Psychophysical Olfactory Tests and Detection of COVID-19 in Patients With Sudden Onset Olfactory Dysfunction: A Prospective Study

Abstract

Objective: To investigate the coronavirus disease 2019 (COVID-19) status of patients with initial sudden olfactory anosmia (ISOA) through nasopharyngeal swabs for reverse transcription–polymerase chain reaction (RT-PCR) analysis and to explore their olfactory dysfunctions with psychophysical olfactory evaluation. Methods: A total of 78 ISOA patients were recruited from April 6, 2020, to April 10, 2020, through a public call of University of Mons (Mons, Belgium). Patients benefited from nasopharyngeal swabs and fulfilled the patient-reported outcome questionnaire. Among them, 46 patients performed psychophysical olfactory evaluation using olfactory identification testing. Based on the duration of the ISOA, 2 groups of patients were compared: patients with olfactory dysfunction duration ≤12 days (group 1) and those with duration >12 days (group 2). Results: In group 1, 42 patients (87.5%) had a positive viral load determined by RT-PCR and 6 patients (12.5%) were negative. In group 2, 7 patients (23%) had a positive viral load and 23 patients (77%) were negative. The psychophysical olfactory evaluation reported that anosmia and hyposmia occurred in 24 (52%) and 11 (24%) patients, respectively. Eleven patients were normosmic. The viral load was significantly higher in patients of group 1 compared with those of group 2. Conclusions: Coronavirus disease 2019 was detected in a high proportion of ISOA patients, especially over the first 12 days of olfactory dysfunction. Anosmia is an important symptom to consider in the detection of COVID-19 infection.

Clinical and Radiological Evaluations of COVID‐19 Patients With Anosmia: Preliminary Report

“…Although 46% of our cohort reported nasal obstruction to some degree, we found no significant correlation between the severity of nasal obstruction and that of the olfactory loss. 19 However, we note that the patient reported by Eliezer et al, also failed to report nasal obstruction, and therefore sought to confirm whether our cohort may have localized obstruction of the olfactory cleft. 4 Due to fear of contamination and ongoing travel restrictions, we have been able to undertake complete evaluation in only 16 patients.…”

Anosmia: an evolution of our understanding of its importance in COVID-19 and what questions remain to be answered

“…First, we carried out a study of 78 patients with sudden and initial anosmia. We were thus able to show that if the swab was performed within the first 14 days of symptoms, 87% of these anosmic patients were COVID-19 + [4]. Using serological testing (Zentec kit), we confirmed with the group showing symptoms for more than 14 days that 93% of anosmic patients were COVID-19 + .…”

Loss of smell in COVID-19 patients: a critical review with emphasis on the use of olfactory tests

“…Nevertheless, self-assessment is not well related to the measured olfactory function 30 , 31 , 33 , as it has been well shown in the few studies where olfactory tests have been performed in COVID-19 positive patients. In particular, Lechein et al 27 found that 24% of COVID-19 patients complaining of olfactory loss were normal by the smell test, whereas Moein and colleagues 28 and Vaira et al 29 observed an underestimation of the self-reported smell dysfunction. In this regard, it is known that in the general population only for anosmia is there correspondence between self-reported olfactory function and the measured one 31 , 33 .…”

“…I ). Most of the publications that we identified in this review are based on olfactory self-assessment that is unreliable in COVID-19 patients compared to psychophysical tests 27-29 , 42 , especially in the context of a pandemic scenario and consequent restrictions in social life 43 . The authors probably opted for self-administered questionnaire because it can be very difficult to perform an olfactory test during SARS-CoV-2 outbreak, especially when testing recently infected patients.…”

“…Ottaviano et al 26 studied 6 COVID-19 patients complaining of sudden hyposmia by the “Le Nez du Vin” test, a six-odours smell identification test and in all cases found an olfactory deficit. In a study by Lechien et al 27 , of 78 subjects complaining of isolated sudden hyposmia, 46 COVID-19 positive patients underwent the “Sniffin Sticks” identification sub-test (16 odours). The authors found that 52% of the patients were anosmic, 11 (24%) were hyposmic.…”