After a one-week applied-behavior-analysis intervention that normally costs up to $20,000 but was free because CNN was permitted to film it, autistic 13-year-old Marissa Bilson has improved dramatically, her mother says, although the family must continue to apply the rules established for Marissa. "It's all about the teaching," said behavioral therapist Rick Schroeder, who administered the intervention. "With a child like Marissa, we can't sit down and discuss it with her -- she's just not going to get that. So we have to take it in small steps. Make them understandable and move on, one step at a time."