Observational study: prospective longitudinal cohort (Green)
Author: Dementia Panel (Blazhenets G)
This prospective cohort study enrolled 8 hospitalized COVID-19 patients and assessed them at subacute and chronic stage (after 6 months) with MoCA and 18F-FDG PET. Similar to previous findings (Hosp et al, 2021), COVID-19 patients exhibited a distinct pattern expression score (PES) compared to controls, with hypometabolism in frontal and parietal cortices and caudate nuclei and positive weights in brainstem and cerebellum, which correlated with MoCA scores. After 6 months, MoCA performance significantly improved over time, but did not revert back to a normal range overall, with persistent deficits in visuospatial, executive functions and memory. At the chronic stage, 4/8 patients did not report cognitive impairment, with 5/8 subjects still performing under the threshold for cognitive impairment (< 26/30). The chronic stage showed wide-spread increase of 18F-FDG uptake in fronto-parietal and, to a lesser extent, temporal regions compared to the subacute stage. The regions with residual hypometabolism were those with the most prominent decreases during the acute stage and may thus take a longer period to fully recover. This study highlights the potential reversibility of cognitive impairment in COVID-19 patients in frontoparietal and, to a lesser extent, temporal hypometabolism, which is accompanied by significant improvement in cognition after 6 months.