Evidence of brain damage found in former soccer players

Evidence of chronic traumatic encephalopathy (CTE), a potential cause of dementia caused by repeated blows to the head, has been found in the brains of former soccer players

UNIVERSITY COLLEGE LONDON

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Evidence of chronic traumatic encephalopathy (CTE), a potential cause of dementia caused by repeated blows to the head, has been found in the brains of former association football (soccer) players examined at the UCL Queen Square Brain Bank.

The study, funded by The Drake Foundation and published in the journal Acta Neuropathologica, looked at 14 retired footballers with dementia who were referred to the Old Age Psychiatry Service in Swansea, Wales, between 1980 and 2010. Permission from their next-of-kin was provided to perform post-mortem examinations, which were carried out in six ex-players. Post-mortem analysis of the brain was carried out by researchers from UCL and the National Hospital for Neurology and Neurosurgery.

The team identified CTE pathology in four of the six brains examined, and all six also had signs of Alzheimer's disease. The rate of CTE identified in the footballers' brains exceeds the 12% average background rate of CTE found in a previous survey of 268 brains of an unselected population at the Queen Square Brain Bank. Like Alzheimer's disease, CTE can cause dementia and they are both characterised by a build-up of abnormal tau protein in the brain, but CTE causes tau to accumulate in a distinctive pattern. Previous studies have found evidence of CTE in the brains of contact sports players, most notably boxers and American football players. Footballers are exposed to repetitive blows to the head from heading the ball and from head-to-player collisions. However, football is unique compared with boxing and American football in that blows to the head are commonly more minor and footballers are less likely to experience significant neurological symptoms or loss of consciousness.

"This is the first time CTE has been confirmed in a group of retired footballers," explains lead author Dr Helen Ling (UCL Institute of Neurology), senior research associate at the Department of Molecular Neuroscience and neurologist. "Our findings of CTE in retired footballers suggest a potential link between playing football and the development of degenerative brain pathologies in later life. However, it is important to note that we only studied a small number of retired footballers with dementia and that we still do not know how common dementia is among footballers." 

"All of the players whose brain autopsies showed signs of CTE also had Alzheimer's pathology, but the relationship between the two diseases remains unclear. Both diseases involve a build-up of an insoluble form of tau protein in the brain. However, in CTE tau tends to accumulate around blood vessels and at the depths of the sulci - the grooves in the brain's surface - which helps to differentiate CTE from Alzheimer's pathology under the microscope. Previous studies have shown that the risk of Alzheimer's disease is increased in people with previous head injuries. On the other hand, the risk of dementia is also increased with age and we don't know if these footballers would have developed Alzheimer's disease anyway if they hadn't played football. The most pressing research question is therefore to find out if dementia is more common in footballers than in the normal population."

The ex-footballers monitored in the study all started playing football and heading the ball in their childhood or early teens and continued to play regularly for an average of 26 years. Only six reported concussion with loss of consciousness while playing football, limiting to a single episode each during their playing career. The earliest symptoms of dementia started while they were in their 60s and they lived for an average of 10 years after symptoms began. Twelve out of 14 of them eventually died of advanced dementia. 

"We do not yet know exactly what causes CTE in footballers or how significant the risk is," says co-lead author Professor Huw Morris (UCL Institute of Neurology), Professor of Clinical Neuroscience and honorary consultant neurologist at the Royal Free Hospital and National Hospital for Neurology and Neurosurgery. "Major head injuries in football are more commonly caused by player collisions rather than heading the ball. The average footballer heads the ball thousands of times throughout their career, but this seldom causes noticeable neurological symptoms. More research is now urgently needed to determine the risks associated with playing football so that any necessary protective measures can be put in place to minimise potential long term damage."

"Of course, any kind of physical activity will be associated with health risks and benefits and it is well-established that playing sports can significantly improve physical and mental health."

Of the 14 footballers included in the study, 13 were former professionals and one was a committed amateur who played every season for 23 years. They were all diagnosed with dementia between 1980 and 2010 and referred to the Old Age Psychiatry Service in Swansea run by consultant psychiatrist Dr Don Williams. He monitored these ex-footballers regularly and collected demographic and clinical data, playing and concussion history from their close relatives. Dr Williams says:

"In 1980 the son of a man with advanced dementia asked me if his father's condition had been caused by heading the ball for many years as a powerful centre-half. As the brain is a very fragile organ, well protected within the skull, this was a constructive suggestion. As a result I looked out for men with dementia and a significant history of playing soccer, followed them up and where possible arranged for post-mortem studies to be carried out. The results suggest that heading the ball over many years, a form of repetitive sub-concussive head injury, can result in the development of CTE and dementia. Thus the original suggestion has been shown to be of merit and worthy of further investigation."

The research was funded by UK-based not-for-profit The Drake Foundation. Chief Scientific Officer Velicia Bachtiar, says: "The Drake Foundation is proud to have funded this important research, which highlights the need for future work to improve our understanding of sports-related head injuries and their long-term implications."

Footballing success in the young can be measured in the brain

KAROLINSKA INSTITUTET

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The working memory and other cognitive functions in children and young people can be associated with how successful they are on the football pitch, a new study from Karolinska Institutet, Sweden, shows. Football clubs that focus too much on physical attributes therefore risk overlooking future stars.

