Purpose: The current study addresses a gap in the literature regarding syntactic development of adolescent boys with fragile X syndrome (FXS) and Down syndrome (DS). Specifically, we ask whether syntactic skills plateau or continue to change during adolescence for these groups and whether the profile of syntactic change differs between boys with…

The objective of this research was to develop robust predictive models of the gains in working memory (WM) and fluid intelligence (Gf) following executive attention training in children, using genetic markers, gender, and age variables. We explore the influence of genetic variables on individual differences in susceptibility to intervention.…

This study investigates the knowledge of binding in 21 English-speaking children with SLI, aged 6;08-16;05, compared to 21 children with WS, language- and age-matched, and 21 language-matched control children, aged 4-7;10. Our results demonstrate no difficulties in the interpretation of reflexive or personal pronouns in SLI, revealing an intact…

We describe the performance of 292 4- to 17-year-olds with Williams syndrome (WS) on the Kaufman Brief Intelligence Test-2 (KBIT-2; Kaufman & Kaufman, 2004). Mean IQ Composite, Verbal standard score (SS), and Nonverbal SS were in the borderline range relative to the general population, with variability similar to the general population.…

Background: Williams syndrome (WS) is associated with a distinct cognitive-behavioural phenotype including mild to moderate intellectual disability, visual-spatial deficits, hypersociability, inattention and anxiety. Researchers typically characterise samples of individuals with WS by their intellectual functioning and adaptive behaviour. Because…

The ability to track moving objects is a crucial skill for performance in everyday spatial tasks. The tracking mechanism depends on representation of moving items as coherent entities, which follow the spatiotemporal constraints of objects in the world. In the present experiment, participants tracked 1 to 4 targets in a display of 8 identical…

Multilevel modeling was used to address the longitudinal stability of standard scores (SSs) measuring intellectual ability for children with Williams syndrome (WS). Participants were 40 children with genetically confirmed WS who completed the Kaufman Brief Intelligence Test--Second Edition (KBIT-2; A. S. Kaufman & N. L. Kaufman, 2004) 4-7…