Correlation of COVID-19 associated olfactory dysfunction and olfactory bulb volumes

Introduction Olfactory dysfunction is a common symptom of COVID-19 infections. The presented study aimed at a verification of the hypothesis that COVID-19 associated olfactory dysfunction correlates to structural changes in the olfactory bulbs.

Methods Data of 233 COVID-19 convalescents from the Hamburg City Health Study COVID Program were analysed. Upon recruitment, patients underwent MR imaging with an automated volumetry of the olfactory bulbs, neuropsychological testing as well as longitudinal assessments of smell (Sniffin’ Sticks, questionnaire). Olfactory bulb volumes and clinical measures were statistically compared between participants with and without persistent smelling impairment.

Results COVID-19 convalescents with post-acute smelling impairment showed significantly lower olfactory bulb volumes than those with perceived normal smelling (mean at baseline: 40.76 mm3 vs. 46.74 mm3, p=0.046; follow-up: 40.45 mm3 vs. 46.55 mm3, p=0.036). Olfactory bulb volume successfully predicted olfactometric scores at follow-up (p=0.025). Performance in neuropsychological testing was not significantly associated with the olfactory bulb volume.

Conclusion The presented data shows a correlation between persistent olfactory dysfunction after COVID-19 disease and olfactory bulb volumes. Vice versa, olfactory bulb volumetry might be used as a surrogate marker for an objective evaluation of the olfactory function after COVID-19 infection.

Publikationsverlauf

Artikel online veröffentlicht:
12. Mai 2023