Mi Yan, Ma Xiaojuan, Du Shan, Du Chengxue, Li Xiaobo, Tan Huihui, Zhang Jie, Zhang Qi, Shi Wenzhen, Zhang Gejuan, Tian Ye
Department of Neurology, The Affiliated Hospital of Northwest University, Xi'an No.3 Hospital, Xi'an, Shaanxi, China.
Xi'an Key Laboratory of Cardiovascular and Cerebrovascular Diseases, The Affiliated Hospital of Northwest University, Xi'an No.3 Hospital, Xi'an, Shaanxi, China.
Front Aging Neurosci. 2023 Feb 13;15:1068708. doi: 10.3389/fnagi.2023.1068708. eCollection 2023.
Olfactory disorder is one of the sensory features that reflects a decline in cognitive function. However, olfactory changes and the discernibility of smell testing in the aging population have yet to be fully elucidated. Therefore, this study aimed to examine the effectiveness of the Chinese Smell Identification Test (CSIT) in distinguishing individuals with cognitive decline from those with normal aging and to determine whether the patients with MCI and AD show changes in their olfactory identification abilities.
This cross-sectional study included eligible participants aged over 50 years between October 2019 and December 2021. The participants were divided into three groups: individuals with mild cognitive impairment (MCI), individuals with Alzheimer's disease (AD), and cognitively normal controls (NCs). All participants were assessed using neuropsychiatric scales, the Activity of Daily Living scale, and the 16-odor cognitive state test (CSIT) test. The test scores and the severity of olfactory impairment were also recorded for each participant.
In total, 366 eligible participants were recruited, including 188 participants with MCI, 42 patients with AD, and 136 NCs. Patients with MCI achieved a mean CSIT score of 13.06 ± 2.05, while patients with AD achieved a mean score of 11.38 ± 3.25. These scores were significantly lower than those of the NC group (14.6 ± 1.57; < 0.001). An analysis showed that 19.9% of NCs exhibited mild olfactory impairment, while 52.7% of patients with MCI and 69% of patients with AD exhibited mild to severe olfactory impairment. The CSIT score was positively correlated with the MoCA and MMSE scores. The CIST score and the severity of olfactory impairment were identified as robust indicators for MCI and AD, even after adjusting for age, gender, and level of education. Age and educational level were identified as two important confounding factors that influence cognitive function. However, no significant interactive effects were observed between these confounders and CIST scores in determining the risk of MCI. The area under the ROC curve (AUC) generated from the ROC analysis was 0.738 and 0.813 in distinguishing patients with MCI and patients with AD from NCs based on the CIST scores, respectively. The optimal cutoff for distinguishing MCI from NCs was 13, and for distinguishing AD from NCs was 11. The AUC for distinguishing AD from MCI was 0.62.
The olfactory identification function is frequently affected in patients with MCI and patients with AD. CSIT is a beneficial tool for the early screening of cognitive impairment among elderly patients with cognitive or memory issues.
嗅觉障碍是反映认知功能下降的感官特征之一。然而，嗅觉变化以及老年人群嗅觉测试的可辨别性尚未得到充分阐明。因此，本研究旨在检验中文版嗅觉识别测试（CSIT）在区分认知功能下降个体与正常衰老个体方面的有效性，并确定轻度认知障碍（MCI）和阿尔茨海默病（AD）患者的嗅觉识别能力是否发生变化。
这项横断面研究纳入了2019年10月至2021年12月期间年龄在50岁以上的合格参与者。参与者被分为三组：轻度认知障碍（MCI）个体、阿尔茨海默病（AD）个体和认知正常对照（NC）个体。所有参与者均使用神经精神量表、日常生活活动量表和16气味认知状态测试（CSIT）进行评估。还记录了每位参与者的测试分数和嗅觉障碍的严重程度。
总共招募了366名合格参与者，包括188名MCI参与者、42名AD患者和136名NC个体。MCI患者的CSIT平均得分为13.06±2.05，而AD患者的平均得分为11.38±3.25。这些分数显著低于NC组（14.6±1.57；<0.001）。分析表明，19.9%的NC个体存在轻度嗅觉障碍，而52.7%的MCI患者和69%的AD患者存在轻度至重度嗅觉障碍。CSIT分数与蒙特利尔认知评估量表（MoCA）和简易精神状态检查表（MMSE）分数呈正相关。即使在调整年龄、性别和教育水平后，CIST分数和嗅觉障碍的严重程度仍被确定为MCI和AD的有力指标。年龄和教育水平被确定为影响认知功能的两个重要混杂因素。然而，在确定MCI风险时，未观察到这些混杂因素与CIST分数之间存在显著的交互作用。基于CIST分数，在将MCI患者和AD患者与NC个体区分开来的ROC分析中生成的ROC曲线下面积（AUC）分别为0.738和0.813。区分MCI与NC个体的最佳截断值为13，区分AD与NC个体的最佳截断值为11。区分AD与MCI的AUC为0.62。
MCI患者和AD患者的嗅觉识别功能经常受到影响。CSIT是对有认知或记忆问题的老年患者进行认知障碍早期筛查的有益工具。
