Intelligence tests and autism

IQ tests are sometimes used during the process of an autism diagnosis. However, this is controversial.

Criticism of intelligence tests
Some people believe intelligence tests are designed to test the intellectual abilities in neurotypicals and are therefore inappropriate for autistics. Suggestions have been made that separate intelligence tests need to be designed specifically for the autistic population. Many autism rights activists oppose the use of intelligence testing altogether, as they believe too much emphasis is placed on IQ within autism.

There are a number of factors that may come into play when considering this issue. There is considerable anecdotal evidence that autistic individuals once thought to be mentally retarded have later been identified as very intelligent. Sue Rubin (subject of the documentary Autism is a world) was believed to be mentally retarded until age 13, after which she was tested to have an IQ of 131.

In addition, there has long been controversy over IQ tests in general. Some people don't believe intelligence is testable at all, and others believe IQ only tests a person's ability to do well on IQ tests and doesn't test anything useful. A fundamental shortcoming of IQ tests is that while a person with high IQ may be said to be intelligent, a low IQ score does not necessarily indicate the opposite. Also, intelligence tests such as the Weschler Intelligence Scale for Children are based upon a large sample of children with an IQ of between 70 and 130, but few from below or above this range, hence the scaling may not be as appropriate for very high or low IQs.

Uses
Intelligence tests are sometimes used to distinguish between autism and Asperger's, and to distinguish between high and low functioning. Sometimes the distiction between high and low functioning is to classify autistic people who score over 70-80 on an IQ test as high functioning and autistic people who score an IQ under 70-80 as low functioning. A common way to distinguish between Asperger's and autism is to use verbal IQ. This is discussed in more detail in the article on controversies about functioning labels in the autism spectrum.

IQ score is sometimes used to determine an autistic person's eligibility for services. Some autistic people with high intelligence believe this is problematic because they assert they still need services despite a high IQ.