認知功能健全年長者大腦白質微結構改變對於高血壓在多重認知功能之負向作用的中介效果研究

Alterations in White Matter Microstructure Mediate Deleterious Hypertension Effect on Multiple Cognitive Functions in Cognitively Intact Older Adults

羅迪華(Di-Hua Luo)

指導教授 ： 張玉玲

國立臺灣大學/理學院/心理學研究所/碩士(2018年)

https://doi.org/10.6342/NTU201801368

摘要

研究顯示，高血壓是與中老年時期認知功能衰退最明顯相關的血管性風險因子之一，然而此關聯性當中潛在的生理病理機制目前尚未完全明瞭。因此，本研究聚焦探討大腦白質微結構完整性，檢驗其在高血壓引起之認知功能衰退歷程中所扮演的中介角色。本研究共募集66位認知功能正常年長者，其中分為41位高血壓患者組，及25位經年齡、性別、與教育年數配對的正常血壓組。本研究採用全面性神經心理衡鑑組合評估所有參與者之認知功能表現，同時運用擴散頻譜造影及腦神經纖維自動化分析技術評估參與者之大腦白質纖維束微結構完整性，並以結構方程模式分析法檢驗大腦白質微結構完整性之中介效果。研究結果發現，高血壓組之處理速度、執行功能、及記憶登錄的表現明顯較正常血壓組差。高血壓組之大腦白質微結構完整性亦明顯低於正常血壓組，主要呈現在長程聯絡神經纖維束。進一步的中介分析結果顯示，聯繫大腦額葉與後端腦區之特定白質纖維束完整性的減損明顯中介高血壓對於多重認知功能的負向作用，包括：處理速度、執行功能、記憶登錄、及記憶保留等認知領域。總結而言，本研究結果顯示，即使在認知功能正常的年長者中，高血壓仍可能藉由損害大腦白質微結構的完整性引發多重認知功能之衰退，因此進一步突顯出控管血管性因素之健康狀態對於預防認知衰退的重要性。

關鍵字

擴散磁振造影 ； 執行功能 ； 記憶功能 ； 神經心理測驗 ； 處理速度

並列摘要

Background and Objective: Although hypertension is a prominent vascular risk factor for late-life cognitive decline, the underlying pathophysiological mechanism remains unclear. Accordingly, the aim of this study was to examine the role of white matter microstructural integrity in hypertension-related cognitive decline. Methods: We recruited 66 cognitively normal older adults, comprising 41 hypertensive patients and 25 normotensive controls. All participants underwent a comprehensive neuropsychological battery. White matter microstructural integrity was assessed using a tract-based automatic analysis approach derived from diffusion spectrum imaging. Mediating effects of white matter integrity were evaluated using structural equation modeling analyses. Results: The results revealed that hypertensive older adults displayed poorer processing speed, executive function, and memory encoding. Reductions of white matter microstructural integrity were observed in the hypertensive elderly patients, primarily in long-range association fiber bundles. In particular, reduced microstructural integrity in specific tract bundles connecting frontal and posterior cerebral regions were found to underlie the adverse effects of hypertension on multiple cognitive domains, including processing speed, executive function, memory encoding, and memory retention. Conclusion: Our findings suggest that hypertension may exert deleterious effects on multiple cognitive functions by undermining white matter microstructures, even in cognitively intact older adults, thus further highlighting the necessity of monitoring vascular health to prevent cognitive decline.

並列關鍵字

Diffusion imaging ； executive function ； memory ； neuropsychological test ； processing speed

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