For one in five Americans who experienced COVID-19, the disease never went away. The symptoms of long COVID—brain fog, fatigue, headaches, chest pain, even digestive problems—affect thousands every day. But University of Denver researchers have uncovered similarities between long COVID and traumatic brain injury (TBI)—findings that offer hope for better treatments.
Last year, Daniel Linseman, a professor in the College of Natural Sciences and Mathematics who runs the Linseman Laboratory, and Allison Grossberg, a fourth-year doctoral student in the cellular and molecular biology program, began studying the symptoms of individuals in three categories: those with a history of TBI but not COVID; those who have had COVID but no TBI history; and those with a history of both.
Linseman and Grossberg wanted to determine whether individuals in the last group have worsened long-term neurological and psychological symptoms, increased inflammation, or an increased risk of neurodegenerative disease and/or autoimmunity.
“We’ve known for a while that brain injury produces a strong inflammatory response,” says Grossberg, who is leading the study. “Why would this be any different for infection?”
So far, the lab has preliminary data for 48 of the study’s participants, collected through a yearly visit in which participants complete a cognitive assessment and a detailed questionnaire and have their blood drawn to check biomarkers.
The findings may change over the five-year study as more participants are recruited, but, Linseman and Grossberg say, the preliminary data is clear: Those with a history of COVID-19 and TBI reported more severe long COVID symptoms, a higher symptom burden and more frequent symptoms, even if it’s been decades since their brain injury.
When the study began, the scientists anticipated that older people with a history of concussions would report the worst long COVID symptoms. So far in their findings, the opposite is true. That leads Linseman to think that the immune system and neuroinflammation are contributing to the symptomology. “The biggest difference between older and younger people is that younger people have a more robust immune system,” he says.
If the Linseman/Grossberg hypothesis is correct, and there’s a neuroinflammatory pathway that’s upended by COVID and TBI, researchers can start to explore potential treatments, particularly one that inhibits the inflammatory pathway.