Olfaction in Neurodegenerative Disease: A Meta-analysis of Olfactory Functioning in Alzheimer's and Parkinson's Diseases
Abstract
BACKGROUND: Olfactory deficits in Alzheimer's disease (AD) and idiopathic Parkinson's disease (PD) have been well established. OBJECTIVE: To clarify and review the literature by evaluating the evidence for olfactory deficits in 3 olfactory domains, including odor identification, recognition, and detection threshold. DATA SOURCES: A literature search of English-language studies of olfaction in AD, PD, and healthy controls was conducted via online databases (PsycInfo and MEDLINE) and reference lists from review articles. STUDY SELECTION: To meet selection criteria for meta-analysis, each study required a control group and complete and usable data. This review yielded 26 publications of olfactory identification, recognition, and/or detection threshold. Because of the inclusion of more than 1 relevant study of olfaction in several of these publications (eg, both identification and threshold assessed), 43 studies were ultimately appropriate for meta-analysis. DATA EXTRACTION: Effect sizes were calculated for each study by expressing differences between patient and control group means in SD units (Cohen's d). DATA SYNTHESIS: Extremely large effect sizes were shown across all tasks in both AD and PD groups. Both between-group analyses using the Mann-Whitney U test and within-group analyses using Friedman 2-way analysis of variance did not reveal any significant differences (all P > .30). CONCLUSIONS: As expected, severe deficits were found for both patients with AD and PD in each of the 3 olfactory domains relative to controls. However, no discriminating olfactory deficits were seen between patient groups or among the 3 measured olfactory domains, suggesting a similar disturbance in olfactory function between patients with AD and PD.
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Olfactory dysfunction is an early feature of Alzheimer disease.
“Olfactory dysfunction is an early feature of Alzheimer disease”
From The scent of emotions: A systematic review of human intra‐ and interspecific chemical communication of emotions (2020) · cites this paper as Mesholam, Moberg, Mahr, & Doty, 1998
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- Authors
- Mesholam, R. I., Moberg, P. J., Mahr, R. N., & Doty, R. L.
- Affiliations
- Drexel University (US)
- ORCID
- Doty, Richard L.
- Venue
- Archives of Neurology
- Publisher
- American Medical Association (AMA)
- Published
- 1998-01-01
- Volume
- 55
- Issue
- 1
- Pages
- 84
- ISSN
- 0003-9942 (ISSN-L)
- OpenAlex
- W2044400428
- Cited by
- 643
- References
- 1
- Citations by year
- 2026: 9 · 2025: 8 · 2024: 16 · 2023: 21 · 2022: 21 · 2021: 38 · 2020: 41 · 2019: 31 · 2018: 29 · 2017: 35 · 2016: 23 · 2015: 24 · 2014: 27 · 2013: 33 · 2012: 34
- FWCI
- 6.40
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Archives of Neurology (publishedVersion)
- PubMed (publishedVersion)
- Funders
- National Institute on Deafness and Other Communication Disorders (P01 DC00161, P01DC000161)
- Topics
- Life Sciences › Neuroscience › Sensory Systems › Olfactory and Sensory Function Studies
- Health Sciences › Medicine › Psychiatry and Mental health › Dementia and Cognitive Impairment Research
- Health Sciences › Medicine › Neurology › Parkinson's Disease Mechanisms and Treatments
- Keywords
- olfaction, olfactory dysfunction, Alzheimer's disease, Parkinson's disease, odor identification, odor recognition, odor detection threshold, neurodegenerative diseases
- MeSH terms
- Adult, Aged, Alzheimer Disease, Female, Humans, Male, Middle Aged, Parkinson Disease, Smell, Effect Modifier, Epidemiologic
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