APHM, Timone Hospital, Epileptology Department, Marseille, France; Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy.
Aix Marseille Univ, APHM, INSERM, INS, Inst Neurosci Syst, Timone Hospital, Epileptology Department, Marseille, France.
Clin Neurophysiol. 2021 Sep;132(9):2046-2053. doi: 10.1016/j.clinph.2021.06.003. Epub 2021 Jun 18.
Parietal lobe seizures (PLS) are characterized by multiple clinical manifestations including motor signs. The mechanisms underlying the occurrence of motor signs are poorly understood. The main objective of this work was to estimate the functional coupling of brain regions associated with this clinical presentation.
We retrospectively selected patients affected by drug-resistant epilepsy who underwent Stereoelectroencephalography (SEEG) for pre-surgical evaluation and in whom the seizure onset zone (SOZ) was located in the parietal cortex. The SOZ was defined visually and quantitatively by the epileptogenicity index (EI) method. Two groups of seizures were defined according to the presence ("motor seizures") or the absence ("non-motor seizures") of motor signs. Functional connectivity (FC) estimation was based on pairwise nonlinear regression analysis (h coefficient). To study FC changes between parietal, frontal and temporal regions, for each patient, z-score values of 16 cortico-cortical interactions were obtained comparing h coefficients of pre-ictal, seizure onset and seizure propagation periods.
We included 22 patients, 13 with "motor seizures" and 9 with "non-motor seizures". Resective surgery was performed in 14 patients, 8 patients had a positive surgical outcome (Engel's class I and II). During seizure onset period, a decrease of FC was observed and was significantly more important (in comparison with background period) in "motor" seizures. This was particularly observed between parietal operculum/post-central gyrus (OP/PoCg) and mesial temporal areas. During seizure propagation, a FC increase was significantly more important (in comparison with seizure onset) in "motor seizures", in particular between lateral pre-motor (pmL) area and precuneus, pmL and superior parietal lobule (SPL) and between inferior parietal lobule (IPL) and supplementary motor area (SMA).
Our study shows that motor semiology in PLS is accompanied by an increase of FC between parietal and premotor cortices, significantly different than what is observed in PLS without motor semiology.
Our results indicate that preferential routes of coupling between parietal and premotor cortices are responsible for the prominent motor presentation during PLS.
顶叶癫痫发作（PLS）的临床表现多样，其中包括运动症状。然而，导致运动症状出现的机制尚不清楚。本研究的主要目的是评估与这种临床表现相关的脑区的功能连接。
我们回顾性选择了接受立体脑电图（SEEG）进行术前评估的耐药性癫痫患者，并在这些患者中，致痫区（SOZ）位于顶叶皮层。SOZ 通过致痫性指数（EI）方法进行视觉和定量定义。根据是否存在（“运动性癫痫发作”）或不存在（“非运动性癫痫发作”）运动症状，将两组癫痫发作进行定义。功能连接（FC）估计基于成对非线性回归分析（h 系数）。为了研究顶叶、额叶和颞叶之间的 FC 变化，对于每个患者，通过比较前发作期、发作起始期和发作传播期的 h 系数，获得了 16 个皮质-皮质相互作用的 z 分数值。
我们共纳入 22 名患者，其中 13 名患者有“运动性癫痫发作”，9 名患者有“非运动性癫痫发作”。14 名患者接受了切除术治疗，其中 8 名患者术后效果良好（Engel Ⅰ级和Ⅱ级）。在发作起始期，与背景期相比，“运动性”癫痫发作时观察到 FC 降低，且降低更为显著。这种情况尤其在顶叶岛盖部/后中央回（OP/PoCg）和内侧颞叶之间更为明显。在发作传播期，与发作起始相比，“运动性”癫痫发作时 FC 增加更为显著，特别是在外侧运动前区（pmL）和楔前叶、pmL 和顶上小叶（SPL）以及顶下小叶（IPL）和辅助运动区（SMA）之间。
本研究表明，PLS 的运动症状伴有顶叶和运动前皮质之间 FC 的增加，与 PLS 无运动症状时观察到的情况明显不同。
我们的研究结果表明，顶叶和运动前皮质之间的耦合优先途径是 PLS 中突出运动表现的原因。
