Head of the ball linked to cognitive impairment in retired professional footballers: new research
The potential long-term neurological effects of concussions and other blows to the head in professional sport have attracted a great deal of attention and research interest in recent years.
Confirmation in 2014 that former England footballer Jeff Astle died from chronic traumatic encephalopathy (a form of dementia) – and that it was caused by a steady head of the ball – sparked fury over the risks of this particular practice.
New guidelines introduced this year limit the number of ‘top strength headers’ English professional footballers are allowed to make in training each week to ten. These are usually heads from a long pass (over 35 yards) or from crosses, corners or free kicks.
Similar guidelines had already been adopted in all children’s football leagues in the UK. But the question remains: do headers really cause dementia?
Recent work at the University of Glasgow by neuropathologist William Stewart and his team analyzed death certificates of Scottish men. They found higher rates of dementia in former professional footballers than in the general population, with former footballers around 3.5 times more likely to die from a neurodegenerative disease, such as the one that causes dementia, than men. who have not played football professionally.
Stewart’s group also showed that dementia deaths among former professional footballers were higher among those who had played in positions where the header tended to be more common, like center-backs, for example.
But evidence of a greater risk of dementia among living former professional footballers is lacking.
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We studied living former professional footballers
Soccer is played by more people around the world than any other sport, so it is important to understand the risks associated with the game. Data on living participants, compared to those who have died, may provide more information. details about the nature of the disability a person may have and help us understand the type of support they might need.
Research has been conducted on the cognitive effects of the ball head on young active players. But young players are unlikely to show signs of neurological deterioration or dementia. If they were to develop a brain deficiency, this would likely only become visible once the reserve mental capacity of the young people had weakened.
Our study of former professional footballers, recently published in the Journal of Neuropsychology, partially fills this gap. We worked with two former professional football associations in England to recruit a total of 60 former male footballers. Their average age was around 68 years old.
First, we wanted to measure the overall cognitive status of former players. We used a self-administered test called Test Your Memory, which compares well to similar tests used by clinicians to screen for dementia.
And second, we wanted to collect as accurate records as possible about the careers of former professionals. Using a survey, we asked them about positions played, length of their careers, training regimes, football-related head injuries and a few other relevant information.
At the same time, we wanted to know the number of headers made by our participants throughout their careers. Of course, that would be hard to guess – so we asked them to estimate the average number of headers made per game and training session. We then multiplied those numbers by the number of training sessions and games per week, and the number of weeks in their football year, out of their career total. While the resulting estimates of total career headers are unlikely to be perfect, there really isn’t a better way to measure this.
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We saw no effect of the reported head injuries on the Test Your Memory score, which was one of the outcomes we sought to measure. But we found strong evidence that the more lead a participant did in their professional football career, the lower their scores.
We estimated that, on average, former professional footballers lost about three points on the Test Your Memory score (a drop that can mean the difference between being classified as normal or having memory problems) for every 100,000 in- career heads reported. It might sound like a lot – and it is – but a professional footballer can make hundreds of thousands of heads over the course of a career. Our participants averaged around 50,000 career headers each, although this number was likely reduced by the custodians in our sample, who generally did not report any headers. And we didn’t include pre-season training.
To our knowledge, this is the first study to provide direct evidence supporting an association between head of the ball and cognitive impairment in retired professional football players. Evidence of cognitive impairment is the first step towards a diagnosis of dementia, so our results suggest that there may be a link between running the ball often and developing neurodegenerative disease.
Overall, the decision to cut headers in training is probably the right one. Although the current limit is set at ten, we need more research to establish what could be a safe number of headers, as well as the precise effects that headers can have on the cognition of former players. – and what else can be done to mitigate these effects.