By adulthood, most males with fragile X syndrome (FXS) require support to navigate day-to-day settings. The present study cross-sectionally: (1) characterized the profile of daily living skills in males with FXS and (2) examined associated participant characteristics (i.e., fragile X mental retardation protein [FMRP] expression, nonverbal…

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…

Purpose: Pragmatic language difficulties have been documented as part of the FMR1 premutation phenotype, yet the interplay between these features in mothers and the language outcomes of their children with fragile X syndrome is unknown. This study aimed to determine whether pragmatic language difficulties in mothers with the "FMR1"…

In light of evidence that receptive language may be a relative weakness for individuals with autism spectrum disorder (ASD), this study characterized receptive vocabulary profiles in boys with ASD using cross-sectional developmental trajectories relative to age, nonverbal cognition, and expressive vocabulary. Participants were 49 boys with ASD…

This study compared the receptive and expressive language profiles of verbally expressive children and adolescents with Down Syndrome (DS) and those with Fragile X syndrome (FXS) and examined the extent to which these profiles reliably differentiate the diagnostic groups. A total of twenty-four verbal participants with DS (mean age: 12 years),…

The authors examined receptive and expressive language profiles for a group of verbal male children and adolescents who had fragile X syndrome along with varying degrees of autism symptoms. A categorical approach for assigning autism diagnostic classification, based on the combined use of the Autism Diagnostic Interview--Revised and the Autism…

Fragile X syndrome (FXS) is the leading inherited cause of intellectual disability. The syndrome is caused by a single gene mutation on the X chromosome. Although individual differences are large, most individuals with FXS display weaknesses across all language and literacy domains compared with peers of the same chronological age with typical…

Signaling noncomprehension of the spoken messages of others was examined for youth with fragile X or Down syndrome in comparison with each other and nonverbal MA-matched typically developing children. A direction-following task was used in which some of the directions were inadequate. Both syndrome groups signaled noncomprehension less often than…

Noncomprehension signaling by 16 school-age children with mild mental retardation was compared with performance of 16 typically developing children matched for nonverbal mental age. Message type and speaker were manipulated in a direction-following task. Message type, not speaker, influenced noncomprehension signaling, with no intergroup…

Twenty individuals (ages 8-18) with mental retardation and 20 controls matched for nonverbal mental age were assessed on receptive language level and nonverbal cognitive functioning. Results indicate that the nondisabled group placed less emphasis on the formal, sequential properties of language and more on semantic, conceptual properties.…

This study compared the receptive language of adolescents and young adults with either Down syndrome (n=25), fragile X syndrome (n=19), or mental age matched typically developing children (n=24). Individuals with the syndromes differed in relative achievements across the domains of receptive vocabulary, receptive syntax, nonverbal cognition, and…

The study examined whether the development of receptive language lags behind nonverbal cognitive development in school age persons with mental retardation. Results indicated that the relationship between receptive language and mental age varied across mental age levels, linguistic forms, and individuals at the same mental age for listeners with…