Cognitive Profile in Higher Functioning Children with An Autism Spectrum Disorder

Background:  Although Autism Spectrum Disorders (ASD) often co-occurs with Intellectual Disability, presentation varies from more subtle to significant impairment in cognitive functioning.   Level of intellectual functioning has been associated with severity of autistic symptoms, ability to acquire skills, and level of adaptive functioning. The Stanford-Binet Intelligence Scales, Fifth Edition (SB-5) is a commonly used measure of cognitive abilities.  Although the normative sample for the SB-5 included children with autism, the number was small (N=83) and no particular pattern of scores was identified.

Objectives:  To determine whether a subset of higher functioning children with ASD present with a specific cognitive profile on the SB-5, specifically a relatively low Knowledge Factor compared other indices of intellectual fucntioning.

Methods:  Individuals between the ages of 2 to 18 years old with a confirmed diagnosis of ASD, including Autistic Disorder, Asperger's Disorder, and Pervasive Developmental Disorder-Not Otherwise Specified, participating in the Autism Treatment Network (ATN) Registry and a Full Scale IQ score of 85 or greater on the SB-5 were included in this analysis. 

Results: A total of 557 ATN Registry participants had a Full Scale SB5 IQ available. Of these, 209 (37.5%) had a score of 85 or greater

Label	N	Mean (SD)	Minimum	Maximum
Fluid Reasoning Knowledge NVIQ FSIQ VIQ	209 209 209 209 209	104.02 (13.76) 97.93 (13.27) 103.62 (11.60) 101.84 (11.33) 100.22 (13.30)	73.00 66.00 79.000 85.00 72.00	135.00 140.00 135.00 131.00 132.00

As predicted, children with ASD had a Knowledge Factor Standard Score (SS) on the SB-5 that was significantly lower than their Fluid Reasoning Factor SS (t Value=-6.14, p<.0001).  Children with an ASD also had a Knowledge Factor SS that was significantly lower than their Non-Verbal IQ SS (t Value=-6.16 p<.0001), significantly lower than their Verbal IQ SS (t Value=-3.26 p<.0013) and significantly lower than their Full Scale IQ standard score on the Stanford-Binet 5 (t Value=-5.56, p<.0001).

Conclusions:  Based on preliminary findings, as predicted a subset of children with ASD and average IQ had Knowledge scores signifcantly below other scores within the cognitive profile.  Knowledge is a person’s accumulated fund of general information acquired at home, school, or work.  The current results suggest that the relatively low Knowledge Factor standard score in this subset of children with ASD could be associated with attention problems and socialization delays.  Uneven cognitive development in children with ASD similar to what we have identified here using the SB-5 also suggests that cognitive assessment measures may be particularly useful in delineating differential patterns of cognitive strengths and weaknesses in children with ASD, as well as indexing an etiologically significant subtype of autism.  If further investigation supports these findings, a distinct cognitive pattern in some higher functioning children with ASD may also lead to more targeted intervention strategies.

We acknowledge the members of the Autism Treatment Network (ATN) for use and analysis of the data and the families who participated in the Registry. The ATN is funded by Autism Speaks and a cooperative agreement (UA3 MC 11054) from HRSA to the Massachusetts General Hospital.