Controversies in autism encompass the disagreement over the exact nature of autism, its causes and manifestations. Autism is considered to be a neurodevelopmental condition which manifests itself in markedly abnormal social interaction, communication ability, and patterns of interests.

The cause(s) of autism and the spectrum of pervasive developmental disorders (PDDs) are either unknown or unclear.

Contents 1 Epidemiology 2 Genetics 3 Vaccines 4 Intelligence 5 Joint attention 6 References

[edit] Epidemiology

There is uncertainty and controversy over whether the incidence of autism spectrum disorders (ASD) is actually increasing or if there simply is an increase in the number of reported cases and better diagnosis.

[edit] Genetics

There is evidence that autism has a genetic component,^[1] and ongoing research focuses on finding the biomarkers that determine autistic phenotypes. One, as yet unproven theory is that there may be genes which contribute to a vulnerability to environmental triggers or have another role in the etiology of autism.

Genetics is viewed as an underlying factor. However, while some parents of those with autism are progressively also being diagnosed on the autism spectrum, at least some autistic children have apparently neurotypical parents. This suggests to some that genetics are either not a necessary cause or that they don't play a part in all cases of ASD, although it could also mean that the gene(s) responsible may be recessive or a spontaneous mutation. The spectrum of autistic disorders is notable for its significant gender disparity, with the incidence of autism in males greatly exceeding the incidence in females. Whilst this could be evidence for a genetic theory, it has also been argued that male brains may be more vulnerable during early development.^[2]

[edit] Vaccines

Several controversial claims have been made with regard to autism and vaccinations, leading notably to the MMR vaccine controversy, the thiomersal controversy, and the theory of vaccine overload. These theories lack scientific evidence and are biologically implausible.^[3]

[edit] Intelligence

The fraction of autistic individuals who also meet criteria for mental retardation has been reported as anywhere from 25% to 70%, a wide variation illustrating the difficulty of assessing autistic intelligence.^[4] For ASD other than autism, the association with mental retardation is much weaker.^[5]

A 2007 study suggested that Raven's Progressive Matrices (RPM), a test of abstract reasoning, may be a better indicator of intelligence for autistic children than the more commonly used Wechsler Intelligence Scale for Children (WISC). Researchers suspected that the WISC relied too heavily on language to be an accurate measure of intelligence for autistics. The neurotypical children scored similarly on both tests, but the autistic children fared far better on the RPM than on the WISC. The RPM measures abstract, general and fluid reasoning, an ability autistics have been presumed to lack.^[6] A 2008 study found a similar effect, but to a much lesser degree and only for individuals with Wechsler IQs less than 85.^[7]

A 2006 review questioned the common assumption that most children with autism are mentally retarded.^[8]

[edit] Joint attention

Joint attention refers to a cluster of behaviors in one of two classes: a child's response to someone else pointing or shifting eye gaze, and a child seeking another's attention. Many joint-attention behaviors differ in children with autism: for example, eye contact is relatively absent or atypical.^[9] These joint attention skills seem to be prerequisites for functional language development.^[10] It has also been hypothesized that autistic children initiate joint attention perhaps even as often as their neurotypical peers, albeit in atypical ways, and that a parent should join an autistic child's focus of attention and try harder to notice the child's atypical requests for attention rather than insist on typical behavior from the child. The empirical data supporting the latter hypothesis has been questioned.^[11]

[edit] References

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