Cognitive Profiles of Children and Adolescents with ASD

Background: Individuals with Autism Spectrum Disorder (ASD) have been characterized as having a heterogeneous cognitive and executive functioning profile. Compared to typically developing peers, individuals with ASD have been found to have deficits in executive functioning, verbal working memory (Ozonoff, Pennington, & Rogers, 1991), cognitive control (Solomon et al., 2009; Solomon, Ozonoff, Cummings, & Carter, 2008), and cognitive flexibility (Ozonoff, et al., 2004) 2008). Although cognitive impairments have been characterized in ASD, more investigation is required to understand these impairments in an epidemiological sample of cognitively matched controls using the NIH Toolbox Cognition Battery (NTCB).

Objectives:

1. Investigate group differences in the NTCB in participants with ASD and an IQ-matched sample Typically Developing controls (TD).
2. Explore the utility of NCTB measures in predicting group membership using stepwise discriminant function analysis.

Methods: Participants: The current study examines an IQ case-matched sample of boys and girls with ASD (n=29, 82.7% male, mean age 13.66 [2.74] years, IQ=101.97), and TD (n=29, 75.86% male, mean age 13.27 [2.60] years, IQ 103.17) originally seen in the CHARGE (Childhood Autism Risks from Genetics and the Environment) study, which now is being followed-up as part of the Environmental influences on Child Health Outcomes (ECHO) cohort. The Stanford-Binet Intelligence Scales, Fifth Edition was used to obtain an Abbreviated Battery IQ. Participants were screened for ASD symptoms using the Social Communication Questionnaire (SCQ). For participants meeting threshold criteria on the SCQ, ASD was determined by care-giver reported history of DSM-V ASD symptom criteria and a clinician administered Autism Diagnostic Observation Schedule, Second Edition (ADOS-2). The NTCB was administered, and includes measures of Fluid Intelligence, Crystalized Intelligence, and Early Childhood Cognition, as well as the Dimensional Change Card Sort (DCCS), the Flanker Inhibitory Control and Attention, the Picture Sequence Memory, List Sorting Working Memory, Pattern Comparison Processing Speed, Picture Vocabulary, and Reading Recognition Tests. Stepwise discriminant function analysis was used to examine the NTCB variables that best predicted diagnosis in ASD versus TD group.

Results:

Stepwise discriminant analysis results determined that NTCB variables that best predicted diagnosis (ASD vs. TD) was for the DCCS task at a classification accuracy of 100% ( Wilks λ =0.881, Chi-square=6.797, p <0.01). No other task on the NCTB met criteria to discriminate between diagnostic groups.

Conclusions:

On a task of cognitive flexibility (DCCS) participants with ASD were more impaired on performance compared to IQ matched TD controls. This was the only cognitive measure that discriminated the diagnostic groups. Cognitive inflexibility is considered a characteristic of ASD; however, the result is novel in indicating this deficit was present even when ASD was compared to an IQ matched control group suing the new well validated NCTB. This is a preliminary exploration of a sample that will increase the number of participants; therefore, future analysis of the sample is required. One novel area of future investigation is comparison with a developmentally delayed sample and a sample with ASD and low IQ. Additionally, the NCTB is a valid tool for cognitive assessment of children with ASD.