The cause of head fog after COVID-19 has been found

Until now, doctors understood that patients had changes in the brain after COVID, but they did not know which processes caused cognitive impairment. There was a lack of biological evidence to help diagnose or develop drugs.

The team of Professor Takui Takahashi from the Medical School of the University of Yokohama was able to show for the first time that the “brain fog” is associated with the work of special molecules — AMP receptors (AMPAR). These receptors play a key role in learning and memory by helping neurons exchange signals.

To test their hypothesis, the scientists applied a new imaging method — PET scanning using a special technology [11C]K-2 AMPAR. It allowed us to literally see the activity of receptors in the brain of a living person.

The study involved 30 patients with Long-term COVID and 80 healthy volunteers. All patients with brain fog had an increased density of AMPA receptors in different areas of the brain. Moreover, the higher this density was, the more pronounced the cognitive problems were.

Scientists have also noticed a link between the level of inflammatory processes in the body and the activity of receptors, which indicates a complex mechanism of interaction between inflammation and brain function.

This discovery can be considered a turning point. For the first time, it has been shown that the “brain fog” in Long-term COVID has a clear biological basis and is not a far-fetched symptom. Moreover, researchers now have a potential target for therapy — drugs that regulate the work of AMPA receptors can help alleviate cognitive impairment.

In addition, the developed PET imaging method can be used for diagnosis: it distinguishes patients with Long-term COVID from healthy people with high accuracy.

“Our results clearly show that brain fog is a real clinical condition, not a subjective complaint,— says Professor Takahashi. “We hope that this will encourage medicine to create new diagnostic and therapeutic approaches.”