Abstract
Following the beginning of the COVID-19 pandemic in 2019, nearly half of the population of
New Zealand has tested positive for the virus. Persistent symptoms of “brain fog” suggest
that COVID-19 may impact the brain, however research into how brain activity is affected
following infection is limited, especially in young populations who often report mild
infections. The present study therefore aimed to investigate differences in neuropsychological
performance and haemodynamic activity as a measure of brain function following COVID-19
infection and brain fog as a symptom in young adults. A control group of 19 undergraduate
students who had not previously tested positive for COVID-19 (M = 21 years, SD = 6, range
= 18 – 46) and a group of 75 who had previously tested positive for COVID-19 (M = 20
years, SD = 2, range = 18 – 31) answered a range of questions relating to their experiences
with COVID-19 infection, before having cerebral haemodynamic activity recorded using
Near Infrared Spectroscopy (NIRS) during completion of a neurocognitive battery. Contrary
to what was hypothesised cognitive impairments were not seen in the COVID-19 group,
including when they were separated based on experiences of brain fog, however those in the
COVID-19 group did self-report as more tense, with ratings numerically higher again if they
reported brain fog. Decreases in haemodynamic correlates of anterior prefrontal cortex
activity were closer to participants’ baseline recordings in the COVID-19 group as was
predicted, and for those who experienced brain fog during their infection there was an
increase from baseline similar to the pattern previously seen in older adults. These results
suggest that haemodynamic activity differs in those who have had COVID-19, especially if
they also experienced brain fog, leading to compensation for neurocognitive impairments.
These results suggest that while younger adults often do not appear to be severely affected by COVID-19, there may be more underlying impacts to their brain functioning.