Home › Research › Getting a diagnosis
Olfactory dysfunction in Parkinson disease
Doty RL.. Nature reviews. Neurology, 2012-05-15
Topic: Brain proteins, microglia and lab models
Olfactory dysfunction is among the earliest nonmotor features of Parkinson disease (PD). Such dysfunction is present in approximately 90% of early-stage PD cases and can precede the onset of motor symptoms by years. The mechanisms responsible for olfactory dysfunction are currently unknown. As equivalent deficits are observed in Alzheimer disease, Down syndrome, and the Parkinson-dementia complex of Guam, a common pathological substrate may be involved. Given that olfactory loss occurs to a lesser extent or is absent in disorders such as multiple system atrophy, corticobasal degeneration, and progressive supranuclear palsy, olfactory testing can be useful in differential diagnosis. The olfactory dysfunction in PD and a number of related diseases with smell loss correlates with decreased numbers of neurons in structures such as the locus coeruleus, the raphe nuclei, and the nucleus basalis of Meynart. These neuroanatomical findings, together with evidence for involvement of the autonomic nervous system in numerous PD-related symptoms, suggest that deficits in cholinergic, noradrenergic and serotonergic function may contribute to the olfactory loss. This Review discusses the current understanding of olfactory dysfunction in PD, including factors that may be related to its cause.
Key findings
- These neuroanatomical findings, together with evidence for involvement of the autonomic nervous system in numerous PD-related symptoms, suggest that deficits in cholinergic, noradrenergic and serotonergic function may contribute to the olfactory loss.
Why it matters
This review describes smell loss as an early feature of Parkinson disease that can appear years before motor symptoms, and notes that equivalent deficits are seen in Alzheimer disease. It suggests that loss of smell may share a common pathological basis across these diseases and could help tell them apart from other disorders, but the mechanisms behind it remain unknown.
New to this subject? Start with our plain-English guide: Getting a diagnosis →
Study details
- Evidence strengthLow
How this study scored 48/100
Published in a peer-reviewed journal. Scored zero for study design, sample size, effect reported, studied in people and randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Nature reviews. Neurology) |
| Journal's citation record | 3 / 4 | Nature Reviews Neurology: journal h-index 269 (OpenAlex, 2026-10-29) |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 2012 — within 20 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 6 / 7 | Cited 746 times (OpenAlex, 2026-10-10) |
| Citations per year | 4 / 5 | 46.6 citations a year over 16 year(s) since 2012 |
| Impact for its field and year | 3 / 6 | Cited 3.6× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 2 / 6 | Cited by 5 other studies in this library |
| Still being cited | 3 / 4 | Cited 182 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 3 / 4 | Last-listed author Richard L. Doty: h-index 90 (OpenAlex, whole career) |
| Institution's track record | 2 / 3 | University of Pennsylvania: institution h-index 1,859 (OpenAlex) |
| Multi-centre collaboration | 1 / 3 | OpenAlex lists 2 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 22584158) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 48 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
May need a subscription OpenAlex found no free copy of the full text (checked 6 Feb 1020), so the publisher may charge for it. The PubMed abstract is free.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. Check the citation against the original before you use it.
APA 7th
Doty, R. L. (2012). Olfactory dysfunction in Parkinson disease. Nature reviews. Neurology. https://doi.org/10.1038/nrneurol.2012.80
Vancouver
Doty RL. Olfactory dysfunction in Parkinson disease. Nature reviews. Neurology. 2012. doi:10.1038/nrneurol.2012.80. PMID: 22584158.
BibTeX
@article{doty2012-22584158,
author = {Doty, R. L.},
title = {{Olfactory dysfunction in Parkinson disease}},
journal = {Nature reviews. Neurology},
year = {2012},
doi = {10.1038/nrneurol.2012.80},
pmid = {22584158},
url = {https://doi.org/10.1038/nrneurol.2012.80}
}
Studies this one cites
Referenced by this study and also in the alzhub library, so you can read them here.
Later studies that cite this one
5 studies in the alzhub library list this one in their references.
Related studies in Getting a diagnosis
Also tagged “bodies”
1,017 studies in the library carry the topic tag “bodies”; these are this study's neighbours in a fixed, alphabetical-by-hash tour of them, not the closest in content. All 1,017 tagged studies.