CTE & Car Accidents: What NFL Research Means for Crash Victims
Decades of NFL concussion research have proven that repeated brain trauma causes lasting damage. Car accidents produce the same forces.
Chronic Traumatic Encephalopathy (CTE) is a progressive brain disease caused by repeated head trauma. Research from the Boston University CTE Center has found CTE in over 91% of former NFL players examined. CTE is not limited to athletes. Car accidents produce the same types of brain trauma: concussions and repeated sub-concussive impacts that trigger abnormal tau protein buildup. A person with a prior concussion from any cause faces elevated risk when a new crash causes another brain injury.
How the NFL Changed What We Know About Brain Trauma
The connection between repeated head trauma and long-term brain disease was not widely accepted until NFL research forced it into the open. The timeline spans more than two decades.
2002–2005
Dr. Omalu’s Discovery
Forensic pathologist Dr. Bennet Omalu examined the brain of Pittsburgh Steelers center Mike Webster and discovered abnormal tau protein deposits. He published his findings in Neurosurgery in 2005.
2005–2009
NFL Denial
The NFL’s Mild Traumatic Brain Injury Committee disputed Omalu’s findings. In 2009, Congressional hearings compared the NFL’s response to the tobacco industry’s denial of cancer risks.
2012
Junior Seau
Former San Diego Chargers linebacker Junior Seau died by suicide. The National Institutes of Health confirmed CTE in his brain tissue.
2015
NFL Settlement
The NFL agreed to a settlement fund exceeding one billion dollars for former players diagnosed with neurodegenerative diseases linked to repeated head trauma.
2017
Aaron Hernandez
Former New England Patriots tight end Aaron Hernandez was diagnosed posthumously with Stage III CTE at age 27, one of the most severe cases ever found in someone that young.
2023
BU CTE Center Study
A study led by Dr. Ann McKee at Boston University found CTE in 345 of 376 former NFL players examined, a rate of 91.7%.
What CTE Does to the Brain
CTE is caused by abnormal accumulations of phosphorylated tau protein in the brain. Tau protein normally stabilizes brain cell structure. After repeated impacts, tau proteins become misfolded and clump together, killing surrounding brain cells. The disease progresses through four stages.
Research published in Nature (2025) from Harvard Medical School and Boston University found that CTE involves DNA damage similar to Alzheimer’s disease, with immune system activation playing a key role in determining who develops the disease after repeated impacts.
Why This Research Matters for Car Accident Victims
CTE is not limited to professional athletes. The Boston University CTE Center has documented CTE in individuals with head trauma from military service, intimate partner violence, and other non-sports sources. The mechanism is the same: repeated impacts to the brain cause progressive tau protein accumulation.
Car accidents produce significant forces on the brain. A rear-end collision at moderate speed generates enough force to cause a concussion, even when the occupant is restrained. For someone who has had a prior concussion from any cause (sports, a fall, a previous crash), a new impact compounds the damage.
Second-impact syndrome occurs when a person sustains a new concussion before fully recovering from a prior one. The brain swells rapidly and the results can be catastrophic. Even without full second-impact syndrome, cumulative brain trauma from multiple concussions over a lifetime creates compounding risk that no single event captures on its own.
A BU-led study found that individuals with repetitive head impact exposure showed an average 56% loss of certain frontal neocortex neurons, along with vascular dysfunction and inflammatory responses, even without the classic tau protein markers. Sub-concussive impacts, not just diagnosed concussions, drive this damage.
What This Means for Your Car Accident Claim
If you had a prior concussion and a car accident caused another brain injury, the cumulative effect matters. A traumatic brain injury that might have resolved in weeks for someone with no prior history can produce lasting cognitive problems for someone with a history of head trauma.
Insurance adjusters treat each crash as an isolated event. They do not account for cumulative brain trauma. They will argue that your current symptoms are from the prior injury, not the crash. The medical research tells a different story: each new impact adds to the total damage, and the crash that pushes someone past a threshold is fully compensable.
Why Concussions Are Not Minor Injuries
A concussion is a traumatic brain injury. The idea that a concussion is “just getting your bell rung” is exactly the thinking the NFL used for decades before the science forced a reckoning. The same research that changed how the NFL treats head injuries applies to car accident victims. Every concussion matters. Every impact adds up.
At Sam Aguiar Injury Lawyers, we work with neurologists and neuropsychologists who understand cumulative brain trauma. We document not just the current injury, but the full history of head impacts, because that context is what makes the case.
Frequently Asked Questions
Can a car accident cause CTE?
CTE is caused by repeated head trauma, not a single event. A car accident that causes a concussion adds to a person’s cumulative brain trauma history. For someone with prior concussions from sports, falls, or previous crashes, a new car accident concussion increases the total damage. The Boston University CTE Center has documented CTE in individuals with non-sports head trauma.
Can CTE be diagnosed while a person is alive?
As of 2026, CTE can only be confirmed through post-mortem brain tissue examination. However, researchers at Boston University and the National Institutes of Health are developing biomarker and PET scan methods that may allow in-vivo diagnosis in the future.
What is second-impact syndrome?
Second-impact syndrome occurs when a person sustains a new concussion before fully recovering from a prior one. The brain can swell rapidly, with potentially fatal results. Even without full second-impact syndrome, a second concussion during the recovery window compounds the damage from the first.
How did the NFL concussion crisis start?
In 2002, Dr. Bennet Omalu discovered abnormal tau protein deposits in the brain of deceased Pittsburgh Steelers center Mike Webster. He published his findings in Neurosurgery in 2005. The NFL initially denied the connection. Congressional hearings in 2009 and continued research eventually forced the league to acknowledge the link between repeated head impacts and long-term brain disease.
Does a prior concussion affect my car accident claim?
Yes. A prior concussion makes your brain more vulnerable to further injury. If a car accident causes a new concussion, the cumulative effect may produce symptoms more severe than either event alone. Under Kentucky’s eggshell plaintiff doctrine, the at-fault driver takes you as they find you, including your history of prior brain trauma.
What research supports the link between CTE and repeated impacts?
The most comprehensive research comes from the Boston University CTE Center, which has examined hundreds of donated brains. A 2023 study led by Dr. Ann McKee found CTE in 91.7% of former NFL players examined. Additional research published in Nature has identified DNA damage and immune system changes in individuals with repetitive head impact exposure.
What imaging tests detect brain damage from repeated concussions?
Standard CT and MRI scans may appear normal after a concussion. Advanced imaging techniques like diffusion tensor imaging (DTI) and functional MRI (fMRI) can detect changes in white matter and brain connectivity that standard imaging misses. Radiology imaging plays a critical role in documenting brain injuries for car accident claims.