NEUROPSYCHOLOGICAL PROFILE DIFFERENCES SUPPORT DIAGNOSTIC DIVERGENCE BETWEEN ASPERGERS SYNDROME AND NONVERBAL LEARNING DISORDER

Objectives: Recent research has suggested a convergence between Aspergers Syndrome (AS) and Nonverbal Learning Disorder (NLD) in terms of presentation and etiology. Still, significant variability exists in terms of the difficulties children with these disorders present, warranting continued clinical distinction.

Methods: Examined neuropsychological performances across groups (AS v NLD) for a clinically referred sample of 6–14 year old children. All subjects were administered measures of intellectual and academic skill development, and tests of psychomotor speed, dexterity, executive functioning, visuospatial and visuoconstructional ability, verbal and visual memory, and psychosocial processes. Performances were compared across groups, using a series of multivariate ANOVAs and t-tests to assess significant differences.

Results: Children with NLD were compromised on measures of nonverbal processing, while children with AS were compromised on measures of verbal functioning. AS subjects showed stronger performances across measures of visuospatial skill. NLD subjects outperformed those with AS on tests of academically based verbal processing and verbal memory. Social processing differences were predominant in children with AS as opposed to those with NLD.

Conclusion: Children with AS appear to present with primary difficulties in the verbal domain, consistent with their situation within the Autism Spectrum. This contrasts with NLD, where the difficulty is relegated to the visuospatial and visual-executive domain, and indicative of right hemisphere dysfunction. Children with AS demonstrate greater difficulty utilizing effective strategies for managing higherorder verbal memory and production tasks, in comparison with those with NLD. While NLD and AS share success with rote verbal capability, divergence is seen with complex linguistic processing.