Background:Studies of elderly subjects using biomarkers that are proxies for Alzheimer’s disease (AD) pathology have the potential to document meaningful relationships between cognitive performance and biomarker changes along the AD continuum. Objective:To document cognitive performance differencesacross distinct AD stages using a categorization based on the presence of PET-assessed amyloid-β (Aβ) burden and neurodegeneration. Methods:Patients with mild dementia compatible with AD (n = 38) or amnestic mild cognitive impairment (aMCI; n = 43) and a cognitively unimpaired group (n = 27) underwent PET with Pittsburgh compound-B (PiB) assessing Aβ aggregation (A+) and [18F]FDG-PET assessing neurodegeneration ((N)+). Cognitive performance was assessed with verbal and visual episodic memory tests and the Mini-Mental State Examination. Results:The A+(N)+ subgroup (n = 32) showed decreased (p < 0.001) cognitive test scores compared to both A+(N)–(n = 18) and A–(N)–(n = 49) subjects, who presented highly similar mean cognitive scores. Despite its modest size (n = 9), the A–(N)+ subgroup showed lower (p < 0.043) verbal memory scores relative to A–(N)–subjects, and trend lower (p = 0.096) scores relative to A+(N)–subjects. Continuous Aβ measures (standard uptake value ratios of PiB uptake) were correlated most significantly with visual memory scores both in the overall sample and when analyses were restricted to dementia or (N)+ subjects, but not in non-dementia or (N)–groups. Conclusion:These results demonstrate that significant Aβ-cognition relationships are highly salient at disease stages involving neurodegeneration. The fact that findings relating Aβ burden to memory performance were detected only at (N)+ stages, together with the similarity of test scores between A+(N)–and A–(N)–subjects, reinforce the view that Aβ-cognition relationships during early AD stages may remain undetectable unless substantially large samples are evaluated.

中文翻译：

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老年受试者 PET 评估的淀粉样蛋白负荷与视觉和言语情景记忆表现之间的关系

背景：使用代表阿尔茨海默病 (AD) 病理学指标的生物标志物对老年受试者进行的研究有可能记录认知表现与 AD 连续体中生物标志物变化之间的有意义的关系。目的：使用基于 PET 评估的淀粉样蛋白 β (Aβ) 负荷和神经变性的分类，记录不同 AD 阶段的认知表现差异。方法：患有 AD（n = 38）或遗忘型轻度认知障碍（aMCI；n = 43）和认知未受损组（n = 27）的轻度痴呆患者接受匹兹堡化合物 B (PiB) PET 评估 Aβ 聚集。 A+) 和 [18F]FDG-PET 评估神经变性 ((N)+)。认知表现通过语言和视觉情景记忆测试和简易精神状态检查进行评估。结果：与 A+(N)–(n = 18) 和 A–(N)–(n = 49) 受试者相比，A+(N)+ 亚组 (n = 32) 的认知测试分数降低 (p < 0.001)呈现高度相似的平均认知分数。尽管规模适中 (n = 9)，但 A–(N)+ 亚组显示出相对于 A–(N)– 受试者较低 (p < 0.043) 的言语记忆分数，并且相对于 A+ 受试者而言，其分数呈下降趋势 (p = 0.096) (N)——受试者。连续 Aβ 测量（PiB 摄取的标准摄取值比率）与整个样本中以及分析仅限于痴呆症或 (N)+ 受试者时的视觉记忆评分最显着相关，但在非痴呆症或 (N)– 受试者中则不然组。结论：这些结果表明，在涉及神经变性的疾病阶段，显着的 Aβ 认知关系非常突出。