Autism Spectrum Disorder

Autism Spectrum Disorder

Autism Spectrum Disorder

Autism is a group of developmental brain disorders, collectively called autism spectrum disorder (ASD).

The term “spectrum” refers to the wide range of symptoms, skills, and levels of impairment, or disability, that children with ASD can have.  Some children are mildly impaired by their symptoms, but others are severely disabled.

ASD is diagnosed according to guidelines listed in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition – Text Revision (DSM-IV-TR).  The manual currently defines five disorders, sometimes called pervasive developmental disorders (PDDs), as ASD:

  • Autistic disorder (classic autism)
    • A disorder of neural development characterized by impaired social interaction and verbal and non-verbal communication, and by restricted, repetitive or stereotyped behavior.  The diagnostic criteria require that symptoms become apparent before a child is three years old
  • Asperger’s disorder (Asperger syndrome)
    • Characterized by significant difficulties in social interaction and nonverbal communication, alongside restricted and repetitive patterns of behavior and interests.
  • Pervasive developmental disorder not otherwise specified (PDD-NOS)
    • PDD-NOS is a diagnosis that is used for “severe and pervasive impairment in the development of reciprocal social interaction or verbal and nonverbal communication skills, or when stereotyped behavior, interests, and activities are present, but the criteria are not met for a specific PDD” or for several other disorders. PDD-NOS is often called atypical autism, because the criteria for autistic disorder are not met, for instance because of late age of onset, atypical symptomatology, or subthreshold symptomatology, or all of these. Even though PDD-NOS is considered milder than typical autism, this is not always true. While some characteristics may be milder, others may be more severe.
  • Rett’s disorder (Rett syndrome)
    • Originally termed as cerebroatrophic hyperammonemia, is a neurodevelopmental disorder of the grey matter of the brain that almost exclusively affects females but has also been found in male patients.  The clinical features include small hands and feet and a deceleration of the rate of head growth (including microcephaly in some).  Repetitive stereotyped hand movements, such as wringing and/or repeatedly putting hands into the mouth, are also noted.  People with Rett syndrome are prone to gastrointestinal disorders and up to 80% have seizures.  They typically have no verbal skills, and about 50% of individuals affected do not walk.  Scoliosis, growth failure, and constipation are very common and can be problematic.
  • Childhood disintegrative disorder (CDD)
    • Also known as Heller’s syndrome and disintegrative psychosis, is a rare condition characterized by late onset of developmental delays in language, social function, and motor skills.  CDD has some similarity to autism, and is sometimes considered a low-functioning form of it.

Quoted from Sources: – autism spectrum disorders – pervasive developmental disorders – Autism – Asperger_Syndrome – PDD-NOS – Rett_Syndrome – Childhood_Disintegrative_Disorder

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