Mild cases of COVID-19 are associated with significant brain changes, especially in older adults, an unusual study of pre- and post-infection brain scans finds.
Investigators examined brain scan images in 785 United Kingdom Biobank participants aged 51 to 81 years, including 400 who experienced a mild case of SARS-CoV-2 infection. The researchers compared pre-diagnosis scans of these patients with second scans taken about five months after COVID-19 diagnosis.
When compared to brain images of their peers who were not infected, the patients who had recovered from COVID-19 had tissue damage, reported neuroscientist Gwenaëlle Douaud, Ph.D., of Oxford University. This included notable shrinkage in brain areas related to smell, and a reduction in overall brain size.
Based on cognitive tests, the participants who were infected with SARS-CoV-2 also had greater cognitive decline between their two scans. This reduction in mental ability was partly related to the brain abnormalities seen in the scans, according to the results of an additional research conducted by Douaud and colleagues.
All of the negative effects shown were more pronounced in older participants, she added. Whether these problems and the damage done is permanent remains unclear.
“A key question for future brain imaging studies is to see if this brain tissue damage resolves over the longer term,” Douaud concluded.
Many COVID-19 brain imaging studies to date have followed patients with severe disease and have no pre-diagnosis scan for comparison, the researchers noted. The current study gives clinicians and researchers better insight into the neurological effects of the disease, they said.
Full findings were published in the journal Nature.