Athletes who suffered concussions in their youth show a far more rapid mental decline as they grow older, according to a new Canadian study that suggests sports-related head injuries may plant the seed for Alzheimer's disease.
The study, which looked at university-level hockey and football players now in their early 60s, found that the group who had no history of concussion scored much higher in tests of memory, motor skills and reaction time compared with former athletes who had suffered one or more concussions at least 30 years ago.
This type of mild cognitive impairment, especially premature memory loss, can be a risk factor for Alzheimer's disease, which most often affects people over 65, said the study's lead author Louis De Beaumont, a graduate student at the University of Montreal.
"To us, this type of cognitive decline in memory and motor impairments could be indicative of problems in future years," said Mr. De Beaumont of the study participants. Though he noted that the people who took part in the study are "still maintaining active daily lives," he added that they are relatively young to be experiencing cognitive problems.
Over the past decade, doctors and scientists have sounded the alarm on the effects of concussions in contact sports. They have found poster boys in high-profile athletes such as hockey star Eric Lindros, whose stunted athletic career, and boxer Muhammad Ali, whose failing health, have been linked to repeated head trauma.
But this study - published yesterday in an online version of the journal Brain - adds to growing evidence that shows concussions can leave long-lasting damage and may even accelerate the aging process.
Yesterday, Boston researchers released another study that showed former Tampa Bay Buccaneer Tom McHale, a nine-year National Football League veteran, was suffering from chronic traumatic encephalopathy, a degenerative brain disease caused by head trauma, when he died in 2008 at age 45.
Since 2002, according to Boston University School of Medicine, six former NFL players have been diagnosed after death with the condition, which is known to develop into debilitating dementia in old age. While more research is needed, the group of researchers from Harvard and Boston University said their results should serve as a wake-up call that radical change is needed to protect people playing football.
In his study, Mr. De Beaumont and his team compared 19 healthy former Canadian university athletes who had sustained one or more concussions 30 years ago with 21 former athletes with no history of concussion.
Medical records were of little use in his search for subjects, because decades ago an athlete would soldier on after getting his bell rung, conked or dinged.
So he turned to athletic and alumni associations for help. Many former athletes didn't know the symptoms of a concussion, which include dizziness, headache, lack of focus, fatigue, blurred vision, despondency and general malaise. But once he described what he was looking for, some could relate. "Athletes who have had a concussion will remember it for the rest of their lives," Mr. De Beaumont said.
Relative to former athletes with no history of concussion, those who had been concussed had significantly lower performance in memory tests, delayed response to unpredictable stimuli, and reduced dexterity.
Mr. De Beaumont said he hopes to do a larger study, which would follow these athletes to see whether they are more vulnerable to developing more severe mental and physical deteriorations in later life, such as Alzheimer's and Parkinson's diseases. In the meantime, the focus has to be on prevention, he said.
But persuading people to be careful isn't easy, says Charles Tator, a neurosurgeon at Toronto Western Hospital and founder of ThinkFirst, a non-profit organization that educates coaches, parents and children about safe sporting practices.
Better equipment, better helmets and changes to the rules have all been suggested as ways to prevent concussions, Dr. Tator said, but "there is a lack of respect among players for the opponent's body, but also for their own body."
It's crucial that athletes take proper precautions when returning to the field or rink. After a concussion, an athlete must stop and rest immediately, Dr. Tator said. Their return to regular activity should be gradual and follow a medically approved protocol, which is available on thinkfirst.ca.
And at the very least, athletes should be forewarned, Mr. De Beaumont said.
"We're not saying that sports should be banished," he said. "We're certainly saying that people should be informed about the risks."