Narrative language competence in children and adolescents with Down syndrome.

This study was designed to examine the narrative language abilities of children and adolescents with Down syndrome (DS) in comparison to same-age peers with fragile X syndrome (FXS) and younger typically developing (TD) children matched by nonverbal cognitive ability levels. Participants produced narrative retells from a wordless picture book. Narratives were analyzed at the macrostructural (i.e., their internal episodic structure) and the microstructural (i.e., rate of use of specific word categories) levels. Mean length of utterance (MLU), a microstructural metric of syntactic complexity, was used as a control variable. Participants with DS produced fewer episodic elements in their narratives (i.e., their narratives were less fully realized) than the TD participants, although MLU differences accounted for the macrostructural differences between participant groups. At the microstructural level, participants with DS displayed a lower rate of verb use than the groups with FXS and typical development, even after accounting for MLU. These findings reflect both similarities and differences between individuals with DS or FXS and contribute to our understanding of the language phenotype of DS. Implications for interventions to promote language development and academic achievement are discussed.

Effect of speaker gaze on word learning in fragile X syndrome: a comparison with nonsyndromic autism spectrum disorder.

PURPOSE: This study examined use of a speaker's direction of gaze during word learning by boys with fragile X syndrome (FXS), boys with nonsyndromic autism spectrum disorder (ASD), and typically developing (TD) boys. METHOD: A fast-mapping task with follow-in and discrepant labeling conditions was administered. We expected that the use of speaker gaze would lead to participants selecting as the referent of the novel label the object to which they attended in follow-in trials and the object to which the examiner attended in the discrepant labeling trials. Participants were school-aged boys with FXS (n=18) or ASD (n=18) matched on age, intelligence quotient, and nonverbal cognition and younger TD boys (n=18) matched on nonverbal cognition. RESULTS: All groups performed above chance in both conditions, although the TD boys performed closest to the expected pattern. Boys with FXS performed better during follow-in than in discrepant label trials, whereas TD boys and boys with ASD did equally well in both trial types. The type of trial administered first influenced subsequent responding. Error patterns also distinguished the groups. CONCLUSION: The ability to utilize a speaker's gaze during word learning is not as well developed in boys with FXS or nonsyndromic ASD as in TD boys of the same developmental level.

Effects of labeling and pointing on object gaze in boys with fragile X syndrome: an eye-tracking study.

We examined the visual processing of a social learning stimulus and the ways in which visual attention was distributed to objects as well as to the examiner's face during word learning under conditions that varied only in the presence or absence of a label. The goal of the current study, then, was to evaluate the effects of differentially providing pointing and labeling during exposure to a novel target object in males with fragile X syndrome (FXS) (n=14, ages 4.33-10.02), autism spectrum disorder (ASD) (n=17, ages 4.04-10.4), or typical development (TD) (n=18, ages 2.05-5.33). In particular, the present study examined attention to the examiner's face as well as target and distracter objects that were presented as video stimuli. An eye-tracker captured gaze to the video stimuli as they were shown in order to examine the way in which children with FXS, ASD, or TD distributed their gaze toward the examiner and the objects. Results indicated that no group showed increased gaze toward the target object compared to the distracter object. However, results revealed that participants with FXS showed significantly increased face gaze compared to the novel objects, whereas children with ASD and TD both showed similar amounts of relative gaze toward the face and objects. Furthermore, the act of pointing at the target object was found to increase gaze toward the target objects compared to when there was no pointing in all groups. Together, these findings suggest that social cues like those employed in a word-learning task, when presented with video, may relate to gaze in FXS in context- or task-dependent ways that are distinct from those expected during live interaction.

Receptive vocabulary in boys with autism spectrum disorder: cross-sectional developmental trajectories.

