A new method for automated olfactory threshold testing

We present a new method for fully self-administered olfactory testing. Technical development and testing and 2 user studies were conducted to test the functionality of a prototype device called Automated Olfactory Threshold Test (AutomOT). Technical testing showed repeatable functioning of the developed olfactory display technology in accurately producing 11 predefined odor intensity levels over 10 different days. In User Study 1, we tested the reliability, usability, and subjective workload of the use of the device. Participants (N = 29) with a normal sense of smell performed an automated threshold test 4 times. The results showed that the correlations between the tests were statistically significant, r = 0.44 to 0.78, all P-values ≤0.018. In User Study 2, we demonstrated the functioning of the device with normosmic and hyposmic/anosmic participants (n = 23 and n = 27, respectively) who performed both the current clinical standard, Sniffin' Sticks test, and the AutomOT test. Also, the usability and subjective workload of the use of the device were evaluated. The overall correlation of olfactory thresholds between the Sniffin' Sticks and the AutomOT was r=0.48, P<0.001. In both user studies, the results indicated good usability as measured by the System Usability Scale and low workload assessed by NASA Task Load Index. Overall, the results suggest that the newly developed AutomOT test is a reliable, valid, and usable tool for clinical assessment of olfactory thresholds.