A single concussion early in an athlete's career can take a toll on memory, attention and reaction time 30 years later, Canadian researchers said on Tuesday.

Compared with athletes with no history of concussion, those who had sustained a concussion had memory and attention problems and had slower reaction times, researchers reported in the journal Brain.

"This study shows that the effects of sports concussions in early adulthood persist beyond 30 years post-concussion and that it can cause cognitive and motor function alterations as the athletes age," Louis De Beaumont of the University of Montreal, who led the study, said in a statement.

De Beaumont studied former university-level athletes aged 50 to 65, most of whom had played hockey. Nineteen had sustained a concussion more that 30 years prior; the remaining 21 had not. All were healthy and physically fit.

The former athletes answered questionnaires on their general health and took a battery of memory and attention tests. Those who remembered having had concussions did more poorly on the tests.

De Beaumont said the findings suggest "athletes should be better informed about the cumulative and persistent effects of sports concussion on mental and physical processes so that they know about the risks associated with returning to their sport."