This study aimed to describe the behavioral profile of individuals with SYNGAP1-ID. Parents/carers of 30 individuals aged 3-18 years old with a diagnosis of SYNGAP1-ID and 21 typically developing individuals completed the Vineland-3 Adaptive Behavior Scale and the Child Behavior Checklist. We found that those with SYNGAP1-ID showed fewer adaptive…

We examined racial and ethnic differences in the prevalence of behavioral problems measured by the Child Behavioral Checklist (CBCL), sleep disturbances measured by the Child Sleep Habits Questionnaire (CSHQ), and medication use among children with Autism Spectrum Disorders (ASD). We analyzed data from the Autism Treatment Network (ATN) dataset…

The use of self-report to assess anxiety in adolescents with intellectual disability (ID) is notably underexplored. This study examined the impact of youth-level factors (i.e., age, verbal and cognitive ability, adaptive skills) on anxiety self-report completion and parent-youth agreement among 72 autistic adolescents with ID. We also examined if…

This study analyzed narratives of male and female adolescents with fragile X syndrome (FXS). The impact of structural language, cognition and autism symptomatology on narrative skills and the association between narratives and literacy were examined. Narratives from 32 adolescents with FXS (24 males, 8 females) were analyzed for macrostructure.…

This 10-year study followed 134 caregivers of young adults with autism and intellectual disability, examining the effects of caregivers' coping strategies, sociodemographic features, and young adult symptomatology on caregiver well-being and depression. Lower caregiver education and higher young adult externalizing behaviors predicted lower…

An innovation in developing the Supports Intensity Scale--Children's Version (SIS-C) was the adoption of latent variable modeling approaches to norm development. In regard to translated versions of the SIS-C, the latent modeling approaches provided opportunities to leverage the large standardization sample generated in the United States (n=4,015)…

Forty-two adolescents with Down syndrome (DS) ages 10 to 21 years completed a battery of language and phonological memory measures twice, 2 years apart. Individual differences were highly stable across two years. Receptive vocabulary scores improved, there was no change in receptive or expressive grammar scores, and nonword repetition scores…

The objectives were to describe the demographic characteristics of children with Fragile X syndrome (FXS) and to determine predictors of attendance at Fragile X (FX) clinics. Findings from the Community Support Network (CSN) and Our Fragile X World (OFXW) samples showed that children who attended FX Clinics were mostly male, high-school aged or…

Expectancy-value theory (EVT) is a popular framework to understand and improve students' motivation. Unfortunately, limited research has verified whether EVT predictions generalize to students with low levels of cognitive ability. This study relies on Grade 5 and 8 data from 177 students with low levels of cognitive ability and a matched sample of…

Limited information is available concerning the specificity of the forms and functions of aggressive behavior exhibited by boys with fragile X syndrome (FXS). To investigate these relationships, we conducted indirect functional assessments of aggressive behavior exhibited by 41 adolescent boys with FXS and 59 age and symptom-matched controls with…

The development of an expressive language score for people with autism based on the ADOS-2 was recently reported by Mazurek et al. (2019). The current study examined the construct validity of the ADOS-2 expressive language score (ELS) in a sample of adolescents with fragile X syndrome (n = 45, 10 girls), a neurodevelopmental disorder with high…

The focus of this study was the ability of adolescents and young adults with Down syndrome to infer meaning from facial expressions in the absence of emotion labels and use this inference in order to adjust their behavior. Participants with Down syndrome (N = 19, mean nonverbal mental age of 5.8 years) and 4- to 7-year-old typically developing…

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.…

Data from 949 children and adolescents with intellectual disability ages 5 to 16 for whom the Supports Intensity Scale-Children's Version-Catalan Translation was completed was used, in combination with data from the U.S. standardization sample, to examine measurement invariance and latent differences in the Catalonian sample. Results suggest that…

Problem behavior of 52 children with Williams syndrome ages 6 to 17 years old was examined based on both parent and teacher report. Generally good inter-rater agreement was found. Common areas of problem behavior based both on parent and teacher report included attention problems, anxiety difficulties, repetitive behaviors (e.g., obsessions,…