Long COVID affects brain's microstructure

We’re going to take a closer look at Long COVID now, and I mean really close. Long COVID is an umbrella term for various clusters of symptoms which can affect people long after infection with COVID-19 in different ways. It’s for this reason the physiology of the condition - what’s actually going on inside the body - is so poorly understood.

One of these clusters of symptoms is neurological: fatigue, brain fog, and loss of taste or smell. Using a special type of MRI which allows scientists to zoom in on the layout of our brains to the tiniest of scales, Alexander Rau from the University Hospital Freiburg was able to identify unique microstructural changes to the brains of people suffering from the neurological symptoms of Long COVID. This could be crucial for developing treatments for those suffering with the condition.

James Tytko spoke with the University of Cambridge’s Stephanie Brown to hear more…

Stephanie - What they saw is that COVID-19 infection induced a very specific pattern of microstructural changes in various brain regions and that this pattern differed between those who had Long COVID and those who did not. So the results showed that there was no brain volume loss, or any other lesions - i.e. changes to macrostructure - that might explain the symptoms of Long COVID, but when we look deeper into the microstructural changes, they did find these symptom specific brain networks associated with impaired cognition, sense of smell and fatigue. So it looks like these changes to the network and the microstructure of the tissue is very specific to Long COVID.

James - So how might we interpret that? What might be causing microstructural changes in the brain of people who've contracted COVID and what might the pathology be? Are there any theories?

Stephanie - That is a very interesting question and I'm sure that's something that the research community looking at Long COVID will be really interested in finding more about. There are theories and I will speak very broadly about this. One would be the amount of water in the tissue, and what that means is there's potentially inflammatory processes which are causing oedema in the tissue. Then, we've got things like neuronal myelination. Basically, the myelin sheath surrounds and protects the neuron so, if that becomes damaged, then that can obviously have some negative effects on brain health.

James - A lot of work to be done, then, and on just one aspect to the whole issue of Long COVID which sadly seems like it's going to be with us for a long time yet to come.

Stephanie - Yes, I think so. Going on the recent numbers and projected people who may be affected by this, it's certainly worrying. I think Long COVID researchers do agree that it's a very broad and difficult syndrome to treat and a mix of treatments will probably be needed.