Long-COVID ‘brain fog’ now likened to dementia
LOS ANGELES: “Brain fog” has emerged as one of the most debilitating symptoms of long COVID, affecting thousands of people globally, impeding their ability to work and function in daily life.
Now, a group of Australian scientists believe they are closer to unlocking the mystery behind the lingering neurological condition, which can trigger memory loss, confusion, dizziness and headaches, and leave people grasping to recall everyday words. The findings of their study, published this week in Nature Communications, suggest there may be distinct parallels between the effects of COVID-19 on the brain and the early stages of neurodegenerative diseases such as Alzheimer’s and Parkinson’s.
As part of the study, the researchers – led by Dr Nick Reynolds from the Institute for Molecular Science at Melbourne’s La Trobe University – used computer algorithms to identify small fragments of proteins (called peptides) in SARS-CoV-2. Reynolds and his colleagues could then study these peptides in the lab, observing they had formed clumps, mirroring amyloid plaques found in the brain in the early stages of neurodegenerative diseases like Alzheimer’s and dementia.
“What we saw is that they formed very similar amyloid clumps, which are basically just ordered assemblies of protein that are stuck together and considered ‘molecular hallmarks’ of the early stages of neurodegenerative disease,” he said. “To cut a long story short, these amyloid plaques are very toxic to the brain cells and we hypothesise that aggregates of SARS-CoV-2 proteins may trigger neurological symptoms in COVID-19 that many of us call brain fog.”
If this is confirmed in future studies, Reynolds believes drugs developed to combat Alzheimer’s and Parkinson’s could be repurposed to revolutionise treatment for the debilitating neurological symptoms of long COVID.
“If brain fog is being caused by these amyloid clumps, then there is 30 years of drug development into neurodegenerative disease, which can now be relooked at in the context of COVID-19,” he said. “Drugs which didn’t quite have a strong enough efficacy to work against very serious and irreversible diseases like Alzheimer’s might have a much better success with brain fog-type symptoms.”
The Australian-first study is part of an emerging body of research that suggests there are similarities in the mechanisms of post-COVID cognitive changes and other long-studied brain conditions, including Alzheimer’s, Parkinson’s and dementia. Earlier this year, a study found COVID-19 may cause greater loss of grey matter and tissue damage in the brain than naturally occurs in people who have not been infected with the coronavirus.
The study, published in the scientific journal Nature, was believed to be the first involving people who underwent brain scans before they contracted coronavirus and in the months after. It examined the brains of more than 400 people aged 51 to 81, finding shrinkage and tissue damage primarily in areas related to sense of smell but also in areas involved in other brain functions, the researchers said.
However, neurological experts cautioned that the implications of the changes were unclear and did not necessarily suggest people might have lasting damage. The new study’s findings were welcomed by Professor Carol Hodgson, from Monash University’s School of Public Health, who led an Australian-first study of long COVID in 200 people admitted to intensive-care wards with COVID-19. A third of those patients had cognitive dysfunction six months later. Hodgson said brain fog was one of the most distressing aspects of long COVID and was difficult to treat.
Reynolds said that while the findings of the Melbourne study were exciting, research into coronavirus-induced brain fog is in “its very early stages”.