Summary: In former college and professional football players, higher levels of inflammation were linked to measurable changes in brain white matter, particularly within limbic pathways, and those structural changes were associated with poorer memory performance. Blood and cerebrospinal fluid markers of inflammation correlated with reduced white matter integrity in regions that support emotion, memory and behavior. While inflammation was not directly tied to cognitive scores, the pattern of associations suggests a biological pathway that could connect repetitive head impacts to later-life cognitive and neurobehavioral symptoms.
Key Findings
- Inflammation and brain structure: Elevated inflammatory biomarkers were associated with poorer white matter microstructure in limbic system tracts.
- Memory link mediated by structure: White matter disruption, not inflammation alone, was associated with worse memory performance.
- Stronger effects in highest-risk players: Associations were most pronounced among players with the greatest exposure to head impacts and the most severe symptom profiles.
- High prevalence of symptoms among players: In this sample of former football players, 59% showed cognitive impairment and 58% had neurobehavioral dysregulation.
- Association, not causation: The study identifies biologically plausible links but does not establish cause and effect.
The research, published February 25, 2026 in Neurology, used data collected through the DIAGNOSE CTE Research Project. Investigators analyzed a well-characterized cohort of men that included 170 former college or professional football players (average age 57) and 53 control participants without a history of contact sports, military service or concussion (average age 59). The study combined clinical evaluation, fluid biomarkers and advanced brain imaging to explore how inflammation and brain microstructure relate to cognitive outcomes in people with prior repetitive head impacts.
Researchers measured three established inflammatory and glial biomarkers in blood and cerebrospinal fluid: interleukin‑6 (IL‑6), tumor necrosis factor alpha (TNF‑α) and glial fibrillary acidic protein (GFAP). Participants underwent diffusion tensor imaging (DTI), a brain MRI technique that reveals microstructural properties of white matter. The investigators focused on fractional anisotropy (FA), which reflects the directional coherence of water diffusion, and mean diffusivity (MD), which indicates the overall freedom of water movement—both sensitive to white matter integrity.
Analyses showed that, among former football players, higher levels of inflammatory markers were associated with reductions in white matter integrity localized to limbic system pathways. The limbic system comprises a network of structures that regulate memory, emotion, motivation and aspects of behavior. In this sample, worse limbic white matter microstructure related to poorer performance on memory tests, suggesting that structural disruption in these circuits may mediate the relationship between inflammation and cognitive symptoms.
Notably, investigators did not find a direct association between inflammation markers and cognitive scores across the entire sample. Instead, the data supported a mediated pathway: inflammation linked to altered white matter microstructure, and those structural changes were associated with memory impairment. The magnitude of these associations increased when analysis was restricted to a subgroup of 57 players considered most likely to have chronic traumatic encephalopathy (CTE) based on symptom severity and level of head-impact exposure.
“Previous work has shown that repetitive head impacts in contact sports can raise the risk for neurodegenerative conditions such as CTE, but the biological steps between those impacts and later-life symptoms have remained unclear,” said Breton M. Asken, PhD, of the University of Florida. “Our findings point to inflammation and limbic white matter microstructure as parts of a pathway that could help explain how repetitive head injury leads to memory and behavioral problems.”
There are important limitations. The study cohort consisted only of male athletes who played American football, so the results may not generalize to women, athletes in other contact sports, or players at lower levels of competition. Also, because the diagnosis of CTE requires postmortem confirmation, researchers used clinical criteria for traumatic encephalopathy syndrome to identify participants at higher risk; this approach cannot substitute for neuropathological confirmation. Finally, the cross-sectional nature of these analyses limits causal inference—longitudinal work will be needed to determine whether inflammation precedes progressive white matter decline and cognitive worsening.
Funding: The DIAGNOSE CTE Research Project received support from the National Institute of Neurological Disorders and Stroke.
Key Questions Answered
Q: What brain pathway links inflammation to memory problems in former football players?
A: The study identified reduced white matter integrity in limbic system pathways as the structural link: higher inflammation correlated with limbic white matter disruption, which in turn correlated with worse memory.
Q: Did inflammation directly cause cognitive decline?
A: No. The study found no direct association between inflammatory markers and cognitive test scores; rather, inflammation related to structural brain changes that were associated with poorer memory.
Q: Why are these findings relevant for understanding CTE risk?
A: The findings suggest inflammation may be a biological step between repetitive head impacts and later brain changes associated with CTE-like symptoms, indicating a potential target for monitoring or therapeutic intervention in future research.
Editorial Notes
- This article was edited by a Neuroscience News editor.
- The journal article was reviewed in full by the editorial team.
- Additional context and clarity were added by staff to summarize the study methods and implications.
About this neurology research news
Author: Renee Tessman
Source: AAN (American Academy of Neurology)
Contact: Renee Tessman – AAN
Image credit: Neuroscience News
Original research: The findings reported here will appear in Neurology.