On 25 December 2015, Concussion, a movie about the National Football League and concussions to its players, will premiere in theaters in the USA. The movie is about Dr. Bennet Omalu, a Nigerian forensic pathologist, who, while working as a neuropathologist at the Allegheny County, Pennsylvania, Coroner’s Office examined the brains of several deceased National Football League (NFL) players. He was the first to publish findings of chronic traumatic encephalopathy (CTE) in American football players.
For those of you who ignore the sport, or find it an American curiosity, it is a very violent sport where 160 kg (about 350 lb) men, running and moving at the speed of world class Olympic athletes, hit other men moving at the same speed.
The game is complex (don’t even think that these young men are stupid, they have to memorize and quickly read hundreds of play combinations just for one game), much like an intricate ballet. Those who belittle the sport don’t understand its elaborate and convoluted movements combined with its brutal and gladiatorial combat.
It’s also a huge business. The National Football League owns Sundays, generating revenue in excess of US$12 billion from TV contracts, merchandise sales, and licensing. It’s difficult to tell what profits it generates (it’s a private “non-profit” corporation), but it’s estimated to be around $1 billion per year.
Put it another way, the second most valuable sports franchise in the world is the Dallas Cowboys, who are estimated to have a value of around US$3.2 billion. Just as a comparison, for those of you who are not Americans, the most valuable sports franchise in the world is the soccer team, Real Madrid, which is valued at US$3.26 billion, just slightly ahead of the Cowboys.
The NFL is such a powerful economic force, that they are very careful with their image, despite ongoing issues with domestic violence and other problems. It was amusing to watch how ESPN, the USA’s leading cable sports network, dealt with the movie about the National Football League and concussions since the network paid the NFL over US$15 billion for TV rights for the next few years. ESPN is reluctant to criticize the NFL for anything, but it also needs advertisers like the promoters of the new movie.
But this isn’t about sports per se. Let’s look at the science behind the claims made by Dr. Bennet Omalu. Let’s look at the credibility of these claims and refutations.
What is chronic traumatic encephalopathy
Chronic traumatic encephalopathy (CTE) is a progressive degenerative disease found in people with a history of repetitive brain trauma, including symptomatic concussions as well as sub-concussive hits to the head that do not cause symptoms.
CTE has been most commonly found in professional athletes, especially those who participate in American football (especially at the college and NFL level), soccer, ice hockey, professional wrestling, stunt performing cheerleading, and other contact sports where athletes have experienced repetitive brain trauma.
Generally, CTE is diagnostically identified by characteristic degeneration of brain tissue and the accumulation of defective tau proteins, an indicator of dementia and associated neurological conditions such as Alzheimer’s Disease. The disease can only diagnosed after death.
Typical signs and symptoms of patients with CTE include a decline of recent memory and executive function, mood and behavioral disturbances (especially depression, impulsivity, aggressiveness, anger, irritability, suicidal behavior and eventual progression to dementia).
There is no known treatment for CTE – there isn’t even a lot of good information on how to prevent it. Recently, investigators published a study in Science Translational Medicine which demonstrated that immobilizing the head during a blast exposure prevented the learning and memory deficits associated with CTE that occurred when the head was not immobilized.
In sports, some teams and leagues utilize baseline testing to assess potential cognitive impairment in athletes in contact sports, especially after observing a potentially concussive event. The baseline test allows the clinician to have information on the cognitive abilities of an uninjured person compared to a post-injury assessment.
However, this type of testing is highly subjective, and there are no tests to determine the presence of CTE while the person is alive.
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National Football League and concussions
The timeline that linked concessions and CTE to NFL players started with Dr. Bennet Omalu, a Nigerian born forensic pathologist working for the Allegheny County medical examiner as a neuropathologist. Omalu’s autopsy of former Pittsburgh Steelers center Mike Webster in 2002 led to Omalu’s discovery of CTE in Webster’s post-mortem brain.
Webster had died suddenly after many years of neurological issues, including struggles with cognitive and intellectual impairment, depression, mood disorders, drug abuse and suicide attempts. Initially, the autopsy of Webster’s brain appeared normal, but Omalu was curious as to what caused the issues Webster experienced prior to death.
