Classic Autism is the most common of the 5 Pervasive Developmental Disorders and can be classified into many forms and degrees of severity.
The types of Autism Spectrum Disorder are Asperger syndrome, Childhood Disintegrative Disorder, Rett Syndrome and Pervasive Developmental Disorder Not Otherwise Specified (PPD-NOS).
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Types of Autism
Before we go on to discuss these, let’s take a look at the general characteristics of autism.
More recently referred to as “mindblindness”, the scientific definition of Autism is “a severe developmental disorder that begins at birth or within the first two-and-a-half years of life”.
Basically, those who are diagnosed with autism have a brain disorder that makes it hard for them to interact in what we consider a normal socially acceptable way.
They find it difficult to communicate and relate to others because the different parts of their brains aren’t able to work together. The severity of autism ranges greatly from one individual to another.
Asperger Syndrome (or simply AS) is characterized by a varying degree of impairment in language and communication skills and repetitive or restrictive patterns of thought and behavior.
The most noticable trait of a child who suffers from Asperger Syndrome is that he/she is obsessively interested in one subject or topic and nothing else. This of course contributes to their poor social skills since they have trouble making normal conversation and interacting.
Children with Asperger syndrome are usually also delayed in learning motor skills like pedaling a bike, catching a ball, or climbing outdoor play equipment. Often, they are somewhat awkward and not so coordinated.
Childhood Disintegrative Disorder
Another of the less frequent types of autsim is Childhood Disintegrative Disorder. Children with CCD develop normally until age 3 or 4, but then show a severe loss of social, communication and other skills.
The onset of Childhood Disintegrative Disorder occurs a little bit later than classic autism which is diagnosed around 2 years of age and the loss of skills with Childhood Disintegrative Disorder is also more dramatic.
With CCD, there is also a greater chance of mental retardation. Fortunately, Childhood Disintegrative Disorder much less common than autism.
Rett syndrome is a unique developmental disorder that is first recognized in infancy and seen almost always in girls.
The onset of Rett syndrome symptoms appear earlier than in classic autism, Asperger Syndrome and Childhood Disintegrative Disorder, usually beginning just after what appears to be normal development until six to eighteen months of life.
At this point, the baby’s skills seem to slow down or stop and then later, she actually loses certain skills that she previously had.
Girls with Rett Syndrome then acquire stereotyped hand movements such as handwashing and disturbances in their walk. and her head growth rate slows down. Over time, motor problems may increase, but in general, irritability lessens and eye contact and communication improve.
Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS)
A pervasive developmental disorder not otherwise specified (PDD-NOS) is one of the four autism spectrum disorders (ASD) and also one of the five disorders classified as a pervasive developmental disorder (PDD).
According to the DSM-IV, PDD-NOS is a diagnosis that is used for “severe and pervasive impairment in the development of reciprocal social interaction or verbal and nonverbal communication skills, or when stereotyped behavior, interests, and activities are present, but the criteria are not met for a specific PDD” or for several other disorders.
PDD-NOS is often called atypical autism, because the criteria for autistic disorder are not met, for instance because of late age of onset, atypical symptomatology, or subthreshold symptomatology, or all of these.
Even though PDD-NOS is considered milder than typical autism, this is not always true. While some characteristics may be milder, others may be more severe.
These are some very general characteristics to help distinguish between the various and related types of Autism – more and more treatments are being researched and tested every day.