Chronic traumatic encephalopathy made headline news in 2002 when Dr Omalu first discovered CTE in the brain of Mike Webster whilst performing an autopsy on the famous Hall of Fame centre for the Pittsburgh Steeler's, who died at the age of fifty. Since then, CTE has continued to make the headlines with stories of how the disease has been found in the brains of many different contact sports athletes such as American football, ice hockey, rugby, and football. It would be easy to think that CTE is a “new” disease, that it has only been known about for around 20 years, but this is not the case. There is a staggering amount of evidence that the scientific community has known the link between concussions, neurodegenerative diseases, and mental health illnesses for one hundred years, with little done to protect or even inform athletes on the possible dangers.

Dr Harrison Martland, a forensic pathologist who wrote a scientific paper in 1928 entitled 'Punch Drunk' , he performed 309 autopsies on individuals who had died from traumatic brain injuries and he observed that 9 of the cases that the brain haemorrhages were not caused by any skull fractures or any other visible injuries, instead the damage to their brains was microscopic in nature. Martland proposed in his paper that there was a connection between these cerebral microhaemorrhages, and the neurological symptoms displayed in ‘over-punished’ boxers who were being labelled with the term ‘punch drunk.’ Martland’s paper studied twenty-three boxers that showed symptoms of punch drunk, he noted how these boxers were displaying parkinsonism, vertigo, tremors, cognitive symptoms and ‘mental deterioration,’ which for some led to them being admitted to mental asylums. Martland believed there was a correlation between these symptoms and repetitive head impacts (Martland, 1928).

H.L. Parker published a paper in 1934 titled 'Traumatic Encephalopathy (Punch Drunk) of professional pugilists', he states that  “Many cases are mild and do not progress, but in the more severe types the legs drag in walking, and tremors, dysarthria, deafness, physical slowing-up and even mental deterioration which requires commitment to an institution may supervene” and that “a progressive neurological syndrome may appear, putting an end to all fighting, and leading finally to mental or physical helplessness” (Parker,1934).

In 1937 J.A. Millspaugh, a naval lieutenant published an article discussing examples of cognitive dysfunction in naval boxers that were suffering from dementia and disorientation, he gave the term ‘punch drunk syndrome’ a new name ‘dementia pugilistica’, this term is still being used today. Millspaugh’s article called on the boxing community to ensure that the ‘mental hygiene’ of a boxer must be looked after by changing the rules and regulations, and to have a medical attendant at bouts to be responsible for the boxer’s safety (Millspaugh, 1937).

Dr Macdonald Critchley, a British neurologist was the first doctor to use the term chronic traumatic encephalopathy (CTE) in his medical study which was published in 1957 in the British Medical Journal, ‘Medical aspects of boxing, particularly from a Neurological- standpoint’ again this study looked at the link between boxers concussions and their symptoms. He states “gradual evolution of mental and physical anomalies marks the insidious onset of the encephalopathy. Among mental symptoms there is the slow appearance of a fatuous or euphoric dementia with emotional lability. The victim displays but little insight into his deterioration. Speech and thought become progressively slower. Memory deteriorates considerably” (Critchley,1957).

Robert's, another British Neurologist, published a book titled 'Brain Damage' in Boxers in 1969  after studying a randomly sampled group of 250 retired professional boxers, he says "The condition can no longer be ignored by the medical profession or the public” and that “The existence of the syndrome has usually been denied by those with a financial interest in professional boxing” (Roberts,1969).

John Corsellis was a British Pathologist, who with his colleagues published a paper ‘The Aftermath of Boxing’ which detailed the neuropathological changes in retired boxers, this study set the groundwork for today’s understanding of CTE (Corsellis,1973).

There are countless other scientific papers describing the link between head trauma, CTE and dementia, we could fill hundreds of pages with the titles of all these papers that date from 1928 to the present day. The examples listed earlier are the most important and well recognised examples up until Dr Omalu’s infamous studies.

Dr Omalu, a Nigerian doctor who emigrated to the US to pursue and further his education, he pursued a career as a forensic pathologist. Omalu was the lead pathologist for the autopsy of Mike Webster, Webster was only 50 years old when he died of a heart attack. Dr Omalu discovered that the once considered one of the greatest centres in NFL history had been plagued by dementia, depression and amnesia and was living in his pick-up truck. Webster’s symptoms were so severe he would taser himself to help him fall asleep. Although the post-mortem showed, with no doubt that Webster died of a heart attack Dr Omalu was fascinated by Webster, how did a successful retired athlete’s mental health deteriorate so much? So Omalu made the decision to examine Webster’s brain, he funded this work himself. He studied slices of Webster’s brain under the microscope for hours upon hours until one day Omalu made a breakthrough, Webster’s brain had high concentrations of Tau protein, which is associated with degenerative neurological diseases such as Alzheimer’s and Parkinsons disease. This discovery in a 50-year-old brain was extremely rare but was documented in similar cases in boxers since the 1930’s, but this was the first time it had been discovered outside of the boxing community. Omalu termed the condition chronic traumatic encephalopathy (CTE) and submitted a paper outlining his discovery to the July 2005 edition of the journal Neurosurgery. Although the NFL denied any link to playing American football and neurodegenerative diseases Omalu tirelessly continued to study NFL’s player’s brains who died in tragic circumstances. His story and his endless pursuit to raise awareness of the dangers of playing contact sports on the brain were catapulted into the world when the film concussion was released in 2015, with Will Smith playing the role of Dr Omalu, up until this point the NFL were still denying the link between their sport and long-term neurological effects but in 2016 they finally acknowledged that CTE was real and that playing their sport would increase the chances in developing a neurodegenerative disease. (Omalu,2005-2010).

