Active olfactory training for the treatment of smelling disorders

Olfactory function appears to be influenced by repeated odor stimulation. We conducted a nonrandomized, non-blinded, retrospective study of the impact of an 8-month period of olfactory training in patients with olfactory dysfunction. Our study population was made up of 46 adults-14 men and 32 women (mean age: 59.17 +/- 13.25 yr)-with olfactory dysfunction of different etiologies (sinonasal: n = 15; post-upper-respiratory-tract infection [URTI]: n = 16; post-traumatic: n = 7; and idiopathic: n = 8). All patients had been previously treated without success with systemic or topical corticosteroids. For their training, patients exposed themselves to four different odors twice a day. Olfactory function was evaluated at baseline and again at 4 and 8 months, and results were quantified in the form of each patient's TDI (threshold, discrimination, and identification) score. Of the 46 patients, 28 had undergone olfactory training only, while the remaining 18 had received topical corticosteroids in addition to training. At study's end, the mean overall TDI score in the entire group increased by 4.09 points over baseline-a statistically significant increase (p = 0.01); this increase was mainly attributable to improvement in the identification component of the TDI, which increased by 2.51 points (p = 0.02). Among the 18 patients who received a topical corticosteroid in addition to training, the mean TDI increased by 6.83 points (p = 0.001), primarily because of improvements in the discrimination and identification components. The 28 patients who underwent olfactory training alone experienced a mean increase in the identification component of only 2.20 points (p = 0.14) after 8 months. Olfactory function in the post-URTI patients increased significantly at 4 months. We conclude that olfactory discrimination and identification can be enhanced by the addition of a topical corticosteroid to a program of defined, daily, short-term exposure to olfactory training.