Elsevier

Auris Nasus Larynx

Volume 47, Issue 6, December 2020, Pages 1003-1008
Auris Nasus Larynx

A study of 30 odors panel smell identification test, smell detection threshold and University of Pennsylvania Smell Identification Test (UPSIT) in Thailand

https://doi.org/10.1016/j.anl.2020.05.017Get rights and content

Abstract

Objectives

This study aims to evaluate the application of the University of Pennsylvania Smell Identification Test (UPSIT) in Thailand, as well as to conduct an odor detection threshold test using phenyl ethyl alcohol and a 30-odor smell identification test.

Methods

This study was conducted from May 2019 to March 2020. We included healthy volunteers without any olfactory complaints. All participants underwent the UPSIT, an evaluation of odor detection threshold, and a 30-odor smell identification test.

Results

One hundred fifty participants were included in our study. The overall mean score on the UPSIT was 26.04 ± 6.59 points and ranged from 9 to 39.7. For participants aged under 60 years, the mean UPSIT score was 29.08 ± 4.67 points, while the mean score of those 60 years of age and over was 19.20 ± 4.97 points (mean difference of 9.88 points), a difference that was statistically significant (95% CI 8.23 to 11.53, p<0.0001). The mean lowest log value on the odor detection threshold test was -7.12 ± 1.64. This was -7.53 ± 1.05 in participants under 60 years of age and -6.20 ± 2.27 in those 60 years of age and over (mean difference of 1.33; 95% CI 0.80 to 1.86, p<0.0001). Items in the 30-odor smell identification test with correct response rates greater than 70% included fish sauce, banana, coffee, patchouli water, coconut, lemongrass, orange, ammonia, vinegar, tea leaf, Thai perfume, jasmine, pandan, curry, lime, durian, cola, corn, pineapple, strawberry, and grape.

Conclusions

This study identified the odor detection threshold, UPSIT scores, and suitable odors to use in smell identification in a Thai population.

Introduction

Olfactory dysfunction can be caused by many etiologies such as any sinonasal diseases, neurological diseases, head trauma and congenital olfactory dysfunction [1], [2], [3], [4], [5], [6]. The olfactory function can be assessed by various assessment techniques which include subjective self-reporting olfactory assessment, psychophysical olfactory assessment and electrophysiological study [7].

For psychophysical olfactory assessment, three major aspects of olfaction can be evaluated: 1) odor threshold, 2) odor discrimination, and 3) odor identification.

Odor threshold test can be assessed effectively with either phenyl ethyl alcohol (PEA) or n-butanol [8]. N-butanol smell banana-like, harsh, alcoholic and sweet while PEA smell like a rose. The PEA was commonly used in clinical practice for its pleasant smell and less trigeminal stimulation [9].

Many tests are available for odor identification assessment such as San Diego Odor Identification test [10], Scandinavian Odor Identification test [11], Barcelona smell test (BAST-24) and University of Pennsylvania Smell Identification Test (UPSIT) [7]. Previous exposure to the smell is one of the most important factors to determine the correct odor identification test. Therefore, odor identification test is culturally specific.

This study aims to evaluate the application of the University of Pennsylvania Smell Identification Test (UPSIT) as well as the smell detection threshold using phenyl ethyl alcohol and smell identification in healthy population in Thailand. Information from this study was essential to develop a proper psychophysical olfactory assessment for Thai population.

Section snippets

Study design and setting

This study was conducted from May 2019 to March 2020 at the Khon Kaen University Faculty of Medicine's Department of Otorhinolaryngology in Thailand.

Participants

We included healthy volunteers without any olfactory complaints. We excluded the non-native Thai, one with underlying diseases can affect olfactory test result, e.g. any sinonasal diseases, psychiatric diseases, neurological diseases, history of head trauma and congenital olfactory dysfunctions and those who had undergone either surgery or

Results

One hundred and fifty healthy volunteers were included in our study. The mean age of the participants was 42.65 years ranged from 15 to 84 years. There were 74.8 percent females and 25.2 percent males. Only 2 percent in these participants were a smoker.

Discussion

Previous exposure to the odors is one of the most important factors to determine the correct odor identification. Therefore, odor identification test is culturally specific. The test validated in one country must be culturally re-adjusted prior to the application in other countries.

UPSIT test is a well-known, validated odor identification test with a number of cross-cultural versions [12]. To date, there is no cross-culturally modified UPSIT for a Thai population.

According to our study, items

Conclusion

This study demonstrated the smell detection threshold, UPSIT scores and suitable odors to use in Thai population.

Authors' contribution

N.K. contributed to protocol, participant recruitment, data collection, data analysis and first draft of manuscript. S.T. contributed to protocol. P.P. conceptualized, designed, and supervised the study, raised funding for the study, performed data collection and data analysis, interpreted results, and drafted the manuscript. All authors contributed to the interpretation and discussion of the results, and read and approved the final manuscript.

Ethics approval and consent to participate

This study was approved by the Khon Kaen University Ethics Committee in Human Research (HE621154). Written informed consent to participate in this study was provided by all patients enrolled.

Consent for publication

Not applicable.

Availability of data and material

Not applicable.

Funding

The UPSIT used in this study was supported by Sensonics International, P. O. Box 112, Haddon Heights, NJ 08035, USA. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Declaration of Competing Interest

The authors declare no conflict interests.

Acknowledgements

The authors thank the patients for their participation in the trial. Associate Professor Masayoshi Kobayashi, M.D., Ph.D. from the Department of Otorhinolaryngology-Head and Neck Surgery, Mie University Graduate School of Medicine, Tsu, Japan for his advice.

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