Effects of Olfactory Training in Patients With Postinfectious Olfactory Dysfunction

Abstract

Objectives. Postinfectious olfactory dysfunction (PIOD) is the most common etiology of olfactory dysfunction, and olfactory training (OT) is an accepted treatment modality for PIOD. Some studies have investigated OT in Korean patients, but they involved odorants unfamiliar to Koreans or had no control group. The aim of this study was to verify the efficacy of OT in PIOD patients, using odorants familiar to Koreans and including a control group. Methods. We enrolled a total of 104 Korean patients with PIOD over the 3-year study period. All participants were assessed using endoscopy and an olfactory function test at the baseline assessment and 3 months after OT. The olfactory function test was performed using the Korean version of Sniffin' stick (KVSS) II. Nasal and psychological function was evaluated using a visual analog scale and the Mini-Mental State Examination. OT was performed over a period of 3 months, using five odorants (rose, lemon, cinnamon, orange, and peach). Results. OT improved olfactory function in approximately 40% of subjects over a period of 12 weeks compared to non-OT subjects. A comparison of changes between the initial and follow-up assessments demonstrated that the OT group had significantly better olfactory results for the total KVSS II, threshold, and identification scores than the non-OT group. The degree of olfactory improvement after OT was affected by the initial score. Conclusion. The effects of OT in patients with PIOD were demonstrated in this study. A meaningful contribution of this study is that Korean patients were tested using odors familiar to them in comparison with a control group.

Long-Term Persistence of Olfactory and Gustatory Disorders in COVID-19 Patients

“…Some authors have performed nasal irrigation studies (including an intranasal steroid/mucolytics/decongestant solution), however, we need more data to confirm the effectiveness of these treatments (19). The effectiveness of olfactory training was observed in post-traumatic and postinfectious patients (20,21). In this non-pharmacological treatment, patients expose themselves twice daily to four different odors (phenyl ethyl alcohol: rose, eucalyptol: eucalyptus, citronellal: lemon, and eugenol: cloves) from 12 to 24 weeks (22).…”

Impact of olfactory dysfunction on quality of life in coronavirus disease 2019 patients: a systematic review

“…This non-invasive intervention, directed at the rehabilitation of olfactory dysfunction, has demonstrated promising outcomes in relation to olfactory dysfunction from various causes. 23 , 24 As well as being easy to administer, olfactory retraining therapy has been reported to decrease depressive episodes amongst patients. 25 The concept behind olfactory retraining therapy is based on daily repeated exposure to selected odorants.…”

Research Progress of Olfactory Nerve Regeneration Mechanism and Olfactory Training

“… 64 Choi et al used five odors (rose, cinnamon, orange, lemon, and peach) to carry out OT in patients with post-infection olfactory dysfunction: the OT group had better olfactory results with regard to the identification of and sensitivity to odors. 65 …”