The Autism Spectrum

Autism is one of five Pervasive Developmental Disorders that vary in the severity of symptoms, age of onset, and association with other disorders like mental retardation. Other Pervasive Developmental Disorders include:

The term autism spectrum disorders, which is frequently used in literature and professional discussion of autism, is not a medical term and is usually used to describe three of the disorders—autism, Asperger Syndrome, and PDD-NOS—because these three disorders share common characteristics that can be manifested on a continuum from mild to severe.

Children with Asperger Syndrome have, by definition, average or above average intelligence, where children with Autism or PDD-NOS can have a range of intellectual functioning from below to above normal. Rett’s Disorder and Childhood Disintegrative Disorder are very different in that they are both regressive in nature (i.e. initial development in both is typical prior to the onset of an extended period of cognitive and behavioral regression). They are considered pervasive developmental disorders in that they affect a child across all developmental domains (pervasive) and they are developmental in that they occur early in and affect the course of a child’s development. Children with these two rare disorders usually have significant cognitive and developmental problems across all domains.


Common Characteristics of Autism Spectrum Disorder

Challenges with Social Interactions
  • Challenges interpreting nonverbal language
  • Difficulty with pretend play
  • Rigid adherence to rules
  • Poor eye gaze or avoidance of eye contact
  • Few facial expressions and trouble understanding the facial expressions of others
  • Poor judge of personal space—may stand too close to other students
  • Trouble controlling emotions and anxieties
  • Difficulty understanding another person’s perspective or how their own behavior affects others
Communication Challenges
  • Often delayed in expressive and receptive language; may not speak at all
  • Very literal understanding of speech; difficulty in picking up on nuances
  • Delays in both expressive and receptive language
  • Echolalia- may repeat last words heard without regard for meaning
  • Lack of pretend play
Behavior Differences
  • Unusually intense or restricted interests in things (maps, dates, coins, numbers/statistics, train schedules)
  • Unusual repetitive behavior, verbal as well as nonverbal (hand flapping, rocking)
  • Unusual sensitivity to sensations: may be more or less than typical students
  • Difficulty with transitions, need for sameness
  • Possible aggressive, disruptive or self-injurious behavior; unaware of possible dangers

The impairment can range from relatively mild resulting in a diagnosis within the spectrum of Asperger Syndrome to more severe leading to a diagnosis of more classic autism. If a child has symptoms of either of these disorders, but does not meet the specific criteria of either, the diagnosis is called Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS).