Department of Neurosurgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; Epilepsy Center, Hiroshima University Hospital, Hiroshima, Japan.
Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Canada.
Epilepsy Res. 2020 Nov;167:106463. doi: 10.1016/j.eplepsyres.2020.106463. Epub 2020 Sep 12.
To determine the correlation between secondary unilateral or bilateral spreading on gradient magnetic-field topography (GMFT) before and after vagus nerve stimulation (VNS), and postoperative seizure outcomes.
We analyzed pre- and post-VNS magnetoencephalography (MEG) in 15 patients with VNS implants. We applied McHugh classification to evaluate seizure outcomes. GMFT visualized the spatiotemporal spread of the gradient magnetic field from MEG (>300 fT/cm) before and after the spike peak. We compared the proportion of bilaterally spreading (PBS) MEG spikes and seizure outcomes. We also compared the interhemispheric time difference (ITD) between patients with and without corpus callosotomy.
We allocated patients with favorable seizure outcomes of class I and II to group A (9 patients) and poor outcomes of class III-V to group B (6 patients). The number of post-VNS MEG spikes was significantly reduced compared to pre-VNS MEG spikes in group A, but not in group B. Group A showed significantly higher preoperative PBS than group B. Postoperative ITD significantly decreased in 5 patients who underwent corpus callosotomy compared to 10 patients without.
GMFT can detect the inter- and intrahemispheric spreading of spikes with high spatiotemporal resolution on the brain surface. Frequent interictal MEG spikes propagating bilaterally on GMFT may reflect a favorable seizure outcome after VNS. GMFT can identify dependent secondary epileptogenic spikes responding to VNS, which may be used to control generalized seizures in a subset of patients with pharmaco-resistant epilepsy.
确定迷走神经刺激（VNS）前后梯度磁场地形图（GMFT）上的继发性单侧或双侧扩散与术后发作结果之间的相关性。
我们分析了 15 例 VNS 植入患者的 VNS 前后磁脑图（MEG）。我们应用 McHugh 分类法评估发作结果。GMFT 可视化了 MEG（>300fT/cm）中从尖峰前后梯度磁场的时空扩散。我们比较了双侧扩散（PBS）MEG 尖峰的比例和发作结果。我们还比较了胼胝体切开术患者和无胼胝体切开术患者之间的半球间时间差（ITD）。
我们将发作结果为 I 级和 II 级的患者归为 A 组（9 例），发作结果为 III 级至 V 级的患者归为 B 组（6 例）。与术前 MEG 尖峰相比，A 组术后 VNS MEG 尖峰数量明显减少，但 B 组未见明显减少。A 组术前 PBS 明显高于 B 组。与 10 例未行胼胝体切开术的患者相比，5 例行胼胝体切开术的患者术后 ITD 显著降低。
GMFT 可以以高时空分辨率检测大脑表面尖峰的半球间和半球内传播。GMFT 上双侧传播的频繁间发性 MEG 尖峰可能反映了 VNS 后发作结果良好。GMFT 可以识别依赖于 VNS 的继发性致痫性尖峰，这可能用于控制某些药物难治性癫痫患者的全面性发作。
