Weigand Research Service, Veterans Affairs San Diego Healthcare System.
Research Service and Psychology Service, Veterans Affairs San Diego Healthcare System.
Neuropsychology. 2019 Jul;33(5):599-608. doi: 10.1037/neu0000532. Epub 2019 Mar 21.
Intraindividual cognitive variability (IIV), a measure of within-person variability across cognitive measures at a single time point, is associated with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Little is known regarding brain changes underlying IIV, or the relationship between IIV and functional ability. Therefore, we investigated the association between IIV and cerebral atrophy in AD-vulnerable regions and everyday functioning in nondemented older adults.
736 Alzheimer's Disease Neuroimaging Initiative (ADNI) participants (285 cognitively normal [CN]; 451 MCI) underwent neuropsychological testing and serial MRI over 2 years. Linear mixed effects models examined the association between baseline IIV and change in entorhinal cortex thickness, hippocampal volume, and everyday functioning.
Adjusting for age, sex, apolipoprotein E genotype, amyloid-β positivity, and mean level of cognitive performance, higher baseline IIV predicted faster rates of entorhinal and hippocampal atrophy, as well as functional decline. Higher IIV was associated with both entorhinal and hippocampal atrophy among MCI participants but selective vulnerability of the entorhinal cortex among CN individuals.
IIV was associated with more widespread medial temporal lobe (MTL) atrophy in individuals with MCI relative to CN, suggesting that IIV may be tracking advancing MTL pathologic changes across the continuum of aging, MCI, and dementia. Findings suggest that cognitive dispersion may be a sensitive marker of neurodegeneration and functional decline in nondemented older adults. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
个体内认知变异性（IIV）是衡量个体在单一时间点上多个认知测量值之间的变异性的指标，与轻度认知障碍（MCI）和阿尔茨海默病（AD）有关。关于导致 IIV 的大脑变化，以及 IIV 与功能能力之间的关系，人们知之甚少。因此，我们研究了 AD 易损区域内的 IIV 与大脑萎缩以及认知正常的老年个体日常功能之间的关系。
736 名阿尔茨海默病神经影像学倡议（ADNI）参与者（285 名认知正常[CN]；451 名 MCI）在 2 年内接受神经心理学测试和连续 MRI 检查。线性混合效应模型研究了基线 IIV 与内侧颞叶（MTL）结构（包括内嗅皮层厚度和海马体积）和日常功能变化之间的关系。
在调整年龄、性别、载脂蛋白 E 基因型、淀粉样蛋白-β阳性、认知表现的平均水平后，较高的基线 IIV 预测了更快的内嗅皮层和海马萎缩以及功能下降的速度。较高的 IIV 与 MCI 参与者的内嗅皮层和海马萎缩均有关，但在 CN 个体中则选择性地易损于内嗅皮层。
与 CN 个体相比，MCI 个体的 IIV 与更广泛的 MTL 萎缩有关，这表明 IIV 可能在整个衰老、MCI 和痴呆连续体中追踪 MTL 病理变化的进展。研究结果表明，认知分散可能是认知正常的老年个体神经退行性变和功能下降的敏感标志物。