Because he suspected a condition called dementia pugilistica, a form of dementia induced by repeated blows to the head, Omalu conducted a more in-depth analysis of the brain tissue, which he self-financed. Omalu observed large accumulations of tau protein in Webster’s brain tissue, which could affect mood, emotions, and executive functions – signs and symptoms similar to those for Alzheimer’s disease.
In conjunction with colleagues in the Department of Pathology at the University of Pittsburgh, Omalu published his observations in the high level journal Neurosurgery in 2005. In the paper, Omalu called for further study of the disease:
[infobox icon=”quote-left”]We herein report the first documented case of long-term neurodegenerative changes in a retired professional NFL player consistent with chronic traumatic encephalopathy (CTE). This case draws attention to a disease that remains inadequately studied in the cohort of professional football players, with unknown true prevalence rates[/infobox]
Omalu hoped that NFL doctors would be “pleased” to read it and that his research could be used to “fix the problem.” Except that the paper received little attention. Part of the reasons for this is that it was a case study, which, in the hierarchy of medical research, is pretty much near the bottom of the list. Omalu, even though it was published in a peer-reviewed journal, was describing one observation, for which it is nearly impossible to establish causality.
However, it did catch the attention of the members of the NFL’s Mild Traumatic Brain Injury (MBTI) Committee. They called for the paper’s retraction in May 2006, as they were trying to protect the NFL’s own policy with respect to concussions. The committee’s letter to the journal regarding the retraction attempted to characterize Omalu’s description of CTE as “completely wrong” and called the paper “a failure.”
In partial response to the NFL’s criticism, Omalu published a second paper in Neurosurgery which was based on his pathological examination of the brain of another former NFL player, Terry Long. Long suffered from depression and committed suicide in 2005 at the age of 45. Omalu found tau protein concentrations consistent with “a 90-year-old brain with advanced Alzheimer’s.” Just like he had with the Mike Webster case, Omalu believed that Long’s NFL activities had caused the neurological damage that led to depression and suicide.
Omalu also found evidence of CTE in brains of other deceased NFL players:
- Justin Strzelczyk (died of suicide in 2004 at 36 years old)
- Andre Waters (died of suicide in 2006 at 44)
- Tom McHale (died of drug overdose in 2008 at 45)
During the summer of 2007, Omalu’s findings were presented to NFL Commissioner Roger Goodall at an NFL “concussion summit.” to put it lightly, the NFL dismissed Omalu’s research. Moreover, the chairman of the NFL’s MBTI committee chair, Dr. Ira Casson, stated publicly that:
[infobox icon=”quote-left”]In my opinion, the only scientifically valid evidence of a chronic encephalopathy in athletes is in boxers and in some Steeplechase jockeys.[/infobox]
Dr. Casson seemed to have failed to see the importance of Omalu’s research – yes, they were case studies, but at some point, after several case studies in peer-reviewed high quality journals are published, one has to do further research to determine if there is an actual link. Denying the importance of one or two studies, maybe that’s not evidence, and I can accept that. But after numerous published studies over 5 or 6 years, Dr. Casson’s “opinion” has little validity.
By 2009, Dr. Omalu was no longer alone in his observations and hypothesis about concussions. Dr. Ann McKee and a team of scientists from the Center for the Study of Traumatic Encephalopathy held a press conference in Tampa, location for the 2009 Super Bowl, where they announce several new cases of CTE.
Nevertheless, it took nearly a year before the NFL would finally publicly acknowledge the link between concussions sustained in football games. In December 2009, they finally announced that they thought there was a link, nearly six years after Omalu’s initial findings.
But the story doesn’t end there, the NFL’s culpability in protecting it’s players gets worse.
