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. 2022 Jun 8;11(12):3275.
doi: 10.3390/jcm11123275.

Olfactory Training in Post-COVID-19 Persistent Olfactory Disorders: Value Normalization for Threshold but Not Identification

Clair Vandersteen  1   2 , Magali Payne  2   3 , Louise-Émilie Dumas  2   4 , Élisa Cancian  1 , Alexandra Plonka  2   5   6 , Grégoire D'Andréa  1 , David Chirio  7 , Élisa Demonchy  7 , Karine Risso  7 , Florence Askenazy-Gittard  2   4 , Charles Savoldelli  1 , Nicolas Guevara  1 , Philippe Robert  2   3   6 , Laurent Castillo  1 , Valeria Manera  2   3 , Auriane Gros  2   3   6
Affiliations

Olfactory Training in Post-COVID-19 Persistent Olfactory Disorders: Value Normalization for Threshold but Not Identification

Clair Vandersteen et al. J Clin Med. .

Abstract

(1) Background: Persistent post-viral olfactory disorders (PPVOD) are estimated at 30% of patients one year after COVID-19 infection. No treatment is, to date, significantly effective on PPVOD with the exception of olfactory training (OT). The main objective of this work was to evaluate OT efficiency on post-COVID-19 PPVOD. (2) Methods: Consecutive patients consulting to the ENT department with post-COVID-19 PPVOD were included after completing clinical examination, the complete Sniffin’ Stick Test (TDI), the short version of the Questionnaire of olfactory disorders and the SF-36. Patients were trained to practice a self-olfactory training with a dedicated olfactory training kit twice a day for 6 months before returning to undergo the same assessments. (3) Results: Forty-three patients were included and performed 3.5 months of OT in average. We observed a significant TDI score improvement, increasing from 24.7 (±8.9) before the OT to 30.9 (±9.8) (p < 0.001). Based on normative data, a significant increase in the number of normosmic participants was observed only for the threshold values (p < 0.001). Specific and general olfaction-related quality of life improved after the OT. (4) Conclusions: Olfactory function appeared to improve only in peripheral aspects of post-COVID-19 PPVOD after OT. Future controlled studies must be performed to confirm the OT role and justify new therapeutic strategies that may focus on the central aspects of post-COVID-19 PPVOD.

Keywords: COVID-19; olfaction disorders; olfactory training; parosmia.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
The evolution of individual TDI scores (from the SST) before and after olfactory training (OT). Colored parts cover anosmic (red), hyposmic (yellow) or normosmic (green) patients according to TDI normative values [20]. Oblique lines represent a patient anosmic (red), hyposmic (yellow) or normosmic (green) subject evolution according to post OT olfactory evaluation. Solid, dashed or pointed lines represent, respectively, patients who did not change category, changed to the upper category or changed from the anosmic to normosmic category.
Figure 2
Figure 2
T, D and I before and after the olfactory training based on age- and sex-normalized values.
See this image and copyright information in PMC

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