Evaluation of Card-Type Odor Identification Test for Japanese Patients With Olfactory Disturbance

Objectives: A card-type odor identification test, Open Essence (OE), was recently developed in order to examine olfactory function in the Japanese population. The purpose of this study was to validate the efficacy of this new test by comparison with established olfactory examinations. Methods: We administered Jet Stream Olfactometry (JSO), an intravenous olfaction test (Alinamin test), a visual analog scale of symptoms of olfactory dysfunction, and the OE test to 50 patients with complaints of olfactory disturbance and 50 healthy volunteers. After comparison of the OE test results with those of existing olfactory examinations and the symptom scores, we tried to estimate a cutoff value compatible with the JSO threshold. Results: The scores on the OE test showed significant correlations with the average detection thresholds of JSO (r = -0.738; p <0.0001), the average recognition thresholds of JSO (r = -0.708; p <0.0001), the symptom scores (r = 0.827; p <0.0001), and the duration scores of the intravenous olfactory test (r = 0.673; p <0.0001). The area under the receiver operating characteristics curve between the OE test results and the average recognition thresholds of JSO was highest when the OE test's cutoff value was set at 8. Conclusions: The OE test proved to be a useful tool for screening olfactory disturbance in the Japanese population. Scores of 8 or higher on the OE test should be judged as normal for screening.