The Effect of Olfactory Training Using Korean Version Odorants: A Preliminary Study

Abstract

Introduction Approximately 5% of the general population are considered to be anosmic, and an additional 15% are considered to be hyposmic. 1) Upper respiratory infections (URIs) are among the most frequent causes of olfactory dysfunction. 2-4) To date, there is no validated pharmacotherapy for post-URI olfacto-ry dysfunction, although attempts have been made to establish treatment modalities through trials involving systemic Background and Objectives Several studies have reported the benefits of olfactory training (OT) for patients with olfactory dysfunction. However, training odorants should be custom-ized according to the characteristics of individual patients. The aim of this study was to evaluate the effects of OT using odorants familiar to Korean patients with post-upper respiratory infection (URI) olfactory dysfunction. Subjects and Methods We prospectively evaluated patients with post-URI olfactory loss. We carried out OT over a period of 6 months using four odorants: pine, cinnamon, lemon, and peppermint. Olfaction was tested before and at 1, 3, and 6 months after training initiation using the following olfactory tests; Butanol threshold test (BTT), Cross-Cultural Smell Identification Test (CCSIT) and Visual Analog Scale (VAS), Nasal Obstruction Symptom Evaluation (NOSE) scale, Sino-Nasal Outcome Test (SNOT-20), and Beck Depression Inventory (BDI). Results Of the 88 patients who initially enrolled, 82 completed the BTT, CCSIT, VAS, NOSE, SNOT-20, and BDI. In total, 10 Korean patients were included in our analysis, nine of whom showed an improvement in olfaction after OT. All patients reported changes in olfaction and the perception of smells over the duration of OT. Some patients reported an increased sense of smell after OT, although he could not distinguish different smells. Conclusion OT using odorants specifically selected for Korean patients resulted in improved olfactory function, as indicated by the BTT and CCSIT scores. The findings of the present study suggest that customization of odorants to fit the characteristics of patients, including ethnicity, environment, and race, among others, increases the effectiveness of OT.