Background. Chemosensitive disorders are very frequent in the early stages of COVID-19 and in paucisymptomatic cases. These patients are typically placed in home quarantine. This study has the aim of validating a new olfactory and gustatory objective evaluation test in these patients.

Methods. Thirty-three home-quarantined COVID-19 patients have undergone a self-administered chemosensitive test the day before the control swab. On this occasion, the patients underwent operator-administered already validated tests. The results were finally compared.

Results. The differences between the results of the two tests were not significant for both the olfaction (P = 0.201) and the taste (P = 0.180).

Conclusion. The olfactory and gustatory evaluation by self-administered test can be considered a valid tool, fundamental for obtaining objective qualitative and quantitative data on the extent of chemosensitive disorders in home-quarantined COVID-19 patients.

INTRODUCTION

Olfactory and gustatory dysfunctions are proving to be frequent symptoms of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The first European reports on coronavirus disease 19 (COVID-19) patients are detecting a frequency of these symptoms ranging between 19.4% and 88% [1-5]. Particularly, chemosensitive dysfunctions appear to be common in the early stages of infection from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and in paucisymptomatic patients [1,2]. However, all the reports published so far are anamnestic or observational and the literature lacks objective studies that evaluate the gustatory and olfactory function in these patients. Assessing the patient in the hospital is difficult due to the entry restrictions into the COVID-19 Departments and to the fact that the most serious cases that require hospitalization, are generally uncooperative. Moreover, hospitalized patients are generally in the late stages of the infection and it would instead be interesting to acquire objective information on asymptomatic or initial cases, in order to find trigger symptoms that can allow early identification and isolation of suspect cases. Generally, the latter patients are in home quarantine. Therefore, checking and evaluating them at home presents almost insurmountable logistical problems during an emergency health situation like the one we are facing. An objective and validated self-administered test would be a valuable tool for the remote evaluation of these patients.

Psycho-physiological tests represent a workhorse in the objective evaluation of the olfactory and gustatory functions as they are easy to perform, standardized, validated and repeatable [6,7]. These tests are generally based on the blindness of the assessed patient, which guarantees the reliability and validity of the results. Clearly, this basic principle cannot be insured if the subject, in home isolation, is asked to self-administer the test.

The aim of this work is to overcome this bias, developing a new self-administered psycho-physiological olfactory and gustatory test that could be used to evaluate COVID-19 patients in home quarantine.

The same group of patients, after the completion of the proposed self-administered test, underwent direct clinical evaluation with widely used and validated tests for anosmia and ageusia. Then, the results of both kind of tests were statistically compared to validate the self-administered evaluation protocol.

MATERIALS AND METHODS

The study was conducted between April 9^th and 10^th 2020, on home-quarantined SARS-CoV-2 positive patients, followed by the Surveillance and Prevention Department of the University of Sassari, University of Salerno and Bellaria-Maggiore Hospital of Bologna. All patients belonged to the healthcare staff of the involved hospitals (i.e. doctors, nurses, auxiliary staff).

The inclusion criteria were: home quarantined adults, age > 18 years old, rhino-pharyngeal swab positive for SARS-CoV-2 infection, scheduled control swab, voluntary participation in the study.

Previous surgery or radiotherapy in the oral and nasal cavities, pre-existing manifestation of smell and taste alterations, history of head trauma, allergic rhinitis, chronic rhinosinusitis and psychiatric or neurological disorders were considered as exclusion criteria.

The study protocol was approved by an independent ethics committee (n° 378-2020-OSS-AUSLBO).

The day before the scheduled control swab, patients in home quarantine were asked to participate in the study. In case of acceptance, some general information was collected for all subjects: gender, age, job position, comorbidity or conditions that could be cause of exclusion, which symptoms presented and when these symptoms started, when positivity to the first nasopharyngeal swab was confirmed. All patients were carefully investigated for the previous or current presence of chemosensitive disorders during the SARS-CoV-2 infection. Finally, the test methodology was explained and patients were asked to collect 7 common household odorants and prepare the 4 basic flavored necessary solutions, thus contacting the operator again to perform the telephone test.

The next morning at the hospital, before the control swab, patient’s chemosensitive functions were directly evaluated by a different trained operator.