Dr Bennet Omalu and CTE became closely connected in the history of American football after Omalu examined the brain of former Pittsburgh Steelers centre Mike Webster following Webster’s death in 2002. The examination led to a landmark 2005 medical paper describing chronic traumatic encephalopathy, or CTE, in a retired National Football League player.
Omalu’s contribution came within a much longer medical history. Doctors had recognised chronic neurological deterioration associated with repeated head trauma in boxers decades earlier. His work brought the condition into the medical literature of professional American football and helped begin a new chapter in the study of sport-related brain injury.
The Webster case became one of the most important early moments in a broader investigation of repetitive head impacts, contact sport and long-term neurological disease.
Before American Football: The Earlier History of CTE
The medical history of chronic traumatic brain injury predates the National Football League controversy by many decades.
In 1928, American pathologist Harrison Martland published a paper titled “Punch Drunk”, describing neurological abnormalities among boxers exposed to repeated blows to the head. The syndrome later became known as dementia pugilistica. Subsequent researchers described symptoms including impaired movement, cognitive decline, speech problems and behavioural changes in some people with long histories of repetitive head trauma.
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By the time Bennet Omalu examined Mike Webster in 2002, medicine already recognised that repeated head impacts could be associated with chronic neurological damage.
What made the Webster case significant was that it brought this condition into the world of professional American football.
Bennet Omalu’s Journey to Forensic Pathology
Bennet Ifeakandu Omalu was born in Nigeria in 1968. He studied medicine at the University of Nigeria and later moved to the United States, where he undertook postgraduate medical training.
His professional development included pathology, forensic pathology and neuropathology. By the early 2000s, he was working in forensic pathology in Pittsburgh, Pennsylvania, under Allegheny County medical examiner Cyril Wecht.
Forensic pathology is concerned with determining causes and mechanisms of death through medical investigation, including post-mortem examination. Neuropathology focuses on diseases affecting the brain, spinal cord and nervous system.
Omalu’s background in these areas placed him in the position to investigate the case that would become closely associated with his career.
Mike Webster: An NFL Legend in Decline
Mike Webster was one of the most accomplished offensive linemen in American football history.
The Pittsburgh Steelers selected him in the 1974 NFL Draft. He became the anchor of an offensive line that helped the Steelers dominate professional football during the 1970s.
Webster won four Super Bowl championships with Pittsburgh, was selected to nine Pro Bowls and spent 15 seasons with the Steelers before finishing his playing career with the Kansas City Chiefs. He was inducted into the Pro Football Hall of Fame in 1997.
His years after football were considerably more troubled.
Accounts of Webster’s later life described cognitive difficulties, physical pain and serious personal problems. His decline became part of the wider discussion surrounding the long-term effects of repeated head trauma.
Webster died in Pittsburgh on 24 September 2002, aged 50.
His death led to the autopsy examination in which Omalu participated.
Dr Bennet Omalu and CTE in Mike Webster’s Brain
The examination of Webster’s brain presented an unusual problem.
The brain’s gross appearance did not explain the neurological and behavioural difficulties associated with Webster’s later years. Omalu pursued further microscopic investigation of brain tissue, including immunohistochemical techniques that can reveal abnormal proteins and cellular changes not visible during ordinary examination.
His findings became the basis of a scientific paper written with Steven DeKosky, Ryan Minster, M. Ilyas Kamboh, Ronald Hamilton and Cyril Wecht.
The paper appeared in the July 2005 edition of Neurosurgery.
Its title was direct: “Chronic Traumatic Encephalopathy in a National Football League Player.”
The researchers described neuropathological changes associated with long-term repetitive brain injury.
The paper became the first published report of CTE in an NFL player and gave the condition a new prominence within American football.
A Second NFL Case Expanded the Debate
Omalu and colleagues soon encountered another case.
Former Pittsburgh Steelers offensive lineman Terry Long died in 2005 at the age of 45. Examination of his brain led Omalu’s group to publish a second paper on CTE in a professional American football player.
The article, published in Neurosurgery in 2006, described the second reported case of autopsy-confirmed CTE in a retired professional football player.
The two cases helped draw greater attention to the possible long-term neurological consequences of repeated head impacts in professional football.
Researchers in the years that followed would study larger numbers of former athletes and develop more detailed criteria for identifying the disease.
