Cognitive Profiles and Restricted and Repetitive Behaviors: An Early Analysis of Data from the Autism Center of Excellence and Simons Simplex Collection Studies at UIC

Background: A wide range of cognitive functioning exists among children with autism spectrum disorders (ASDs). Intelligence quotients (IQs) for individuals with ASDs range from the immeasurably low to immeasurably high. Unusual splits in cognitive ability are common. For example, relative, and often normative, strengths in verbal ability occur alongside visual-spatial processing deficits with high frequency in certain individuals with ASD (Williams, Goldstein, Kojkowski, & Minshew, 2008), while strength in visual processing and relative deficit in verbal processing are also commonly observed (Happé, 1994). The heterogeneity in presentation of restricted and repetitive behaviors (RRBs) is also well documented in this population (Lewis & Bodfish, 1998).

The relationship between cognitive functioning and RRBs is not yet entirely clear, however. Individuals with intellectual disabilities and ASDs have a higher rate of repetitive motor mannerisms than individuals with ASDs and no cognitive deficit, as well as children with intellectual deficits alone (Szatmari et al., 1989). However, we know less about the relationship of cognitive functioning to other categories of RRBs, such as resistance to change and circumscribed interests. In particular, we have yet to examine the relationship between unusual cognitive profiles, such as highly significant differences between verbal and nonverbal ability, and RRBs.

Objectives: Broadly, this study will explore the relationship between cognitive profiles and RRBs in individuals with ASDs. In particular, whether three factors of RRBs (motor mannerisms, insistence on sameness and circumscribed interests) (Cuccaro et al, 2003; Lam, Bodfish, & Piven, 2008) occur at different rates relative to cognitive functioning, in particular among individuals with significant VIQ/NVIQ splits (i.e., a difference of more than 1.5 standard deviations).

Methods: Participants will include approximately 120individuals, ages 3-28years, participating in genetic studies of autism with a clinical diagnosis of an ASD based on the Autism Diagnostic Interview-Revised (ADI-R), Autism Diagnostic Observation Schedule (ADOS), and DSM-IV. Measures of cognitive functioning were chosen based on the participants' age and language level, and included the DAS-II, WISC-IV, and WASI. The subscales from the Repetitive Behavior Scale-Revised (RBS-R) will be used as a measure of severity of current RRBs. The three RRB FACTORS derived from the ADI-R will also be used to provide measures of past RRB. The current factors will also be derived for comparison on the same measure. Correlations between RRB scores, and IQ scores (verbal, non-verbal, overall) will be calculated. Patterns of RRB and cognitive functioning will be explored by comparing the mean and variance of RRB scores. Patterns of RRBs for individuals whose VIQ differ by more than 1.5 standard deviations from their NVIQ will be further examined.

Results: Results of the data analysis described above will be presented.

Conclusions: These results will suggest whether different profiles of RRBs emerge among individuals with significant splits in cognitive ability in this relatively diverse sample of individuals with ASD.