[Characteristics of postviral olfactory disorder]

Gustatory event-related potential alterations in olfactory dysfunction patients

The phenomenon that longstanding impaired olfactory function is associated with the decreased gustatory function was described in present studies, which was seems attributed to mutual chemosensory interactions. And the interaction between olfaction and gustation still needs more research to figure out. The objective of the study was to investigate how the taste was influenced by olfactory impairment in the central pathway. We tested 33 subjects with normal (n = 19) or impaired (n = 14) olfactory function for their gustatory event-related potentials (gERPs). Validated tests were used for olfactory and gustatory testing (Sniffin’ Sticks, gERPs, and three-drop test). This study reported an objective gustatory function decline in olfactory dysfunction participants. However, it also reported the increased gustatory event-related potentials of olfactory dysfunction participants, especially at the frontal electrode (F_Z) and electrode 16 (E16), and the reduced latency of P2 peak of them at electrode 21 (E21), while no obvious difference was observed at the centro-parietal electrode (P_Z). Inferior insula might be the main response area for the increase in gERPs, and this increase averaged amplitude of the P2 component may attribute to compensation of the secondary gustatory response that occurred in the gustatory processing of olfactory-impaired patients.

Paranasal sinuses computed tomography findings in anosmia of COVID-19

Objective

Olfactory dysfunction in coronavirus disease-2019 (COVID-19) is poorly understood. Thus, mechanistic data are needed to elucidate the pathophysiological drivers of anosmia of COVID-19.

Methods

We performed the current study in patients who presented with anosmia and COVID-19 as documented by the polymerase chain reaction (PCR) assay between April 1st and May 15st, 2020. We assessed for the conductive causes of anosmia with computed tomography (CT) of paranasal sinuses.

Results

49 patients who presented with anosmia and positive PCR assay for COVID-19 were included. The average age was 45 ± 12.2 years. Complete anosmia was present in 85.7% of patients and 91.8% of patients reported sudden onset of olfactory dysfunction. Taste disturbance was common (75.5%). There were no significant pathological changes in the paranasal sinuses on CT scans. Olfactory cleft and ethmoid sinuses appeared normal while in other sinuses, partial opacification was detected only in some cases.

Conclusion

We did not find significant mucosal changes or olfactory cleft abnormality on CT imaging in patients with anosmia of COVID-19. Conductive causes of anosmia (i.e., mucosal disease) do not seem play a significant role in anosmia of COVID-19.