How CTE Became More Precisely Defined
As research expanded, scientists worked to create consistent standards for identifying CTE.
An important development came through expert meetings supported by the US National Institute of Neurological Disorders and Stroke and the National Institute of Biomedical Imaging and Bioengineering.
The first consensus report, published in 2016, described a distinctive CTE lesion involving abnormal hyperphosphorylated tau protein concentrated around small blood vessels at the depths of cortical sulci.
A second consensus process later refined the criteria and established clearer standards for neuropathological diagnosis.
These developments gave researchers a more consistent framework for identifying CTE and distinguishing it from other disorders involving abnormal tau accumulation.
The field had developed considerably since Webster’s brain was first examined in 2002.
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Repetitive Head Impacts, Not Only Concussions
Another important shift in CTE research has involved the distinction between concussion and repetitive head impacts.
A concussion is a clinical brain injury associated with symptoms and neurological disturbance. Football players, however, can experience numerous head impacts that do not produce a diagnosed concussion.
Researchers have therefore increasingly studied the cumulative effects of repeated impacts over years of participation.
A 2023 study published in Nature Communications analysed 631 deceased former American football players whose brains had been donated for research. Scientists estimated lifetime repetitive head-impact exposure using information derived from helmet accelerometer studies.
Measures incorporating cumulative linear and rotational acceleration showed stronger relationships with CTE pathology than reported concussion counts.
The study added to growing concern about the total number and intensity of head impacts experienced across a playing career, rather than focusing exclusively on recognised concussions.
New Research Into Earlier Brain Changes
Research continued to develop more than two decades after Webster’s death.
In September 2025, a study published in Nature examined younger and middle-aged athletes with histories of repetitive head trauma. Researchers identified neuronal loss, inflammation and changes involving small blood vessels, including in some individuals who did not yet display the characteristic tau pathology used to diagnose CTE.
The findings suggested that brain changes associated with repetitive head impacts may begin before the better known pathological features of CTE become apparent.
A separate NIH-funded study published in 2026 examined 614 brain donors with histories of repetitive head impacts.
Researchers found that severe CTE, particularly stages III and IV, was strongly associated with cognitive impairment, functional decline and dementia. Stage IV disease was associated with a substantially greater likelihood of a dementia diagnosis than brains without CTE.
Milder stages were not associated with the same levels of cognitive impairment or dementia.
The study also found no significant relationship between CTE stage and mood or behavioural symptoms, adding further complexity to the relationship between brain pathology and the psychiatric difficulties sometimes reported among former athletes.
Why Brain Bank Findings Matter
Some of the most important CTE studies have relied on donated brains from former contact-sport athletes.
These collections have allowed researchers to examine the physical changes associated with the disease in detail and to compare patterns across different levels of exposure.
Boston University and other research centres have identified CTE pathology in numerous former football players and other athletes with histories of repetitive head impacts.
The studies have also shown why the long-term effects of collision sports became an important medical and public-health issue.
At the same time, the overall prevalence of CTE among everyone who has played American football remains unknown because donated brains represent only a portion of former players.
Why CTE Is Still Diagnosed After Death
As of 2026, CTE is definitively diagnosed through neuropathological examination of brain tissue after death.
Researchers have developed clinical criteria for a condition called traumatic encephalopathy syndrome, or TES.
The criteria consider substantial exposure to repetitive head impacts, progressive cognitive impairment or neurobehavioural dysregulation and whether another neurological, psychiatric or medical condition better explains the symptoms.
TES is used in research involving living patients, while confirmation of CTE itself still depends on examination of brain tissue after death.
Scientists continue to investigate biomarkers, brain-imaging techniques and other methods that may eventually make diagnosis during life possible.
The Wider Impact on American Football
The medical debate surrounding repeated head trauma expanded rapidly after the early CTE cases involving former NFL players.
Researchers studied additional former athletes, while public discussion increasingly focused on concussion management, player safety and the cumulative effects of years spent in collision sports.
Football organisations introduced changes to concussion protocols and rules governing certain forms of contact. Greater attention was also paid to recognising symptoms and removing players from competition after suspected concussions.
The discussion eventually spread beyond the NFL to college, school and youth football.
What had begun with individual post-mortem cases became part of a much wider debate about how contact sports should balance tradition, competition and long-term neurological health.
