Monday, March 24, 2014

The Autism Spectrum: Autism Definition and Differentiation

 Autism Spectrum
Autism describes a group of neurodevelopmental disorders collectively known as the autism spectrum. The autism spectrum encompasses:
·         Autism
·         Asperger’s Syndrome
·         Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS)

Although these disorders are related and may all be included in the definition of autism, they are actually quite distinct from one another. At one time they were recognized as separate disorders; however, the latest psychological Diagnostic and Statistical Manual of Mental Disorders, fifth Edition, known as the DSM-V, combines them within the autism spectrum.


Autism


Autism is a developmental disorder characterized by social impairment; impaired verbal and non-verbal communication; and restrictive, repetitive, or stereotyped behavior. These characteristics are usually apparent before the age of three.

Autism carries with it a wide range of symptoms, skills, and levels of impairment. Some individuals with autism are severely developmentally disabled and may never acquire verbal communication, while others have high-functioning autism, defined as an IQ higher than 70.

A typical autism definition refers primarily to this form of autism; however, Asperger’s syndrome and pervasive developmental disorder-not otherwise specified (PDD-NOS) have recently been included with autism on the autism spectrum.


Asperger’s Syndrome


Asperger’s syndrome is an autism spectrum disorder marked by difficulties with social functioning and nonverbal communication, although verbal and cognitive development is often otherwise intact.

Those with Asperger’s syndrome tend to be high functioning, although this syndrome is distinct from high-functioning autism. Despite having high intelligence, people with Asperger’s syndrome have difficulty with social interaction. They often have difficulty understanding subtle forms of nonverbal communication cues, such as eye contact and body posturing, and they may lack normal empathy.

Asperger’s syndrome is also distinguished by the tendency to pursue unusually narrow and specific topics of interest.  Individuals may also exhibit repetitive, stereotypical physical movements, such as flapping or rocking motions.

Asperger’s syndrome is distinguished from high-functioning autism in that language delays in Asperger’s syndrome tend to be minimal; however, it is often still included within a comprehensive autism definition.


Pervasive Developmental Disorder- Not Otherwise Specific (PDD-NOS)


Pervasive developmental disorder- not otherwise specified (PDD-NOS) is sometimes called atypical autism. PDD-NOS is a DSM-IV diagnosis for individuals who may not fit all of the criteria for autism or another pervasive developmental disorder on the spectrum. Individuals with PDD-NOS often have a lower level of impairment in social skills and a higher level of functioning than individuals who meet the full criteria for autism. They may also exhibit a lesser degree of stereotypical or repetitive behavior.

Many individuals with PDD-NOS have the following characteristics:
·         Difficulties using and understanding language
·         Difficulty with social behavior
·         A need for routine and an intolerance of changes in the environment
·         Uneven skill development with higher proficiency in some areas than others, for example, delayed verbal skills but normal or elevated spatial reasoning skills
·         Unusual play with toys and other objects
·         Unusual likes and dislikes



The DSM-V, the most recent diagnostic and statistical manual for psychology and psychiatry, takes a dimensional approach to constructing a relevant autism definition. The DSM-V uses the term autism spectrum to encompass the three related disorders: autism, Asperger’s syndrome, and pervasive developmental disorder- not otherwise specified (PDD-NOS). Although these conditions are distinct from one another, they are closely related, and considered to lie along a spectrum of types of verbal and social dysfunction.

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