Laboratory of Vision, Institute of Psychology, University of São Paulo, São Paulo, Brazil.
Prevent Senior Private Health Operator, São Paulo, Brazil.
Invest Ophthalmol Vis Sci. 2022 May 2;63(5):20. doi: 10.1167/iovs.63.5.20.
To evaluate color vision changes and retinal processing of chromatic and luminance pathways in subjects with Alzheimer disease (AD) and mild cognitive impairment (MCI) compared with a matched control group and whether such changes are associated with impaired brain glucose metabolism and β-amyloid deposition in the brain.
We evaluated 13 patients with AD (72.4 ± 7.7 years), 23 patients with MCI (72.5 ± 5.5 years), and 18 controls of comparable age (P = 0.44) using Cambridge color test and the heterochromatic flicker ERG (HF-ERG). The Cambridge color test was performed using the trivector protocol to estimate the protan, deutan and tritan color confusion axes. HF-ERG responses were measured at a frequency of 12 Hz, which ERGs reflect chromatic activity, and at 36 Hz, reflecting luminance pathway. A study subsample was performed using neuropsychological assessments and positron emission tomography.
Patients with AD presented higher mean values indicating poorer color discrimination for protan (P = 0.04) and deutan (P = 0.001) axes compared with the controls. Along the tritan axis, both patients with AD and patients with MCI showed decreased color vision (P = 0.001 and P = 0.001) compared with controls. The analyses from the HF-ERG protocol revealed no differences between the groups (P = 0.31 and P = 0.41). Diffuse color vision loss was found in individuals with signs of neurodegeneration (protan P = 0.002, deutan P = 0.003 and tritan P = 0.01), but not in individuals with signs of β-amyloid deposition only (protan P = 0.39, deutan P = 0.48, tritan P = 0.63), regardless of their clinical classification.
Here, patients with AD and patients with MCI present acquired color vision deficiency that may be linked with impaired brain metabolism.
评估阿尔茨海默病（AD）和轻度认知障碍（MCI）患者与匹配对照组相比，色觉和亮度通路的视网膜处理以及这些变化是否与大脑葡萄糖代谢和β-淀粉样蛋白在大脑中的沉积受损有关。
我们使用剑桥色觉测试和异色闪烁视网膜电图（HF-ERG）评估了 13 名 AD 患者（72.4±7.7 岁）、23 名 MCI 患者（72.5±5.5 岁）和 18 名年龄匹配的对照组（P=0.44）。剑桥色觉测试采用三矢量方案进行，以估计红绿色盲、蓝黄色盲和绿色盲的色觉混淆轴。HF-ERG 反应在 12 Hz 的频率下进行测量，该频率反映了色觉活动，在 36 Hz 的频率下进行测量，反映了亮度通路。一个研究子样本进行了神经心理学评估和正电子发射断层扫描。
AD 患者的平均色觉值较高，表明其对红绿色盲和蓝黄色盲的色觉辨别力较差（分别为 P=0.04 和 P=0.001）。沿着绿色盲轴，AD 患者和 MCI 患者的色觉均下降（分别为 P=0.001 和 P=0.001）。HF-ERG 协议的分析显示，各组之间没有差异（P=0.31 和 P=0.41）。在有神经退行性病变迹象的个体中发现弥漫性色觉丧失（红绿色盲 P=0.002，蓝黄色盲 P=0.003，绿色盲 P=0.01），但在仅有β-淀粉样蛋白沉积迹象的个体中没有发现（红绿色盲 P=0.39，蓝黄色盲 P=0.48，绿色盲 P=0.63），无论其临床分类如何。
在这里，AD 患者和 MCI 患者出现获得性色觉缺陷，这可能与大脑代谢受损有关。
