The autism spectrum includes a range of developmental disorders affecting communication skills, social interactions, and repetitive behavior patterns. Severe disorders that are included in the spectrum are Rett syndrome and childhood disintegrative disorder. These disorders can often be reliably detected by the age of 3 years, and in some cases as early as 18 months.
What Is the Autism Spectrum?Not until the middle of the twentieth century was there a name for a disorder that now appears to affect an estimated one of every five hundred children, a disorder that causes disruption in families and unfulfilled lives for many children.
In 1943, Dr. Leo Kanner of the Johns Hopkins Hospital studied a group of 11 children and introduced the label "early infantile autism" into the English language. At the same time a German scientist, Dr. Hans Asperger, described a milder form of the disorder that became known as Asperger syndrome.
Today these two disorders are listed in the Diagnostic and Statistical Manual of Mental Disorders [DSM-IV-TR (fourth edition, text revision)] as two of the five pervasive developmental disorders (PDD), more often referred to today as autism spectrum disorders.
All of the disorders within the autism spectrum are characterized by varying degrees of impairment in communication skills, social interactions, and restricted, repetitive and stereotyped patterns of behavior.
Types of Disorders Within the SpectrumThe pervasive developmental disorders, or disorders in the autism spectrum, range from a severe form, called autistic disorder, to a milder form, Asperger syndrome.
If a child has symptoms of either of these disorders, but does not meet the specific criteria for either, then the diagnosis is what's referred to as pervasive developmental disorder not otherwise specified (PDD-NOS).
Other rare, very severe disorders that are within the autism spectrum are Rett syndrome and childhood disintegrative disorder.