Objective:

To compare patterns of grey matter atrophy (GMA) in post-COVID syndrome according to four different strains of SARS-CoV-2

Background:

The neuropsychiatric symptoms of the post-COVID syndrome are frequent and debilitating and represents a major public health concern. Unfortunately, neither the physiopathology nor the underlying cerebral alterations are understood.

Design/Methods:

We analyzed 3T T1 MRI of 300 post-COVID subjects (non-hospitalized, median age 40 years, 209 women, an average of 150 days from diagnosis): 188 infected with the Alpha strain, 29 infected with the P.2-Gamma strain, 61 infected with the P.1+P.1.*-Gamma strain, 22 infected with the Delta strain and 90 healthy controls scanned during the pandemic. We used the Fiocruz database (http://www.genomahcov.fiocruz.br/dashboard/) to separate groups according to the predominant strains by intervals. The CAT12-toolbox/SPM12/MATLAB2019 was used to perform Voxel-Based Morphometry (VBM) analysis and investigate GMA among groups (adjusted for intracranial volume, age, and sex). We reported significant p-values<0.001 corrected for multiple comparisons.

Results:

Overall, all four groups of strains presented GMA atrophy of the bilateral anterior cingula and ventromedial frontal lobes. Besides, Strain P.2-Gamma showed GMA of the right cuneus and left superior occipital gyrus. The P.1+P.1.*-Gamma Strain presented more widespread atrophy (right angular gyrus, fusiform gyrus, frontal operculum and precuneus, and left frontal operculum and precuneus). Interestingly, the Alpha and Delta Strains revealed exclusive frontal lobe GMA.

Conclusions:

Despite the mild acute infection, all four groups presented GMA of the anterior cingula and ventromedial frontal area, suggesting similarities in neurotropism, cerebral injury, and physiopathology. Additionally, different strains showed individual variations of GMA. These findings. The atrophy of the limbic system and frontal lobes may be somehow associated with the highly prevalent neuropsychiatric symptoms (dysexecutive syndrome, depression, and anxiety) in the post-COVID syndrome. Further analyses are necessary to correlate brain atrophy with neuropsychiatric dysfunction and eventually provide therapeutic targets.