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Omalu’s Place in Medical and Sporting History
The story of Bennet Omalu belongs within a much broader history of traumatic brain injury research.
Physicians studying boxers had already established the medical foundations for understanding chronic neurological injury caused by repeated blows to the head.
Omalu’s contribution was to bring that history into professional American football through the examination of Mike Webster and the publication of the 2005 Neurosurgery paper.
The work that followed involved many scientists, including Ann McKee, Robert Cantu, Robert Stern, Jesse Mez, Michael Alosco and others.
Large brain banks, consensus pathology studies and increasingly sophisticated exposure research expanded understanding of CTE far beyond the knowledge available during the early 2000s.
Omalu’s Webster paper remains an important milestone because it marked the beginning of the modern NFL chapter of that medical history.
Conclusion
The story of Dr Bennet Omalu and CTE is part of a larger history of medicine, sport and changing understanding of brain trauma.
When Omalu examined Mike Webster’s brain in 2002 and his team published their findings in 2005, they produced the first published report of chronic traumatic encephalopathy in an NFL player.
That case helped bring an older neurological condition into the centre of the American football debate.
In the years that followed, researchers identified CTE in other contact-sport athletes, developed consensus diagnostic criteria, studied the effects of cumulative head impacts and investigated biological changes that may appear long before advanced disease.
Questions remain about individual susceptibility, prevalence and diagnosis during life, but the field has changed dramatically since Webster’s death.
His autopsy became one of the defining early moments in the modern history of football and brain trauma.
Author’s Note
Bennet Omalu’s examination of Mike Webster stands as an important moment in the history of sport and medicine because it connected an older medical understanding of repeated head trauma with the world of professional American football. The publication of CTE in an NFL player encouraged a wider scientific discussion that grew far beyond a single autopsy or researcher. Over the following decades, the work of many scientists reshaped how repeated head impacts are understood and helped place long-term brain health at the centre of debates about collision sport.
References
Omalu, B. I., DeKosky, S. T., Minster, R. L., Kamboh, M. I., Hamilton, R. L. and Wecht, C. H. “Chronic Traumatic Encephalopathy in a National Football League Player.” Neurosurgery, Vol. 57, No. 1, 2005, pp. 128–134.
Omalu, B. I., DeKosky, S. T., Hamilton, R. L., Minster, R. L., Kamboh, M. I., Shakir, A. M. and Wecht, C. H. “Chronic Traumatic Encephalopathy in a National Football League Player: Part II.” Neurosurgery, 2006.
Martland, H. S. “Punch Drunk.” Journal of the American Medical Association, 1928.
McKee, A. C. et al. “The First NINDS/NIBIB Consensus Meeting to Define Neuropathological Criteria for the Diagnosis of Chronic Traumatic Encephalopathy.” Acta Neuropathologica, Vol. 131, 2016, pp. 75–86.
Bieniek, K. F. et al. “The Second NINDS/NIBIB Consensus Meeting to Define Neuropathological Criteria for the Diagnosis of Chronic Traumatic Encephalopathy.” Journal of Neuropathology & Experimental Neurology, Vol. 80, 2021, pp. 210–219.
Katz, D. I. et al. “National Institute of Neurological Disorders and Stroke Consensus Diagnostic Criteria for Traumatic Encephalopathy Syndrome.” Neurology, 2021.
Daneshvar, D. H. et al. “Leveraging Football Accelerometer Data to Quantify Associations Between Repetitive Head Impacts and Chronic Traumatic Encephalopathy in Males.” Nature Communications, Vol. 14, 2023.
Butler, M. L. M. D. et al. “Repeated Head Trauma Causes Neuron Loss and Inflammation in Young Athletes.” Nature, 2025.
Layden, R. M. et al. “CTE Neuropathology Alone Associated with Dementia and Cognitive Symptoms.” Alzheimer’s & Dementia, 2026.
National Institutes of Health. “Repeated Head Impacts Cause Early Neuron Loss and Inflammation in Young Athletes.” 17 September 2025.
National Institutes of Health. “Severe CTE Clearly Linked to Dementia.” NIH Research Matters, 24 February 2026.
University of Wisconsin Athletics. “Former Badger Football Great Mike Webster Passes Away.” 24 September 2002.
Pro Football Hall of Fame. “Mike Webster, Class of 1997.” Pro Football Hall of Fame historical records.
