Objectives

Vagus nerve stimulation (VNS) has been widely used as an effective treatment for patients with drug-resistant epilepsy (DRE). However, little is known about grey matter (GM) and white matter (WM) microstructure changes caused by VNS. This study aimed to detect consistent GM and WM alterations in epilepsy patients with vagus nerve stimulators.

Methods

The diffusion tensor imaging data was acquired from 15 patients who underwent VNS implantation. The voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) were used to detect group differences in GM and WM microstructure and explore their correlation with postoperative seizure reduction.

Results

After 3 months of stimulation, GM density reduced in right cerebellum, left superior temporal gyrus, right inferior temporal gyrus and left thalamus, and increased in left cerebellum, left inferior parietal lobule, left middle occipital gyrus and left gyrus rectus. No significant volume changes had been found in 14 subcortical nuclei. The fractional anisotropy (FA) values reduced in left superior longitudinal fasciculus and left corticospinal tract, and increased in bilateral cingulum and body of corpus callosum. The mean diffusivity (MD) values reduced in right retrolenticular part of internal capsule, right posterior corona radiata and right superior longitudinal fasciculus. The seizure reduction had positive correlation trends with the volume reduction in left nucleus accumbens and right amygdala, and MD reduction in right medial lemniscus and right posterior corona radiata.

Conclusions

The results showed that VNS could cause changes of GM density, WM FA and MD values in epilepsy patients. The volume and MD reduction in some subcortical structures might participate in the seizure frequency reduction of VNS.

中文翻译：

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迷走神经刺激器对癫痫患者灰质和白质微观结构的改变

目标

迷走神经刺激（VNS）已被广泛用作耐药性癫痫（DRE）患者的有效治疗方法。然而，关于 VNS 引起的灰质 (GM) 和白质 (WM) 微观结构变化知之甚少。本研究旨在检测具有迷走神经刺激器的癫痫患者中一致的 GM 和 WM 改变。

方法

扩散张量成像数据来自 15 名接受 VNS 植入的患者。基于体素的形态计量学 (VBM) 和基于束的空间统计 (TBSS) 用于检测 GM 和 WM 微观结构的组差异，并探讨它们与术后癫痫发作减少的相关性。

结果

刺激3个月后，右侧小脑、左侧颞上回、右侧颞下回和左侧丘脑GM密度降低，左侧小脑、左侧顶下小叶、左侧枕中回和左侧直回GM密度增加。在 14 个皮质下核中未发现显着的体积变化。左上纵束和左皮质脊髓束的分数各向异性（FA）值降低，而双侧扣带回和胼胝体体的分数各向异性（FA）值增加。内囊右侧晶状体后部、右侧后放射冠和右侧上纵束的平均扩散率（MD）值降低。癫痫发作减少与左侧伏隔核和右侧杏仁核体积减少呈正相关趋势，

结论

结果表明，VNS 可引起癫痫患者 GM 密度、WM FA 和 MD 值的变化。一些皮质下结构的体积和MD减少可能参与VNS癫痫发作频率的降低。