Williams syndrome (WS) is a rare genetic syndrome. As with all rare syndromes, obtaining adequately powered sample sizes is a challenge. Here we present legacy data from seven UK labs, enabling the characterisation of cross-sectional and longitudinal developmental trajectories of verbal and non-verbal development in the largest sample of…

Background: Developmental research provides considerable evidence of a strong relationship between verbal and visuospatial working memory (WM) and mathematics ability across age groups. However, little is known about how components of WM (i.e., short-term storage, processing speed, the central executive) might relate to mathematics sub-categories…

The aim of the study was to validate an instrument and propose standards to measure the language skills of school adolescents. 2270 adolescents (1134 males and 1136 females) in the region of Maule (Chile) was studied. The age range is between 10 to 18 years. The validated instrument has three categories (verbal, paralinguistic and non-verbal) and…

Atypical social communication is a key indicator of autism spectrum disorder and has long been presumed to interfere with friendship formation and first impressions among typically developing youth. However, emerging literature suggests that such atypicalities may function differently among groups of peers with autism spectrum disorder. The…

Extreme prematurity is known as a risk factor for autism spectrum disorder (ASD). However, the association between prematurity and ASD, for children born moderately and late preterm (MLPT) and those born early term (ET), is less established. This retrospective study aimed to characterize the phenotypic characteristics (i.e. behavioral profile and…

Purpose: The aim of this study was to investigate language growth in individuals with fragile X syndrome (FXS) from early childhood to adolescence and the influence of maternal responsivity on language growth. Method: We conducted a longitudinal analysis of language development in 55 youths (44 males, 11 females) with FXS. Data collection spanned…

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.…

This study examined two main questions: (1) Is there a direct link between psychopathic traits and intelligence? (2) Is the combination of psychopathic traits and high IQ related to more severe antisocial behaviour in adolescents?

Children with autism spectrum disorder present with a variety of social communication deficits such as atypicalities in social gaze and verbal and non-verbal communication delays as well as perceptuo-motor deficits like motor incoordination and dyspraxia. In this study, we had the unique opportunity to study praxis performance in deaf children…

Adolescence is a developmental period characterized by intense changes, which impact the interaction between individuals and their environments. Moral reasoning (MR) is an important skill during adolescence because it guides social decisions between right and wrong. Identifying the cognitive underpinnings of MR is essential to understanding the…

Purpose: To investigate the longitudinal trajectories of verbal and nonverbal skills in individuals with a history of specific language impairment (SLI) from childhood to adolescence. This study focuses on SLI only and investigates within-participant measures across abilities. Method: Verbal and nonverbal skills were assessed in 242 children with…

Empirical examination of the Reynolds Intellectual Assessment Scales (RIAS; C. R. Reynolds & R. W. Kamphaus, 2003a) has produced mixed results regarding its internal structure and convergent validity. Various aspects of validity of RIAS scores with a sample (N = 521) of adolescents and adults seeking psychological evaluations at a university-based…

We investigated phonemic competence in production in three age groups of children (7 and 8, 10 and 11, 12 and 13 years) using rhyme and phoneme monitoring. Participants were required to name target pictures silently while monitoring covert speech for the presence or absence of a rhyme or phoneme match. Performance in the verbal tasks was compared…

Background: The Autism Diagnostic Interview-Revised (ADI-R) is a gold standard assessment of Autism Spectrum Disorder (ASD) symptoms and behaviours. A key underlying assumption of studies using the ADI-R is that it measures the same phenotypic constructs across different populations (i.e. males/females, younger/older, verbal/nonverbal). The…

This study examines the academic abilities of children and adolescents who were once diagnosed with an autism spectrum disorder, but who no longer meet diagnostic criteria for this disorder. These individuals have achieved social and language skills within the average range for their ages, receive little or no school support, and are referred to…