Autism is a complex developmental disability with many different levels of severity. Technically, there is one diagnosis that is Autism. People do however refer to the Pervasive Developmental Disorders as disorders on the Autism spectrum or Autism Spectrum Disorders (ASD). Autism Spectrum Disorders are developmental brain disorders that cause impaired social interaction, problems with verbal and nonverbal communication, and unusual, repetitive, or severely limited activities and interests. Autism is just one of five different types of Autism disorders.
Below are definitions and characteristics of the five different autism disorders.
Autism is the second leading childhood developmental disorder and is considered the most severe of the different types of Autism disorders. People with Classic Autism develop language late, or not at all. People affected with Classic Autism have difficulties talking with other people or a profound lack of affection or emotional contact with others, an intense wish for sameness in routines, muteness or abnormality of speech, high levels of Visio-spatial skills, but major learning difficulties in other areas. Symptoms of autism usually appear during the first three years of childhood and continue throughout life. Autism is a spectrum disorder because the severity of impairment in each of these areas differs in each individual.
A Person with Aspergers Syndrome can exhibit a variety of characteristics and the disorder can range from mild to severe. Children show deficiencies in social skill and have difficulties with transitions or changes. They compulsively cling to rituals and any changes in their routine can upset them. They have a great difficulty reading body language and determining proper body space. Some children with Aspergers Syndrome have reduced sensitivity to pain and an increased sensitivity to bright lights and loud noises. With this type of Autism disorders they also have average or above-average intelligence.
Childhood Disintegrative Disorder:
Childhood Disintegrative Disorder includes severe regression in communication skills, social behavior, and all developmental motor skills. At the beginning these children seem perfectly normal. They start to regress at between ages 2-4 years. At that time these children stop socializing, lose potty-training skills, stop playing, lose motor skills and stop making friends.
Rett syndrome is a neurological and developmental disorder that mostly occurs in females and is marked by poor head growth. Loss of muscle tone is usually the first symptom. Other early symptoms may include problems crawling or walking and diminished eye contact. They stop using their hands to do things and often develop stereotyped hand movements, such as wringing, clapping, or patting their hands. The inability to perform motor functions is perhaps the most severely disabling feature of Rett syndrome, interfering with every body movement, including eye gaze and speech. Infants with Rett syndrome seem to grow and develop normally at first, but then stop developing and even lose skills and abilities.
Pervasive Developmental Disorder-Not Otherwise Specified:
This tends to describe people who have many or all of the different types of Autism disorders. Children with PDDNOS either do not fully meet the criteria of symptoms used to diagnose any of the four specific types above, and/or do not have the degree of impairment described in any of the above four specific types.