The impact of olfactory training using a nasal clip and extended periods of odor exposure

The standard olfactory training (OT) protocol involves briefly sniffing four different odors, twice per day, for 12 weeks and significantly increases olfactory function. The current study's aim was to explore the effectiveness of enhancing olfactory function using a new OT methodology, specifically, presenting odors over a longer exposure period. Participants were 50 patients with smell loss (25 idiopathic and 25 sinonasal) who wore an odorized nasal clip for 3 hr per day, for 4 weeks. The results showed that only idiopathic patients experienced a significant increase in odor discrimination after OT. Acoustic rhinometric measurements of nasal cavity surface area and volume, CO2 threshold scores, and self-reported olfactory function did not significantly change. While the results provide limited support for the effectiveness of using a nasal clip for OT, research that more fully explores the factors that are associated with enhancing olfactory function (e.g., number of odors and exposure duration) is required to determine its effectiveness more conclusively.

Practical Application
Although the current findings provide limited support, it remains possible that varying the hours of daily exposure, the duration of treatment and number of odors may make using an odorized nasal clip an effective, novel, and convenient olfactory training method to improving olfactory function.