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A study has found that even mild cases of COVID-19 can cause structural changes in brain regions related to memory and smell.
On the 7th local time, a research team led by Professor Gwenel Duwood of Oxford University, UK, announced in the international scientific journal Nature that "even with mild COVID-19, there was tissue damage and size reduction in olfactory and cognitive-related brain regions."
The research team reached this conclusion as a result of comparing the brain MRI (magnetic resonance imaging) of the corona 19 confirmed patients before and after the diagnosis.
The study participants were elderly people aged 51 to 81 who participated in the UK health database project 'Biobank', which started in 2012, and among them, 401 patients with COVID-19 were hospitalized as those diagnosed with COVID-19 between March 2020 and April 2021. All but 15 were mild.
The researchers compared their brains with MRI before infection with COVID-19 and 4.5 months after infection, and compared them with non-infected individuals with similar age, health status, and social and economic background.
As a result, it was found that the gray matter in the brain regions responsible for memory, smell, and cognition decreased significantly in the infected than in the uninfected.
In the case of healthy people, gray matter decreases by 0.2~0.3% every year as they get older, and it was confirmed that the gray matter of Corona 19 confirmed patients decreased by 0.2~2% more than non-infected people.
In addition, in the brains of confirmed COVID-19 patients, the thickness of gray matter in the orbitofrontal cortex and hippocampal gyrus, which are areas related to smell and memory, became thinner, and various changes such as damage to the olfactory cortex area and a general decrease in brain size were observed.
It was found that people with significantly reduced gray matter had poorer test scores for diagnosing dementia-related cognitive impairment, and the degree of brain area reduction was greater with age.
Professor Duwood, who conducted the study, said, "It was very surprising that the changes in the brain were evident even in mild patients." He explained that the effect is mostly in the olfactory-related areas, but the reason is not clear.
He added, "The abnormal changes observed in the brain are likely to decrease as the sense of smell is restored over time."
This study was evaluated as meaningful in that it compared brain data collected unrelated to COVID-19 with data tracked after the COVID-19 outbreak, but Dr. "It may be that the brain is affected by immunity, inflammation, blood vessels, psychological/behavioral changes, etc., rather than being infected with COVID-19. What this study showed is the effect of nerve changes, but it does not explain the mechanism of cognitive change caused by Corona." pointed out.
Those who participated in the study also said, "Most of the participants suffered from mild COVID-19, but gray matter loss and tissue damage were observed." But "The results of this study will not be generalized to all infected people. Further investigations are needed on brain regions that are more vulnerable to COVID-19." do,” he explained.
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