Fragile X syndrome (FXS), the leading heritable cause of intellectual disability, has a co-occurrence rate of autism spectrum disorder (ASD) estimated at ~60%. The onset and rates of motor development in FXS are slower relative to neurotypical development, and even more so in the context of co-occurring FXS + ASD. Extant evidence suggests these…

Social cognition is a set of complex processes that mediate much of human behavior. The development of these skills is related to and interdependent on other cognitive processes, particularly inhibitory control. Brain regions associated with inhibitory control and social cognition overlap functionally and structurally, especially with respect to…

Background: Oppositional Defiant Disorder (ODD) appears more prevalent among children with intellectual disabilities (ID) as compared to children with typical development. However, it remains unclear what drives this difference. Methods: Data from 70 youth with typical development (TD) and 20 youth with ID were drawn from (The Collaborative Family…

Family outcomes of early intervention (EI) for autism spectrum disorder (ASD) have received limited research attention to date. This study explored potential predictors of family outcomes and EI perceived helpfulness on the Family Outcomes Survey--Revised, utilizing an adapted double ABCX framework. Participants were 97 mothers of children aged 4…

This prospective study examined the developmental changes over time of adolescents diagnosed in toddlerhood with autism spectrum disorder and searched for child characteristics at toddlerhood that predict outcome at adolescence. The study included 65 participants who were divided into low cognitive (developmental quotient [less than] 85; N = 41)…

'High functioning autism' is a term often used for individuals with autism spectrum disorder without an intellectual disability. Over time, this term has become synonymous with expectations of greater functional skills and better long-term outcomes, despite contradictory clinical observations. This study investigated the relationship between…

Little is known about their stability and the factors that influence their persistence or change over the life-course. To address this, we use data from 158 participants from the Special Needs and Autism Project cohort studied at three time-points from 12 to 23 years. We used latent growth models to study the role of child, family, and contextual…

Clinical predictors of 2-year outcome in preschoolers with ASD were studied in a population-based group of very young children with ASD (n = 208). Children who gained the most (n = 30) and lost the most (n = 23), i.e., increased or decreased their adaptive functioning outcome according to the Vineland Composite Score between study entry (T1) and…

Recent studies have suggested that skill acquisition rates for children with autism spectrum disorders receiving early interventions can be predicted by child motivation. We examined whether level of interest during an Autism Diagnostic Observation Schedule assessment at 2?years predicts subsequent rates of verbal, nonverbal, and adaptive skill…

This prospective study of the FIRST WORDS® Project examined restricted and repetitive behaviors in a sample of 55 toddlers at a mean age of 20 months who were later diagnosed with autism spectrum disorder. Restricted and repetitive behaviors were coded using the Repetitive Movement and Restricted Interest Scales in two video-recorded observation…

Daily living skills (DLS), such as personal hygiene, meal preparation, and money management, are important to independent living. Research suggests that many individuals with autism spectrum disorder exhibit impairments in daily living skills relative to their cognitive skills. This study examined predictors of daily living skills attainment and…

The present quasi-experimental study examines the outcomes for a group of 102 children diagnosed with an autism spectrum disorder at age 2 who attended an inclusive toddler program (described by Stahmer and Ingersoll, 2004) until age 3. Outcomes on standardized developmental assessments indicate significant improvement, with large effect sizes, in…