Controversies in autism

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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

For more details on this topic, see Epidemiology of autism.

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

For more details on this topic, see Heritability of autism.

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 argue against a genetic theory, it has also been argued that male brains may be more vulnerable during early development.^[2]

Variations in the gene for protein kinase C beta 1 (PRKCB1), a protein with an important role in brain function, may be associated with autism.^[3]

[edit] Vaccines

Several controversial claims have been made with regard to autism and vaccinations, leading notably to the MMR vaccine controversy and the thiomersal controversy. None of these claims have been verified to date.

[edit] Intelligence

Scientific literature suggests that mainstream intelligence tests do not accurately measure the cognitive abilities of autistics because autistic cognition differs from typical human cognition. According to the Association for Psychological Science, a 2007 study by Dawson et al. 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. They administered both tests to neurotypical and autistic children. The neurotypical children scored similarly on both tests, but the autistic children fared far better on the RPM than on the WISC.^[4]

This study contradicts the widely held assumption that autistics suffer from cognitive deficits in high-level abstract thinking. The RPM is considered a "paradigmatic measure" of abstract, general and fluid reasoning, which is precisely the ability autistics have been presumed to lack. This theory would predict that autistics fare dramatically worse on the RPM than on other measures of intelligence, whereas Dawson et al. showed that the opposite is true.^[5][6]

A recent review questioned the validity of IQ testing of autistic people.^[7] As those with normal or high intelligence are less likely to be diagnosed with autism, the average IQ of the autistic community as a whole may not be able to be reliably determined. Furthermore, anecdotal accounts of autistic children whose IQ scores have increased dozens of points over a relatively short period of time are not uncommon. Some of these cases, however, may not correspond to an increase in actual intelligence, however; perhaps, as with neurotypical children, children with autism may simply get better at taking IQ tests (the so-called practice effect).

[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.^[8] These joint attention skills seem to be prerequisites for functional language development.^[9] 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.^[10]

[edit] References

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