In football players with repeated head impacts, inflammation related to brain changes

EMBARGOED FOR RELEASE UNTIL 4:00 P.M. ET, WEDNESDAY, FEBRUARY 25, 2026

Highlights:

A new study of former American football players looked at how a history of repetitive head impacts may be associated with cognitive and behavioral symptoms later in life. Researchers found higher levels of inflammation were associated with worse brain structure, which in turn was associated with poorer memory. The study does not prove cause and effect. It only shows associations. MINNEAPOLIS — In former college and professional football players, a new study has found higher levels of inflammation were associated with worse brain structure, which in turn was related to worse memory. The study was published February 25, 2026, in Neurology®, the medical journal of the American Academy of Neurology. The study does not prove cause and effect; it only shows associations.

Repetitive head impacts are multiple jolts to the head that may not cause symptoms right away but could cause brain problems over time. These impacts can increase the risk of chronic traumatic encephalopathy (CTE), a neurodegenerative disease that can lead to cognitive changes and dementia.

“Experiencing repetitive head impacts during contact sports like American football has been found in previous research to increase the risk for neurodegenerative diseases like CTE,” said study author Breton M. Asken, PhD, of the University of Florida in Gainesville. “However, the paths linking these head impacts to symptoms later in life are not well understood. Our study found that higher levels of inflammation were associated with brain changes that were, in turn, related to poorer cognition.”

The study was conducted using data from the Diagnostics, Imaging, and Genetics Network for the Objective Study and Evaluation of CTE (DIAGNOSE CTE) Research Project. It involved 223 male participants, including 170 who played college or professional football with an average age of 57, and 53 who had no history of contact sports, military service or concussion with an average age of 59.

Researchers measured participants’ levels of three biomarkers in the blood and spinal fluid related to inflammation: interleukin-6, tumor necrosis factor alpha and glial fibrillary acidic protein. Participants had brain scans to evaluate brain structure. Researchers used the scans to measure fractional anisotropy, the direction of water movement in the brain, and mean diffusivity, how freely water moves through the brain.

Since CTE can be confirmed only in autopsy, participants were also evaluated for traumatic encephalopathy syndrome, symptoms associated with potential CTE. Of football players in the study, 59% had cognitive impairment and 58% had neurobehavioral dysregulation, an impaired ability to manage emotions and behavior. Participants who were not football players reported that they had no cognitive concerns, and few, 2%, reported they had neurobehavioral dysregulation.

Researchers found in football players, higher levels of inflammation biomarkers were associated with worse microstructure in the white matter of the brain, specifically the limbic system. The limbic system is a set of brain structures that regulate emotions, motivation, memory, and other behaviors.

Inflammation was more strongly related to worse brain microstructure in football players than in those who did not play football.

Researchers then found that worse brain microstructure in football players was, in turn, associated with worse memory. However, they found no direct link between inflammation and cognition.

When researchers looked at a subgroup of 57 football players who were considered most likely to have CTE based on the severity of their symptoms and amount of head impact exposure, most of the associations were stronger.

“Because the limbic system influences both cognition and behavior, targeting inflammation could offer a way to potentially reduce the risk for developing brain changes that lead to worsening symptoms associated with repetitive head injuries,” said Asken. “We are excited to continue to explore this path in future research.”

A limitation of the study was it looked at male athletes who played football, so the results may not be the same for female athletes, athletes in other contact sports or at lower levels of play.

The DIAGNOSE CTE Research Project was supported by the National Institute of Neurological Disorders and Stroke.

Discover more about brain health at Brain & Life®, from the American Academy of Neurology. This resource offers a website, podcast, and books that connect patients, caregivers and anyone interested in brain health with the most trusted information, straight from the world’s leading experts in brain health. Follow Brain & Life® on Facebook, X, and Instagram.

The American Academy of Neurology is the leading voice in brain health. As the world’s largest association of neurologists and neuroscience professionals with more than 44,000 members, the AAN provides access to the latest news, science and research affecting neurology for patients, caregivers, physicians and professionals alike. The AAN’s mission is to enhance member career fulfillment and promote brain health for all. A neurologist is a doctor who specializes in the diagnosis, care and treatment of brain, spinal cord and nervous system diseases such as Alzheimer's disease, stroke, concussion, epilepsy, Parkinson's disease, multiple sclerosis, headache and migraine.

Explore the latest in neurological disease and brain health, from the minds at the AAN at AAN.com or find us on Facebook, X, Instagram, LinkedIn, and YouTube.

END