Experiencing multiple concussions may be associated with poorer brain function later in life, a study of nearly 16,000 people suggests.
Of the 15,764 people aged 50 to 90, those who reported three or more concussions had worse scores for complex planning and attention on a battery of cognitive tests.
People who had four or more concussions showed poorer attention, processing speed and working memory.
“What we found was that … you only need to have three lifelong concussions to have some form of cognitive impairment in the long run,” said Dr. Matthew Lennon, the study’s lead author and a doctoral student at the University of or New South Wales’s Center for Healthy Brain Aging.
“If you had multiple concussions in your teens, 20s, 30s, and 40s, you’re still going to feel the effects in your 70s or 80s.”
The findings come the day after the first hearings of a Senate inquiry into concussion and repetitive head trauma in contact sports. The inquiry was prompted by growing public concern and continued reporting by Guardian Australia about the management of concussions by sports organizations and the effects of prolonged exposure to severe impacts that may not result in a clinical diagnosis of concussion but still cause harm. to the brain.
A large and growing body of scientific evidence has shown links between repeated exposure to head injuries and subconcussive blows in contact sports and the neurodegenerative disease chronic traumatic encephalopathy (CTE), which has been found in the brains of multiple Australian athletes, from amateurs to professionals.
Lennon’s research found that while people who had repeated concussions had measurably poorer cognitive performance, the differences weren’t drastic. “We’re not talking about 20 or 30 IQ points — we’re talking maybe a few IQ points difference,” said Lennon, who is also a doctor.
The benefits of exercise for physical and cognitive health were significant, Lennon emphasized. “When we looked at the subgroup analysis [in data yet to be published] … if you suffered a concussion during sports, you actually had better working memory and processing speed than those who had never suffered a concussion.
“What that tells us is that even if you have a concussion, the benefits of exercising, especially as a young person, outweigh the long-term risks to your cognition,” Lennon said. “That makes sense when we look at the overall data because we know that blood pressure, high cholesterol, diabetes… are all really significant risks to our cognitive health.”
Lennon’s research did not examine CTE or the cumulative effect of exposure to subconcussive blows.
However, the paper argued that given the “hotly debated” issue of when people should stop participating in higher-risk activities such as contact sports, the finding that three or more concussions caused long-term cognitive impairment provided a benchmark.
“This is a critically important result. It provides a clear threshold at which cognitive deficits in mid to late life can realistically be expected,” the paper said. “In making recommendations for those who have suffered relapses [traumatic brain injury] clinicians should be aware that some long-term cognitive deficits can be expected after 3 or more.
The research, published in the Journal of Neurotrauma, is part of a wider project known as the Protect Study, which is following UK participants for up to 25 years to understand factors that influence brain health later in life. .
Lennon said an advantage of his study was the non-athlete cohort, as most previous studies examining the link between concussion and cognitive outcomes had focused on professional or college athletes. “They didn’t really include the average person.”
On average, participants reported their last head injury 30 years prior to the study. The study authors admitted that the long period of time that had elapsed since the concussion experiences was a potential limitation.
“The retrospective design of the study, in which older participants often recall details of events more than three decades ago, may have led to an underreporting of head injuries and thus an underestimation of the magnitude of their effect,” they wrote.