University of Pennsylvania Smell Identification Test (UPSIT)

Olfactory dysfunction, known as hyposmia, is very common in patients with PD, and can be an early symptom.³ The University of Pennsylvania Smell Identification Test (UPSIT) was developed at the University of Pennsylvania, to be a valid and useful test of disorders of the chemical senses.¹

The UPSIT consists of 4 booklets containing 10 odorants apiece, 1 odorant per page.¹ The stimuli are embedded in 10–50 μm diameter microencapsulated crystals located on brown strips at the bottom of each page.¹ Above each odorant strip is a multiple-choice question with 4 alternative responses for each item (see the example on the slide).¹ The patient is required to answer 1 of the 4 alternatives, even if no smell is perceived.¹ The range of odours were chosen to span a range of pleasant and unpleasant smells.¹

Scores on the UPSIT scale have been correlated with the degree of neurodegeneration in some areas of the brain linked to PD (specifically hippocampal regions).³ When combined with modern α-synuclein seed amplification assays (α-syn-SAA), the UPSIT can be used as a marker of prodromal PD.⁴

References:
1.Doty RL, Shaman P, Kimmelman CP, Dann MS. University of Pennsylvania Smell Identification Test: a rapid quantitative olfactory function test for the clinic. Laryngoscope 1984; 94 (2 Pt 1): 176–178.

2.Alonso CCG, Silva FG, Costa LOP, Freitas SMSF. Smell tests can discriminate Parkinson’s disease patients from healthy individuals: a meta-analysis. Clin Neurol Neurosurg 2021; 211: 107024.

3.Bohnen NI, Gedela S, Herath P, et al. Selective hyposmia in Parkinson disease: association with hippocampal dopamine activity. Neurosci Lett 2008; 447 (1): 12–16.

4.Siderowf A, Concha-Marambio L, Lafontant DE, et al.; Parkinson’s Progression Markers Initiative. Assessment of heterogeneity among participants in the Parkinson’s Progression Markers Initiative cohort using α-synuclein seed amplification: a cross-sectional study. Lancet Neurol 2023; 22 (5): 407–417.