岛叶-扣带皮质网络γ振荡与癫痫发作中“宪兵帽”征的电-临床关联机制

Electro-clinical correlation for “Chapeau de gendarme” sign and gamma oscillations

目的 低波幅快节律,尤其是γ振荡,在癫痫发作的形成与症状学表达中发挥重要作用。本研究通过对无颗粒-乏颗粒岛叶-扣带皮质网络γ振荡与“宪兵帽”征发生的时间关系进行定量分析,探索二者之间可能的因果关系。方法 回顾性分析2017年3月—2020年3月于上海德济医院完成立体定向脑电图和癫痫外科切除的局灶性癫痫病例,收集惯常发作中出现“宪兵帽”征,且在岛叶前-中部及前-中扣带皮质均有电极植入的病例(7例),对“宪兵帽”征的临床特征及相关皮质受累区进行详尽采集,共69次癫痫发作、403个电生理样本纳入分析,计算无颗粒-乏颗粒岛叶-扣带皮质低波幅快节律潜伏期以及症状出现的潜伏期;分析低波幅快节律的频段范围;通过Pearson相关分析、线性回归分析验证两者之间是否存在时间线性关系。结果 (1) 7例患者中,“宪兵帽”征发生之前颅内电极脑电图均出现无颗粒-乏颗粒岛叶-扣带皮质低波幅快节律活动;(2)该皮质网络低波幅快节律均为γ频段振荡;(3) γ频段“共激活”潜伏期与“宪兵帽”征潜伏期之间存在时间线性关系。结论 无颗粒-乏颗粒岛叶-扣带皮质γ频段“共激活”与“宪兵帽”征发生之间存在因果关系。“宪兵帽”征是无颗粒-乏颗粒岛叶-扣带皮质受累的症状学标志。

Objective The time relationship between seizure semiology and epileptic discharges during focal epileptic seizures is a crucial predictor for the localization of epileptogenic zone. Low voltage fast activities(LVFA),especially gamma band oscillations, are confirmed to play a central role in ictogenesis and semiology production. In the present study, we focus on the “electro-clinical correlation” between LVFA in agranulo-dysgranular insulo-cingulate cortices and the sign of “Chapeau de gendarme(CDG)” via detailed analysis of ictal video-stereoencephalography(video-SEEG) of focal epileptic seizures. Methods We retrospectively analyzed the ictal video-SEEG of the 7 cases in which CDG signs were presented in habitual seizures and intracerebral electrodes were co-implanted in agranulodysgranular insular and cingulate cortices. We calculate the latency of LVFA in each of cortical regions of interest,agranulo-dygranular insular cortex, agranulo-dysgranular cingulate cortex, and the latency of CDG signs via visual and spectral analysis of the ictal SEEG. Moreover, Pearson correlation analysis and linear regression were used to test the time relationship between gamma band oscillations in agranulo-dysgranular insulo-cingulate cortices and generation of CDG signs. Results The co-activation of LVFA occurred in agranulo-dysgranular insulo-cingulate cortices always preceded the appearance of CDG sign in all of the 69 seizures. The LVFA were confirmed as gamma band oscillations via spectral analysis of SEEG. A linear relationship between the latencies of CDG signs and the latencies of co-activation of agranulo-dysgranular insulo-cingulate cortices in gamma band was furth confirmed by Pearson correlation analysis and linear regression. Conclusions There is a causal relationship between the involvement of agranulo-dysgranular insulocingulate cortices and the generation of CDG sign, and thus the CDG sign could be view as semiological marker of activation of emotional insulo-cingulate cortex in focal epilepsy.