Department of Psychiatry and Behavioral Sciences, School of Medicine, Stanford University, Stanford, CA, USA.
Aging Research Center, Karolinska Institutet and Stockholm University, Stockholm, Sweden.
J Alzheimers Dis. 2024;101(1):249-258. doi: 10.3233/JAD-231458.
Age represents the largest risk factor for Alzheimer's disease (AD) but is typically treated as a covariate. Still, there are similarities between brain regions affected in AD and those showing accelerated decline in normal aging, suggesting that the distinction between the two might fall on a spectrum.
Our goal was to identify regions showing accelerated atrophy across the brain and investigate whether these overlapped with regions involved in AD or where related to amyloid.
We used a longitudinal sample of 137 healthy older adults from the Alzheimer's Disease Neuroimaging Initiative (ADNI), who underwent magnetic resonance imaging (MRI). In addition, a total of 79 participants also had longitudinal positron emission tomography (PET) data. We computed linear-mixed effects models for brain regions declining faster than the average to investigate variability in the rate of change.
23 regions displayed a 0.5 standard deviation (SD) above average decline over 2 years. Of these, 52% overlapped with regions showing similar decline in a matched AD sample. Beyond this, the left precuneus, right superior frontal, transverse temporal, and superior temporal sulcus showed accelerated decline. Lastly, atrophy in the precuneus was associated with increased amyloid load.
Accelerated decline in normal aging might contribute to the detection of early signs of AD among healthy individuals.
年龄是阿尔茨海默病（AD）的最大风险因素，但通常被视为协变量。然而，AD 患者受影响的大脑区域与正常衰老过程中快速衰退的大脑区域之间存在相似性，这表明两者之间的区别可能存在于一个连续谱上。
我们的目标是确定大脑中出现加速萎缩的区域，并研究这些区域是否与 AD 相关区域重叠，或者与淀粉样蛋白相关。
我们使用了来自阿尔茨海默病神经影像学倡议（ADNI）的 137 名健康老年纵向样本进行磁共振成像（MRI）。此外，共有 79 名参与者还具有纵向正电子发射断层扫描（PET）数据。我们计算了大脑区域的线性混合效应模型，这些区域的衰退速度快于平均值，以研究变化率的可变性。
在 2 年内，有 23 个区域的下降速度超过平均水平 0.5 个标准差。其中，52%的区域与匹配的 AD 样本中表现出相似下降的区域重叠。除此之外，左楔前叶、右额上回、横颞叶和颞上回显示出加速的衰退。最后，楔前叶的萎缩与淀粉样蛋白负荷的增加有关。
正常衰老过程中的加速衰退可能有助于在健康个体中检测到 AD 的早期迹象。