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 (4-11 years) and 80 typically developing boys (2-11 years). Receptive vocabulary, assessed with the Peabody Picture Vocabulary Test, was a weakness for boys with ASD relative to age and nonverbal cognition. Relative to expressive vocabulary, assessed with the Expressive Vocabulary Test, receptive vocabulary increased at a lower rate for boys with ASD. Vocabulary trajectories in ASD are distinguished from typical development; however, nonverbal cognition largely accounts for the patterns observed.

Object interest in autism spectrum disorder: a treatment comparison.

A randomized control trial comparing two social communication treatments for children with autism spectrum disorder examined the effect of treatment on object interest. Thirty-two children, 18-60 months, were randomly assigned to the Picture Exchange Communication System (PECS) or Responsive Education and Prelinguistic Milieu Teaching (RPMT) condition. Assessment of object interest was conducted in an unstructured play session with different toys, activities, adult, and location than experienced in treatment. Results indicated children in the RPMT condition showed greater increases in object interest as compared to children in the PECS condition. Because child characteristics such as interest in objects may influence response to interventions using object play as contexts for treatment, it is important to improve our understanding of whether intervention can affect object interest.

A comparison of contexts for assessing joint attention in toddlers on the autism spectrum.

Children on the autism spectrum often demonstrate atypical joint attention, leading some researchers to consider joint attention deficits a core feature of the autism spectrum. Structured measures, such as the Early Social Communication Scales (ESCS), are commonly used to provide a metric of joint attention. To explore the assessment of joint attention in multiple contexts, we implemented an alternative system for coding joint attention behaviors. We compared initiation of joint attention (IJA) and response to joint attention (RJA) behaviors coded from naturalistic examiner-child play samples with similar IJA and RJA behaviors elicited within the structured ESCS protocol. Participants were 20 toddlers on the autism spectrum. Levels of IJA and RJA within the two assessment contexts were significantly and positively correlated, providing support for the use of naturalistic sampling of joint attention skills as a viable alternative, or supplement, to structured measures.

Use of speaker intent and grammatical cues in fast-mapping by adolescents with Down syndrome.

PURPOSE: The authors asked whether adolescents with Down syndrome (DS) could fast-map novel nouns and verbs when word learning depended on using the speaker's pragmatic or syntactic cues. Compared with typically developing (TD) comparison children, the authors predicted that syntactic cues would prove harder for the group with DS to use and that action verbs would be harder to fast-map than nouns. METHOD: Twenty participants with DS, aged 12-18 years, and 19 TD participants, aged 3-6 years, were matched on syntax comprehension and engaged in 4 fast-mapping tasks. Both comprehension and production of novel words were assessed for each task. Through use of hierarchical regression models, hearing, cognition, and working memory were considered as predictors of total comprehension and production performance for each group. RESULTS: Both groups used speaker intent in fast-mapping labels to object referents but performed more poorly on fast-mapping verbs. Neither group appeared to use grammatical cues to disambiguate the intended referent. Syntax comprehension was replicated as a predictor of fast-mapping comprehension for the DS group. Syntax comprehension and chronological age were replicated as predictors of TD fast-mapping. CONCLUSION: Participants with DS had better recall for the object or action seen most recently during speaker intent tasks. They had better recall for the object presented first and the action presented last during grammatical cue tasks. Response patterns may have depended on the structure of specific task paradigms. Verb acquisition may be facilitated when either the action or label is familiar.

Labels increase attention to novel objects in children with autism and comprehension-matched children with typical development.

This study used an intact group comparison to examine attention following in 34 children aged 2 years diagnosed with autism spectrum disorder (ASD) matched pairwise for vocabulary comprehension with a group of typically developing toddlers. For both groups of children, the presence of verbal labels during a referential task increased attention to a novel object over and above the attention-facilitating effect of child-directed talking without labeling. The typically developing children displayed more attention following than comprehension matched children with ASD across experimental conditions and there was no significant difference between the groups in the facilitative effect of hearing verbal labels. Implications for word-learning theory, intervention strategies and future research are considered.