Introduction

Hyposmia and metacognitive errors are related to aging, depression, male gender, and cognitive decline. The current study investigated the awareness of olfactory dysfunction in subjective cognitive decline (SCD), mild cognitive impairment (MCI), and Alzheimer’s disease (AD), as well as the influence of additional factors.

Methods

A sample of 641 patients, including controls, SCD, non-amnestic MCI (naMCI), amnestic MCI (aMCI), and AD patients, was assessed with the Sniffin’ Sticks odor identification test (OIT) and the subjective olfactory capability (SOC) scale, in addition to measures of depressive symptoms, verbal memory, and executive functioning. Olfactory awareness groups were formed by means of the cutoffs of the OIT and the SOC.

Results

Moderate and small, although significant, correlations between the OIT and the SOC were found among the study groups, with a significant discrimination of measured olfactory function via subjective assessment existing among controls but not among patients with AD. Of all AD patients, 34% overrated their sense of smell while 21% correctly identified themselves as being hyposmic, as opposed to corresponding 6% and 1% of healthy elderly. Overraters and correct hyposmic participants showed higher age and worse verbal memory and executive functions.

Conclusions

Reduced odor identification might underlie the same pathological changes within the brain as cognitive impairment and could serve as an additional marker for the development of AD.

Implications

Although people with AD are aware of hyposmia to some extent, the majority is affected by overestimation of the ability to smell, making the combination of subjective ratings and measures of olfactory function an interesting topic for further research.

中文翻译：

---

主观认知下降，轻度认知下降和阿尔茨海默氏病患者嗅觉功能障碍的意识

介绍

嗅觉减退和元认知错误与衰老，抑郁，男性性别和认知能力下降有关。本研究调查了嗅觉功能障碍对主观认知下降（SCD），轻度认知障碍（MCI）和阿尔茨海默氏病（AD）的认识，以及其他因素的影响。

方法

通过嗅嗅棒气味识别测试（OIT）和主观嗅觉能力（SOC）评估了641名患者的样本，包括对照，SCD，非记忆MCI（naMCI），记忆MCI（aMCI）和AD患者量表，以及抑郁症状，言语记忆和执行功能的测量。嗅觉意识小组是通过切断OIT和SOC的方式而成立的。

结果

在研究组之间发现了OIT和SOC之间的适度和小但显着的相关性，通过对照组之间存在主观评估而对嗅觉功能进行了显着区分，而在AD患者之间却没有。在所有AD患者中，有34％的人高估了他们的嗅觉，而21％的人正确地认为自己患有低氧血症，而健康老人的这一比例为6％和1％。高估者和正确的低氧参与者表现出较高的年龄和较差的言语记忆和执行功能。

结论

气味识别的减少可能是大脑内与认知障碍相同的病理变化的基础，并且可以作为AD发生的附加标志。

含义

尽管AD患者在一定程度上意识到了低渗症，但大多数患者仍受到过高估计嗅觉能力的影响，因此将主观评分与嗅觉功能的测量结合起来是一个值得进一步研究的有趣话题。