Autism is a variation of neural development diagnosed as impaired social interaction and communication, and by restricted and repetitive behavior. It affects an estimated 1 in 100 people. Autism is one of three recognized variations in the autism spectrum (ASDs), the other two being Asperger syndrome, which lacks delays in cognitive development and language, and pervasive developmental disorder, not otherwise specified (PDD-NOS), which is diagnosed when the full set of criteria for autism or Asperger syndrome are not met. In this article, the word autism is used for referring to the whole range of variations on the autism spectrum, which is not uncommon.