Background: While delays in cognitive development are detectable during early development in Down syndrome, the neuropsychological and biomedical underpinnings of cognitive skill acquisition in this population remain poorly understood. Method: To explore this issue, 38 infants with Down syndrome [mean chronological age = 9.65 months; SD = 3.64]…

Background: Several studies show that socio-economic status (SES) is related to the developmental trajectories of children with typical development (TD). However, few studies have analysed this relationship regarding children with neurodevelopmental disorders such as Down syndrome (DS). In this paper, we analyse the impact of SES in the…

Background: Despite an increase in international studies examining the experiences of parents with intellectual impairments and their children, few have utilised population-based data. This study investigated the behavioural and cognitive outcomes of 3-year-old US children of mothers with intellectual impairments compared with children of mothers…

Background: Sleep affects children's cognitive development, preparedness for school and future academic outcomes. People with Down syndrome (DS) are particularly at risk for sleep-disordered breathing (SDB). To our knowledge, the association between SDB and cognition in preschoolers with DS is unknown. Methods: We assessed sleep by using…

Background: There is conjecture regarding the profile of cognitive development over time in children with Down syndrome (DS). Characterising this profile would be valuable for the planning and assessment of intervention studies. Method: A systematic search of the literature from 1990 to the present was conducted to identify longitudinal data on…

Background: Individuals with fragile-X syndrome exhibit developmental delay, hyperexcitation and social anxiety; they also show lack of attention and hyperactivity. Few studies have investigated whether levels of functioning change with increasing age. Here, we explored developmental changes across adolescence in the cognitive and behavioural…

Characterising how socio-cognitive abilities develop has been crucial to understanding the wider development of typically developing children. It is equally central to understanding developmental pathways in children with intellectual disabilities such as Down's syndrome. While the process of acquisition of socio-cognitive abilities in typical…

Background: Marshall-Smith syndrome (MSS) is an infrequently described entity characterised by failure to thrive, developmental delay, abnormal bone maturation and a characteristic face. In studying the physical features of a group of patients, we noticed unusual behavioural traits. This urged us to study cognition, behavioural phenotype and…