(CNN) - Former NFL Quarterback Brett Favre played 321 straight games before retiring.
Now the former Pro Bowler is admitting he suffers from memory loss.
In a recent radio interview, Favre said he can't remember his daughter playing youth soccer one summer, even though he knows she did.
Memory lapses could be a sign of a brain disease found in many athletes who suffer repeated blows to the head.
The condition is called chronic traumatic encephalopathy or CTE. Currently, CTE can only be diagnosed by analyzing brain tissue after a person dies.
Scientists are working to identify some common symptoms to help diagnose living players.
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