Intelligence Quotient Assessment in Children With Autistic Spectrum Disorders.

Autism Spectrum Disorders (ASDs) are characterized by deficits in both social interaction and communication, as well as by restricted and repetitive patterns of behavior, and are a type of Pervasive Developmental Disorder (PDD). Intellectual disability (ID) is characterized by deficits in adaptive functioning, an intelligence quotient (IQ) that falls at least two standard deviations below average (i.e., below 70), and onset prior to adulthood (American Psychiatric Association, 2000).

Although ID is not a core symptom of ASD, there is an established relationship between the two constructs. Seventy percent of children with AD have a co-morbid diagnosis of ID (Bolte & Poustka, 2002; Fombonne, 2005). It has been suggested that many children who would have been diagnosed with ID in the past would today receive an ASD diagnosis, even with identical symptomatology (Lecavalier et al., in press).

The SB5 is a descendent of the very first intelligence measure ever created. It tests general intellectual ability, and the Fifth Edition affords the ability to report Full Scale, Abbreviated, Nonverbal, and Verbal IQ scores(Roid, 2003).. One of the updated features of the SB5 is the nonverbal component, in that close to half of the responses no longer require verbal answers (Coolican, Bryson & Zwaigenbaum, 2008).The Full Scale IQ is derived from the verbal and nonverbal scales, each with five subtests bearing the same names: Fluid Reasoning, Knowledge, Quantitative Reasoning, Visual Spatial Processing, and Working Memory.