Football players may be cognitively impaired at a younger age, a study showed, adding evidence to the theory that the head trauma viewed as a natural part of the game may have long-term harm. The study, to be presented today by Christopher Randolph of Loyola University in Chicago, found that athletes who play American football showed symptoms of mild brain dysfunction at an earlier age than nonplaying peers. In addition, there was more illness among the retired athletes than in those who were about the same age.