Screening performance of abbreviated versions of the UPSIT smell test

J Neurol. 2019 Aug;266(8):1897-1906. doi: 10.1007/s00415-019-09340-x. Epub 2019 May 3.


Background: Hyposmia can develop with age and in neurodegenerative conditions, including Parkinson's disease (PD). The University of Pennsylvania Smell Identification Test (UPSIT) is a 40-item smell test widely used for assessing hyposmia. However, in a number of situations, such as identifying hyposmic individuals in large populations, shorter tests are preferable.

Methods: We assessed the ability of shorter UPSIT subsets to detect hyposmia in 891 healthy participants from the PREDICT-PD study. Shorter subsets included Versions A and B of the 4-item Pocket Smell Test (PST) and 12-item Brief Smell Identification Test (BSIT). Using a data-driven approach, we evaluated screening performances of 23,231,378 combinations of 1-7 smell items from the full UPSIT to derive "winning" subsets, and validated findings separately in another 191 healthy individuals. We then compared discriminatory UPSIT smells between PREDICT-PD participants and 40 PD patients, and assessed the performance of "winning" subsets containing discriminatory smells in PD patients.

Results: PST Versions A and B achieved sensitivity/specificity of 76.8%/64.9% and 86.6%/45.9%, respectively, while BSIT Versions A and B achieved 83.1%/79.5% and 96.5%/51.8%. From the data-driven analysis, 2 "winning" 7-item subsets surpassed the screening performance of 12-item BSITs (validation sensitivity/specificity of 88.2%/85.4% and 100%/53.5%), while a "winning" 4-item subset had higher sensitivity than PST-A, -B, and even BSIT-A (validation sensitivity 91.2%). Interestingly, several discriminatory smells featured within "winning" subsets, and demonstrated high-screening performances for identifying hyposmic PD patients.

Conclusion: Using abbreviated smell tests could provide a cost-effective means of large-scale hyposmia screening, allowing more targeted UPSIT administration in general and PD-related settings.

Keywords: Hyposmia; PREDICT-PD; Parkinson’s disease; Smell tests; UPSIT.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Cohort Studies
  • Female
  • Humans
  • Male
  • Mass Screening / methods*
  • Mass Screening / standards*
  • Middle Aged
  • Neuropsychological Tests / standards
  • Odorants*
  • Olfaction Disorders / diagnosis*
  • Olfaction Disorders / physiopathology
  • Olfaction Disorders / psychology*
  • Parkinson Disease / diagnosis
  • Parkinson Disease / physiopathology
  • Parkinson Disease / psychology
  • Smell / physiology*