Senin, 21 April 2008

About Autism

Autism is a brain development disorder that impairs social interaction and communication, and causes restricted and repetitive behavior, all starting before a child is three years old. This set of signs distinguishes autism from milder autism spectrum disorders (ASD) such as Asperger syndrome.

Autism has a strong genetic basis, although the genetics of autism are complex and it is unclear whether ASD is explained more by multigene interactions or by rare mutations. In rare cases, autism is strongly associated with agents that cause birth defects. Other proposed causes, such as childhood vaccines, are controversial and the vaccine hypotheses lack convincing scientific evidence. Most recent reviews estimate a prevalence of one to two cases per 1,000 people for autism, and about six per 1,000 for ASD, with ASD averaging a 4.3:1 male-to-female ratio. The number of people known to have autism has increased dramatically since the 1980s, at least partly due to changes in diagnostic practice; the question of whether actual prevalence has increased is unresolved.

Autism affects many parts of the brain; how this occurs is poorly understood. Parents usually notice signs in the first two years of their child's life. Early behavioral or cognitive intervention can help children gain self-care, social, and communication skills. There is no cure. Few children with autism live independently after reaching adulthood, but some become successful, and an autistic culture has developed, with some seeking a cure and others believing that autism is a condition rather than a disorder.

Repetitive behavior
A young boy with autism, and the precise line of toys he made

Autistic individuals display many forms of repetitive or restricted behavior, which the Repetitive Behavior Scale-Revised (RBS-R) categorizes as follows.

* Stereotypy is apparently purposeless movement, such as hand flapping, head rolling, or body rocking.
* Compulsive behavior is intended and appears to follow rules, such as arranging objects in a certain way.
* Sameness is resistance to change; for example, insisting that the furniture not be moved or refusing to be interrupted.
* Ritualistic behavior involves the performance of daily activities the same way each time, such as an unvarying menu or dressing ritual. This is closely associated with sameness and an independent validation has suggested combining the two factors.
* Restricted behavior is limited in focus, interest, or activity, such as preoccupation with a single television program.
* Self-injury includes movements that injure or can injure the person, such as biting oneself. Dominick et al. reported that self-injury at some point affected about 30% of children with ASD.

No single repetitive behavior seems to be specific to autism, but only autism appears to have an elevated pattern of occurrence and severity of these behaviors.

Source: http://en.wikipedia.org/wiki/Autism

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