Department of Pathophysiology, School of Basic Medicine, Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Department of Radiology, Wuhan Brain Hospital, Wuhan, China.
J Alzheimers Dis. 2023;93(1):169-178. doi: 10.3233/JAD-230023.
Olfactory dysfunction appears prior to cognitive decline, and thus it has been suggested to be an early predictor of Alzheimer's disease. However, it is currently not known whether and how olfactory threshold test could serve as a quick screening tool for cognitive impairment.
To define olfactory threshold test for screening cognitive impairment in two independent cohorts.
The participants are comprised of two cohorts in China, 1,139 inpatients with type 2 diabetes mellitus (T2DM, Discovery cohort) and 1,236 community-dwelling elderly (Validation cohort). Olfactory and cognitive functions were evaluated by Connecticut Chemosensory Clinical Research Center test and Mini-Mental State Examination (MMSE), respectively. Regression analyses and receiver operating characteristic (ROC) analyses were carried out to determine the relation and discriminative performance of the olfactory threshold score (OTS) regarding identification of cognition impairment.
Regression analysis showed that olfactory deficit (reducing OTS) was correlated with cognitive impairment (reducing MMSE score) in two cohorts. ROC analysis revealed that the OTS could distinguish cognitive impairment from cognitively normal individuals, with mean area under the curve values of 0.71 (0.67, 0.74) and 0.63 (0.60, 0.66), respectively, but it failed to discriminate dementia from mild cognitive impairment. The cut-off point of 3 showed the highest validity for the screening, with the diagnostic accuracy of 73.3% and 69.5%.
Reducing OTS is associated with cognitive impairment in T2DM patients and the community-dwelling elderly. Therefore, olfactory threshold test may be used as a readily accessible screening tool for cognitive impairment.
嗅觉功能障碍先于认知能力下降出现，因此它被认为是阿尔茨海默病的早期预测指标。然而，目前尚不清楚嗅觉阈值测试是否以及如何可以作为认知障碍的快速筛查工具。
在两个独立队列中定义嗅觉阈值测试以筛查认知障碍。
参与者包括中国的两个队列，共 1139 例 2 型糖尿病（T2DM，发现队列）住院患者和 1236 例社区居住的老年人（验证队列）。通过康涅狄格州化学感觉临床研究中心测试和简易精神状态检查（MMSE）分别评估嗅觉和认知功能。进行回归分析和受试者工作特征（ROC）分析，以确定嗅觉阈值评分（OTS）与识别认知障碍的关系和判别性能。
回归分析显示，嗅觉缺陷（OTS 降低）与两个队列中的认知障碍（MMSE 评分降低）相关。ROC 分析显示，OTS 能够区分认知障碍与认知正常个体，曲线下面积平均值分别为 0.71（0.67，0.74）和 0.63（0.60，0.66），但无法区分痴呆与轻度认知障碍。3 的截断值显示出最高的筛查有效性，其诊断准确性分别为 73.3%和 69.5%。
OTS 降低与 T2DM 患者和社区居住的老年人的认知障碍有关。因此，嗅觉阈值测试可能被用作认知障碍的便捷筛查工具。
