利用靜息態腦功能聯結網路研究高血壓對血管性認知障礙的影響

Abstract

全世界罹患高血壓的人口數已超過 12 億人，目前診斷為高血壓的定義是收縮壓 (BP) ?140 mmHg 和舒張壓 ?90 mmHg。高血壓也被認為是引發腦血管疾病的主因，例如血管性認知障礙。血管性認知障礙主要表現出執行功能缺陷，同時也被認為是高血壓與血管性癡呆症之間的過渡階段。因此，對於研究出可靠的血管性認知障礙嚴重性的診斷方法至關重要。我們旨在通過使用平均分率低頻振幅 （mean fractional amplitude of low-frequency fluctuations, mfALFF）、平均區域同質性（mean regional homogeneity, mReHo）、圖論分析（graph theoretical analysis, GTA）及基於網路統計分析（network-based statistical analysis, NBS）的方法，研究28位高血壓患者（HTN）與28位正常血壓的受試者（HC），用客觀的角度觀測因高血壓造成的血管性認知障礙，和相關腦區的靜息態功能性聯結變化。在 mfALFF與mReHo 的組間比較中，相較於正常血壓組，高血壓組顯示出與血管或代謝功能障礙相對應腦區的自發性活動減少；反之，亦發現在初級體感皮層和額葉區域的自發性活動增強。除此之外，我們還進行了高血壓組的功能性影像與認知功能量表的多元迴歸分析，探討高血壓組的執行功能、處理速度和記憶力。 在圖論分析和基於網路統計分析中均表明，高血壓組具有較複雜的局部聯結、較差的全腦整合能力和較弱的功能性聯結網絡。

Hypertension approximate affects over 1.2 billion individuals worldwide and is defined as systolic blood pressure (BP) ?140 mmHg and diastolic BP ?90 mmHg. Hypertension is also considered a high risk of cerebrovascular diseases, such as vascular cognitive impairment (VCI). VCI plays a key role in executive dysfunction and is also considered to be the transitional stage between hypertension and vascular dementia. Hence, this is essential in investigating a reliable approach to diagnosing the severity of the VCI. We aimed to investigate which regions perform alterations in resting-state functional connectome according to the vascular cognitive impairment in HTN by using a method of mfALFF, mReHo, GTA, and NBS. In the group comparison between mfALFF/ mReHo, HTN showed reduced spontaneous activity in the regions corresponding to vascular or metabolic dysfunction and enhanced brain activity mainly in the primary somatosensory cortex and prefrontal areas. We also observed the cognitive dysfunction in HTN, such as executive function, processing speed, and memory. Both GAT and NBS analyses indicated that the HTN demonstrated complex local segregation, worse global integration, and weak functional connectivity.