Laboratory-based measures of executive function and daily living skills in young children with Down syndrome: informing future interventions.

BACKGROUND: Adaptive behaviour refers to the practical skills necessary for independence and is considered a high-priority intervention target for children with neurogenetic conditions associated with intellectual disability, like Down syndrome (DS). Daily living skills (DLS) are a critical aspect of adaptive behaviour, but they have received little intervention attention, possibly because they involve a wide variety of skills across many settings. The present study aimed to advance DLS intervention science by examining the concurrent and longitudinal association between DLS performances and a cognitive skillset hypothesised to support DLS skill acquisition, executive function (EF). METHODS: Participants were 71 children with DS between the ages of 2.5 and 8.7 years (M = 5.23 years; standard deviation = 1.65) who completed a battery of adapted EF tasks and a primary caregiver who completed the Vineland Adaptive Behavior Scales 3rd Edition Parent/Caregiver Comprehensive Report Form. A subset of caregivers also provided 6- and 12-month follow-up adaptive behaviour information. RESULTS: Results demonstrated a positive association between EF task performance and DLS standard scores and v-scores both concurrently and longitudinally. CONCLUSIONS: The findings have implications for potential future intervention approaches that aim to strengthen DLS performances by advancing EF skills in this population.

Description and predictors of self-determination in males and females with fragile X syndrome on the verge of adulthood.

BACKGROUND: Self-determination refers to setting goals and making decisions regarding one's own life with support from others as needed. Research on people with intellectual and developmental disabilities has established the importance of self-determination for quality of life outcomes, such as increased independence and life satisfaction. However, self-determination has not been characterised specifically in fragile X syndrome (FXS), the leading inherited cause of intellectual disability. Relative to youth with other forms of intellectual and developmental disabilities, youth with FXS may face exceptional barriers to the development of self-determined behaviour. In addition to intellectual disability, the FXS behavioural profile is characterised by high rates of autism and anxiety that may further limit opportunities for youth with FXS. The heritable nature of the condition can also yield a distinctive family environment, with siblings and parents also living with fragile X or its associated conditions. Considering these unique challenges, the present study examined self-determination in young adult males and females with FXS and explored whether factors such as language skills, adaptive behaviour and autism traits were associated with self-determination capacity and opportunities. METHODS: The present study included 9 females and 36 males with FXS between the ages of 17 and 25 years. Caregivers (mothers or fathers) completed the American Institute for Research Self-Determination Assessment, which is a questionnaire that yields three scores: self-determination capacity, opportunities for self-determination at home and opportunities for self-determination at school. RESULTS: Caregivers endorsed a wide range of self-determination capacity and opportunities, with ratings for opportunities at home and school exceeding ratings of capacity. Better adaptive behaviour skills were associated with more self-determination capacity, and the presence of more autism traits was associated with fewer opportunities at school. CONCLUSIONS: Results from this study contribute to our understanding of avenues to best support young adults with FXS as they transition to adulthood. Our findings also have implications for practice, such that interventions targeting adaptive behaviours and self-determination may be an effective approach for promoting autonomy and independence for young adults with FXS. Additionally, caregivers and educators should continue to provide opportunities to practise self-determination, regardless of their perception of capacity.

Characterising the social interaction style of autism in young adult males with fragile X syndrome.

BACKGROUND: The characterisation of autism in fragile X syndrome (FXS) has been a source of controversy due to the complexity of disentangling autism traits from common features of the FXS phenotype. Autism in FXS is significantly underdiagnosed in the community, which may be partly due to insufficient clinical description of the social interaction profile of autism within the FXS phenotype. In this study, we applied a classic framework for characterising social interaction styles in autism to a sample of young adult males with FXS and co-occurring autism to enhance understanding of how the social challenges associated with autism manifest within FXS. METHODS: Participants were 41 males (M age = 18 years) with FXS and co-occurring autism. Interaction samples were coded for expression of predominately 'active' (characterised by a desire to make social approaches) or 'passive' (characterised by lack of initiation of social approach towards others) interaction profiles. Differences in the expression of phenotypic features of FXS, including anxiety, attention-deficit/hyperactivity disorder, cognitive, adaptive and language impairments and autism symptom severity, were examined across those with passive and active interaction styles. RESULTS: Approximately half of the sample was classified as active and half as passive, demonstrating diversity in the social phenotype of autism associated with FXS. The two subtypes did not differ in autism severity, anxiety or attention-deficit/hyperactivity disorder symptoms or in cognitive, adaptive or language abilities. CONCLUSIONS: This study enhances understanding of FXS-associated autism by documenting phenotypic variability in the social interaction profile in this group, with active and passive social interaction styles represented. The two social interaction styles were not associated with differential expression of common phenotypic features of FXS, suggesting similar support needs.

