The digital scent device as a new concept for olfactory assessment

There are major challenges in olfactory measurements in clinical practice; therefore, a handheld digital scent device (DSD; Noar MultiScent 20) was developed as a tablet with an integrated storage system for odors. The DSD is a self-administered, handheld device that controls the duration of odor release to the nasal cavity through a touchscreen digital interface with automatic database generation. In this study we aimed to determine the feasibility of this DSD as an olfactory assessment test.

We recruited 180 participants (age [mean ± standard deviation], 34.58 ± 9.71 years; 114 women and 66 men) to participate in smell tests using both the DSD and the 40-item Smell Identification Test (SIT-40), which contained the same type and order of odors and the same multiple-choice answers. The scores were compared and evaluated for correlation between the tests, and test-retest reliability was calculated.

The DSD test scores were higher than the SIT-40 scores (median [interquartile range], 32 [5.0] vs 31 [7.0]; p = 0.005). The completion time was less for the DSD test than for the SIT-40 (12.5 [5.0] vs 16 [6.0] minutes; p < 0.001). The tests were strongly correlated (Spearman rho = 0.74; p < 0.001) and exhibited a high level of agreement (Bland-Altman regression coefficient = 0.672; p = 0.003). The DSD test-retest reliability coefficient was 0.820.

The DSD is feasible as an olfactory assessment test. The digitalization of olfactory assessment combined with data science may enable new research perspectives in the field of olfaction.