Figure 3

Association of olfactory bulb volume and olfactory function. (a) Trajectory of olfactory function along timepoints. Blue dots indicate proportion of individuals with self-reported olfactory dysfunction. Gray dots show the average impairment as operationalized by the visual analogue scale. (b) Group differences of olfactory bulb volume at baseline between participants with and without self-reported olfactory dysfunction with respect to different timepoints. Olfactory bulb volume at baseline was significantly lower in individuals that exhibited self-reported olfactory dysfunction during both examination timepoints but not during the acute infection. (c) Association of the time interval from positive PCR to examination and olfactory bulb volume. A smaller interval was significantly associated with lower olfactory bulb volume. Non-hospitalized participants are represented by blue dots, hospitalized participants by white dots. (d) Linear associations between olfactory bulb volume and olfactometry scores. A low olfactory bulb volume at baseline was significantly associated with a lower olfactometry score at follow-up. Dot colors indicate hospitalization status as in c. (e) Group differences of olfactory bulb volume between participants with sustained self-reported olfactory dysfunction at follow-up and those with recovered olfaction to that point. Olfactory bulb volume was significantly lower in participants with sustained self-reported olfactory dysfunction. Abbreviations: \({eta}_{p}^{2}\) = partial eta squared indicating the effect size as provided by the analysis of covariance, p p-value, \({r}_{sp}\) Spearman correlation coefficient, PCR polymerase chain reaction, E1 examination at baseline, E2 examination at follow-up.