Assessment of odor hedonic perception: the Sniffin\u2019 sticks parosmia test (SSParoT)

David T Liu,Bertold Renner,Christian A Mueller,Gerold Besser,Antje Welge-Lüssen

doi:10.1038/s41598-020-74967-0

Abstract

Qualitative olfactory dysfunction is characterized as distorted odor perception and can have a profound effect on quality of life of affected individuals. Parosmia and phantosmia represent the two main subgroups of qualitative impairment and are currently diagnosed based on patient history only. We have developed a test method which measures qualitative olfactory function based on the odors of the Sniffin’ Sticks Identification subtest. The newly developed test is called Sniffin’ Sticks Parosmia Test (SSParoT). SSParoT uses hedonic estimates of two oppositely valenced odors (pleasant and unpleasant) to assess hedonic range (HR) and hedonic direction (HD), which represent qualitative olfactory perception. HR is defined as the perceivable hedonic distance between two oppositely valenced odors, while HD serves as an indicator for overall hedonic perception of odors. This multicenter study enrolled a total of 162 normosmic subjects in four consecutive experiments. Cluster analysis was used to group odors from the 16-item Sniffin’ Sticks Identification test and 24-additional odors into clusters with distinct hedonic properties. Eleven odor pairs were found to be suitable for estimation of HR and HD. Analysis showed agreement between test–retest sessions for all odor pairs. SSparoT might emerge as a valuable tool to assess qualitative olfactory function in health and disease.

Highlights

Qualitative olfactory dysfunction is characterized as distorted odor perception and can have a profound effect on quality of life of affected individuals
Based on the consideration that patients with parosmia and phantosmia usually complain about unpleasant odor perceptions, the Sticks Parosmia Test (SSParoT) measures hedonic range (HR) and hedonic direction (HD) of pairwise presented, pleasant and unpleasant odors based on a 9-point hedonic scale (Supplementary Fig. S1)
Distorted odor perceptions have long been a well-known symptom of qualitative Olfactory disorders (OD), little is known about the pathophysiology, clinical course, and potential prognostic value[9, 10, 22, 50,51,52]

Summary

Introduction

Qualitative olfactory dysfunction is characterized as distorted odor perception and can have a profound effect on quality of life of affected individuals. It is well known that patients usually experience the hedonic tone of these sensations as unpleasant (usually described as “rotten” or “foul”), which can either be odor-specific or non-specific triggered by any o dor[8,9,10, 12, 13] This is contrasted to a distorted odor perception in the absence of any odor source (phantosmia), which is often described as unpleasant[8, 14, 15]. Objective methods are established in clinical routine for the assessment, diagnosis, and follow-up testing of quantitative OD, the diagnosis of qualitative OD is currently mainly based on the medical history or the use of a questionnaire only[27]. This shortcoming highlights the need for higher acceptance of previously proposed methods that focus on qualitative OD in a clinical c ontext[34,35,36,37,38,39]

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