Familiarity with odors does not play a role in olfactory training efficiency

Introduction: Olfactory training (OT) is known to be beneficial for olfactory disorders. The study aimed to explore whether the familiarity of odors influences the effectiveness of OT. Methods: Participants were divided into three groups: original training (OG), modified training with familiar odors to the Japanese population (FG), and modified training with unfamiliar odors to the Japanese population (UFG). Over 3 months, all participants completed OT. Olfactory function was evaluated using T&T olfactometry (combined odor detection threshold and odor recognition threshold test), intravenous olfactory test (retronasal olfactory test), and an open essence (OE) (odor identification test) before and after OT. Results: Sixty participants (mean age 53 years, SD 18) completed the study. Two participants were in the normosmic range, 10 were mild hyposmia, 14 were moderate hyposmia, 13 were severe hyposmia, and 21 were anosmia. Significant improvements were observed in olfactory detection threshold and recognition threshold function and retronasal olfactory function tests across all groups following OT. However, there was no significant effect observed on OE score. Furthermore, no significant differences were found among the OG, FG, and UFG groups. Conclusion: These findings suggest that regardless of odor familiarity, OT led to notable enhancements in olfactory function among participants. The study contributes to understanding the impact of odor familiarity on the effectiveness of OT, indicating that both familiar and unfamiliar odors yielded similar improvements. These results underscore the robustness of OT as a therapeutic approach for olfactory dysfunction, regardless of the familiarity of the odors used.