Department of Psychological and Brain Sciences, Texas A&M University, College Station.
Baylor Scott and White Neurosciences Institute, Temple, Texas.
J Gerontol B Psychol Sci Soc Sci. 2018 Aug 14;73(6):964-973. doi: 10.1093/geronb/gbx156.
Alzheimer's disease (AD) is a progressive disease reflected in markers across assessment modalities, including neuroimaging, cognitive testing, and evaluation of adaptive function. Identifying a single continuum of decline across assessment modalities in a single sample is statistically challenging because of the multivariate nature of the data. To address this challenge, we implemented advanced statistical analyses designed specifically to model complex data across a single continuum.
We analyzed data from the Alzheimer's Disease Neuroimaging Initiative (ADNI; N = 1,056), focusing on indicators from the assessments of magnetic resonance imaging (MRI) volume, fluorodeoxyglucose positron emission tomography (FDG-PET) metabolic activity, cognitive performance, and adaptive function. Item response theory was used to identify the continuum of decline. Then, through a process of statistical scaling, indicators across all modalities were linked to that continuum and analyzed.
Findings revealed that measures of MRI volume, FDG-PET metabolic activity, and adaptive function added measurement precision beyond that provided by cognitive measures, particularly in the relatively mild range of disease severity. More specifically, MRI volume, and FDG-PET metabolic activity become compromised in the very mild range of severity, followed by cognitive performance and finally adaptive function.
Our statistically derived models of the AD pathological cascade are consistent with existing theoretical models.
阿尔茨海默病（AD）是一种在各种评估模式中都有体现的进行性疾病，包括神经影像学、认知测试和适应功能评估。由于数据的多变量性质，在单个样本中识别横跨各种评估模式的单一衰退连续体在统计学上具有挑战性。为了解决这个挑战，我们实施了专门设计的高级统计分析，旨在对单一连续体中的复杂数据进行建模。
我们分析了阿尔茨海默病神经影像学倡议（ADNI；N=1056）的数据，重点关注磁共振成像（MRI）体积、氟脱氧葡萄糖正电子发射断层扫描（FDG-PET）代谢活性、认知表现和适应功能评估的指标。项目反应理论用于识别衰退的连续体。然后，通过统计缩放过程，将所有模式的指标与该连续体相关联并进行分析。
研究结果表明，MRI 体积、FDG-PET 代谢活性和适应功能等测量指标在认知测量提供的精度之外增加了测量精度，特别是在疾病严重程度的相对轻度范围内。更具体地说，MRI 体积和 FDG-PET 代谢活性在严重程度的非常轻度范围内受损，其次是认知表现，最后是适应功能。
我们通过统计学方法得出的 AD 病理级联模型与现有的理论模型一致。
