Concussions linked with worse brain function in later life

Experiencing three or more concussions is linked with worsened brain function in later life, according to new research published in the Journal of Neurotrauma.

The UK-based study, featuring researchers from UNSW Sydney, the University of Oxford and the University of Exeter, analysed data from 15,764 participants of the online PROTECT study — an ongoing long-term research project seeking to better understand how the brain ages and why people develop dementia. This makes it the largest known study to explore the cognitive effects of concussion, or traumatic brain injury (TBI), to date.

Participants, all aged 50 to 90 years old and based in the UK, were asked to report the severity and frequency of concussions they had experienced throughout their lives using a detailed questionnaire and completed annual, computerised tests over four years to measure changes in cognitive function over time. Individuals were excluded from the study if they had a diagnosis of dementia at baseline.

“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, senior author of the study from the University of Oxford.

Participants who reported just three episodes of even a mild concussion had significantly worse concentration and ability to complete complex tasks. Those with four or more mild concussion episodes also showed worse processing speed and working memory. Each additional concussion correlated with progressively worse cognitive deficits. Furthermore, the study found just one moderate-to-severe concussion was associated with worse concentration, ability to complete complex tasks and processing speed.

“Our findings suggest concussions are associated in the long term with a fixed chronic deficit that seems to increase with each additional TBI,” said Matthew Lennon, a PhD candidate from the Centre for Healthy Brain Ageing (CHeBA) at UNSW Medicine & Health and lead author of the study.

“As our population ages, we urgently need new ways to empower people to live healthier lives in later life,” said Helen Brooker, a study co-author from the University of Exeter.

“We’re learning that life events that might seem insignificant, like experiencing a mild concussion, can have an impact on the brain. Our findings indicate that cognitive rehabilitation should focus on key functions such as concentration span and completion of complex tasks, which we found to be especially susceptible to long-term damage.”

People with a history of concussions should be wary of the potential dangers of continuing activities that may place them at risk of further head trauma, like contact sports and dangerous work, the researchers said. According to Raymont, “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.”

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