Cultural Adaptation of the Iranian Version of the "Sniffin' Sticks" Olfactory Test

Background :Psychophysical tests are typically used for clinical assessment of human smelling function. Given that olfactory identification is linked to the regional culture, the main aim of this study was to provide the comprehensive "sniffin' sticks" olfactory test, culturally adapted on the Iranian population as well as to examine the discriminatory power of this test between normal people and patients with olfactory disorder. Methods : This cross-sectional study consisted of 3 steps. A total of 200 healthy people were recruited to determine odor familiarity (using Likert- scale) for the first step. In the second step, based on the original sniffin' sticks test and odor familiarity, 16 odor items were selected. Odor modification was performed and the identification part of the sniffin' sticks test was created. Then, 99 patients with olfactory disorders and 214 healthy participants were tested using the Iranian sniffin' sticks test (Ir-SST). After 2 to 4 weeks, participants were reexamined and test reliability was evaluated by using a Pearson correlation coefficient test. Results : The Ir-SST showed that scores of patients with smell loss were significantly lower than normosmic participants (13.6 ± 5.24 vs 34.3 ± 3.41, P < 0.001). The sensitivity (95.2%) and specificity (93.5%) of the test were also found to be high. Test-retest reliability was as follows: composite score: r = 0.8; odor identification: r = 0.83; odor threshold: r = 0.77; and odor discrimination test: r = 0.56; P < 0.001. Conclusion : The results suggest that the Ir-SST can be effectively adapted to the Iranian population. The current study validates that the sniffin' sticks olfactory test is applicable as a useful screening tool for comprehensive assessment of olfactory function in an Iranian population.