Even Mild Covid-19 Causes Brain Damage
New findings could lead to a better understanding of how the brain ages, normally and otherwise
Normal aging comes with some loss of gray matter, the stuff in the brain where neurons process information. But new brain imaging reveals that Covid-19 accelerates that process in some parts of the brain, reducing the volume of gray matter and affecting thought processing.
While it’s not yet clear if the damage will prove lasting, the results along with further study could eventually help scientists better understand normal brain aging, the damage that causes dementia, and the extent to which such damage can be prevented or reversed.
Among the key findings:
- People who’d had Covid-19 lost more gray matter, on average, compared with people who had not been infected. The atrophy was most evident in the cerebellum, and brain structure linked to cognition.
- Those with Covid-19 also did worse on cognitive tests, involving complex tasks, after their recovery compared to those who had not contracted the disease.
- The results held true even for people with relatively mild Covid-19 symptoms.
- Damage included areas related to the sense of smell, which can also be affected by Alzheimer’s disease, the most common form of dementia.
- The older the person, the greater the effect.
Will the damage last?
The study, detailed this week in the journal Nature, involved 785 U.K. residents ages 51 to 81 who had already been participating in an ongoing research project, so their brains were imaged pre-Covid-19, allowing before-and-after comparisons among roughly half of them who caught the coronavirus and half who did not.
Previous research had shown Covid-19 can damage the brain, but most of it involved patients with severe cases. In this new study, the majority of the Covid-19 patients had mild symptoms. Their brains were imaged on average 4.5 months after recovery. The loss of gray matter was between 0.2% and 2% more than what was seen in people who had not had Covid-19.