Individual importance of olfaction decreases with duration of smell loss

The personal importance of a lost neurologic - motor or sensory - function in several conditions has been shown to decrease as the afflicted patient becomes accustomed to not having that function. It is unknown how the importance of olfaction changes with duration of olfactory dysfunction (OD). The aim of this study was to evaluate the association between duration of smell loss and individual significance of olfaction, and whether this relationship would be modulated by other factors, such as etiology of smell loss.

This is a retrospective study including a total 163 subjects with different degrees of olfactory function. Individual significance of olfaction was measured using the Importance of Olfaction Questionnaire (IOQ). Demographics, olfactory function, duration and etiology of OD were evaluated. Group comparisons, bivariate correlations, analyses of variance and multivariate linear regression were applied to detect differences and associations with the outcome measure of IOQ.

A significant negative correlation was found between duration of OD and the IOQ. Other important findings include a significantly higher IOQ in patients with posttraumatic- compared to idiopathic OD and in patients with higher aggravation scores compared to the lower aggravation group. Multivariate regression analysis further confirmed that duration of smell loss was independently associated with IOQ.

The duration of smell loss is negatively correlated with the individual importance of olfaction, suggesting that patients develop coping mechanisms for adjusting to OD.