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NFL plays offense
In a 2008, Dr. Lester Mayers published a review paper in Archives of Neurology (now known as JAMA Neurology) which analyzed evidence from tests such as balance and gait testing, along with MRI and PET imaging studies, after a concussion. Mayers, who died recently, concluded that it takes at least four weeks — rather than one or two — for the brain to heal following a concussion. In other words, players will be at risk of further damage if they don’t allow the brain to fully heal after damage. Mayers commented that:
[infobox icon=”quote-left”]This idea is a significant departure from current practice and will probably provoke concern and resistance at all levels of sport. Nevertheless, given the prevalence of sports head injury and the numbers of young brains at risk, a postconcussion RTP [return-to-play] interval of at least 4 weeks is imperative. Future studies that use longer follow-up periods may conclude that even this time requires extension to permit complete healing.[/infobox]
The NFL certainly didn’t like this study, because it meant that star athletes who bring in money to the league might be on the injured list for much longer than in the past. So three physicians serving on the NFL’s MBTI committee – including the aforementioned neurologist Dr. Casson, along with rheumatologist Elliot Pellman and biomechanics expert David Viano – strongly criticized Dr. Mayers’ study in a reply:
[infobox icon=”quote-left”]In essence, Dr Mayers concludes that since current clinical practices regarding RTP (return to play) are not based on scientific evidence and because some basic laboratory research suggests that changes in the brain following concussion persist for at least 4 weeks following injury, clinicians must revise their current practice by mandating at least a 4-week RTP interval for all concussed athletes. We believe that the foundation for Dr Mayers’ conclusion is flawed owing to a misinterpretation and misapplication of basic research results to the clinical sphere and his omission of the current state of clinical research on sports-related concussions.[/infobox]
Casson et al., predictably since they were “consultants” to the NFL, did not agree with Dr. Mayers. This is probably not shocking to those who follow these things.
But it gets worse. In the reply to Mayers work, the three authors stated, in the section entitled “Financial Disclosure,” the authors replied with “none reported.” Of course, the three authors worked for the NFL’s committee studying the issue, and Dr. Pellman was the NFL’s medical director. I guess by “none reported” they meant “we actually work for the NFL, but it’s not that important.”
By the way, JAMA Neurology has decided to not get involved. I generally don’t care about “conflicts of interest,” because it mostly is just a strawman. But, in this case, they authors are plainly lying about their own conflict of interest. That makes me very suspicious, since transparency should be paramount in a discussion about players’ health.
But the story gets worse. PLOS ONE, not exactly one of my favorite science journals, was forced to correct a systematic review article that claimed CTE in football players may not result from football itself. The author failed to disclose the close relationship between the lead author, Dr. Joseph Maroon, had an extensive relationship with the Pittsburgh Steelers football team for many years.
In the corrected paper, the authors stated that:
[infobox icon=”quote-left”]The authors wish to amend the Competing Interests Statement for this article, which should have included additional information in relation to potential competing interests relevant to this work. The authors apologize for this omission and revise the Competing Interests Statement to read as below.
The University of Pittsburgh Medical Center has received grants from the National Football League and the Pittsburgh Steelers. Dr. Joseph Maroon is an unpaid consultant for the Pittsburgh Steelers football club. He has been the team neurosurgeon for the Pittsburgh Steelers since 1981 and the medical director for World Wrestling Entertainment Corporation since 2008 for the management of spine and brain-related injury. He also has served on the National Football League’s Head, Neck and Spine Committee since 2007 and is currently a consultant to the committee.
Dr. Maroon is a founder and shareholder in ImPACT (Immediate Post Concussion Assessment and Cognitive Testing), and the WWE has partnered with ImPACT to provide concussion management. Dr. Maroon has served as an expert witness in medical legal cases involving concussions. This does not alter the authors’ adherence to PLOS ONE policies on sharing data and materials.[/infobox]
That’s not just a minor relationship, it’s a pretty deep one, where there are obvious close ties between the NFL (and one of its teams) and Dr. Maroon over a very long period of time, almost 4 decades.
But there’s more. The correction also included some key data points that would lead one to question all of the conclusions:
[infobox icon=”quote-left”]In addition, the authors would like to correct statements in the published article and provide additional clarification regarding the searches underlying the systematic review:
Figure 1 indicates that the authors conducted a meta-analysis on 40 studies, which is incorrect. The text in the last box of the flow chart should read “40 studies included in quantitative analysis.” For the qualitative analysis of 58 studies, the authors gathered information on observed pathology, associated symptoms and suspected risk factors of chronic traumatic encephalopathy (CTE). The 18 qualitative studies that were excluded from the quantitative analysis did not present any pathologically confirmed case reports of CTE.
