By PERRI KLASS, M.D. Published: May 9, 2011  The mother had brought in a note from her son’s elementary school teacher: Dear doctor, I think this child needs to be tested for attention “She’s worried about how he can’t sit still in school and do his work,” the mother said. “He’s always getting into trouble.” But then she brightened. “But he can’t have attention deficit, I know that.”Why? Her son could sit for hours concentrating on video games, it turned out, so she was certain there was nothing wrong with his attention span. It’s an assertion I’ve heard many times when a child has attention problems. Sometimes parents make the same point about television: My child can sit and watch for hours — he can’t have A.D.H.D.  If you would like to read more of this article, please click HERE to go to the New York Times site.