Evaluating an adapted reverse categorisation task to assess cognitive flexibility in young children with Down syndrome.

BACKGROUND: Accurate measurement of cognitive skills is necessary to advance both developmental and intervention science for individuals with Down syndrome (DS). This study evaluated the feasibility, developmental sensitivity and preliminary reliability of a reverse categorisation measure designed to assess cognitive flexibility in young children with DS. METHODS: Seventy-two children with DS ages 2.5-8 years completed an adapted version of a reverse categorisation task. Twenty-eight of the participants were assessed again 2 weeks later for retest reliability. RESULTS: This adapted measure demonstrated adequate feasibility and developmental sensitivity, and preliminary evidence for test-retest reliability when administered to children with DS in this age range. CONCLUSIONS: This adapted reverse categorisation measure may be useful for future developmental and treatment studies that target early foundations of cognitive flexibility in young children with DS. Additional recommendations for use of this measure are discussed.

Latent profiles of autism symptoms in children and adolescents with Down syndrome.

BACKGROUND: Down syndrome (DS) is associated with elevated rates of autism spectrum disorder (ASD) and autism symptomatology. To better characterise heterogeneity in ASD symptomatology in DS, profiles of caregiver-reported ASD symptoms were modelled for children and adolescents with DS. METHODS: Participants (n = 125) were recruited through several multi-site research studies on cognition and language in DS. Using the Social Responsiveness Scale-2 (SRS-2; Constantino and Gruber 2012), two latent profile analyses (LPA) were performed, one on the broad composite scores of social communication and interaction and restricted interests and repetitive behaviour, and a second on the four social dimensions of social communication, social motivation, social awareness, and social cognition. RESULTS: A three-profile model was the best fit for both analyses, with each analysis yielding a low ASD symptom profile, an elevated or mixed ASD symptom profile and a high ASD symptom profile. Associations were observed between profile probability scores and IQ, the number of co-occurring biomedical conditions reported, sex, and SRS-2 form. CONCLUSIONS: Characterising heterogeneity in ASD symptom profiles can inform more personalised supports in this population, and implications for potential therapeutic approaches for individuals with DS are discussed.

Characterising repetitive behaviours in young boys with fragile X syndrome.

BACKGROUND: Repetitive behaviours are frequently observed in individuals with intellectual disability (ID). The present study examined the profile, inter-correlations and predictive correlates of repetitive behaviours in boys with fragile X syndrome (FXS), the leading inherited cause of ID. Specific child characteristics examined as predictors included anxiety, nonverbal cognition and autism social-affective symptomatology. METHOD: Participants were 39 boys with FXS (aged 6-10 years). Repetitive behaviours were measured using the Repetitive Behavior Scale - Revised (RBS-R) - a 43-item caregiver-report measure normed on individuals with ID. RESULTS: Restricted Interests and Sensory Motor behaviours were reported as most problematic for this sample of boys, whereas Self-injurious behaviours were less problematic. All subscales of the RBS-R were significantly inter-correlated. Nonverbal IQ was negatively related, whereas anxiety and social affective symptoms of autism spectrum disorder were positively related, to scores for Restricted Interests. Anxiety was also positively related to scores for Compulsive behaviours and Ritualistic Sameness behaviours. CONCLUSIONS: This study provides a preliminary description of repetitive behaviours in boys with FXS, which may form the groundwork for future research.