Self‐reported olfactory and gustatory dysfunction and psychophysical testing in screening for COVID‐19: A systematic review and meta‐analysis

Abstract

Background A substantial proportion of coronavirus disease‐2019 (COVID‐19) patients demonstrate olfactory and gustatory dysfunction (OGD). Self‐reporting for OGD is widely used as a predictor of COVID‐19. Although psychophysical assessment is currently under investigation in this role, the sensitivity of these screening tests for COVID‐19 remains unclear. In this systematic review we assess the sensitivity of self‐reporting and psychophysical tests for OGD. Methods A s ystematic search was performed on PubMed, EMBASE, and ClinicalTrials.gov from inception until February 16, 2021. Studies of suspected COVID‐19 patients with reported smell or taste alterations were included. Data were pooled for meta‐analysis. Sensitivity, specificity, and diagnostic odds ratio (DOR) were reported in the outcomes. Results In the 50 included studies (42,902 patients), self‐reported olfactory dysfunction showed a sensitivity of 43.9% (95% confidence interval [CI], 37.8%‐50.2%), a specificity of 91.8% (95% CI, 89.0%‐93.9%), and a DOR of 8.74 (95% CI, 6.67‐11.46) for predicting COVID‐19 infection. Self‐reported gustatory dysfunction yielded a sensitivity of 44.9% (95% CI, 36.4%‐53.8%), a specificity of 91.5% (95% CI, 87.7%‐94.3%), and a DOR of 8.83 (95% CI, 6.48‐12.01). Olfactory psychophysical tests analysis revealed a sensitivity of 52.8% (95% CI, 25.5%‐78.6%), a specificity of 88.0% (95% CI, 53.7%‐97.9%), and a DOR of 8.18 (95% CI, 3.65‐18.36). One study used an identification test for gustatory sensations assessment. Conclusion Although demonstrating high specificity and DOR values, neither self‐reported OGD nor unvalidated and limited psychophysical tests were sufficiently sensitive in screening for COVID‐19. They were not suitable adjuncts in ruling out the disease.

Two-Year Follow-Up on Chemosensory Dysfunction and Adaptive Immune Response after Infection with SARS-CoV-2 in a Cohort of 44 Healthcare Workers

“…The observed 25% prevalence of self-reported persistent chemosensory dysfunction two years post-infection seems to be high. Nevertheless, one must keep in mind that self-reports of chemosensory dysfunction poorly correlate with psychophysical test results and mostly underestimate the prevalence of chemosensory dysfunction [ 22 , 23 , 42 ]. Therefore, the usage of psychophysical tests is recommended to assure a more reliable assessment of chemosensory function [ 43 , 44 ].…”

“…Only a few studies report on PCD two years after infection, showing varied results with a self-reported prevalence of 11–61% [ 13 , 19 , 20 , 21 ]. Since self-reports tend to poorly correlate and often underestimate psychophysically measured chemosensory dysfunction, it is important to additionally apply psychophysical testing [ 22 , 23 ]. So far, only one other study reports on psychophysically tested chemosensory function after two years [ 19 ].…”

Taste and Smell Disorders: A Critical Look at Olfactory and Gustatory Dysfunction

“…However, even before COVID-19, progress was being made. Novel diagnostic methods like psychophysical olfactory testing, gustatory evoked potentials, and objective biomarkers of nerve damage are enhancing our ability to identify and characterize smell and taste deficits [ 21 ]. Meanwhile, emerging treatments ranging from corticosteroids and olfactory training to platelet-rich plasma and neuromodulation are providing new options for sensory rehabilitation [ 22 , 23 , 24 , 25 ].…”

SARS‐CoV‐2 Effects on Psychophysical Olfactory Scores: Prospective Study With Evaluation Before and 60‐Days After Infection

“…T he prevalence of olfactory dysfunction (OD) during and after COVID-19 has been the subject of numerous studies that reported reliable data based on psychophysical tests. [1][2][3][4][5] A common limitation of all these studies is the lack of an objective olfactory assessment prior to infection. For this reason, it has never been possible to understand exactly to what extent the SARS-CoV-2 infection impacted psychophysical scores or whether recovery was actually complete.…”

“…The prevalence of olfactory dysfunction (OD) during and after COVID‐19 has been the subject of numerous studies that reported reliable data based on psychophysical tests 1‐5 . A common limitation of all these studies is the lack of an objective olfactory assessment prior to infection.…”