| Cross-sectional case-control studies  

Microstructural brain abnormalities, fatigue, and cognitive dysfunction after mild COVID-19

Although some studies have shown neuroimaging and neuropsychological alterations in post-COVID-19 patients, fewer combined neuroimaging and neuropsychology evaluations of individuals who presented a mild acute infection. In this cross-sectional study the authors investigated cognitive dysfunction and brain changes in a group of mildly infected individuals. 97 consecutive subjects (median age of 41 years) without current or history of psychiatric symptoms (including anxiety and depression) after a mild infection, with a median of 79 days (and mean of 97 days) after diagnosis of COVID-19 were included. Semi-structured interviews, neurological examinations, 3T-MRI scans, and neuropsychological assessments were performed. For MRI analyses, the authors included a group of non-infected 77 controls. The MRI study included white matter (WM) investigation with diffusion tensor images (DTI) and functional connectivity with resting-state functional MRI (RS-fMRI). The patients reported memory loss (36%), fatigue (31%) and headache (29%). The quantitative analyses confirmed symptoms of fatigue (83% of participants), excessive somnolence (35%), impaired phonemic verbal fluency (21%), impaired verbal categorical fluency (13%) and impaired logical memory immediate recall (16%). The WM analyses with DTI revealed higher axial diffusivity values in post-infected patients compared to controls. Compared to controls, there were no significant differences in the functional connectivity of the posterior cingulum cortex. There were no significant correlations between neuropsychological scores and neuroimaging features (including DTI and RS-fMRI). The authors concluded underlying that their results suggest persistent cognitive impairment and subtle white matter abnormalities in individuals mildly infected without anxiety or depression symptoms. The longitudinal analyses will clarify whether these alterations are temporary or permanent.

Scardua-Silva L, Amorim da Costa B, Karmann Aventurato Í, Batista Joao R, Machado de Campos B, Rabelo de Brito M, Bechelli JF, Santos Silva LC, Ferreira Dos Santos A, Koutsodontis Machado Alvim M, Vieira Nunes Ludwig G, Rocha C, Kaue Alves Silva Souza T, Mendes MJ, Waku T, de Oliveira Boldrini V, Silva Brunetti N, Nora Baptista S, da Silva Schmitt G, Duarte de Sousa JG, Marchiori de Oliveira Cardoso TA, Schwambach Vieira A, Barbosa Santos LM, Dos Santos Farias A, Nogueira MH, Cendes F, Lin Yasuda C. Microstructural brain abnormalities, fatigue, and cognitive dysfunction after mild COVID-19. Sci Rep. 2024 Jan 19;14(1):1758. doi: 10.1038/s41598-024-52005-7.