The following statement in the third paragraph of the Discussion section is incorrect: “This is also true for athletes of contact sports with risk for head impact but with no confirmed CTE cases to date, such as rugby or soccer players.” There are both rugby and soccer players included in the authors’ dataset of pathologically confirmed cases of CTE (Table S1).[/infobox]
Those are some major changes that not only put the biases of Dr. Maroon in the spotlight, but also kind of destroy much of the NFL’s arguments about CTE.
Part of the NFL offensive was against Omalu himself. NFL doctors publicly attacked his research, and, curiously, demanded a retraction of his studies. They never were retracted, in case you were wondering.
Recently, Omalu spoke publicly about this incident for the 2013 documentary, League of Denial: The NFL’s Concussion Crisis, in which he stated, “You can’t go against the NFL. They’ll squash you.”
What does the evidence say?
Typical of a lot of scientific studies, one can cherry pick a lot of different data to support whatever you want about the National Football League and concussions – but is there a scientific consensus, or even, is there one that’s developing?
At first, the NFL’s MTBI Committee concluded in a series of scientific papers that “no NFL player” had developed CTE from repeat concussions. Moreover, they believed that “professional football players do not sustain frequent repetitive blows to the brain on a regular basis.”
But independent research, like what Drs. Omalu and Mayers have done, contradicts the NFL’s “beliefs.” In a review of CTE in athletes, the researchers provide evidence that there is a causal link between concussions and CTE. Moreover, they state that it’s not the number of concussions, but it’s the number of years of exposure that matter to the development of CTE and it’s symptoms like depression.
A large scale study is going to examine brains, post-mortem, of athletes and soldiers who have suffered multiple concussions. Early results show that a total of 87 out of 91 former NFL players have tested positive for CTE. That’s 95.6%, a ridiculously high number. We don’t have data as to what’s the absolute increase in risk from a person who has never played football, but the evidence is strongly on the side of concussions causing brain damage.
Dr. McKee has stated that the biggest challenge regarding the research on CTE is “convincing people this is an actual disease. People want to make this just Alzheimer’s disease or aging and not really a disease. I think there’s fewer of those people, but that’s still one of our major hurdles.” She also believes that the remaining pockets of resistance have primarily come from those with a “vested interest” in football.
Omalu himself has not just focused on CTE in NFL players. He has also discovered CTE in the brains of war veterans. Omalu found evidence of CTE in a 27-year-old Iraq War veteran who suffered from post-traumatic stress disorder (PTSD) and who had committed suicide. Omalu’s paper links PTSD to the CTE spectrum of diseases and, like with the NFL, has requested more researcher into the link.
To be fair, the NFL does have a “Concussion Protocol” for players who have had concussions. It’s a five step process that requires medical approval for the last step, playing again.
But there are numerous weaknesses in this protocol:
- Sometimes obviously concussed players are not taken out of the game, either because obviously symptoms are ignored to win a game, players don’t report symptoms, or the system breaks down and no one notices. In a recent game, a St. Louis Rams quarterback, Case Keenum, was hit hard during a play, and his head hit the turf. He tried to get back up, wobbled, and fell down again. It was appalling to watch, yet he wasn’t tested for a concussion until AFTER the game.
- The protocol ignores the link between CTE and concussions is not just one event, it’s a number of them over time. The NFL needs to accept this and protect players from getting concussions, then remove them from the sport at some level of repeated neurological events.
- There’s too much pressure for players to return, and a standard 4 weeks of no football should be enforced. The NFL wants to make money from advertising, and people won’t watch if a bunch of good players are sitting on the bench because of concussions. Moreover, as Dr. McKeen commented, coaches, players, and management of teams just don’t think concussions are important. It’s a tough sport for tough men–they think they should just shake off the headache and get back into the game.
The evidence that repeated head injury leads to long-term damage is compelling. I think the current status of research has moved beyond the fallacy of the Precautionary Principle – this has become scary for the players. However, from a scientific perspective, we are far from a broad consensus on this matter. But that doesn’t mean that there is nothing there, it’s just that the evidence is being compiled, and we’ll have to see where it leads.
Arguments are made that players are compensated very well, and if they want to play a brutal sport, so be it. There are some problems with this argument, including the fact that players generally don’t have guaranteed contracts. They won’t be paid if they need to retire early (either voluntarily or forcibly).
