Xie Fangfang, Xing Wu, Wang Xiaoyi, Liao Weihua, Shi Wei
a Department of Radiology , Xiangya Hospital Central South University , Changsha , China.
Int J Neurosci. 2017 Aug;127(8):667-672. doi: 10.1080/00207454.2016.1229668. Epub 2016 Dec 20.
A disturbance in the level of consciousness is a classical clinical sign of several seizure types. Recent studies have shown that altered states of consciousness in seizures are associated with structural and functional changes of several brain regions. Prominent among these are the thalamus, the brain stem and the default mode network, which is part of the consciousness system. Our study used diffusion tensor imaging (DTI) to evaluate these brain regions in patients with three different types of epilepsies that are associated with altered consciousness: complex partial seizures (CPS), primary generalized tonic-clonic seizures (PGTCS) or secondary generalized tonic-clonic seizures (SGTCS). Additionally, this study further explores the probable mechanisms underlying impairment of consciousness in seizures.
Conventional MRI and DTI scanning were performed in 51 patients with epilepsy and 51 healthy volunteers. The epilepsy group was in turn subdivided into three subgroups: CPS, PGTCS or SGTCS. Each subgroup comprised 17 patients. Each subject involved in the study underwent a DTI evaluation of the brain to measure the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values of nine regions of interest: the postero-superior portion of midbrain, the bilateral dorsal thalamus, the bilateral precuneus/posterior cingulate, the bilateral medial pre-frontal gyri and the bilateral supramarginalgyri. The statistical significance of the measured ADC and FA values between the experimental and control groups was analysed using the paired t-test, and one-way analysis of variance was performed for a comparative analysis between the three subgroups.
Statistically significantly higher ADC values ( p < 0.01) were observed in the bilateral dorsal thalamus and postero-superior aspect of the midbrain in the three patient subgroups than in the control group. There were no significant changes in the ADC values ( p > 0.05) in the bilateral precuneus/posterior cingulate, bilateral medial pre-frontal gyri or bilateral supramarginalgyri in the experimental group. Among the three patient subgroups and the ADC values of corresponding brain regions, there were no statistically significant changes. Statistically significantly lower FA values ( p < 0.05) were observed in the bilateral dorsal thalamus of the patients in the three subgroups than in the control group. Significantly lowered FA values from the postero-superior aspect of the mid brain ( p < 0.01) were observed in patients with PGTCS compared with the control group. There were no significant changes in the FA values ( p > 0.05) from the bilateral precuneus/posterior cingulate, bilateral medial frontal gyri or bilateral supramarginalgyri in the experimental group. Among the three patient subgroups and the FA values of the corresponding brain regions, there were no statistically significant changes.
In epileptic patients with CPS, PGTCS or SGTCS, there seems to be a long-lasting neuronal dysfunction of the bilateral dorsal thalamus and postero-superior aspect of the midbrain. The thalamus and upper brain stem are likely to play a key role in epileptic patients with impaired consciousness.
意识水平紊乱是多种癫痫发作类型的典型临床症状。最近的研究表明，癫痫发作时意识状态的改变与多个脑区的结构和功能变化有关。其中突出的是丘脑、脑干以及作为意识系统一部分的默认模式网络。我们的研究使用扩散张量成像（DTI）来评估三种与意识改变相关的不同类型癫痫患者的这些脑区：复杂部分性发作（CPS）、原发性全面强直阵挛发作（PGTCS）或继发性全面强直阵挛发作（SGTCS）。此外，本研究进一步探讨了癫痫发作时意识受损的潜在机制。
对51例癫痫患者和51名健康志愿者进行了常规MRI和DTI扫描。癫痫组又分为三个亚组：CPS、PGTCS或SGTCS。每个亚组包括17例患者。参与研究的每个受试者都接受了脑部DTI评估，以测量九个感兴趣区域的表观扩散系数（ADC）和分数各向异性（FA）值：中脑后上部、双侧背侧丘脑、双侧楔前叶/后扣带回、双侧内侧前额叶回和双侧缘上回。使用配对t检验分析实验组和对照组之间测量的ADC和FA值的统计学显著性，并进行单因素方差分析以对三个亚组进行比较分析。
在三个患者亚组中，双侧背侧丘脑和中脑后上部的ADC值在统计学上显著高于对照组（p < 0.01）。实验组双侧楔前叶/后扣带回、双侧内侧前额叶回或双侧缘上回的ADC值无显著变化（p > 0.05）。在三个患者亚组及其相应脑区的ADC值之间，没有统计学上的显著变化。三个亚组患者的双侧背侧丘脑的FA值在统计学上显著低于对照组（p < 0.05）。与对照组相比，PGTCS患者中脑后上部的FA值显著降低（p <
