Diseases need heroes: men or women who have triumphed despite the disease. For the child with polio, one could always point to Franklin Delano Roosevelt, who campaigned on leg braces to become governor of New York and then president of the United States. For epilepsy, there is always Joan of Arc or Napoleon. The blind and deaf have Helen Keller. provides a similarly inspiring story for both dyslexia and stroke victims--but the story of his last two years in office provides a troubling example of how brain damage can affect judgment and even b ....