There are several ASD categories – autistic (classic) disorders, Asperger’s syndrome; Rhett syndrome, pervasive development disorder (not otherwise specified) and childhood disintegrative disorder.
Classic autism – the most severe disorders on the spectrum – is characterized by impaired social interaction, difficulty communicating verbally or nonverbally, and unusual or severely limited activities or interests, which are often obsessive or repetitive. These characteristics manifest themselves in a variety of different behaviors, such as a lack of language and eye contact, extreme withdrawal and violent or repetitive behavior. Many participate in self-stimulatory behaviors, such as hand flapping, rocking and unusual noises. Those diagnosed with classic autism tend to be low functioning, which means that they are unable to care for themselves.
Asperger’s Syndrome is the mildest form of autism. The National Institute of Neurological Disorders and Strokes reports that two of every 10,000 children have Asperger’s, and that it occurs three times more often in boys than girls. Individuals with Asperger’s tend to have good language and cognitive skills, average or above average intelligence and are often gifted in areas such as art, drama and music.
Unlike those diagnosed with classic autism, who tend to isolate themselves, people with Asperger’s often want to connect with others but don’t know how. They generally lack the ability to read facial expressions and body language and tend to be clumsy and uncoordinated due to underdeveloped motor skills.
Those with Asperger’s are considered high functioning, thus they need little assistance.
Rhett’s Syndrome is a rare autism disorder, occurring in one of every 10,000-15,000 live female births. While babies with the disorder initially develop normally, signs generally appear between six and eighteen months. The early signs of Rhett’s include a regression of previously learned skills, such as walking, crawling and sitting up, inappropriate infantile crying, teeth grinding, loss of muscle tone, delayed head and brain growth and severe dementia.
Like Rhett’s Syndrome, children with Childhood Disintegrative Disorder (CDD) initially begin developing appropriate verbal and nonverbal communication skills, social relationships and behaviors. However, they begin showing signs of regression in the areas of language, as well as social and motor skills, between the ages of two and ten, with average age of onset occurring between the ages of three and four. Other common signs of CDD are problems with bowel and bladder control, seizures, very low IQs, and the loss of language, which is much more severe than other disorders on the spectrum.
Individuals with specific behaviors – difficulties interacting socially and communicating with others that cannot be applied to other identifiable disorders on the spectrum are diagnosed with Pervasive Developmental Disorder (PDD).
