Related Experiment Video
Updated: Nov 21, 2025
10:42
A Free-breathing fMRI Method to Study Human Olfactory Function
Published on: July 30, 2017
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Olfactory Identification in Subjective Cognitive Decline: A Meta-Analysis.
Benoît Jobin1,2,3, Rayane Zahal2,4, Eve-Line Bussières1
1Department of Psychology, Université du Québec à Trois-Rivières, QC, Canada.
Journal of Alzheimer'S Disease : JAD
|January 18, 2021
Summary
Subjective cognitive decline (SCD) may indicate early Alzheimer's disease (AD). This meta-analysis found a slight decrease in smell identification ability in individuals with SCD, suggesting it could be an early AD marker.
Area of Science:
- Neuroscience
- Gerontology
- Psychology
Background:
- Subjective cognitive decline (SCD) is a potential early indicator of Alzheimer's disease (AD).
- SCD is sensitive but not specific to AD, necessitating additional markers for accurate prediction.
- Olfactory dysfunction is present in both AD and mild cognitive impairment (MCI), making it a promising diagnostic marker.
Purpose of the Study:
- To determine if subjective cognitive decline (SCD) is associated with reduced olfactory identification ability.
- To evaluate olfactory identification as a potential early marker for Alzheimer's disease progression.
Main Methods:
- A meta-analysis was conducted using studies from PsychNet, PubMed, Ebsco, and ProQuest.
- Keywords included "SCD," "subjective cognitive decline," "olfac*," and "smell."
- Included studies featured participants aged 50+, an SCD group, a healthy control group, and olfactory identification assessment.
Main Results:
- Five studies met the inclusion criteria.
- A small, homogeneous effect indicated altered olfactory identification in individuals with SCD compared to controls (g = -0.16).
Conclusions:
- Olfactory identification appears slightly altered in individuals with SCD compared to healthy older adults.
- This subtle change in smell identification may serve as an early marker for Alzheimer's disease.
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