Smell, taste and trigeminal function: similarities and differences between results from home tests and examinations in the clinic*

Background: This study aimed to examine an easy-to-conduct home chemosensory test as a screening tool prior to clinical tes-ting and to investigate the associations between home and clinical tests. Methods: We examined 200 participants who performed a chemosensory test including subjective ratings as well as psychop-hysical smell, taste and trigeminal function tests at their homes. Following that, they were invited to the clinic for standardized testing using the Sniffin'sticks test for assessment of olfactory function, taste sprays and strips for taste function, and a lateraliza-tion test for trigeminal function. Results: The home smell test correlated well with the Sniffin'sticks test. The home test had acceptable sensitivity for detecting smell loss (sensitivity of 67% at a specificity of 92%). The home test could distinguish between patients with olfactory loss and healthy controls. In contrast, the home tests for taste and trigeminal function did not provide valid results. When comparing home and clinical smell and taste tests older age and olfactory loss were the most influencing confounders in various models, while participants who had olfactory loss and admitted to drink alcohol regularly were more likely to have consistency between home and clinical smell measurements. Conclusions: Although the standardized psychophysical tests are valid and reliable and should be recommended, simple me-thods used at home could reflect the patients' information to some degree and provide useful data prior to clinical testing. The present home chemosensory test allows motivated individuals to screen their olfactory function in a simple way at home. Results from smell tests, but not from tests of taste or trigeminal function, obtained at home correlate with tests obtained at the clinic. Moreover, tests conducted at home or in the clinic have confounders that should be considered by researchers and clinicians.