Characterization of Self-Administered Olfactory Assessments Novel Olfactory Sorting Task (NOST) and Odor Dilution...

Olfactory evaluation beyond conventional domain testing may inform how olfactory impairment presents among the general population. Recently reported assessments based on odor matching (NOST) and intensity sorting (ODS) may provide additional insight into olfactory function. Characterizing performance of these simple and self-administered tasks among a community-based population offers a valuable benchmark for subsequent evaluation in aging and cognition-impaired cohorts.

Seventy community-based individuals completed Sniffin' Sticks TDI testing, NOST, and ODS. NOST is an odor matching task among twelve pairs of odorants, and ODS is an odor intensity scaling task. Scores were compared to TDI using Spearman correlations and Wilcoxon signed-rank tests.

NOST median score was 6 (IQR: 4, 9) while ODS was 0.80 (0.70, 0.85). NOST correlated with TDI (r; [confidence interval]: 0.640, [0.47, 0.76]), threshold (0.342; [0.11, 0.54]), discrimination (0.556; [0.36, 0.70]), and identification (0.297, [0.06, 0.50]), but not with ODS. Participants performed significantly better on the ODS-Eugenol trial than on the ODS-PEA trial, with median scores of 0.90 (IQR: 0.80, 1.0) and 0.70 (0.50, 0.80), respectively (p < 0.001).

NOST correlates strongly with odor discrimination in this community-based population, while ODS shows no significant correlations with any TDI subdomains. The lack of several strong correlations on either assessment with overall TDI suggests these assessments may evaluate domains of smell and cognition not previously captured by standalone TDI testing. Continued validation of NOST and ODS across a broad population with ranging olfactory and cognitive statuses is needed to fully characterize the utility of these well-tolerated, self-administered olfactory tests.