4 DISCUSSION
Based on the SSOI test, the CMOI test proposed in this study significantly improved the score of the olfactory test and the correct recognition rate of odors by using the distra-ctors and odors more familiar to Chinese people. It is an effective tool for evaluating the olfactory function of Chinese people.
From the odor familiarity survey, we found that, out of the 64 odor descriptors in S-SOI test, the familiarity scores of 31 odor descriptors were <75 points; nearly half of the odors in SSOI test were unfamiliar to the volunteers. In the olfactory test, it is likely that although the subjects perceived the odors, they found it difficult to make a correct choice because they were unfamiliar with the odors or distractors.
After adjusting the 23 distractors of the SSOI test according to the odor familiarity survey results, the scores of the olfactory identification test of healthy volunteers were si-gnificantly improved. Taking the odor ”cinnamon” as an example, in the SSOI test, only 59% of the volunteers could correctly identify the odor ”cinnamon”. However, after ch-anging the distractors, the correct recognition rate of the odor ”cinnamon” reached 88%. This may be because volunteers were more familiar with the smell of some new distrac-tors and could choose the correct answer through exclusion. However, the correct recog-nition rates of some odors were still low, such as apple, leather, and pineapple, whose c-orrect recognition rates were 20%, 57%, and 60%, respectively; many volunteers could not recognize them correctly. This may be because volunteers were unfamiliar with some odors; even if the distractors were modified, the recognition rate of the odor “leather” w-as only improved from 53% to 57%. It may also be because the odor was familiar, but the name was inaccurate. Take the odor ”apple” as an example, there are many varieties of a-pples in the world, and the smell is not exactly the same. The odor ”apple” does not spec-ify the specific apple variety, and the apple aroma is relatively light, which can be easily ignored. Therefore, it was difficult for volunteers to make the correct choice in the test. If the names of both odors and distractors are inaccurate, the interference of volunteers may be more serious. The last reason is that the similarity between odors and distractors was high, and the difference was insignificant. Take the odor ”apple” as an example again; the distractors of the odor were melon, peach, and orange. In the identification test, most vol-unteers could only smell fruit flavour, and these four options all had fruit flavour, increa-sing the difficulty of accurate identification. To further improve the score of the olfactory identification test and enable it to have the ability to test unpleasant odors, through litera-ture search, tetrahydrothiophene, 2-methylpyrazine, and trimethylindole were selected to simulate natural gas, burnt smell, and Fecal odor respectively, and replace three odors: a-pple, leather, and pineapple. After randomly assigning distractors, the CMOI test was co-mposed of 16 odors: 3 tested for the third time, and the other 13 unchanged odors.
The CMOI test scores of volunteers were significantly higher than that of the MDOI test scores and SSOI test scores, which reduced the occurrence of wrong choices due to t-heir unfamiliarity with some odors to avoid some subjects being misdiagnosed with olfa-ctory disorder due to the error of the olfactory test. Moreover, after adjusting the SSOI te-st, the score of the olfactory identification test was improved so that the degree of olfact-ory dysfunction can be diagnosed more accurately when testing patients with poor olfact-ion. Therefore, the CMOI test focuses on detecting the severity of patients’ olfactory dys-function and makes it easier to identify patients who are not sensitive to unpleasant odor-s. It is more suitable for clinical diagnosis of olfactory disorder and evaluation of treatm-ent effect. Also, with the overall improvement of the CMOI test score, the olfactory det-ection ability of people who are too sensitive to smell may decline.
At present, patients with olfactory disorders mostly use pleasant odor reagents in ol-factory training but rarely use unpleasant odor reagents with important warning functions, such as natural gas odorant and simulated burnt odor reagents used in the experiment, w-hich may lead to poor recovery effect of patients’ olfactory ability to this kind of odor. In this experiment, the unpleasant smell with a warning function was introduced into the ol-factory test, which could better detect the recovery degree of patients’ perception of this kind of smell; this was of great significance to evaluate the effect of olfactory treatment.
It is hoped to screen patients who cannot correctly identify natural gas, burnt smell, and Fecal odor for the next treatment to reduce patients’ risk in natural gas leakage, fire, and other dangerous events.