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Observational Study
. 2021 May 27;23(5):e29583.
doi: 10.2196/29583.

Olfactory Training and Visual Stimulation Assisted by a Web Application for Patients With Persistent Olfactory Dysfunction After SARS-CoV-2 Infection: Observational Study

Fabrice Denis  1 , Anne-Lise Septans  2 , Lea Periers  3 , Jean-Michel Maillard  4 , Florian Legoff  5 , Hirac Gurden  6 , Sylvain Moriniere  3
Affiliations
Free PMC article
Observational Study

Olfactory Training and Visual Stimulation Assisted by a Web Application for Patients With Persistent Olfactory Dysfunction After SARS-CoV-2 Infection: Observational Study

Fabrice Denis et al. J Med Internet Res. .
Free PMC article

Erratum in

Abstract

Background: Persistent olfactory dysfunction is a significant complication of SARS-CoV-2 infection. Olfactory training involving aromatic oils has been recommended to improve olfactory recovery, but quantitative data are missing.

Objective: We aimed to quantify the benefit of olfactory training and visual stimulation assisted by a dedicated web application for patients who experienced olfactory dysfunction for ≥1 month.

Methods: We performed an observational, real-life, data-based study on a cohort of patients who experienced at least 1 month of persistent olfactory dysfunction between January 30 and March 26, 2021. An analysis was performed after a mean olfactory training time of 4 weeks, and at least 500 patients were assessable for primary outcome assessment. Participants exposed themselves twice daily to odors from 4 high-concentration oils and visual stimulation assisted by a dedicated web application. Improvement was defined as a 2-point increase on a 10-point, self-assessed olfactory visual analogue scale.

Results: In total, 548 patients were assessable for primary outcome assessment. The mean baseline, self-assessed olfactory score was 1.9 (SD 1.7), and this increased to 4.6 (SD 2.8) after a mean olfactory training time of 27.7 days (SD 17.2). Olfactory training was associated with at least a 2-point increase in 64.2% (352/548) of patients. The rate of patients' olfactory improvement was higher for patients who trained for more than 28 days than that rate for patients who trained for less than 28 days (73.3% vs 59%; P=.002). The time to olfactory improvement was 8 days faster for patients with hyposmia compared to the time to improvement for patients with anosmia (P<.001). This benefit was observed regardless of the duration of the olfactory dysfunction.

Conclusions: Olfactory training and visual stimulation assisted by a dedicated web application was associated with significant improvement in olfaction, especially after 28 days of olfactory training.

Keywords: COVID-19; SARS-CoV-2; app; dysfunction; nose; observational; olfactory; olfactory dysfunction; olfactory training; real-life study; senses; smell; stimulation; training; web application, eHealth.

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Conflict of interest statement

Conflicts of Interest: FD and FL are founders of Kelindi. The other authors have no conflicts of interest.

Figures

Figure 1
Figure 1
Flowchart of patients who used a web application for olfactory training.
Figure 2
Figure 2
Cumulative incidence of olfactory improvement according to the olfactory training durations of patients with anosmia and hyposmia. The data of patients with mild, moderate, and severe hyposmia were pooled in the blue curve.
Figure 3
Figure 3
Mean improvement of olfactory function stratified by the duration of persistent olfactory dysfunction. Improvement was assessed with a self-assessed olfactory scale of 0-10 after olfactory training.
See this image and copyright information in PMC

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