Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Haeundae-ro 875, Haeundae-gu, Busan, Republic of Korea.
Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
Neuroradiology. 2021 Sep;63(9):1441-1449. doi: 10.1007/s00234-021-02645-7. Epub 2021 Jan 23.
This study aimed to evaluate alterations in structural covariance network and effective connectivity of the intrahippocampal circuit in patients with transient global amnesia (TGA). We also investigated whether there were differences of them according to recurrence.
We enrolled 88 patients with TGA and 50 healthy controls. We classified patients with TGA into two groups: the single event group (N = 77) and recurrent events group (N = 11). We performed volumetric analysis using the FreeSurfer program and structural covariance network analysis based on the structural volumes using a graph theoretical analysis in patients with TGA and healthy controls. The effective connectivity of the intrahippocampal circuit was also evaluated using structural equation modeling.
There were no significant differences between patients with all TGA events/a single TGA event and healthy controls with regard to global structural covariance network. However, patients with recurrent events had significant alterations in global structural covariance network with a decrease in the small-worldness index (0.907 vs. 0.970, p = 0.032). In patients with all events/a single, there were alterations in effective connectivity from the entorhinal cortex to CA4, only. However, in patients with recurrent events, there were alterations in effective connectivity from the subiculum to the fimbria as well as from the entorhinal cortex to CA4 in bilateral hemispheres.
Our study revealed significant alterations in structural covariance network and disruption of the intrahippocampal circuit in patients with TGA compared to healthy controls, which is more prominent when amnestic events recurred. It could be related to the pathogenesis of TGA.
本研究旨在评估短暂性全面性遗忘症（TGA）患者内海马回路的结构协变网络和有效连接的变化。我们还探讨了根据复发是否存在差异。
我们纳入了 88 例 TGA 患者和 50 例健康对照者。我们将 TGA 患者分为两组：单发事件组（N=77）和复发事件组（N=11）。我们使用 FreeSurfer 程序进行容积分析，并在 TGA 患者和健康对照者中使用结构体积进行基于图论分析的结构协变网络分析。我们还使用结构方程模型评估内海马回路的有效连接。
所有 TGA 事件/单次 TGA 事件患者与健康对照者的全脑结构协变网络无显著差异。然而，复发事件患者的全脑结构协变网络存在显著改变，小世界指数降低（0.907 比 0.970，p=0.032）。在所有事件/单次事件患者中，只有从内嗅皮层到 CA4 的有效连接发生改变。然而，在复发事件患者中，双侧半球的内嗅皮层到 CA4 以及从下托到穹窿的有效连接都发生了改变。
与健康对照者相比，我们的研究显示 TGA 患者的结构协变网络和内海马回路存在显著改变，在遗忘事件复发时更为明显。这可能与 TGA 的发病机制有关。
