到的CCEP的电生理学特点有所不同.

Objective To describe the physiological features of cortico-cortical evoked potentials （CCEP） obtained through the intracranial electrodes （subdural or stereotactic electrodes） in the patients with medically intractable focal epilepsy.Methods Ten patients with medically intractable focal epilepsy,who underwent presurgical evaluation with extraoperative invasive recordings between February 2012 and February 2013 in Beijing Sanbo Brain Hospital,were included in the study.Subdural and depth electrodes were used in 7 patients and stereotactic electrodes in 3 patients.A repetitive 1 Hz bipolar electrical stimulus was applied to one region and CCEP were recorded from other electrodes.We measured the waveforms,latencies,amplitudes,and occurrence rates of CCEP.Results （1） The CCEP consisted mainly of 3 components：positive potential （P1）,early negative potential （N1） and later negative potential （N2）.CCEP were recorded in 1749 electrode-times.The occurrence rates of N1 and N2 were 77.2％ and 49.1％,respectively.The latencies and amplitudes were 19.0 （range,2.8-260.0） ms and 54.9 （range,3.1-1895.1） μV for N1 peak.The latencies and amplitudes of N2 were 91.0 （range,19.8-433.0） ms and 62.1 （range,1.9-1361.4） μV.（2） The occurrence rate of P1 recorded by stereotactic electrodes was higher than those by subdural electrodes.The latencies of N1 and N2 were longer in the stereotactic electrodes group.There were also significant differences between the amplitudes of N1 recorded by stereotactic and subdural electrodes.Conclusions The components of CCEP recorded by stereotactic electrodes are similar to those recorded by subdural electrodes,including P1,N1 and N2.But the physiological features of CCEP are different in the two types of electrode.