(CBS News) PHILADELPHIA -- Former pro-football players lined up against the NFL Tuesday in federal court in Philadelphia. One-third of all ex-players -- more than 4,000 -- want to sue the league over concussions they say led to brain disease.
Ralph Wenzel played for the Pittsburgh Steelers and San Diego Chargers in seven NFL seasons beginning in 1966.
When he died last year after suffering from dementia, a scientist who examined his brain said it had shrunk to the size of a one-year-old's. His wife, Eleanor Perfetto, took care of him.
"It's very difficult to watch your husband, over a probably 15- to 20-year period of time, very, very slowly, slowly slip away," she says.
Perfetto is one of more than 4,000 players and family members suing the NFL.
Forty-two-year-old Dorsey Levens is among them. He played for three teams in his 11-year career, retiring in 2004. He believes the league should have done more to warn players about the dangers of multiple concussions.
"I do know I'm going to take hard hits, and I did know that," Levens says. "What we didn't know was the impact of traumatic brain injury. We didn't know back when I played that this could give you dementia."
The NFL's lead attorney, Paul Clement, argued Tuesday that the players' union signed a collective bargaining agreement, which makes the teams and players' union itself responsible for their safety -- and therefore the lawsuit should be dismissed.
Watch: Jim Axelrod reports on the toll concussions can take on players and veterans, below.
"This didn't happen in a vacuum," Clement said. "The players' union had certain information. The team had certain information. The training associations that train trainers had certain information. And all of that has to be factored in before you can evaluate these claims."
Eleanor Perfetto attended Tuesday's hearing because she wants players to get help now.
"I think that they should have been gathering this information all along," she says. "It is their business -- it's what they do. And they say that they are trying to make the game safer and that they want to protect their players. To do that, you have to actually make an effort."XXXX
The NFL strongly denies that it misled players about the dangers of concussions. The judge is not expected to rule for several months. She could decide to dismiss the case or let parts of it move forward.