A tool for the psychophysical assessment of olfactory dysfunction in patients with COVID-19

Numerous studies have reported that patients with coronavirus disease 2019 (COVID-19) experience alterations in the sense of smell. Therefore, there is an increased need for a psychophysical evaluation tool for olfactory dysfunction in patients with COVID-19 without increasing the risk of virus spread. We applied a single-use sniffing-bead system, which consisted of small beads and a disposable plastic handpiece, to patients with COVID-19 presenting with olfactory dysfunction. The bead sets contained eight concentrations of 2-phenylethyl alcohol (PEA), which has been used in olfactory function tests for many years, and the lowest concentration at which the participant detected the PEA odor was recorded as the PEA threshold. The test was easily administered at the clinic during the consultation with the doctor without increasing the risk of virus spread. Based on the test results, anosmia was objectively confirmed in a patient with subjective anosmia, and another patient with subjective hyposmia was diagnosed with normosmia. Both patients started olfactory training after diagnosis. In conclusion, we present a system to psychophysically assess olfactory dysfunction in patients with COVID-19 using a universal odorant without the risk of virus spread, and suggest that this system might enable early diagnosis and management of patients with COVID-19.