Six-Month Psychophysical Evaluation of Olfactory Dysfunction in Patients with COVID-19

TLDR

The study prospectively evaluated the 6‑month prevalence of self‑reported and psychophysically measured olfactory dysfunction in patients with mild‑to‑moderate COVID‑19. Self‑reported smell or taste impairment was assessed with SNOT‑22 at diagnosis, 4‑, 8‑week, and 6‑month intervals, and at 6 months psychophysical testing was performed using the 34‑item culturally adapted University of Pennsylvania Smell Identification Test (CA‑UPSIT). Among 145 participants, 60 % exhibited olfactory dysfunction on CA‑UPSIT, including 6.9 % anosmic and 4.8 % severely microsmic, and 11.7 % were anosmic or severely microsmic despite most reporting normal smell, indicating a high long‑term rate of persistent dysfunction.

Abstract

Abstract This study prospectively assessed the 6-month prevalence of self-reported and psychophysically measured olfactory dysfunction in subjects with mild-to-moderate COVID-19. Self-reported smell or taste impairment was prospectively evaluated by SNOT-22 at diagnosis, 4-week, 8-week, and 6-month. At 6 months from the diagnosis, psychophysical evaluation of olfactory function was also performed using the 34-item culturally adapted University of Pennsylvania Smell Identification Test (CA-UPSIT). 145 completed both the 6-month subjective and psychophysical olfactory evaluation. According to CA-UPSIT, 87 subjects (60.0%) exhibited some smell dysfunction, with 10 patients being anosmic (6.9%) and seven being severely microsmic (4.8%). At the time CA-UPSIT was administered, a weak correlation was observed between the self-reported alteration of the sense of smell or taste and olfactory test scores (Spearman’s r = −0.26). Among 112 patients who self-reported normal sense of smell at last follow-up, CA-UPSIT revealed normal smell in 46 (41.1%), mild microsmia in 46 (41.1%), moderate microsmia in 11 (9.8%), severe microsmia in 3 (2.3%), and anosmia in 6 (5.4%) patients; however, of those patients self-reporting normal smell but who were found to have hypofunction on testing, 62 out of 66 had a self-reported reduction in sense of smell or taste at an earlier time point. Despite most patients report a subjectively normal sense of smell, we observed a high percentage of persistent smell dysfunction at 6 months from the diagnosis of syndrome coronavirus 2 (SARS-CoV-2) infection, with 11.7% of patients being anosmic or severely microsmic. These data highlight a significant long-term rate of smell alteration in patients with previous SARS-COV-2 infection.