Concussed athletes must wait until cognitive function returns to normal before resuming their sport, researchers are urging, after prospectively comparing performance of Australian rules footballers with and without symptoms days after their initial injury. Waiting until symptoms resolve, as currently recommended, is not enough, they say.

Footballers showed significantly reduced performance in motor function and divided attention on computerised tests if they still had even minimal symptoms at the time of testing. Performance dipped only for divided attention if the footballers had no symptoms; their cognitive function equalled that at baseline and that of uninjured control players. On pencil and paper neuropsychological tests footballers with symptoms performed as well as at baseline but did not show the significant improvements evident in those without symptoms and the controls. Footballers with symptoms took longer to return to sport, and it seemed that symptoms at injury, symptom resolution, cognitive performance, and time before resuming training and competition may turn out to be interrelated.

The prospective study was performed on 615 footballers, all of whom completed cognitive and neuropsychological tests at the start to the season. Those footballers concussed during the season, 25 with symptoms and 36 without, were retested up to 11 days after their injury, and the controls were tested at the end of the season.

This study is one of the few to test the assumption that lack of symptoms after concussion indicates a return to full mental fitness and cognitive functioning.