Active Olfactory Training for the treatment of Smelling Disorders

Abstract

Olfactory function appears to be influenced by repeated odor stimulation. We conducted a nonrandomized, nonblinded, 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.

Examination of olfactory training effectiveness in relation to its complexity and the cause of olfactory loss

“…We also found that odor identification (I score) significantly improved after OT in postinfectious patients. This is in line with previous reports suggesting that OT may induce changes in subjects' higher cognitive processes, leading to improved perception of suprathreshold odors . Therefore, our results support the two lines of research showing that OT might positively influence both cognitive processes involved in odor perception and neural processes responsible for odor detection …”

Changes in olfactory function after immersive exposure to odorants

“…However, the positive impact of OT is well‐established (Damm et al, ; Pekala et al, ; Sorokowska et al, ) and the control group in such studies have never demonstrated a significant increase in olfactory function as per the patient group (Sorokowska et al, ). Moreover, and the increase in TDI score in studies with similar patient groups has been of the same magnitude as per our patient group (e.g., 4.09 TDI increase; Fleiner, Lau, & Göktas, ) buttressing our conclusion that the enhancement in olfactory function is due to the odorant exposure.…”

Hidden consequences of olfactory dysfunction: a patient report series

“…Peroral caroverine, an N-methyl-D-aspartic acid (NMDA) receptor antagonist [88], as well as sodium citrate nasal spray [95] have been shown to be effective in placebo-controlled studies. In addition to drug treatments, acupuncture [96-99] and olfactory training [100,101] have also been investigated. It is likely that any successful treatment of smell loss would also improve the associated symptoms of distorted olfactory perception.…”