Intellectual Development in Autism Spectrum Disorder

The article presents an overview of the current understanding of the intellectual development of children and adults with autism spectrum disorder (ASD). A review of research indicates a wide heterogeneity in the levels of intellectual development in autism (from severe intellectual disability to giftedness) and demonstrates a lack of specific cognitive and intellectual profiles. The assessment of "strengths" and "weaknesses" of individual cognitive abilities and/or subtests of the measures comes to the fore. At the same time, the incidence of ASD and intellectual disability is higher than in the general population (33% to 70% in the studies reported in this article), indicating that these conditions are comorbid. These rates vary according to the methodological design of the studies, especially the type of data used (administrative, medical, educational, etc.) and the instruments used to assess intellectual ability. For example, Wechsler tests may underestimate scores in children and adults with ASD because of the large number of verbal instructions that are difficult for people with severe communication difficulties. Comprehensive nonverbal intelligence tests (e.g., Leiter-3 or UNIT-2) are the most appropriate methods. Assessing the level of intellectual ability in people with autism spectrum disorders in Russia is complicated by the existing deficit of methods, the elimination of which is an important task that researchers face.