Normal Olfaction Range of Rasht Residents with a New Test Designed for the Region
Abstract
Background: An important part of one's information from surrounding environment comes through olfactory system. So its disorders regardless of the reason can lead to many problems. An appropriate diagnostic smell test is needed to determine the normal range of olfactory sense, to evaluate patient's complaints and to determine the severity of the problem. It is also helpful in follow- up and choosing the most effective surgical or medical treatment. Unfortunately there is no any locally designed test currently used in Iran. Also, the current tests are difficult to interpret and are usually expensive to run. The objective of this study was developing a standard smell test for Iranians and determination of the normal range of olfactory sense in this region.
Methods: In order to find popular odorous items in the region, fifty six well known materials were presented to two hundred, 15-60 years old, normal residents of Rasht. Then 16 materials with the highest scores were selected (based on this consensus) as the test materials. These were: gasoline, alcohol, tea, rice, soap, cinnamon, origan, garlic, onion, washing powder, mint, rose water, lemon juice, olive oil, vinegar, vix. Then, these 16 selected materials were presented to 150 people of study group (77 women, 73 men). All materials were presented in identical containers. Participants were requested to smell material at 2 centimeter distance for 3 seconds, without being able to see the material. Then they would choose an answer in a multiple choice questionnaire. Each nostril was tested separately, therefore the total score for two nostril and 16 materials was 32 for each person.
Results: Considering 97 percentile, the normal range of olfactory score for 15-60 years old residents of Rasht was 28 – 32. Test re test reliability was more than 97%.
Conclusion: This olfactory identification test is simple and reliable, with familiar items for Iranian population. It is helpful to evaluate the patients who complain of hyposmia or anosmia and could be use for future studies.