Odor identification performance in children aged 3-6 years.

BACKGROUND: While valid and reliable olfactory tests have been developed for children aged >5 years, olfactory testing has not systematically been evaluated in younger children. The aim of this study was to evaluate the reliability and validity of the "U-Sniff" odor identification test in children aged 3-6 years. METHODS: We included 160 healthy children (age range 3-6 years) and 14 congenitally anosmic children. Participants were investigated in two identical sessions. The "U-Sniff" test was used to evaluate olfactory function. A picture identification test (PIT) and the Kasel-Concentration-Task (KKA) were administered to identify factors influencing odor identification performance. RESULTS: Age significantly influenced odor identification performance, with older children achieving higher scores. PIT and KKA scores correlated positively with odor identification scores. The "U-Sniff" test demonstrated a high test-retest reliability (r160 = 0.75, p < 0.001). It was possible to distinguish between healthy and anosmic children by means of "U-Sniff" scores starting at age 4 years with high sensitivity (79-93%) and specificity (88-95%). CONCLUSIONS: The "U-Sniff" test is feasible for children starting at age 3 years. In children aged ≥4 years, it is a reliable and valid method to distinguish between normal olfactory function and anosmia. IMPACT: Olfactory testing is reliable and valid starting at an age of 4 years. The study adds a systematic evaluation of olfactory testing in young children. Results of this study are especially interesting for clinicians in the diagnosis of olfactory dysfunction.