University ofTexas, Dallas, TX, USA.
Neurology. 2012 Feb 7;78(6):387-95. doi: 10.1212/WNL.0b013e318245d295. Epub 2012 Feb 1.
Several lines of evidence suggest that pathologic changes underlying Alzheimer disease (AD) begin years prior to the clinical expression of the disease, underscoring the need for studies of cognitively healthy adults to capture these early changes. The overall goal of the current study was to map the cortical distribution of β-amyloid (Aβ) in a healthy adult lifespan sample (aged 30-89), and to assess the relationship between elevated amyloid and cognitive performance across multiple domains.
A total of 137 well-screened and cognitively normal adults underwent Aβ PET imaging with radiotracer (18)F-florbetapir. Aβ load was estimated from 8 cortical regions. Participants were genotyped for APOE and tested for processing speed, working memory, fluid reasoning, episodic memory, and verbal ability.
Aβ deposition is distributed differentially across the cortex and progresses at varying rates with age across cortical brain regions. A subset of cognitively normal adults aged 60 and over show markedly elevated deposition, and also had a higher rate of APOE ε4 (38%) than nonelevated adults (19%). Aβ burden was linked to poorer cognitive performance on measures of processing speed, working memory, and reasoning.
Even in a highly selected lifespan sample of adults, Aβ deposition is apparent in some adults and is influenced by APOE status. Greater amyloid burden was related to deleterious effects on cognition, suggesting that subtle cognitive changes accrue as amyloid progresses.
有几条证据表明，阿尔茨海默病（AD）的病理变化早在疾病临床表现之前就已经开始了，这突显了对认知健康成年人进行研究以捕捉这些早期变化的必要性。本研究的总体目标是在健康成年人的一生中（年龄在 30-89 岁之间）绘制β-淀粉样蛋白（Aβ）的皮质分布，并评估在多个领域中，淀粉样蛋白升高与认知表现之间的关系。
共有 137 名经过充分筛选且认知正常的成年人接受了放射性示踪剂（18）F-氟比他滨的 Aβ PET 成像。从 8 个皮质区域估计 Aβ 负荷。参与者接受 APOE 基因分型，并接受处理速度、工作记忆、流体推理、情景记忆和言语能力测试。
Aβ 沉积在皮质中呈不同分布，在皮质脑区随年龄以不同速度进展。一部分年龄在 60 岁及以上的认知正常成年人表现出明显升高的沉积，并且 APOE ε4（38%）的发生率也高于无升高的成年人（19%）。Aβ 负荷与处理速度、工作记忆和推理等认知测试的认知表现较差有关。
即使在高度选择的成年人寿命样本中，也可以在一些成年人中看到 Aβ 沉积，并且受到 APOE 状态的影响。更大的淀粉样蛋白负荷与认知功能的有害影响有关，这表明随着淀粉样蛋白的进展，会出现微妙的认知变化。
