 From VOA Learning English, we welcome you to news about health. Children with autism have difficulty with social skills and communication. They may seem different, have repetitive behaviors, and have abnormally intense interests. A widely used medical guide will now list autism under a new definition and name, Autism Spectrum Disorder. The changes will appear in the diagnostic and statistical manual of mental disorders to be published in May. The spectrum represents a group of developmental brain disorders, ranging from mild to severely disabling. A milder form, called Asperger's syndrome, will no longer be listed as a separate disorder with its own name. Autism is more common in boys than girls. What causes autism is not clear. Scientists are studying genes and possible environmental influences. Doctors usually cannot confirm a diagnosis of autism until a child is about three years old. Rebecca Landa is a researcher at the Kennedy Krieger Institute and Johns Hopkins University School of Medicine in Maryland. She wanted to find out what differences in development showed up earliest. She led a new study that observed 235 babies between six and 36 months of age. She says at six months, a baby may show risk signs for autism in the form of delays in communication or movement. By the time a baby is one year old, signs include difficulty in using words and not looking eye-to-eye or reaching out to other people. By 14 months, the baby might smile less and use language less. The earlier parents notice signs, she says, the sooner they can begin doing things to improve their development, like playing games and talking with their child. For VOA Learning English, I'm Alex Villareal.