By Stephen Beech via SWNS
The brain “fog” people suffering from long Covid describe is linked to the lungs, suggests a new study.
Researchers found that lower pulmonary gas exchange may be associated with difficulty concentrating in people suffering from the long-term effects of the virus.
Around one in six adults have experienced a post-Covid condition, referred to as long Covid.
People with long Covid experience a range of symptoms, including problems concentrating sometimes referred to as “brain fog,” change in sense of smell or taste, fatigue, joint or muscle pain, shortness of breath, and digestive issues.
The symptoms may persist for weeks, months, or even years following the initial Covid infection.
Researchers at the University of Iowa set out to assess associations between pulmonary MRI gas exchange, structural and functional brain MRI, and brain function in long Covid patients.
They explained that, in pulmonary gas exchange, oxygen moves from the lungs to the bloodstream, while carbon dioxide moves from the bloodstream to the lungs.
Study lead author Keegan Staab said: “This is the first time that MRI has been used to jointly assess lung and brain function to investigate their relationship in long Covid.
“This research is new in that it combines multiple unique imaging types to study a multiorgan relationship in a disease population.”
Study senior author Dr. Sean Fain said: “If these findings can be generalized to the long Covid population, the study suggests that there may be a causative relationship between cognitive dysfunction and lung dysfunction, suggesting a potential treatment strategy using methods that target improved gas exchange.”
Ten women and two men with an average age of 59 who had persistent shortness of breath or fatigue following acute Covid infection were recruited for the study and underwent a series of brain and lung scans.
Staab, a graduate research assistant in the Department of Radiology at the University of Iowa, explained that 129Xe MRI allows for advanced measurements of ventilation and gas exchange.
He said: “The literature also indicates that 129Xe may be more sensitive to pulmonary injury compared to standard breathing tests, making it better suited to study long Covid in which patients typically have normal breathing tests.”
Perceived cognitive difficulties were measured, and objective cognitive performance was also assessed.
Staab said: “There was a range of cognitive difficulties among the patients in the study.
“Some were mild and indicated slight dysfunction, while others were more serious and indicated that some patients have slow thinking and trouble concentrating several times per day.”
The results showed that lower pulmonary gas exchange may be associated with cognitive dysfunction, as well as lower gray matter and white matter volumes in patients with long Covid.
The research team also observed “significant” relationships suggesting that increased cerebral blood flow is associated with decreased gas exchange in long Covid patients.
Staab says larger studies are needed to investigate the association between gas exchange and cerebral blood flow in long Covid.
He added: “This relationship could be a compensatory mechanism where lower lung function is compensated by higher cardiac output and higher brain perfusion.
“It’s also a possibility that the disease mechanism that impairs pulmonary gas exchange also leads to higher brain perfusion through downstream vascular injury in both lung and brain.”
The researchers say their findings, due to be presented next week at the annual meeting of the Radiological Society of North America (RSNA) in Chicago, suggest gas exchange abnormalities may help identify long Covid patients who require additional treatment or long-term management.
