Chen Ben, Espin Melanie, Haussmann Robert, Matthes Claudia, Donix Markus, Hummel Thomas, Haehner Antje
Smell & Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany.
Department of Geriatric Psychiatry, Memory Clinic, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong, China.
J Alzheimers Dis. 2022;85(2):745-754. doi: 10.3233/JAD-215257.
The olfactory system is affected very early in Alzheimer's disease and olfactory loss can already be observed in patients with mild cognitive impairment (MCI), an early stage of AD.
The aim of this randomized, prospective, controlled, blinded study was to evaluate whether olfactory training (OT) may have an effect on olfactory function, cognitive impairment, and brain activation in MCI patients after a 4-month period of frequent short-term exposure to various odors.
A total of 38 MCI outpatients were randomly assigned to OT or a control training condition, which were performed twice a day for 4 months. Olfactory testing, comprehensive neuropsychological assessment, and a passive odor perception task based on magnetic resonance imaging were performed before and after training.
The results suggested that OT exhibited no significant effect on olfaction and cognitive function. Additionally, OT exhibited a positive effect on frontal lobe activation (left middle frontal gyrus and orbital-frontal cortex) but exhibited no effect on grey matter volume. Moreover, the change of olfactory scores was positively associated with the change of frontal activation.
OT was found to have a limited effect on olfaction and cognition in patients with MCI compared to a non-OT condition but increased their functional response to odors in frontal area.
嗅觉系统在阿尔茨海默病早期就会受到影响，在轻度认知障碍（MCI，AD的早期阶段）患者中已经可以观察到嗅觉丧失。
这项随机、前瞻性、对照、双盲研究的目的是评估在4个月频繁短期接触各种气味后，嗅觉训练（OT）是否可能对MCI患者的嗅觉功能、认知障碍和脑激活产生影响。
总共38名MCI门诊患者被随机分配到OT组或对照训练组，每天进行两次，持续4个月。在训练前后进行嗅觉测试、综合神经心理学评估以及基于磁共振成像的被动气味感知任务。
结果表明，OT对嗅觉和认知功能没有显著影响。此外，OT对额叶激活（左额中回和眶额皮质）有积极影响，但对灰质体积没有影响。而且，嗅觉评分的变化与额叶激活的变化呈正相关。
与非OT条件相比，发现OT对MCI患者的嗅觉和认知影响有限，但增加了他们额叶区域对气味的功能反应。
