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Three mild blows to the head linked to lifelong damage to attention span

Brain scan - Roxana Wegner/Moment
Brain scan - Roxana Wegner/Moment

Suffering three or more concussions can lead to worse attention spans and brain functioning in later life, a study has found.

Analysis of more than 15,000 people aged between 50 and 90 found that if a person received three mild traumatic brain injuries at any point in their life they performed poorer on cognitive tasks than people who had never had a big blow to the head.

A mild traumatic brain injury was defined by the Oxford and Exeter university scientists as “a head injury followed by loss of consciousness of less than 30 minutes or a dazed or confused episode”.

“We know that head injuries are a major risk factor for dementia, and this large-scale study gives the greatest detail to date on a stark finding: the more times you injure your brain in life, the worse your brain function could be as you age,” said Dr Vanessa Raymont, lead author of the study from the University of Oxford.

Protect athletes and employees

“Our research indicates that people who have experienced three or more even mild episodes of concussion should be counselled on whether to continue high-risk activities.

"We should also encourage organisations operating in areas where head impact is more likely to consider how they can protect their athletes or employees.”

Three episodes of even mild concussion throughout life was linked to inferior brain functionality while four or more also showed diminished processing speed and working memory.

Each additional reported concussion was linked to progressively worse cognitive function, data show.

The findings offer yet more evidence that the long-term health of the brain is damaged by hits to the head, with several severe or milder concussions causing negative effects to the mind decades later.

Diseases in retired professionals

Sports such as rugby, American football and football are now investigating how hits to the head impact long-term health after evidence found a higher than normal level of neurodegenerative diseases in retired professionals.

"We're learning that life events that might seem insignificant, like experiencing a mild concussion, can have an impact on the brain,” co-author, Dr Helen Brooker, from the University of Exeter, said.

"Our findings indicate that cognitive rehabilitation should focus on key functions such as attention and completion of complex tasks, which we found to be susceptible to long-term damage."

Dr Susan Kohlhaas, director of research at Alzheimer's Research UK, said: "Studies like this are so important in unravelling the long-term risks of traumatic brain injury, including their effect on dementia risk.

"These findings should send a clear message to policy makers and sporting bodies, who need to put robust guidelines in place that reduce risk of head injury as much as possible."

The study was published in the Journal of Neurotrauma.