So, if you’re seeing that new movie about the National Football League and concussions – be aware that there’s a lot of science that support the protagonist in the movie, Dr. Bennet Omalu. The NFL needs to protect its players.
Key citations
- Casson IR, Pellman EJ, Viano DC. National football league experiences with return to play after concussion. Arch Neurol. 2009 Mar;66(3):419-20. doi: 10.1001/archneurol.2008.592. PubMed PMID: 19273769.
- Goldstein LE, Fisher AM, Tagge CA, Zhang XL, Velisek L, Sullivan JA, Upreti C, Kracht JM, Ericsson M, Wojnarowicz MW, Goletiani CJ, Maglakelidze GM, Casey N, Moncaster JA, Minaeva O, Moir RD, Nowinski CJ, Stern RA, Cantu RC, Geiling J, Blusztajn JK, Wolozin BL, Ikezu T, Stein TD, Budson AE, Kowall NW, Chargin D, Sharon A, Saman S, Hall GF, Moss WC, Cleveland RO, Tanzi RE, Stanton PK, McKee AC. Chronic traumatic encephalopathy in blast-exposed military veterans and a blast neurotrauma mouse model. Sci Transl Med. 2012 May 16;4(134):134ra60. doi: 10.1126/scitranslmed.3003716. PubMed PMID: 22593173; PubMed Central PMCID: PMC3739428.
- Maroon JC, Winkelman R, Bost J, Amos A, Mathyssek C, Miele V. Chronic traumatic encephalopathy in contact sports: a systematic review of all reported pathological cases. PLoS One. 2015 Feb 11;10(2):e0117338. doi: 10.1371/journal.pone.0117338. eCollection 2015. Erratum in: PLoS One. 2015;10(6):e0130507. PubMed PMID: 25671598; PubMed Central PMCID: PMC4324991.
- Mayers L. Return-to-play criteria after athletic concussion: a need for revision. Arch Neurol. 2008 Sep;65(9):1158-61. doi: 10.1001/archneur.65.9.1158. Review. PubMed PMID: 18779417.
- Mez J, Solomon TM, Daneshvar DH, Murphy L, Kiernan PT, Montenigro PH, Kriegel J, Abdolmohammadi B, Fry B, Babcock KJ, Adams JW, Bourlas AP, Papadopoulos Z, McHale L, Ardaugh BM, Martin BR, Dixon D, Nowinski CJ, Chaisson C, Alvarez VE, Tripodis Y, Stein TD, Goldstein LE, Katz DI, Kowall NW, Cantu RC, Stern RA, McKee AC. Assessing clinicopathological correlation in chronic traumatic encephalopathy: rationale and methods for the UNITE study. Alzheimers Res Ther. 2015 Oct 12;7(1):62. doi: 10.1186/s13195-015-0148-8. PubMed PMID: 26455775; PubMed Central PMCID: PMC4601147.
- Omalu B, Hammers JL, Bailes J, Hamilton RL, Kamboh MI, Webster G, Fitzsimmons RP. Chronic traumatic encephalopathy in an Iraqi war veteran with posttraumatic stress disorder who committed suicide. Neurosurg Focus. 2011 Nov;31(5):E3. doi: 10.3171/2011.9.FOCUS11178. PubMed PMID: 22044102.
- Omalu BI, DeKosky ST, Minster RL, Kamboh MI, Hamilton RL, Wecht CH. Chronic traumatic encephalopathy in a National Football League player. Neurosurgery. 2005 Jul;57(1):128-34; discussion 128-34. PubMed PMID: 15987548.
- Omalu BI, DeKosky ST, Hamilton RL, Minster RL, Kamboh MI, Shakir AM, Wecht CH. Chronic traumatic encephalopathy in a national football league player: part II. Neurosurgery. 2006 Nov;59(5):1086-92; discussion 1092-3. PubMed PMID: 17143242.
- 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 Jun;31(2):130-2. doi: 10.1097/PAF.0b013e3181ca7f35. PubMed PMID: 20032774.
- Stein TD, Alvarez VE, McKee AC. Concussion in Chronic Traumatic Encephalopathy. Curr Pain Headache Rep. 2015 Oct;19(10):47. doi: 10.1007/s11916-015-0522-z. PubMed PMID: 26260277; PubMed Central PMCID: PMC4633042
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