Institute of Imaging Science, Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, USA.
Department of Neurological Surgery, Vanderbilt University Medical Center, USA.
Epilepsy Behav. 2021 Apr;117:107834. doi: 10.1016/j.yebeh.2021.107834. Epub 2021 Feb 18.
Patients with temporal lobe epilepsy (TLE) commonly experience a broad range of language impairments. These deficits are thought to arise from repeated seizure activity that damages language regions. However, connectivity between the seizure onset region in the hippocampus and regions related to language processing has rarely been studied, and could also have a strong impact on language function. The purpose of this study was to use resting-state functional connectivity (FC) measures to assess hippocampal network patterns and their relation to language abilities in patients with right TLE (RLTE), left TLE (LTLE), and healthy controls.
Presurgical resting-state 3T functional MRI data were acquired from 40 patients with mesial TLE (27 RTLE, 13 LTLE) and 54 controls. The regions of interest were the anterior and posterior bilateral hippocampi and eleven regions grouped by frontal or temporo-parietal locations, including large areas of language-related cortex. FC values were computed with the right/left anterior and posterior hippocampi as the seeds and frontal and temporo-parietal regions as targets. Resting-state lateralization indices were also calculated (LI-Rest), and all FC measures were correlated to neuropsychological language scores and measures related to manifestation of epilepsy including age of onset, duration of disease, monthly seizure frequency, and hippocampal volume.
We found significant group differences between the anterior hippocampi and temporo-parietal regions closest to the seizure focus, in which RTLE and LTLE showed stronger connectivity to their contralateral hippocampus, while controls showed similar connectivity to both hippocampi. In addition, LI-Rest demonstrated significantly more right lateralization in LTLE compared to RTLE for temporo-parietal regions only. In LTLE, we found significant associations between stronger hippocampal network resting-state FC and later age of onset and decreased left anterior hippocampal volume.
The results of our study indicate that the presence of TLE impacts hippocampal-temporo-parietal networks relevant to language processing.
颞叶癫痫（TLE）患者常经历广泛的语言障碍。这些缺陷被认为是由反复的癫痫活动损害语言区域引起的。然而，海马体起始区与语言处理相关区域之间的连接很少被研究，也可能对语言功能有强烈的影响。本研究的目的是使用静息态功能连接（FC）测量来评估右侧 TLE（RTLE）、左侧 TLE（LTLE）患者和健康对照者的海马网络模式及其与语言能力的关系。
从 40 名内侧 TLE 患者（27 名 RTLE，13 名 LTLE）和 54 名对照者中采集术前静息态 3T 功能 MRI 数据。感兴趣区为双侧前、后海马体和 11 个按额或颞顶位置分组的区域，包括与语言相关的大片皮质。以右侧/左侧前、后海马体为种子，以额部和颞顶区域为目标，计算 FC 值。还计算了静息状态侧化指数（LI-Rest），并将所有 FC 测量值与神经心理学语言评分以及与癫痫表现相关的测量值（包括发病年龄、疾病持续时间、每月发作频率和海马体体积）相关联。
我们在前海马体与靠近癫痫灶的颞顶区域之间发现了组间显著差异，其中 RTLE 和 LTLE 与对侧海马体的连接更强，而对照组则与双侧海马体的连接相似。此外，LI-Rest 仅在 LTLE 中显示出与 RTLE 相比颞顶区域的右偏侧化明显更多。在 LTLE 中，我们发现更强的海马网络静息态 FC 与发病年龄较晚和左侧前海马体体积减小之间存在显著相关性。
本研究结果表明 TLE 的存在会影响与语言处理相关的海马体-颞顶网络。