In 2005 Dr Ann McKee discovered CTE whilst examining brains in Alzheimer’s patients, she discovered it in a boxer’s brain, Paul Pender, she then discovered CTE in a former NFL player in 2008. These two cases cemented her belief that there was a connection between repetitive head trauma in sports and CTE. McKee and her team at the Boston university work with the Brain bank to study brains from former athletes and veterans to study the link between repetitive head injuries and neurodegenerative diseases. Later, in 2013 McKee and her colleagues published a study where they outlined a proposed criteria for the staging of CTE based on severity. Dr McKee and her colleagues then published a paper in JAMA in 2017, this was one of the largest studies of all levels of American football players (202 subjects), they found that 86% were diagnosed with CTE and that 110 of the 111 deceased NFL players had CTE (McKee,2005-2014).

Even though there are countless scientific papers that have been published over the past 100 years, from scientists all over the world, we are still unable to diagnose CTE in a living person, this is because the damage in the brain in CTE is microscopic and to date we do not have anyway of viewing this damage without examining the brain under a microscope and this is why at present someone who is suspected of having CTE will be given the diagnosis of probable CTE.  However, we now know that CTE has been found in the brains of not just athletes in contact sports, it has also been found in the brains of military personnel, victims of domestic violence and within the brains of individuals with developmental disorders that have engaged in repetitive head banging behaviours and poorly controlled epilepsy, as documented by Shively in 2021.

In 2014, McKee and her colleagues published a paper on 'TES (traumatic encephalopathy syndrome) for CTE pathology', this key step in the hope to enable diagnose CTE in a living person within our lifetime (McKee,2014). And in 2021 the National Institute of Neurological Disorders and Stroke (NNDS) published their criteria for TES, which was designed to aid medical professionals to diagnose what the likelihood that a patient has CTE by looking at their repetitive head injury history, any impairment in their cognitive functioning, any behavioural disfunction, if their symptoms are on a progressive course and if there is an absence of any other cause that could be the reason for their symptoms. However, at the time of writing this article the TES criteria can only be used in the role of research and not as a formal diagnosis in the medical field (Katz,2021).

References (in chronological order): 

Martland HS. Punch drunk. JAMA. 1928

Millspaugh JA. Dementia Pugilistica. US Naval Med Bull. 1937

Critchley, M. Punch-Drunk Syndromes: The Chronic Traumatic Encephalopathy of Boxers. British Medical Journal. 1957 

Parker, H. L. Traumatic Encephalopathy (`Punch Drunk) of Professional Pugilists. Journal of Neurology, Neurosurgery & Psychiatry. 1934

Roberts, A.H. Brain Damage in Boxers: A Study of the Prevalence of Traumatic Encephalopathy among Ex-Professional Boxers. Pitman Medical & Scientific Publishing Co., Ltd. 1969

Corsellis J, Bruton C, Freeman-Browne D. The aftermath of boxing. Psychology Med. 1973

Omalu BI, DeKosky ST, Minster RL, Kamboh MI, Hamilton RL, Wecht CH. Chronic traumatic encephalopathy in a National Football League player. Neurosurgery. 2005

Omalu BI, DeKosky ST, Hamilton RL, Minster RL, Kamboh MI, Shakir AM, et al. Chronic traumatic encephalopathy in a national football league player: part II. Neurosurgery. 2006

McKee AC, Cantu RC, Nowinski CJ, Hedley-Whyte ET, Gavett BE, Budson AE, et al. Chronic traumatic encephalopathy in athletes: progressive tauopathy after repetitive head injury. J Neuropathol Exp Neurol. 2009

Omalu BI, Fitzsimmons RP, Hammers J, Bailes J. Chronic traumatic encephalopathy in a professional American wrestler. J Forensic Nurs. 2010

Omalu BI, Hamilton RL, Kamboh MI, DeKosky ST, Bailes J. Chronic traumatic encephalopathy (CTE) in a National Football League Player: case report and emerging medicolegal practice questions. J Forensic Nurs. 2010

Omalu BI, Bailes J, Hammers JL, Fitzsimmons RP. Chronic traumatic encephalopathy, suicides and parasuicides in professional American athletes: the role of the forensic pathologist. Am J Forensic Med Pathol. 2010

McKee AC, Gavett BE, Stern RA, Nowinski CJ, Cantu RC, Kowall NW, et al. TDP-43 proteinopathy and motor neuron disease in chronic traumatic encephalopathy. J Neuropathol Exp Neurol. 2010

McKee AC, Stern RA, Nowinski CJ, Stein TD, Alvarez VE, Daneshvar DH, et al. The spectrum of disease in chronic traumatic encephalopathy. Brain. 2013

S.B. Shively, D.S. Priemer, M.B. Stein, D.P. Perl Pathophysiology of traumatic brain injury, chronic traumatic encephalopathy, and neuropsychiatric clinical expression, Psychiatric Clinics of North America.2021

Katz DI, Bernick C, Dodick DW, et al. National Institute of neurological disorders and stroke consensus diagnostic criteria for traumatic encephalopathy syndrome. Neurology 2021