Longitudinal changes in global structural brain connectivity and cognitive performance in former hospitalized COVID-19 survivors: an exploratory study

Abstract

Background Long-term sequelae of COVID-19 can result in reduced functionality of the central nervous system and substandard quality of life. Gaining insight into the recovery trajectory of admitted COVID-19 patients on their cognitive performance and global structural brain connectivity may allow a better understanding of the diseases' relevance. Objectives To assess whole-brain structural connectivity in former non-intensive-care unit (ICU)- and ICU-admitted COVID-19 survivors over 2 months following hospital discharge and correlate structural connectivity measures to cognitive performance. Methods Participants underwent Magnetic Resonance Imaging brain scans and a cognitive test battery after hospital discharge to evaluate structural connectivity and cognitive performance. Multilevel models were constructed for each graph measure and cognitive test, assessing the groups' influence, time since discharge, and interactions. Linear regression models estimated whether the graph measurements affected cognitive measures and whether they differed between ICU and non-ICU patients. Results Six former ICU and six non-ICU patients completed the study. Across the various graph measures, the characteristic path length decreased over time (β = 0.97, p = 0.006). We detected no group-level effects (β = 1.07, p = 0.442) nor interaction effects (β = 1.02, p = 0.220). Cognitive performance improved for both non-ICU and ICU COVID-19 survivors on four out of seven cognitive tests 2 months later (p < 0.05). Conclusion Adverse effects of COVID-19 on brain functioning and structure abate over time. These results should be supported by future research including larger sample sizes, matched control groups of healthy non-infected individuals, and more extended follow-up periods.

COVID-19 and cognitive function: Evidence for increased processing speed variability in COVID-19 survivors and multifaceted impairment with long-COVID symptoms

“…Against the backdrop of a limited general cognitive impact of COVID-19, our findings suggest reduced cognitive function across multiple domains in people who needed hospitalisation due to COVID-19. This is consistent with recent literature suggesting that brain and cognitive impairment may be more salient in people with a severe infection [37] or hospitalisation [38], highlighting the need for longitudinal cognitive monitoring and improvement efforts in such cohorts [39], for example using non-invasive brain stimulation [40, 41]. Furthermore, we found sizable associations between overall long-COVID symptom load and cognitive function across all domains, suggesting that affected individuals may also benefit from longitudinal cognitive monitoring and rehabilitation efforts.…”

Olfactory Loss and Brain Connectivity after COVID-19: Structural Follow-Up at One Year

“…In contrast, it remains equally plausible that the infection might have actually stimulated an acute structural plasticity response of the brain olfactory connectivity, which was initially (i.e., shortly after infection) stronger and more tightly associated with olfactory symptoms, but later (i.e., after several months) progressively slower, until restoring an approximately normal connectivity pattern, definitely uncoupled from the actual olfactory performance. This scenario would be in line with a recent longitudinal study on the global structural connectivity of former hospitalized COVID-19 survivors suggesting that adverse effects on brain functioning and structure would abate over time [ 13 ]. Thus, while much larger samples would be needed for a proof of this scenario, it is now less likely that the SCI would work as a prognostic tool to identify individuals whose COV+ related olfactory loss will resolve or persist over a term as long as one year.…”

Is Recovery Just the Beginning? Persistent Symptoms and Health and Performance Deterioration in Post-COVID-19, non-hospitalised University Students - A Cross-Sectional Study

“…The exceptions were a decrease in symptoms of impaired physical health among men and an increase in fatigue among women. This finding appears to contrast with anecdotal evidence and numerous published studies, which suggest that symptoms generally lessen with time since infection for most individuals (Poole-Wright et al, 2023; Tassignon et al, 2023), although in some cases they may stay constant or intensify (Carbone et al, 2022; Lucette et al, 2022; Qin et al, 2023). Visual inspection of Figure 3 and further analyses indicate that these inconsistencies may be attributed to a non-monotonic trajectory of changes as time since infection progresses, as well as to insufficient follow-up time after the illness.…”