Jobin Benoît, Boller Benjamin, Frasnelli Johannes
Department of Psychology, Université du Québec à Trois-Rivières, Trois-Rivieres, QC G8Z 4M3, Canada.
Research Centre of the Institut Universitaire de Gériatrie de Montréal, Montréal, QC H3W 1W5, Canada.
Brain Sci. 2021 Jul 30;11(8):1010. doi: 10.3390/brainsci11081010.
Olfactory decline is an early symptom of Alzheimer's disease (AD) and is a predictor of conversion from mild cognitive impairment (MCI) to AD. Olfactory decline could reflect AD-related atrophy of structures related to the sense of smell. The aim of this study was to verify whether the presence of a clinical diagnosis of AD or MCI is associated with a volumetric decrease in the olfactory bulbs (OB) and the primary olfactory cortex (POC). We conducted two systematic reviews, one for each region and a meta-analysis. We collected articles from PsychNet, PubMed, Ebsco, and ProQuest databases. Results showed large and heterogeneous effects indicating smaller OB volumes in patients with AD (k = 6, = -1.21, 95% CI [-2.19, -0.44]) and in patients with MCI compared to controls. There is also a trend for smaller POC in patients with AD or MCI compared to controls. Neuroanatomical structures involved in olfactory processing are smaller in AD and these volumetric reductions could be measured as early as the MCI stage.
嗅觉减退是阿尔茨海默病（AD）的早期症状，也是轻度认知障碍（MCI）向AD转化的预测指标。嗅觉减退可能反映了与嗅觉相关结构的AD相关性萎缩。本研究的目的是验证AD或MCI的临床诊断是否与嗅球（OB）和初级嗅觉皮层（POC）的体积减小有关。我们进行了两项系统评价，每个区域一项，并进行了荟萃分析。我们从PsychNet、PubMed、Ebsco和ProQuest数据库收集文章。结果显示，与对照组相比，AD患者（k = 6， = -1.21，95%CI [-2.19，-0.44]）和MCI患者的OB体积明显较小，且存在异质性。与对照组相比，AD或MCI患者的POC也有变小的趋势。AD患者中参与嗅觉处理的神经解剖结构较小，这些体积减小最早可在MCI阶段测量到。
