TORONTO -- A degenerative brain disease linked to repetitive brain injuries, such as concussions in athletes, may initially affect people in one of two major ways: dramatically altering their behaviour and mood or impairing memory and thinking abilities, a study suggests.
That disease -- chronic traumatic encephalopathy, or CTE -- has been found in the brains of deceased professional and amateur athletes, members of the military injured by blasts during combat, and others who experienced repeated head trauma.
"CTE has only been found in individuals with repetitive brain trauma -- concussions and subconcussive hits to the head," said Robert Stern, a professor of neurology and neurosurgery at the Boston University School of Medicine, who led the study.
"The disease is not injury. The brain trauma sets it off," said Stern, explaining that post-mortem examinations have shown there's a progressive buildup of an abnormal protein in certain areas of the brain.
For the study, published online Wednesday in the journal Neurology, the research team looked at the brains of 36 male athletes, aged 17 to 98, and diagnosed with CTE after death.
Most had played amateur or professional football, while the rest had played hockey or were involved in wrestling or boxing.
None of the subjects had other brain diseases, such as Alzheimer's disease.
Researchers interviewed family members about the athletes, asking whether they had developed dementia, changes in thinking, memory, behaviour, mood or the ability to carry out tasks of everyday living. They also reviewed the athletes' medical records.
Stern said 22 of the athletes exhibited behaviour and mood problems as their first symptoms of CTE, while 11 were initially bothered by memory and cognitive impairments.
Curiously, three of the athletes did not show any signs of CTE before their deaths, although the disease was present in their brains.
-- The Canadian Press