June 19, 2024

I, Science

The science magazine of Imperial College

Can seamlessly painless headers, which cause subconcussive injury leading to serious brain damage?

One area that has recently brought about a lot of media attention is brain injury from sport, particularly the types of sport that expose an individual to repetitive insults to the head. Young children often dream of being professional athletes without the fear of one day developing life-changing neurological disorders such as dementia. The BBC documentary Alan Shearer: Dementia, Football and Me is a thought-provoking piece investigating the potentially devastating link between footballers heading the ball and dementia. The documentary gives us an insight into how football has affected the lives of former professional footballers, detailing stories from West Bromwich Albion legend Jeff Astle, Nobby Stiles, who played professionally for Manchester United, and Scottish professional footballer Matt Tees, who have all suffered from impairments resulting from dementia. What was gripping about the documentary was the response of Matt Tees’ grandchildren, who, although having witnessed their grandfather’s dementia, which may or may not have arose owing to football, were still very eager to play, and to one day play professionally. An interview with John Terry revealed that he encourages his children to head the ball when they play football. The debate remains open as to whether change should be seen, especially in the way we see these young sporting professionals and what they may be subjecting themselves too. It is clear that there still remains no conclusive evidence for a causal link between heading a ball and brain damage. However, the question remains: “are those seamlessly painless headers, which cause subconcussive injury leading to serious brain damage?”

Research has shown that repeated minor trauma to the head of athletes who partake in contact sports such as American football, boxing, rugby, football, and wrestling, can cause devastating irreversible damage to the brain. Studies of retired contact-sport athletes, such as National Football League (NFL) players, show a higher rate of mood disturbances, such as depression, irritability, and impulsiveness. This is coupled with the development of mild cognitive impairment (MCI), a risk state for dementia, and dementia itself in some former players. This has brought about some cause for concern and has led to people wanting serious changes to be implemented by the big sporting federations.

Chronic traumatic encephalopathy (CTE), a form of progressive neurodegeneration, is believed to be intrinsically coupled with repetitive head trauma in those partaking in contact sport and can cause debilitating memory and mood problems. One study looked at neuropathological data in 202 deceased former American football players. The severity of CTE pathology was distributed across the highest level of play, with all former high school players having mild pathology and the majority of former college, semi-professional, and professional players having severe pathology. Therefore, this study suggests that the increased exposure to head injury had a fundamental impact on the brain. Deficits in behaviour, mood, and cognition were evident in those with mild and severe CTE pathology, and signs of dementia were seen in those with severe CTE pathology. These findings suggest that CTE may be related to prior participation in football and that a high level of play may be related to substantial disease burden. Diagnoses of comorbid neurodegenerative diseases, including Alzheimer’s disease, Lewy body disease, motor neuron disease, and frontotemporal lobar degeneration, were also common in cases with severe CTE pathology. Furthermore, a study in 2013 scanned five former NFL players and found a build-up of the abnormal tau protein, which is often found in those with dementia. This build-up of tau was consistent with that found in CTE-diagnosed brains during autopsy.

Although research has pointed towards a possible link between CTE and brain injury from contact sport, critics urge caution. Christopher Randolph, professor of neurology at Loyola University Medical Center in Maywood, Illinois, has stated that “we don’t yet have adequate research to draw direct connections between football and neurological issues”. He also questions the validity of CTE research, stating that the sampling is biased. His argument may be because the brain banks that support many CTE studies use tissue donated by players or their families, who often know or suspect that the individual has suffered from a severe neurological problem.

It is evident that small changes occurring in the brains of sporting professionals accumulate over time, producing changes that manifest later in life. Therefore, it is important that sporting professionals, governing bodies, and federations forewarn the next generation of sporting professionals of the possible risks of developing neurodegenerative disorders such as dementia. This is fundamental because there is a lack of understanding that tackling with the head is damaging; furthermore, there seems to be a lot of sensitivity surrounding the subject of any sort of illness or ailment associated with sport. There is no doubt that the risks associated with brain injury in sport need to be addressed, and regulations should be instigated. Tackling of the head in American football should be banned all over the world in under 11s, just like it is in the United

Angela Bonsu is studying for a PhD in the Systems Neuroscience and Bioengineering at Imperial College London

Banner Image: Football match, Wikimedia Commons