The long-term experiment, which involved 782 volunteers, compared brain scans of individuals before the pandemic. For an analogy between pre-pandemic and post-pandemic brain scans, researchers then invited 394 COVID-19 survivors to return for follow-up scans, as well as 388 healthy volunteers.
Among those participants who recovered from COVID-19, researchers saw significant effects of the virus on human cerebral matter, with a loss of gray matter in regions of the brain.
It should be noted that the study has yet to undergo rigorous peer review.
The authors wrote: "Our findings thus consistently relate to loss of grey matter in limbic cortical areas directly linked to the primary olfactory and gustatory system," or areas in the brain related to the perception of senses such as smell and taste.
The gray matter in our brains is part of our central nervous system and essentially controls all our brain's functions, as previously reported by Insider.
It enables individuals to control movement, memory, and emotions, so an abnormality in the gray matter of the brain can affect communication skills and brain cells.
The study also suggests that a loss of gray matter in memory-related regions of the brain "may in turn increase the risk of these patients of developing dementia in the longer term."
This finding follows a study published by Lancet Psychiatry journal last year, suggesting that serious infections of COVID-19 may damage the brain leading to long-term complications such as stroke or dementia-like symptoms. The authors noted that more data is needed to adequately assess the effects of COVID-19 on brain health, though.
Most of the COVID-19 survivors involved in the research experienced mild-to-moderate symptoms or had none at all. This was viewed as a strength of the analysis, as most brain-imaging publications have focused on moderate-to-severe cases of COVID-19.
"There is a fundamental need for more information on the cerebral effects of the disease even in its mildest form," the Biobank study read.
It is important to note, however, that changes in the brain were not seen in the group that had not been infected, as reported by Reuters. The authors of the study said more research is needed to determine whether COVID-19 survivors will have issues in the long-term regarding their ability to remember emotion-evoking events.
They also cannot confirm whether the loss of gray matter is a result of the virus spreading into the brain, or some other effect of the illness, per Reuters.
This article was originally published by Business Insider.
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