No abstract

Background: Little is known about the underpinning mechanisms of neurological dysfunction in post-COVID syndrome. Methods: We conducted a cross-sectional study of 87 consecutive subjects after a mild infection, with a median of 54 days after diagnosis of COVID-19. We performed structured interviews, neurological examinations, 3T-MRI scans, and neuropsychological assessments. The MRI study included white matter investigation with diffusion tensor images (DTI) and functional connectivity with resting-state functional MRI (RS-fMRI). Results: Subjects self-reported headaches (40%) and memory difficulties (33%). The quantitative analyses confirmed symptoms of fatigue (68% of participants), excessive somnolence (35%), symptoms of anxiety (29%), impaired cognitive flexibility (40%), and language dysfunction (33%). Besides, we observed a correlation between DTI fractional anisotropy (FA) and abnormal attention and cognitive flexibility in the Trail Making Test part B. Elevated levels of fatigue and somnolence associated with higher connectivity of the posterior cingulate cortex (PCC) in the RS-fMRI study of the default mode network. While higher connectivity of the PCC with bilateral angular gyri was associated with higher fatigue levels, the elevated levels of somnolence correlated with higher connectivity between the PCC and both the left thalamus and putamen. Conclusions: COVID-19 is associated with long-term neuropsychiatric symptoms and cerebral functional and microstructural alterations.