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TYPES OF AUTISM
Autism presents in a wide degree,
from those who are nearly dysfunctional and apparently mentally disabled
to those whose symptoms are mild or remedied enough to appear
unexceptional ("normal") to others. Although not used or accepted by
professionals or within the literature, autistic individuals are often
divided into those with an IQ<80 referred to as having "low-functioning
autism" (LFA), while those with IQ>80 are referred to as having
"high-functioning autism" (HFA). Low and high functioning are more
generally applied to how well an individual can accomplish activities of
daily living, rather than to IQ. The terms low and high functioning are
controversial and not all autistics accept these labels. Additionally, a
recent review also questioned the validity of IQ testing of autistic
people.
This discrepancy can lead to confusion among service providers who equate
IQ with functioning and may refuse to serve high-IQ autistic people who
are severely compromised in their ability to perform daily living tasks,
or may fail to recognize the intellectual potential of many autistic
people who are considered LFA. For example, some professionals refuse to
recognize autistics who can speak or write as being autistic at all,
because they still think of autism as a communication disorder so severe
that no speech or writing is possible.
As a consequence, many "high-functioning" autistic persons, and autistic
people with a relatively high IQ, are under diagnosed, thus making the
claim that "autism implies retardation" self-fulfilling. The number of
people diagnosed with LFA is not rising quite as sharply as HFA,
indicating that at least part of the explanation for the apparent rise is
probably better diagnostics. Many also think that ASD's are being over
diagnosed: (1) because the growth in the number and complexity of symptoms
associated with autism has increased the chances professionals will
erroneously diagnose autism and (2) because the growth in services and
therapies for autism has increased the number who falsely qualify for
those often free services and therapies.
Asperger's and Kanner's syndrome
Dr. Hans Asperger described a form of autism in the 1940s that later
became known as Asperger syndrome.Main article: Asperger syndrome
In the current Diagnostic and Statistical Manual of Mental Disorders
(DSM-IV-TR), the most significant difference between Autistic Disorder
(also known as Kanner's syndrome) and Asperger's syndrome is that a
diagnosis of the former includes the observation of "delays or abnormal
functioning in at least one of the following areas, with onset prior to
age 3 years: (1) social interaction, (2) language as used in social
communication, or (3) symbolic or imaginative play",[41] while a diagnosis
of Asperger's syndrome observes "no clinically significant delay" in the
latter two of these areas.
While the DSM-IV does not include level of intellectual functioning in the
diagnosis, the fact that those with Asperger's syndrome tend to perform
better than those with Kanner's autism has produced a popular conception
that Asperger's syndrome is synonymous with "higher-functioning autism",
or that it is a lesser disorder than autism. Similarly, there is a popular
conception that autistic individuals with a high level of intellectual
functioning in fact have Asperger's syndrome, or that both types are
merely 'geeks' with a medical label. The popular depiction of autism in
the media has been of relatively severe cases (for example, as seen in the
films Rain Man and Mercury Rising), and in turn many close friends and
relatives of those who have been diagnosed in the autistic spectrum choose
to speak of their loved ones as having Asperger's syndrome rather than
autism.
The extent to which someone with higher functioning autism or Asperger's
syndrome may excel is theoretically quite high. For example, Henry
Cavendish, one of history's foremost scientists, may have been autistic.
George Wilson, a notable chemist and physician, wrote a book about
Cavendish entitled, "The Life of the Honourable Henry Cavendish",
published in 1851. From Wilson's detailed description it seems that while
Cavendish may have exhibited many classic signs of autism, he nevertheless
had an extraordinary mind.
Autism as a spectrum disorder
For more details on this topic, see Autistic spectrum.
Another view of these disorders is that they are on a continuum known as
autistic spectrum disorders. Autism spectrum disorder is an increasingly
popular term that refers to a broad definition of autism including the
classic form of the disorder as well as closely related conditions such as
PDD-NOS and Asperger's syndrome. Although the classic form of autism can
be easily distinguished from other forms of autism spectrum disorder, the
terms are often used interchangeably.
A related continuum, Sensory Integration Dysfunction, involves how well
humans integrate the information they receive from their senses. Autism,
Asperger's syndrome, and Sensory Integration Dysfunction are all closely
related and overlap.
Some people believe that there might be two manifestations of classical
autism, regressive autism and early infantile autism. Early infantile
autism is present at birth while regressive autism begins before the age
of 3 and often around 18 months. Although this causes some controversy
over when the neurological differences involved in autism truly begin,
some speculate that an environmental influence or toxin triggers the
disorder. This triggering could occur during gestation due to a toxin that
enters the mother's body and is transferred to the fetus. The triggering
could also occur after birth during the crucial early nervous system
development of the child.
A paper published in 2006 concerning the behavioral, cognitive, and
genetic bases of autism argues that autism should perhaps not be seen as a
single disorder, but rather as a set of distinct symptoms (social
difficulties, communicative difficulties and repetitive behaviors) that
have their own distinct causes.[44] An implication of this would be that a
search for a "cure" for autism is unlikely to succeed if it is not
examined as separate, albeit overlapping and commonly co-occurring,
disorders.
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1
Terminology
2
History
3
Characteristics
Key Behaviors
Noted behaviors
Social development
Sensory system
Autism and blindness
Communication difficulties
Repetitive behaviors
Effects in education
4
DSM definition
5
Types of autism
Asperger's and Kanner's syndrome
Autism as a spectrum disorder
6
Epidemiology
7
Treatment
8
Causes
Physiology and Neurology
Genetic Component
9
Sociology
Community and politics
Culture
Autistic adults
Terminology
Autistic savants
References |
