Junior Seau's family sues NFL over brain injuries

''The NFL knew or suspected that any rule changes that sought to recognize that link (to brain disease) and the health risk to NFL players would impose an economic cost that would significantly and adversely change the profit margins enjoyed by the NFL and its teams,'' the Seaus said in the suit.

The National Institutes of Health, based in Bethesda, Md., studied three unidentified brains, one of which was Seau's, and said the findings on Seau were similar to autopsies of people ''with exposure to repetitive head injuries.''

''It was important to us to get to the bottom of this, the truth,'' Gina Seau told the AP then. ''And now that it has been conclusively determined from every expert that he had obviously had CTE, we just hope it is taken more seriously. You can't deny it exists, and it is hard to deny there is a link between head trauma and CTE. There's such strong evidence correlating head trauma and collisions and CTE.''

In the final years of his life, Seau went through wild behavior swings, according to Gina and to 23-year-old son, Tyler. There also were signs of irrationality, forgetfulness, insomnia and depression.

''He emotionally detached himself and would kind of 'go away' for a little bit,'' Tyler Seau said. ''And then the depression and things like that. It started to progressively get worse.''