Physical attributes such as size, fitness and strength in combination with ball control have long been considered critical factors in the hunt for new football talent. The third, slightly elusive factor of "game intelligence" -- making the best play under the circumstances-- has been difficult to measure. In 2012, researchers at Karolinska Institutet provided a possible scientific explanation for the phenomenon, and showed that the so-termed "executive cognitive functions" in adult players could be associated with their success on the pitch. In a new study, which is published in the scientific journal PLOS ONE, they show that cognitive faculties can be similarly quantified and linked to how well children and young people do in the game.

"This is interesting since football clubs focus heavily on the size and strength of young players," says study leader Predrag Petrovic, at Karolinska Institutet's Department of Clinical Neuroscience. "Young players who have still to reach full physical development rarely get a chance to be picked as potential elite players, which means that teams risk missing out on a new Iniesta or Xavi."

Executive functions are special control functions in the brain that allow us to adapt to an environment in a perpetual state of change. They include creative thinking in order to quickly switch strategy, find new, effective solutions and repress erroneous impulses. The functions are dependent on the brain's frontal lobes, which continue to develop until the age of 25.

For this present study, the researchers measured certain executive functions in 30 elite footballers aged between 12 and 19, and then cross-referenced the results with the number of goals they scored during two years. The metrics were taken in part using the same standardised tests used in healthcare. Strong results for several executive functions were found to be associated with success on the pitch, even after controlling for other factors that could conceivably affect performance. The clearest link was seen for simpler forms of executive function, such as working memory, which develops relatively early in life.

"This was expected since cognitive function is less developed in young people than it is in adults, which is probably reflected in how young people play, with fewer passes that lead to goals," says Predrag Petrovic.

The young elite players also performed significantly better than the average population in the same age group on several tests of executive function. Whether these faculties are inherited or can be trained remains the object of future research, as does the importance of the different executive functions for the various positions on the field.

"We think that the players' positions on the pitch are linked to different cognitive profiles," continues Dr Petrovic. "I can imagine that trainers will start to use cognitive tests more and more, both to find talented newcomers and to judge the position they should play in."

Soccer ball heading may commonly cause concussion symptoms

ALBERT EINSTEIN COLLEGE OF MEDICINE

Frequent soccer ball heading is a common and under recognized cause of concussion symptoms, according to a study of amateur players led by Albert Einstein College of Medicine researchers. The findings run counter to earlier soccer studies suggesting concussion injuries mainly result from inadvertent head impacts, such as collisions with other players or a goalpost. The study was published online today in Neurology®, the medical journal of the American Academy of Neurology.

"The prevailing wisdom is that routine heading in soccer is innocuous and we need only worry about players when they have unintentional head collisions," says study leader Michael L. Lipton, M.D., Ph.D., professor of radiology and of psychiatry and behavioral sciences at Einstein and director of MRI Services at Montefiore. "But our study suggests that you don't need an overt collision to warrant this type of concern. Many players who head the ball frequently are experiencing classic concussion symptoms such as headache, confusion, and dizziness during games and practice, even though they are not actually diagnosed with concussion. Concussion sufferers should avoid additional collisions or head impacts during the following days or weeks, when their risk of incurring a second concussion is extremely high. Because these injuries go unrecognized and unmanaged, there may be important clinical consequences for the short and long term."

Studies clearly show that single or repeated concussion causes neurologic problems. But little is known about the effects of frequent but lesser impacts, such as those experienced while heading a soccer ball. Some research, notably a recent study of adolescent players published in JAMA Pediatrics, suggest that heading is not a common cause of concussion. "However, these studies did not actually measure heading, and thus they were unable to separate the relative contributions of intentional and unintentional head impacts," says Dr. Lipton. 

In the current study, a part of the Einstein Soccer Study, Dr. Lipton and his colleagues asked 222 adult amateur soccer players (80 percent men, ages 18 to 55) to fill out online questionnaires on their soccer-related activities during the previous two weeks, including details about heading and other unintentional head impacts and any resulting headaches, pain and dizziness as well as more severe symptoms, such as feeling dazed, needing medical attention, and becoming unconscious. Some of the 222 players filled out questionnaires for more than a single two-week span, resulting in a total of 470 questionnaires during a nine-month period in 2013-2014.

Approximately 35 percent of the participants reported one unintentional head impact, and 16 percent reported more than one such impact. The median number of headings during the two-week reporting period for all respondents was 40.5. Twenty percent of the participants reported experiencing moderate-to-very severe concussion symptoms, with 18 percent reporting severe and 7 percent very severe symptoms. Although these symptoms were more strongly connected with unintentional head impacts, heading was shown to be an independent risk factor for concussion symptoms.

"This finding is consistent with one of our previous studies, where 30 percent of soccer players who'd had more than 1,000 headings per year had a higher risk of microstructural changes in the brain's white matter, typical of traumatic brain injury, and worse cognitive performance," says Dr. Lipton

In the new study, players who headed the most were the most susceptible to concussion. "The extent to which lesser degrees of exposure to heading lead to cumulative injury over time is not known and deserves further study," Dr. Lipton says. "Our findings certainly indicate that heading is more than just a 'sub-concussive' impact, and that heading-related concussions are common. We need to give people who have these injuries proper care and make efforts to prevent multiple head impacts, which are particularly dangerous."