Background: Objective smell tests not only identify levels of smelling ability but also provide information on changes in olfaction after treatment. Odor identification is strongly socially and culturally dependent; therefore, the odorants used in a smell identification test should be familiar to the test population. We developed this smell test for Taiwanese populations with two aims: the test odors should be familiar to Taiwanese and the test should be easily and quickly administered in a busy clinic.
Methods: Additives that are familiar to Taiwanese people were selected for this smell identification test. Subsequently, the test was validated with the traditional Chinese version of the University of Pennsylvania Smell Identification Test (TC-UPSIT). Finally, this Taiwan Smell Identification Test (TWSIT) was implemented in daily clinical use, and cut-off points of "normosmia," "hyposmia," and "anosmia" were established.
Results: A total of 1000 subjects were included in the market survey to identify commonly recognized odors. Eight odorants with identification rate greater than 95% were selected. The TWSIT is an array of multiple-choice questions to select the odor. In addition, patient also reported the strength of the odor. The full score was 48. Thirty-seven patients simultaneously received both TWSIT and TC-UPSIT, and the correlation was high (r = 0.874). Based on the testing results of an additional 187 subjects, we concluded that scores of 47-48, 15-44, and 2-12 corresponded to normosmia, hyposmia, and anosmia, respectively. Patients with scores falling in the gaps require retesting at a later time.
Conclusion: The TWSIT is a quick, office-based, and useful odor identification tool for Taiwanese. The experience of developing a culturally specific olfaction test like the TWSIT can be applied in different countries and cultures.