Three or More Concussions Linked with Worse Brain Function in Later Life
The largest study of its kind finds cumulative concussions have a measurable, progressive impact on cognitive function — and even one moderate-to-severe TBI leaves a lasting mark.
The largest study of its kind — drawing on data from more than 15,000 participants — has found that three or more concussions are linked with significantly worse cognitive function in later life, with effects worsening progressively after each subsequent injury.
- Three or more mild concussions significantly worsened attention and ability to complete complex tasks
- Four or more mild concussions also impaired processing speed and working memory
- Each additional concussion was linked to progressively worse cognitive outcomes
- Even a single moderate-to-severe concussion was associated with worsened attention, complex task completion and processing speed
"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. People who have experienced three or more even mild episodes of concussion should be counselled on whether to continue high-risk activities."
Dr Vanessa Raymont — Department of Psychiatry, University of Oxford"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 attention and completion of complex tasks, which we found to be susceptible to long-term damage."
Dr Helen Brooker — University of Exeter"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."
Dr Susan Kohlhaas — Director of Research, Alzheimer's Research UKThe PROTECT study is conducted entirely online over up to 25 years, tracking cognitive function annually in participants aged 40 and over. It represents one of the richest longitudinal datasets on brain ageing currently available.
For HIT, this research reinforces a central belief: every impact matters, and the ability to track frequency and magnitude over time is not a luxury — it is essential. The data HIT collects across a user's lifetime is precisely the kind of longitudinal record that makes informed decisions possible.
- University of Oxford
- University of Exeter
- University of New South Wales
- King's College London
- University College London
- Stavanger University Hospital
- Harvard Medical School
The full paper, 'Lifetime TBI and cognitive domain deficits in late life: The PROTECT-TBI cohort study', is published in the Journal of Neurotrauma. Credit: University of Oxford.
