Examining the Association between Brain MRI Measures at 7 Tesla and cognition following COVID-19 Infection

The long-term neuropsychological, cognitive, and neurobiological effects of the severe acute respiratory syndrome (SARS-CoV-2) in survivors with milder symptoms are still poorly understood. In this thesis we evaluated cognitive and psychological changes approximately five weeks after a wide range of symptoms in COVID-19 illness and determined whether advanced diffusion magnetic resonance imaging measures within subcortical brain structures of the limbic system were related to neurological, respiratory, psychiatric, and gastric symptoms experienced during the acute phase of illness. Cognitive and neuropsychological evaluations were performed in 45 participants who experienced neurological symptoms during the acute phase of COVID-19 illness. Participants also underwent a 7 Tesla MRI neurological exam on the same day. The group showed a significant reduction in attention compared to a normative population, but no differences in other cognitive domains. Although white matter hyperintensities were visible on fluid attenuated inversion recovery (FLAIR) images in 22 of 43 participants consistent with small vessel ischemic disease and migraine, this incidence is consistent with that expected in a normative population. Participants were divided into groups based on the presence or absence of symptoms at their acute illness from the medical history collected over the phone or in-person during recruitment. No differences were observed in subcortical brain structure volumes when comparing participants between subgroups. Differences in advanced diffusion metrics were observed within several subcortical structures (p\u3c0.0036, Bonferroni corrected Mann-Whitney U-test) when comparing groups suggesting subtle tissue changes in several regions that were mostly related to respiratory and gastric symptoms. There were no strong associations between diffusion measurements and attention. Future studies should follow participants longitudinally to determine whether the observed changes persist