Effects of COVID-19 on the Human Central Olfactory System: A Natural Pre-Post Experiment

• DOI: 10.3174/ajnr.a7713
• Publication Date: 2022-11-24T17:24:22Z
• Authors: E. Thunell; M.G. Peter; V. Lenoir; P. Andersson; B.N. Landis; M. Becker; J.N. Lundström
• Keywords: 2019-20 coronavirus outbreak; Anosmia; Betacoronavirus

Reduced olfactory function is the symptom with highest prevalence in coronavirus disease 2019 (COVID-19) nearly 70% of infected individuals experiencing partial or total loss their sense smell at some point during disease. The exact cause not known, but beyond peripheral damage, studies have demonstrated insults to both bulb and central brain areas. However, these often lack baseline pre-COVID-19 assessments control groups, effects could, therefore, simply reflect pre-existing risk factors.Shortly before COVID-19 outbreak, we completed an olfactory-focused study, which included structural MR images a full clinical test. Opportunistically, invited participants back 1 year later, including 9 who had experienced mild-to-moderate (C19+) 12 (C19-), creating natural pre-post experiment group.Despite C19+ reporting subjective dysfunction, few showed signs objectively altered function. Critically, all except individual group reduced volume (average reduction, 14.3%), this did amount significant statistical difference compared (2.3%) using inference statistics. We found no morphologic differences areas stronger functional connectivity between postmeasure.Our data suggest that might long-term reduction discernible cerebral regions.