Courtney E. Venker, Ph.D. - US grants

DESCRIPTION (provided by applicant): Many children with autism spectrum disorders (ASD) have difficulty learning words, which negatively impacts their functional independence and quality of life. Unfortunately, relatively little is known about the learning mechanisms that underlie these deficits, which has important theoretical and clinical implications. This study will address this gap in knowledge by examining the impact of statistical learning and non-social visual attention on word learning in children with ASD. Implicit eye-gaze methods will be the primary methodology because they capture real-time information about learning and attention. Because of their limited task demands, these methods are appropriate for children with a range of abilities. Many studies have focused exclusively on high-functioning children with ASD, thus limiting research and clinical implications for the broader population. The use of eye-gaze methodology in this study facilitates the inclusion of children with a broad range of language and attentional abilities. Statistical learning (i.e., sensitivity to linguistic regularities) is a roust language-learning mechanism in typical development, but almost nothing is known about statistical learning in autism. Specific Aim 1 (Study 1) investigates a form of statistical learnin known as cross-situational word learning, which supports word learning in ambiguous contexts. Because children with ASD have difficulty using social cues to determine word meanings and thus experience many ambiguous learning situations, it is vital to characterize their cross-situational word-learning abilities. It is hypothesized that the ASD group will have impaired cross-situational learning abilities but that considerable variability will emerge. Specific Aim 2 will characterize this variability by examining two prerequisite skills--the ability to recognize recurring visual stimuli across contexts (Study 2a) and the ability to form a label-object association (Study 2b). A significant relationship between prerequisite skills and cross-situational learning is anticipated in the ASD group. It is well known that children with ASD demonstrate atypical social attention (e.g., joint attention), but many children also demonstrate impairments in non-social visual attention. Specifically, many children with ASD show atypical attentional orienting (e.g., prolonged disengagement of attention) that may impact their ability to use cross-situational learning mechanisms. Specific Aim 3 (Study 3) will investigate the relationship between cross-situational learning and an established, independent visual orienting task. Study 4 will be an exploratory study that examines the relationship between visual orienting during the training phase of the cross-situational learning task (Study 1), and learning outcomes. This study is based on recent work with typically developing infants. Visual orienting, specifically disengagement, is expected to predict cross-situational learning in children with ASD in Studies 3 and 4. Findings from this study will inform theories of ASD and language acquisition, and may have clinical implications for maximizing the effectiveness of existing treatment paradigms and designing new intervention programs to facilitate language acquisition in children with ASD. PUBLIC HEALTH RELEVANCE: The goal of this research is to understand the mechanisms that underlie word-learning deficits in children with autism spectrum disorders (ASD). Specifically, this study will evaluate cross-situational word learning in children with ASD, examine the impact of prerequisite learning skills, and characterize the relationship between non-social attention and cross-situational word learning. This work will inform theories of autism and theories of language acquisition. Study findings may also have implications for maximizing the effectiveness of existing language treatments and designing novel intervention programs for children with ASD.

PROJECT SUMMARY/ABSTRACT In addition to their well-known deficits in language learning, young children with autism spectrum disorder (ASD) show abnormal visual preferences for perceptually salient features of the environment (e.g., complex geometric patterns). Recent studies have revealed an association between these two aspects of the ASD phenotype, leading to the provocative hypothesis that abnormal visual preferences have cascading negative effects on language development. However, we do not yet know how abnormal visual preferences impact language in children with ASD, or which children are most vulnerable to these effects. In the absence of such knowledge, we have an incomplete understanding of why these children struggle to learn language and how to alleviate their difficulties. The long-term goal is to identify the developmental mechanisms that underlie language-learning deficits in children with ASD. The overall objective of the proposed project is to determine how abnormal visual preferences impact familiar word processing and novel word learning, and to identify the children who are most severely affected. The central hypothesis is that abnormally strong visual preferences for perceptual salience will disproportionately disrupt word processing and word learning in children with ASD, and that the amount of disruption will correlate with key behavioral characteristics. The rationale is that determining how abnormal visual preferences impact word processing and word learning will help us understand why children with ASD have difficulty learning language, thereby yielding valuable theoretical and clinical advances. Guided by strong preliminary data, the proposed project will investigate three specific aims: 1) To assess the impact of competing perceptual salience on familiar word processing in children with ASD and age-matched, typically developing children; 2) To assess the impact of competing perceptual salience on novel word learning in children with ASD and age-matched, typically developing children; and 3) To identify behavioral characteristics that correlate with the amount of disruption in word processing and word learning created by competing perceptual salience. These aims will be addressed using eye-gaze methodology, an approach that the PI has used extensively and has shown to be feasible with the target populations. Novel adaptations of two well-established eye-gaze tasks will assess the impact of competing perceptual salience on familiar word processing (Aim 1) and novel word learning (Aim 2). Growth curve analyses will measure the amount of disruption experienced by individual children, as well as the contributions of key behavioral characteristics (e.g., receptive vocabulary; Aim 3). The proposed project is innovative because it adopts a novel methodological approach and integrative theoretical framework that maximize its potential to exert a substantial and lasting impact on the field. The proposed research is significant because it is expected to advance theories of autism and language acquisition and enable the development of novel treatment strategies that limit detrimental effects of competing perceptual salience.