The Effects of Covid-19 “brain Fog” on Electrophysiological Measures of Attention and Working Memory: a P300 Study

COVID-19 has led to significant global health impacts, with over 776 million confirmed cases worldwide. While it is primarily known for respiratory symptoms, COVID-19 has also been linked to cognitive impairments, particularly "brain fog," which affects attention, memory, and processing speed. The long-term effects, especially in non-hospitalized individuals, remain poorly understood. Brain fog affects the hippocampus and prefrontal cortex, regions responsible for generating the P300, an electrophysiological measure of attention and working memory. The P300 has been used to assess cognitive deficits in various neurological conditions, though rarely in COVID-19. A dual-task paradigm, such as the n-back task, can help detect subtle cognitive impairments. This study compared P300 responses in three groups: individuals with COVID-19 and brain fog, individuals with COVID-19 but no brain fog, and a control group (pre-pandemic). We hypothesized that the brain fog group would show reduced P300 amplitudes, especially under higher n-back loads. Results showed that the brain fog group had smaller P300 amplitudes compared to the other two groups, regardless of task load. No significant differences were found between the brain fog negative and control groups, nor in behavioral measures. These findings suggest that the P300 is a sensitive tool for detecting subtle cognitive impairments in COVID-19 brain fog, which may not be evident in behavioral tests.