Many risk factors have been identified that predict future progression to Alzheimer’s disease (AD). However, clear links have yet to be made between these risk factors and how they affect brain functioning in early stages of AD. We conducted a narrative review and a quantitative analysis to better understand the relationship between nine categories of AD risk (i.e., brain pathology, genetics/family history, vascular health, head trauma, cognitive decline, engagement in daily life, late-life depression, sex/gender, and ethnoracial group) and task-evoked fMRI activity during episodic memory in cognitively-normal older adults. Our narrative review revealed widespread regional alterations of both greater and lower brain activity with AD risk. Nevertheless, our quantitative analysis revealed that a subset of studies converged on two patterns: AD risk was associated with (1) greater brain activity in frontal and parietal regions, but (2) reduced brain activity in hippocampal and occipital regions. The brain regions affected depended on the assessed memory stage (encoding or retrieval). Although the results clearly indicate that AD risks impact brain activity, we caution against using fMRI as a diagnostic tool for AD at the current time because the above consistencies were present among much variability, even among the same risk factor.

已经确定了许多危险因素，这些危险因素可预测将来会发展为阿尔茨海默氏病（AD）。但是，这些危险因素与它们如何影响AD早期脑功能之间尚无明确的联系。我们进行了叙述性回顾和定量分析，以更好地了解9种类别AD风险之间的关系（即，脑病理学，遗传学/家族史，血管健康，头部创伤，认知能力下降，日常生活参与，晚年抑郁，性别/性别和族裔群体）和认知正常的成年人的情节记忆期间任务诱发的功能磁共振成像活动。我们的叙述性回顾显示，患有AD风险的大脑活动的上下区域分布广泛。但是，我们的定量分析显示，一部分研究集中在两种模式上：AD风险与（1）额叶和顶叶区域大脑活动增加有关，但（2）海马和枕叶区域大脑活动减少。受影响的大脑区域取决于评估的记忆阶段（编码或检索）。尽管结果清楚地表明，AD风险会影响大脑活动，但我们建议当前不要使用fMRI作为AD的诊断工具，因为上述一致性存在很大的可变性，即使在相同的风险因素中也是如此。