Introduction: COVID-19 has been associated with various neurological
complications, including cognitive impairments such as memory deficits,
attention difficulties, and executive dysfunction. These symptoms raise concerns
about potential long-term effects, particularly in individuals with preexisting
neurodegenerative conditions. Emerging evidence suggests that systemic
inflammation, blood-brain barrier (BBB) dysfunction, and neuroinflammation
may contribute to cognitive decline in COVID-19 patients. However, the impact
of COVID-19 on functional brain connectivity, particularly in dementia patients,
remains unclear.
This study aims to investigate the differences in functional connectivity across
different frequency bands (delta, theta, alpha, beta, and gamma) in dementia
patients with and without a history of COVID-19 (D-COVID and D-nCOVID)
compared to a healthy control (HC) group. The study explores whether COVID-19
accelerates neurodegenerative processes by disrupting functional brain networks.
Methods: Functional connectivity was assessed using electroencephalography
(EEG)-based network analysis in three groups: D-COVID, D-nCOVID, and HC.
Connectivity metrics were compared across frequency bands, with a focus on
local efficiency (LE) and global network alterations. The Kruskal-Wallis test assessed
statistical significance, while the Dunn test was used for post-hoc analysis.
Results: Findings indicate a significant reduction in functional connectivity across
multiple brain regions in dementia patients, with the D-COVID group exhibiting
more pronounced declines. The observed decrease in connectivity suggests that
COVID-19 may accelerate neurodegenerative processes. Additionally, the HC
group demonstrated stronger connectivity and higher LE metrics, highlighting the
widespread impact of dementia on brain networks.
Conclusion: These findings support the hypothesis that COVID-19 contributes to
cognitive decline by exacerbating neurodegenerative mechanisms. The disruption
of functional brain connectivity observed in D-COVID patients aligns with
previous studies suggesting that SARS-CoV-2 may indirectly promote neuronal
degeneration. Further longitudinal studies are needed to determine the long-term
cognitive consequences of COVID-19 and potential therapeutic interventions to
mitigate these effects.
Keywords: COVID-19, dementia, electroencephalography, functional connectivity,
neurodegeneration