Validity and Reliability of Persian Smell Identification Test.

INTRODUCTION: Smell Identification Tests (SIT) are routinely utilized for the clinical evaluation of olfactory function. Since Iran consists of various ethnic subgroups, the reliability and validity of this test as a national SIT are required to be evaluated across the country. MATERIALS AND METHODS: This cross-sectional study evaluated the cultural adaptation of SIT administered to 420 healthy volunteers from 6 various ethnic subgroups (i.e., Fars, Turk, Kurd, Lor, Baluch, and Arab) living in 7 cities (one city for each subgroup, and Tehran [capital of Iran] with mixed ethnicities). The SIT consists of pens pre-filled with 24 odorants. The correct identification response rate was evaluated in all and each subgroup. The test was performed twice on 60 participants with a 2-week interval to assess its reliability. The SIT was further administered to 150 cases with documented abnormal olfactory function to evaluate its validity. RESULTS: The correct identification response rate was estimated at 70% for all odorants in all and each subgroup. The mean odor identification score was 21.41±1.37 (score range: 17- 24) with no significant difference among various subgroups. Moreover, the test-retest correlation coefficient was obtained at 0.77. The mean odor identification score in patients with olfactory impairment was 10.69±3.76, which was significantly different from that in healthy participants (P<0.001). The best cut-point for the beginning of olfactory impairment was 17.5 (95% CI: 9-100, Sensitivity=99, Specificity=81). Females obtained higher scores of odor identification, compared to males (P=0.025). CONCLUSION: The results indicated the reliability and validity of the SIT, which can be used nationally for the assessment of olfactory function in various ethnic subgroups across the country.

Evaluation of Culturally-Familiar Odorants for a Persian Smell Identification Test.

INTRODUCTION: Processing odor information by the olfactory system depends greatly on the odor concentration. In order to use an odorant in a smell identification test (SIT), the minimum identification concentration (MIC) needs to be determined. MATERIALS AND METHODS: This study was conducted in 60 healthy native individuals aged 20 to 60 years, selected from patients' companions in a tertiary hospital. In the first step, 25 odorants were presented to evaluate familiarity among the subjects. Then, the MICs for the eligible odorants were measured using the ascending method of limits. RESULTS: Out of 25 odorants, only one (cacao) was distinguished by less than 70% of the subjects, and was therefore removed from the list. The MICs of the remaining 24 odorants ranged from 6.87±2.74% for menthol to 27.62±18.98% for cantaloupe. There was significant correlation between age and the MIC only for coffee (P=0.02, r=-0.300). There was a significant difference in MIC between men and women only for hazelnut (P=0.03). CONCLUSION: We present the MICs of 24 culturally-familiar odorants in a sample of the Persian population in a SIT.

Is the Persian Version of the "Olfactory Disorder Questionnaire" Reliable and Valid?

INTRODUCTION: The Questionnaire for Olfactory Dysfunction (QOD) is a self-reporting olfactory-related quality of life questionnaire. The aim of this study was to determine the reliability and validity of the Persian version of this questionnaire. MATERIALS AND METHODS: One hundred and thirteen patients with olfactory problems were enrolled in this study. The English version of the QOD was first translated into Persian. The reliability was then tested by determining the Cronbach alpha coefficient to assess internal consistency. The QOD was reviewed by a panel of experts, followed by calculating the content validity index to determine the content validity. RESULTS: Based on the reliability analysis, the total Cronbach alpha was 0.88. The items in the "life quality" and "parosmia" domains had a good internal consistency in total, as well as in both genders and in different age subgroups. For the "sincerity" domain, however, low internal consistency was revealed (Cronbach alpha = 0.25). When questions related to the sincerity domain were omitted, the Cronbach alpha reached 0.89. The overall scale validity index for clarity and relevance were 0.88 and 0.87, respectively. CONCLUSION: The Persian version of the QOD seems to be a reliable and valid tool for the assessment of quality of life in patients with olfactory dysfunction. The "sincerity" domain cannot be used separately or should be substantially modified in order to be applicable to the Iranian population. However, there is no need to change the whole format of the questionnaire.