Background: 

The relation of retinal thickness to neuropsychological indexes of cognitive impairment in patients with Alzheimer disease (AD) remains an area of investigation. The scope of this investigation was to compare volume and thickness changes of neuronal retinal layers in subjects with AD with those of age-matched healthy controls and to estimate the relation between cognitive functioning evaluated by neuropsychological assessment and thickness changes of the retina.

Methods: 

This was a prospective single-site study where we evaluated 25 subjects with probable AD matched for age, sex, and education to 17 healthy control subjects (HC). All participants underwent a full medical evaluation, neuropsychological assessment, and optical coherence tomography (OCT) to evaluate the peripapillary retinal nerve fiber layer (pRNFL) thickness, ganglion cell complex (GCC) thickness, and macular volume.

Results: 

The pRNFL thickness of AD patients showed a significant overall reduction compared with healthy controls (P = <0.0001). Furthermore, pRNFL was reduced in each retinal quadrant, particularly the inferior, nasal, and superior quadrants. GCC thickness and macular volume were reduced in AD patients in comparison with HC (P = 0.004; P = 0.001). Of particular interest was the correlation between OCT findings and neuropsychological assessment; we did not find a significant association of retinal thinning with worse MMSE score, but reduction of macular volume was associated with worse constructional praxis performance. Impairment of semantic-lexical and processing speed was associated with attenuation of macular GCC thickness.

Conclusions: 

OCT can show early thickness changes in AD patients with subtle memory disturbances. These results suggest that correlations between retinal thinning and cognitive performance warrant further investigation.

中文翻译：

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神经认知评估和阿尔茨海默病视网膜厚度改变：有相关性吗？

背景： 

视网膜厚度与阿尔茨海默病（AD）患者认知障碍的神经心理学指标之间的关系仍然是一个研究领域。本研究的范围是比较患有AD的受试者与年龄匹配的健康对照者的神经元视网膜层的体积和厚度变化，并估计通过神经心理学评估评估的认知功能与视网膜厚度变化之间的关系。

方法： 

这是一项前瞻性单点研究，我们评估了25位年龄，性别和受教育程度与AD相匹配的受试者，并对17位健康对照受试者（HC）进行了评估。所有参与者均进行了全面的医学评估，神经心理学评估和光学相干断层扫描（OCT），以评估乳头周围视网膜神经纤维层（pRNFL）厚度，神经节细胞复合物（GCC）厚度和黄斑体积。

结果： 

与健康对照组相比，AD患者的pRNFL厚度总体上显着降低（P = <0.0001）。此外，在每个视网膜象限中，特别是在下，鼻和上象限中，pRNFL降低。与HC相比，AD患者的GCC厚度和黄斑体积减少（P = 0.004；P = 0.001）。特别令人感兴趣的是OCT结果与神经心理学评估之间的相关性。我们没有发现视网膜变薄与MMSE评分越差之间存在显着相关性，但黄斑体积的减少与较差的结构实践表现有关。语义词法和处理速度的降低与黄斑区GCC厚度的降低有关。

结论： 

OCT可以显示患有轻微记忆障碍的AD患者的早期厚度变化。这些结果表明，视网膜变薄与认知能力之间的相关性值得进一步研究。