Kensington NeuroBlog 3 : Contact sports concussion and dementia by Dr Mark Weatherall Consultant Neurologist

A paper just published in the respected journal Acta Neuropathologica presents the results of post-mortem inspections of the brains of six former footballers, mostly professionals, part of cohort of 14 footballers with dementia gathered by David Williams, a consultant psychiatrist in Swansea. Four of the footballers’ brains showed evidence of chronic traumatic encephalopathy (CTE), a condition first described in boxers with so-called dementia pugilistica, and more recently found widely in former American footballers with dementia and other neurodegenerative diseases.

What is the significance of this paper? Should footballers be worried that their sport is putting them at risk of developing dementia later in life? Should we all be lobbying FIFA to ban the heading of the ball? And how does this relate to developments in the management of concussion in contact sports?

We know from detailed studies of the immediate effects of brain trauma, that concussion (that is, head injury of sufficient force to cause effects of headache, nausea, blurred vision, dizziness, and/or clouding of consciousness) is accompanied by temporary changes in the cells at the surface of the brain that make them vulnerable to more permanent damage if they receive a second injury within a short timescale. This work forms the basis of, amongst others, the RFU’s HeadCase campaign and Return to Play guidelines.

Repeated concussions are clearly bad news. But what about repetitive head trauma that isn’t sufficient to cause concussion? After all, the footballers in this study only experienced on average one episode of actual concussion in their playing careers. Here the picture is less clear, because the changes of CTE are not that uncommon in the population as a whole. A survey carried out by the Queen Square Brain Bank found CTE changes at post-mortem in 12% of elderly people with or without dementia. And other causes of dementia are common: all six of the footballers’ brains in this study, for example, also showed evidence of Alzeheimer’s disease.

So, it’s too early to answer these questions with any certainty. For the time being, recreational footballers and kids kicking a ball around at school should rest easy: the health benefits of exercise are clear and unequivocal. As far as the long-term consequences of repetitive brain trauma are concerned, there seems little doubt that such trauma can cause specific changes in the brain, and in some cases this can cause (or at least contribute to) cognitive problems later in life. Why this affects some people, and not others, is not at all understood, and until it is, it is going to be difficult to draw conclusions and guidelines from the existing information.

By Dr Mark Weatherall, Consultant Neurologist