Purpose: This study examined short-term predictive associations between 5 different types of parent verbal responsiveness and later spoken vocabulary for 32 young children with a confirmed diagnosis of autism spectrum disorder (ASD). Method: Parent verbal utterances were coded from videotapes of naturalistic parent–child play sessions using interval and event-based coding. A vocabulary difference score, calculated using the MacArthur Communicative Development Inventories (L. Fenson et al., 1993), was used as the outcome measure of spoken vocabulary 6 months later. Results: Parent follow-in comments and follow-in directives predicted spoken vocabulary after controlling for child engagement. Parent expansions of child verbal utterances predicted spoken vocabulary after controlling for child talkativeness. When entered together into a regression analysis, metrics that represented (a) the number of parent utterances following into the child’s focus of attention and (b) the number of parent utterances responding to child verbal communication acts both accounted for unique variance in predicting change in spoken vocabulary from Time 1 to Time 2. Conclusion: Parent verbal utterances that follow into the child’s current focus of attention or respond to child verbal communication acts may facilitate the process of early vocabulary acquisition by mitigating the need for children with ASD to use attention-following as a word-learning strategy.

Purpose This study examined the impact of sampling context on multiple aspects of expressive language in males with fragile X syndrome in comparison to males with Down syndrome or typical development. Method Participants with fragile X syndrome (n = 27), ages 10 to 17 years, were matched groupwise on nonverbal mental age to adolescents with Down syndrome (n = 15) and typically developing 3- to 6-year-olds (n = 15). Language sampling contexts were an interview-style conversation and narration of a wordless book, with scripted examiner behavior. Language was assessed in terms of amount of talk, MLU of communication unit (MLCU), lexical diversity, fluency, and intelligibility. Results Participants with fragile X syndrome had lower MLCU and lexical diversity than participants with typical development. Participants with Down syndrome produced yet lower MLCU. A differential effect of context among those with fragile X syndrome, Down syndrome, and typical development emerged for the number of attempts per minute, MLCU, and fluency. For participants with fragile X syndrome, autism symptom severity related to the number of utterances produced in conversation. Aspects of examiner behavior related to participant performance. Conclusions Sampling context characteristics should be considered when assessing expressive language in individuals with neurodevelopmental disabilities.

The Autism Diagnostic Interview-Revised was used to examine diagnostic profiles and age-related changes in autism symptoms for a group of verbal children and adolescents with FXS, with and without autism. After controlling for nonverbal IQ, statistically significant between-group differences for lifetime and current autism symptoms were found for the Communication and Restricted Interests/Repetitive Behaviors domains, but not the Reciprocal Social Interaction domain. Effect sizes for differences in Reciprocal Social Interaction also were smaller than effect sizes for the other domains with one exception. Overall, severity of autism symptoms improved with age for all participants, with the least improvement noted for Restricted Interests and Repetitive Behaviors. FMRP did not account for unique variance in autism symptoms over and above nonverbal IQ. KeywordsFragile X syndrome; autism; diagnosis; intellectual disability; behavioral phenotype Autism Spectrum Disorder in Children and Adolescents with Fragile X Syndrome: Within-Syndrome Differences and Age-Related ChangesFragile X syndrome (FXS) is the most common inherited cause of intellectual disability. In general, prevalence rates have been reported as 1 in 4000 males and 1 in 8000 females (Crawford et al., 2001); however, recent studies have yielded rates closer to 1 in 2500 (Fernandez-Carvajal., Walichiewicz, Xiaosen, Pan, Hagerman, & Tassone, 2009;Hagerman, 2008). FXS is caused by an expansion of a repetitive CGG nucleotide sequence in the FMR1 gene, located on the X chromosome (Kaufmann & Reiss, 1999). This expansion causes methylation and transcriptional silencing of the gene, resulting in a reduction or absence of the protein that is normally produced (Kaufmann, Cortell, Kau, et al., 2004). This protein (FMRP) is critical for the regulation of processes involved in synaptic maturation, axonal guidance, and experience-dependent learning (Darnell, Warren, & Darnell, 2004;Hagerman, Ono, & Hagerman, 2005). Behaviors characteristic of autism are frequent in FXS, with many individuals meeting diagnostic criteria for autism (Hagerman, 1999 NIH Public Access Author ManuscriptAm J Intellect Dev Disabil. Author manuscript; available in PMC 2011 January 1. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript prevalence of autism in FXS at 25%, although recent studies utilizing diagnostic criteria for the full spectrum of autism disorders (i.e., inclusive of PDD-NOS) have reported rates approaching 50% (Demark, Feldman, & Holden, 2003;Kaufmann et al, 2004;Philofsky, Hepburn, Hayes, Hagerman, & Rogers, 2004). In the present study, we were interested in within-syndrome differences in, and the age-related trajectories of, autism symptoms in FXS.Although the association between FXS and autism has been well documented, the developmental course of autism within FXS is not well understood. It is not known whether the symptoms of autism are stable across development in FXS or whether there is an abatement of symptoms with age as has been observ...

Background: The evaluation of treatment efficacy for individuals with fragile X syndrome (FXS) or intellectual disability (ID) more generally has been hampered by the lack of adequate outcome measures. We evaluated expressive language sampling (ELS) as a procedure for generating outcome measures for treatment research in FXS. We addressed: (a) feasibility, (b) practice effects over two administrations, (c) test-retest reliability over the repeated administrations, and (d) construct validity. We addressed these issues for the full sample as well as for subgroups defined by age, IQ, and ASD status. Methods: Participants were 106 individuals with FXS between ages 6 and 23 years who had IQs within the range of intellectual disability (IQ < 70). ELS procedures for collecting samples in conversation and narration were followed and analyzed separately. Five measures were derived from transcripts segmented into C-units (i.e., an independent clause and its modifiers): number of C-units per minute (talkativeness), number of different word roots (vocabulary), C-unit length in morphemes (syntax), percentage of C-units containing dysfluency (utterance planning), and percentage of C-units that were fully or partly unintelligible (articulatory quality). ELS procedures were administered twice at 4-week intervals for each participant. Standardized tests and informant reports were administered and provided measures for evaluating construct validity of ELS measures.

Purpose Longitudinal associations between two categories of parent verbal responsiveness and language comprehension and production one year later were examined in 40 toddlers and preschoolers with a diagnosis of an autism spectrum disorder (ASD). Method Parent-child play samples using a standard toy set were digitally captured and coded for child engagement with objects and communication acts and for parent verbal responses to play and communication. Results After controlling for parent education, child engagement and initial language level, only parent directives for language that followed into the child's focus of attention accounted for unique variance in predicting both comprehension and production one year later. A series of exploratory analyses revealed that parent comments that followed into the child's focus of attention also accounted for unique variance in later comprehension and production for children who were minimally verbal at the initial time period. Conclusions Child developmental level may warrant different types of linguistic input to facilitate language learning. Children with ASD who have minimal linguistic skills may benefit from parent language input that follows into the child’s focus of attention. Children with ASD who are verbally fluent may need more advanced language input to facilitate language development.