A 28-day olfactory training and visual stimulation assisted by a devoted web app were linked with remarkable improvements in olfaction in COVID-19 infected individuals with a minimum of 1 month of persistent olfactory dysfunction or anosmia, a study published in the Journal of Medical Internet Research elucidated.

This observational study by Fabrice Denis and investigators was performed to study the quantitative data supporting the use of olfactory training involving aromatic oils to improve olfactory recovery for 4 weeks. These patients subjected themselves to odors from 4 high-concentration oils 2 times a day and visual stimulation backed by a devoted web application. A self-assessed olfactory visual analogue scale (VAS) was used to define improvement as a 2-point increase on 10-point.

A total of 548 individuals with olfactory dysfunction were assessable for training. The self-assessed olfactory score increased to 4.6 (standard deviation [SD] 2.8) from 1.9 (SD 1.7) (mean baseline) after 27.7 days (SD 17.2) of olfactory training. About 64.2 % (352 out of 548 patients) portrayed at least a 2-point increase.

As compared to participants who trained for <28 days, the olfactory improvement was higher for participants who trained for >28 days, as shown in Table 1:

Patients with hyposmia had an 8 days faster time to olfactory improvement than patients with anosmia. This advantage was perceived irrespective of the duration of olfactory dysfunction.