Influence of Repeated Testing on the Olfactory Threshold

Abstract

BACKGROUND: Many factors influence the ability to smell, including olfactory adaptation. When the ability to smell is evaluated by olfactory tests, even more factors influence the results, for example, repeated testing. The influence of these factors varies among different tests. METHODS: the phenyl ethyl alcohol (PEA) odor detection threshold test was used to test the olfactory thresholds of 25 normal Chinese young people. To evaluate the effect of laterality on the test results, the testing orders were counterbalanced. Every person was tested in 6 different testing orders (i.e., right R nostril followed by left L nostril, and by bilateral b nostrils; R,B,L; L,R,B;L,B,R;B,R,L; and B,L,R). RESULTS: The mean threshold values among these persons were -8.172, -8.355, -8.12, -8.35,-8.33, and -8.25 for the right nostril in the aforementioned 6 testing orders. There was no difference between these 6 values. For the left nostril, the mean threshold values were -7.574,-8.595,-8.145,-8.555,-8.555, and -8.432. The value in the (R,L,B) testing order was significantly higher than those in other testing orders (p＜0.05). For the bilateral nostrils, the mean threshold values were -8.395,-8.83, -8.555, -8.64, -8.729, and -8.755. There was no difference between these 6 values. CONCLUSION: Except that a different result was produced in one testing order for the left nostril, the results of the PEA odor detection threshold test were not influenced by different testing orders.