Development of a simplified smell test to identify Parkinson’s disease using multiple cohorts, machine learning and item response theory
To develop a simplified smell test for identifying patients with Parkinson's disease (PD), we reevaluated the Sniffin'-Sticks-Identification-Test (SST-ID) and University-of-Pennsylvania-Smell-Identification-Test (UPSIT), using three case-control studies. These included 301 patients with PD or dementia with Lewy bodies (DLB), 68 subjects with multiple-system atrophy (MSA) or progressive supranuclear palsy (PSP), and 281 healthy controls (HC). Scents were ranked by area-under-the-curve values for group classification and results leveraged by 8 published studies with 5853 individuals. PD/DLB patients showed markedly worse olfaction than controls, whereas scores for MSA/PSP subjects were intermediate. We identified and validated a subset of 7 shared odorants that performed similarly to the traditional 16-scent SST-ID and 40-scent UPSIT tests in distinguishing PD/DLB from HC. There, the identification of 4 or fewer scents out of 7 served as an effective cut-off between the two groups. We also identified a critical role for distractors (from correct answers) and age on olfaction performance.
Authors
- Michael G. Schlossmacher (ORCID: https://orcid.org/0000-0002-0394-0300)
- Juan Li (ORCID: https://orcid.org/0000-0003-1565-2477)
- Tim Ramsay (ORCID: https://orcid.org/0000-0001-8478-8170)
- Sandrina Weber (ORCID: https://orcid.org/0000-0001-5713-2141)
- Mohammed Dakna (ORCID: https://orcid.org/0000-0001-8341-0360)
- Claudia Trenkwalder (ORCID: https://orcid.org/0000-0001-6407-1199)
- Joseph Saade (ORCID: https://orcid.org/0009-0001-5913-3575)
- Elisabeth Lang (ORCID: https://orcid.org/0000-0001-5748-1376)
- Douglas G. Manuel (ORCID: https://orcid.org/0000-0003-0912-0845)
- Tamara Wicke (ORCID: https://orcid.org/0000-0001-9779-4692)
- Tiago Mestre (ORCID: https://orcid.org/0000-0002-6973-7479)
- Sebastian Schade (ORCID: https://orcid.org/0000-0002-6316-6804)
- Julianna J. Tomlinson (ORCID: https://orcid.org/0000-0003-2997-5162)
- Brit Mollenhauer (ORCID: https://orcid.org/0000-0001-8437-3645)
- Andrew Frank (ORCID: https://orcid.org/0009-0009-2368-2538)
- Natalina Salmaso (ORCID: https://orcid.org/0000-0002-9661-5194)
- Kelsey F. Grimes (ORCID: https://orcid.org/0000-0002-0545-3813)
Institutions
- University of Ottawa (CA)
- Ottawa Hospital (CA)
- German Center for Neurodegenerative Diseases (DE)
- MIND Research Institute (US)
- Collaborative Group (United States) (US)
- Nephrologisches Zentrum Goettingen (DE)
- Paracelsus Elena Klinik Kassel (DE)
- Short and Associates (United States) (US)
- Bruyère (CA)
- Research Network (United States) (US)
- Ottawa Hospital Research Institute (CA)
- uOttawa Brain and Mind Research Institute
- Carleton University (CA)
Publication Details
- Journal
- npj Parkinson s Disease
- Published
- 2025-04-23
- DOI
- https://doi.org/10.1038/s41531-025-00904-5
- Citations
- 2
- Primary Topic
- Olfactory and Sensory Function Studies
- Type
- article
- Field-Weighted Citation Impact
- 2.93
Funders
- Michael J. Fox Foundation for Parkinson's Research
- TD Bank
- University of Ottawa
- Parkinson Canada
- Deutsche Parkinson Vereinigung
- Ottawa Hospital Foundation