Effectiveness of olfactory training in COVID-19 patients with olfactory dysfunction: a prospective study

Area of Science:

• Otolaryngology
• Infectious Diseases
• Neurology

Background:

• Persistent olfactory dysfunction (OD) is a common sequela of COVID-19.
• Olfactory training (OT) is a potential therapeutic intervention for post-viral OD.

Purpose of the Study:

• To evaluate the effectiveness of a standardized olfactory training protocol in COVID-19 patients with persistent olfactory dysfunction.
• To assess the impact of adherence to OT on olfactory recovery outcomes.

Main Methods:

• Prospective follow-up of 57 COVID-19 patients with OD over 18 months across three European centers.
• Standardized OT protocol recommended; adherence assessed.
• Olfactory function evaluated using patient-reported outcomes and psychophysical tests at baseline, 6, 12, and 18 months.

Main Results:

• Psychophysical scores significantly improved from baseline to 6 months in both adherent and non-adherent groups.
• The fully adherent OT group showed continued significant improvement from 6 to 12 months.
• Phantosmia occurrence was significantly higher in the OT group compared to the no-OT group (34.4% vs 16.0%).

Conclusions:

• Adherence to an olfactory training protocol is associated with improved mid-term olfactory psychophysical scores in COVID-19 patients.
• Further large-cohort randomized controlled trials are necessary to definitively establish OT efficacy for post-COVID-19 olfactory dysfunction.