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：

---

对主观认知下降、轻度认知下降和阿尔茨海默病中嗅觉功能障碍的认识

介绍

嗅觉减退和元认知错误与衰老、抑郁、男性和认知能力下降有关。目前的研究调查了主观认知衰退（SCD）、轻度认知障碍（MCI）和阿尔茨海默病（AD）中嗅觉功能障碍的认知，以及其他因素的影响。

方法

使用 Sniffin' Sticks 气味识别测试 (OIT) 和主观嗅觉能力 (SOC) 对 641 名患者样本进行评估，包括对照、SCD、非遗忘性 MCI (naMCI)、遗忘性 MCI (aMCI) 和 AD 患者除了抑郁症状、言语记忆和执行功能的测量外，还包括量表。嗅觉意识小组是通过 OIT 和 SOC 的切断而形成的。

结果

在研究组中发现了 OIT 和 SOC 之间虽然显着但中度和较小的相关性，通过主观评估测量的嗅觉功能在对照组中存在显着差异，但在 AD 患者中则不然。在所有 AD 患者中，34% 的人高估了自己的嗅觉，而 21% 的人正确地认为自己嗅觉低下，而健康老年人的这一比例为 6% 和 1%。高估者和正确的低嗅觉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与认知障碍相同的大脑病理变化的基础，并且可以作为 AD 发展的另一个标志。

影响

尽管 AD 患者在一定程度上意识到嗅觉减退，但大多数人受到高估嗅觉能力的影响，这使得主观评分和嗅觉功能测量的结合成为进一步研究的有趣课题。