Some 43 percent of retired American football players studied show signs of traumatic brain injury, raising new concerns about the long-term effects of hitting and tackling, researchers said Monday. The study involved 40 retired National Football League (NFL) players, who underwent thinking and memory tests as well as brain scans. "This is one of the largest studies to date in living retired NFL players and one of the first to demonstrate significant objective evidence for traumatic brain injury in these former players," said study author Francis Conidi of the Florida State University College of Medicine.
