Even mild COVID cases can result in brain damage and shrinkage
Key Takeaways:
- Even mild COVID-19 infections can cause brain damage and shrinkage, especially in areas that control the sense of smell and memory processing.
- The study had flaws, which Douaud pointed out and said indicated the need for more in-depth research.
As per the study, even mild cases of COVID-19 can cause brain damage and shrinkage, particularly in areas that control the sense of smell and memory processing.
The researchers from the University of Oxford discovered that the virus was linked to a greater loss of grey matter as well as tissue damage than what would normally occur with ageing.
The study, issued in the journal Nature on Monday, looked at brain scans from 401 people aged 51 to 81, both before and after they contracted COVID-19. Only 15 people were hospitalized with more serious illnesses because they had mild virus cases.
The scans were compared to 284 people who did not test positive for COVID-19. Still, they had related rates of obesity, smoking, diabetes, blood pressure, and similar age, sex, and socioeconomic status.
The researchers discovered that those with COVID-19 had significantly more brain tissue loss and shrinkage. Normal ageing causes people to lose 0.2-0.3 percent of their grey matter each year, but those with COVID-19 lost up to 2%. They also suffered more tissue damage and lost more overall brain volume.
Gwenalle Douaud, an assistant professor at Oxford's Nuffield Department of Clinical Neurosciences as well as the paper's lead author, told NBC News that the harm was equivalent to at least an additional year of ageing.
"It's brain damage, but it might be reversible," she explained. "However, it is still frightening because it was found in people who were only mildly infected."
Researchers believe that changes in the areas of the brain that control smell and memory processing might explain some long-term COVID symptoms like loss of smell and taste and brain fog.
The study had flaws, which Douaud noted and said indicated the need for more comprehensive research. They only gave the patients basic cognitive testing to see how they did on memory tests, as well as the scans were only done up to about five months after the COVID-19 infection, so the brain damage may have improved by then.
Even with the most basic memory tests, they noticed a difference in the amount of brain damage that occurred due to age.
COVID-19 infected people performed equally to those who did not contract the virus in their 50s and early 60s, but the gap widened significantly after that.
"I'm not sure if it's because younger people recover faster or because they were less affected, to begin with," Douaud told The New York Times. "It could be either or both," says the narrator.