Fig. 2.

Correlation between Sniffin-test scores and whole-brain metabolism in COVID-hyposmia (A) and PD-hyposmia patients (B). A significant direct correlation was highlighted between olfaction and brain metabolism in rectus, middle temporal, and medial frontal gyri on both hemispheres and in the right precentral gyrus and anterior cingulate in COVID-hyposmia patients and in cuneus/precuneus on both hemispheres and in the lateral occipital cortex in the left hemisphere in PD-hyposmia patients. Clusters with significant hypometabolism are shown superimposed on an MRI template. The color bars indicate the level of z-scores for significant voxels. (See Table 2 for details on coordinates and z-scores.)