Introduction: COVID-19 infection affects many systems, particularly the central nervous system. These effects are observed at different levels across various age groups. Although there are studies in the literature examining the negative effects of COVID-19 infection on cognitive functions, research including neurophysiological tests supporting these effects is limited. The aim of this study is to demonstrate the effect of COVID-19 infection on cognitive functions according to age through neurophysiological parameters.
Methods: This prospective study was conducted at the COVID-19 clinic from June 2020 to June 2021. Inclusion criteria comprised PCR-confirmed mild to moderate COVID-19 patients aged under 50 and over 65, as well as a PCR-negative control group comprised of individuals aged under 50 and over 65. Exclusion criteria included individuals under 18 years old, and participants from both the patient and control groups were selected without conditions such as dementia that could influence cognitive functions, as well as severe clinical presentations of COVID-19. In hospitalized patients, N200/P300 latencies and N2P3 amplitudes were measured on the first day of admission and again on the 60th day post-discharge for those with positive COVID-19 PCR tests. For PCR-negative patients, measurements were taken only once on the first day of admission.
Results: The study encompassed a cohort of 48 COVID-19 PCR-positive patients alongside 47 PCR-negative subjects (constituting the control group). Statistically significant differences were observed between the COVID-19 PCR-positive and negative groups (p<0.05). Additionally, significant differences in event-related potentials were found between the PCR-positive groups aged under 50 and those over 65 years (p<0.05). After discharge, significant improvement was observed on the 60th day in the group under 50 years of age (p<0.05), while no statistically significant improvement was detected in the group over 65 years (p>0.05).
Conclusion: Our study demonstrated that COVID-19 has a negative impact on cognitive functions, which becomes more pronounced with advancing age.
Keywords: Cognition, COVID-19, event-related potentials, N200, P300