Autism symptoms appear on a spectrum. Some people have severe impairments that alter the way they do almost everything. Others havemild issues they can hide from outsiders. Years ago, experts placed people with autism into groups or types, depending on symptom severity. Professionals no longer use these terms, but you might hear them in casual conversation among families affected by autism. When people discuss Asperger's syndrome, high-functioning autism, or pervasive developmental disorder, they're talking about autism types. While they're not diagnostic terms, they can be useful to understand asyou learn more about autism and how it manifests in different people.