前临床期痴呆的认知特征：当前研究进展和未来研究展望

在这篇文章中, 我将讨论从正常老化到痴呆, 这一通常被称为痴呆前临床阶段的认知功能的转变。研究表明, 阿尔茨海默症和血管性痴呆病人在临床确诊之前的几年中, 会出现明显的认知损伤。早期最突出的损伤存在于情节记忆、加工速度以及执行功能。这些功能性损伤与神经生物学研究证实的边缘系统和新皮层区存在多重损伤是相一致的。虽然早在临床诊段之前, 病人组和控制组的平均成绩存在巨大差异, 但同时这两组测试成绩的分布在很大程度上是重叠的。寻求降低这种重叠度的方法是未来研究的一个重要任务。这有可能通过将认知的和其他指标(如基于脑的、基因的、临床的、社会的)相结合构建预测模型来实现。此外, 在未来研究中以下三方面也是急需考虑问题: (a) 找出在 前临床期间认知功能急速下降的时间点: (b) 评估从前临床到临床诊断变化速率中存在的个体差异; (c) 确定特定因素与随后发生的痴呆之间的关联强度是如何随时间向临床确诊推进而逐渐变化的。

Cognition in Preclinical Dementia: Current Knowledge and Future Prospects

In this article, I discuss the cognitive transition from normal aging to dementia--a period often referred to as the preclinical phase of dementia. Research shows marked preclinical cognitive deficits several years before diagnosis in both Alzheimer's disease and vascular dementia. The most pronounced prodromal impairment is observed for measures of episodic memory, speed, and executive functioning. The global nature of the impairment is consistent with neurobiological evidence that multiple lesions in limbic and neocortical regions. Despite large mean-level differences between cases and controls long before diagnosis, the performance distributions for the two groups overlap to a large degree. An important task for future research is to find means by which to decrease this overlap. This could be accomplished by combining cognitive and other (e.g., brain-based, genetic, clinical, social) markers into the prediction models. Other pressing issues for future research include (a) delineating the point at which precipitous decline normally occurs during the preclinical period; (b) asesssing individual differences in rate of change from preclinical to clinical dementia; and (c) determining how the strength of the association between a certain factor and subsequent dementia varies as a function of time to diagnosis.