People with long Covid accompanied with neurological symptoms such as brain fog have less activity in certain brain regions normally used for memory tasks, revealed a study. The study, published in the journal ‘Neurology’, also showed that people with long Covid have poorer scores on tests of dexterity and motor endurance than those without Covid. They also report more negative feelings, such as anger and sadness, and higher levels of stress, and they have lower scores for life satisfaction compared to those who never had Covid.

In addition, they have higher scores for depression, anxiety, fatigue, and pain than the control group. People in the post-Covid group who have greater changes in their brain activity are more likely to have poorer scores in many of these symptom domains. These patients could benefit from neurorehabilitation or psychiatric treatments, and the researchers recommend that doctors consider these approaches to help manage this condition.

“The greater activity occurred outside of the normal working memory brain network. We often see such changes in patients with a brain injury: Deficits in the default mode network of the brain leads to an increase in activity in other regions to help maintain brain function,” said Linda Chang, professor of diagnostic radiology and nuclear medicine at the University of Maryland School of Medicine (UMSOM).

“While our study doesn`t prove that Covid caused these brain changes, there appears to be a strong association with these changes and lingering neuropsychiatric symptoms,” she added.

For the study, the team performed functional magnetic resonance imaging (MRI) scans on 29 patients who had Covid an average of seven months earlier and had at least one ongoing neuropsychiatric symptom like memory loss, depression, or anxiety.

Nine of these study participants had Covid infection severe enough to require prior hospitalisation. The researchers also conducted brain imaging scans in 21 healthy volunteers who had no history of Covid and were of similar age, health status and vaccination status to those with long Covid.

All the participants had tests for thinking and memory skills, emotional health, motor function, as well as measures for symptoms of depression, anxiety, fatigue, and pain.

“Even though the majority of the people who had Covid in our study reported ongoing problems with concentration and memory, they had scores on various tests for thinking skills that were similar to those who had no history of Covid,” Chang said, adding, “This could be because their brains were compensating for these deficits by using more of other parts of their networks to maintain their performance.”

“While the study provides crucial information on brain function in those who suffer neuropsychiatric symptoms from long Covid, we now need longitudinal follow-up studies to determine whether or when these abnormal imaging patterns will normalise and whether that correlates to a resolution in symptoms,” added Mark T. Gladwin, Dean, UMSOM.