AFL star blames concussion for memory loss DUAL Brownlow medallist and AFL premiership player Greg Williams believes his failing memory can be traced back to the heavy knocks he took while playing football. Williams, 49, says the memories of his career are fading fast and he can no longer recall much of it. Williams, who played 250 games with Geelong, Sydney and Carlton, told the Seven network he knows he was in the winning premiership team in 1995 but does not remember a lot of the game. He and former North Queensland player Shaun Valentine underwent tests at Deakin University covering memory, dexterity and response times, with worrying results. Their response times matched those of much older men. In fact, the doctor running the tests, Alan Pearce, advised both men to see a neurologist. Williams said that in his playing days there were no club rules regarding concussion. If you were knocked out and you recovered you were sent back on. "If you didn't you were a wimp - it was just tradition, you got up and kept going," he said. His wife Mary has noticed the changes in her husband of 26 years - his forgetfulness and his temper, which she says is getting worse. "He'll snap at me for no reason, and you think, what's going on here?" she said. She said the worst part would be if she had to care for him as he got older and he didn't recognise her. Valentine, 36, left the game after suffering six concussions in two years. "That's footy, I guess," he said. The last time he was knocked out, against Melbourne, was the final straw for the Cowboys who decided he had had enough and it was too dangerous for him to play on. In the United States, concussion expert Chris Nowinski, believes every footballer who's ever played the game has suffered brain damage from concussion. He said he could not justify exposing children to contact sport until they were at least 13 to 14 years old. The program visited eight-year US NFL veteran John Hilton, 69, who is a dementia patient in a Virginia nursing home. He endured repeated concussion during his career and is unable to count back from 10. His doctor said Mr Hilton now had the cognitive abilities of a pre-school age child.