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

Jeremy P Tervo ¹, Patricia T Jacobson ², Brandon J Vilarello ¹

⁰Columbia University Vagelos College of Physicians and Surgeons New York New York USA.

World Journal of Otorhinolaryngology - Head and Neck Surgery +

|

June 10, 2024

View abstract on PubMed

Summary

Persistent olfactory dysfunction (OD) after COVID-19 remains common, with many patients showing deficits one year later. Improvements were seen in smell detection thresholds, not identification or discrimination.

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.

Keywords:

long COVID olfaction post‐COVID condition smell dysfunction