Recovery rates of persistent post-COVID-19 olfactory dysfunction using psychophysical assessment: A longitudinal...

Area of Science:

• Otolaryngology
• Infectious Diseases
• Neurology

Background:

• Persistent olfactory dysfunction (OD) is a significant sequela of SARS-CoV-2 infection, impacting long COVID patients.
• Current understanding of persistent OD relies heavily on self-reported symptoms, with limited longitudinal data from objective assessments.
• Standardized psychophysical testing is crucial for accurate patient counseling regarding olfactory recovery post-COVID-19.

Purpose of the Study:

• To quantify the extent of persistent olfactory dysfunction in post-COVID-19 patients.
• To compare subjective olfactory reports with objective psychophysical assessments over time.
• To evaluate longitudinal recovery rates of olfactory function one year after COVID-19 infection.

Main Methods:

• Participants with a history of COVID-19 and olfactory dysfunction were enrolled.
• Olfactory function was assessed at baseline and 1-year follow-up using visual analogue scales and the Sniffin' Sticks extended test.
• Participants were categorized into cohorts based on subjective and psychophysical olfactory status.

Main Results:

• Of 122 baseline participants, 53 completed the 1-year follow-up.
• At baseline, 74.5% of participants with perceived OD showed confirmed psychophysical OD, decreasing to 55.1% at 1 year.
• The total TDI score improved by 3.25 points (p=0.0005), driven by threshold improvements (+2.75 points; p=0.0004).

Conclusions:

• Olfactory dysfunction persists in a substantial proportion of individuals post-COVID-19, with deficits evident at the 1-year mark.
• Improvements in olfactory threshold contribute to overall TDI score recovery, while discrimination and identification abilities show less change.
• Objective, longitudinal psychophysical data are essential for understanding and managing persistent olfactory dysfunction after SARS-CoV-2 infection.