"Like searching for the link between traumatic injury and more subtle and insidious effects like depression, suicide, and dementia," said Annese. "This has been particularly crucial in the world of sports where unprecedented body mass and acceleration create the scenario for severe trauma if there is a collision."
Warner said his comments were in his role as a father, and, while he loves the game, he wants to see his children take care of their children and families.
"My kids are 13 years old and my son has already suffered a concussion," Warner said on ESPN. "Do I think about that? Of course I think about that. And the bottom line for me as a parent is, as much as I love the game and what it's all about and what it's done for me, the most important thing for me is the safety of my kids. And so that's my point, is that I consider it. And it's in my thought process. And when they play and when they want to play and when they talk about playing professionally, I'm very conscious of that."
The death of Seau, a 12-time Pro Bowl player, came only one day before more than 100 former NFL players filed a federal lawsuit in Atlanta, claiming the league did not properly protect them against concussions and did not provide proper medical care after they finished their careers.
The AP reported that the league has said any accusation that the NFL intentionally misled players is not true.
Seau's death bears a resemblance to that of other athletes in hard-hitting sports, including Chicago Bears football player Dave Duerson. Duerson shot himself in the chest in February of last year. Duerson's family filed a wrongful death suit against the NFL, saying the league did not protect against concussions.
Several former NFL players have committed suicide in recent years, and many experts believe the deaths could be related to repeated blows to the head. In addition to Duerson, ex-Pittsburgh Steelers offensive lineman Terry Long and Philadelphia Eagles defensive back Andre Waters took their own lives. Chronic traumatic encephalopathy, or CTE, a degenerative and progressive disease found in people who have experienced multiple blows to the head, has shown up in the brains of several former athletes who committed suicide, including Duerson.
CTE has similar brain features to those of Alzheimer's, Parkinson's and Lou Gehrig's disease.