COVID-19 may cause long-term loss in gray matter and other brain tissues, according to a new study by UK Biobank.
The UK Biobank scanned over 40,000 participants before the COVD-19 pandemic and invited back hundreds of imaged participants for a second visit, with an average of 3 years between visits. 394 of the 782 participants tested positive for COVID-19 between their two scans, and a loss of gray matter surrounding the olfactory and gustatory system (smell and taste respectively) was found.
Most of the those who had recovered from COVID-19 had only mild or moderate symptoms or were asymptomatic.
Three types of structural MRI scans were utilized, as well as both task functional and resting MRI scans. These were performed to assess functional connectivity between brain regions.
Many of the results, specifically loss of gray matter in memory-related regions, were found similar to those associated with Alzheimer's disease and other forms of dementia. This has caused concerns that the long term affects of COVID-19 may include these disorders.
This is one of the first imaging studies where patients were initially scanned before they contracted COVID-19, as well as one of the largest COVID-19 brain imaging study. The study, published on medRxiv, has not yet been peer reviewed.