Memory Profiles Between Individuals with ASD with High or Low Cognitive Abilities: A Cautionary Tale about Generalizing Across the Autism Spectrum.

Background:  Findings from studies of individuals with high functioning autism are often generalized to the entire spectrum that includes individuals with a broad range of intellectual abilities, as well as varying levels of symptoms.

Objectives: The aim of the present study was to add to the discussion about the practice of generalizing across the autism spectrum by directly comparing the memory profiles of individuals with autism who were grouped according to cognitive abilities on a standardized measure of memory.

Methods: 37 children with an autism spectrum disorder with both high (HCA) and low cognitive abilities (LCA) were tested on a non-verbal IQ test, and a subset of these (n = 17) also completed the conormed attention and memory battery of the Leiter-R (Roid & Miller, 1997).

Results: Profiles of scores were examined via both traditional null hypothesis testing, as well as Bayesian analysis, since evidence of group differences in patterns of performance would be reflected in a lack of differences between the HCA and LCA participants. The findings suggest similarities in patterns of cognitive strengths and weaknesses but clear difference in terms of memory profiles. Using Bayesian analyses, we confirm that HCA and LCA did not differ in terms of their recognition memory skills. Examination of standard scores suggest that while recognition memory might be a weakness for HCA participants, this was not the case for the LCA group.

Conclusions: These findings suggest that researchers should be cautious when making generalizations to the entire spectrum, as recognition memory weaknesses noted in the HCA group were not reflected in the LCA group. These findings also provide further support for the use of non-verbal tests in assessing the performance of individuals with autism with lower cognitive abilities.