Boyle P A, Wilson R S, Schneider J A, Bienias J L, Bennett D A
Rush Alzheimer's Disease Center, Department of Behavioral Sciences, Rush University Medical Center, 600 S. Paulina, 1020B, Chicago, IL 60612, USA.
Neurology. 2008 Apr 22;70(17):1534-42. doi: 10.1212/01.wnl.0000304345.14212.38. Epub 2008 Mar 19.
The cognitive abilities of older persons vary greatly, even among those with similar amounts of Alzheimer disease (AD) pathology, suggesting differences in neural reserve. Although its neurobiologic basis is not well understood, reserve may reflect differences in the ability to compensate for the deleterious effects of pathology by recruiting alternative or additional brain networks to perform a specific task. If this is an effective compensatory strategy, then involvement of additional cognitive systems may help maintain function in other cognitive systems despite the accumulation of pathology.
We tested the hypothesis that processing resources, specifically perceptual speed and working memory, modify the associations of AD pathology with other cognitive systems.
A total of 103 older participants of the Rush Memory and Aging Project underwent detailed annual clinical evaluations and brain autopsy. Five cognitive systems including perceptual speed, working memory, semantic memory, visuospatial abilities, and episodic memory were assessed proximate to death, and AD pathology including tau tangles and amyloid load were quantified postmortem.
In multiple regression models adjusted for age, sex, and education, processing resources reduced the associations of tangles with other cognitive systems, such that persons with higher levels of perceptual speed and working memory performed better on semantic memory and visuospatial abilities despite the burden of tangles. Perceptual speed also reduced the associations of amyloid with semantic memory, visuospatial abilities, and episodic memory.
These findings suggest that processing resources may help compensate for the deleterious effects of Alzheimer disease pathology on other cognitive systems in older persons.
老年人的认知能力差异很大，即使在患有相似程度阿尔茨海默病（AD）病理的人群中也是如此，这表明神经储备存在差异。尽管其神经生物学基础尚未完全了解，但储备可能反映了通过招募替代或额外的脑网络来执行特定任务，从而补偿病理有害影响的能力差异。如果这是一种有效的补偿策略，那么尽管病理在累积，但额外认知系统的参与可能有助于维持其他认知系统的功能。
我们检验了这样一种假设，即加工资源，特别是感知速度和工作记忆，会改变AD病理与其他认知系统之间的关联。
拉什记忆与衰老项目的103名老年参与者接受了详细的年度临床评估和脑尸检。在临近死亡时评估了包括感知速度、工作记忆、语义记忆、视觉空间能力和情景记忆在内的五个认知系统，并在死后对包括tau缠结和淀粉样蛋白负荷在内的AD病理进行了量化。
在针对年龄、性别和教育程度进行调整的多元回归模型中，加工资源减少了缠结与其他认知系统之间的关联，以至于感知速度和工作记忆水平较高的人尽管有缠结负担，但在语义记忆和视觉空间能力方面表现更好。感知速度也减少了淀粉样蛋白与语义记忆、视觉空间能力和情景记忆之间的关联。
这些发现表明，加工资源可能有助于补偿阿尔茨海默病病理对老年人其他认知系统的有害影响。
