Coarticulation facilitates lexical processing for toddlers with autism

Role of pitch in toddler looking to new and given referents in American English

This study examined how toddler looking to a discourse referent is mediated by the information status of the referent and the pitch contour of the referring expression. Eighteen-month-olds saw a short discourse of three sets of images with the proportion of looking time to a target analyzed during the final image. At test, the information status of the referent was either new or given and the referring expression was presented with one of three pitch contours (flat f0, monotonal (~H*), or bitonal (~L+H*)). In Experiment 1, toddlers looked reliably longer to a target referent when it was either new to the discourse or carried a non-flat pitch contour. In Experiment 2, the referring expression was removed to observe effects of information status alone on looking to a target referent. Toddlers looked significantly longer to a target when it was new versus given. More fine-grained time course analyses of eye movements revealed differences in the speed and duration of fixation to a target. Overall, the experiments show that discourse reference in toddlers is mediated by the presence of newness and pitch contours, even in the case of given information.

Neural Tracking in Infancy Predicts Language Development in Children With and Without Family History of Autism

During speech processing, neural activity in non-autistic adults and infants tracks the speech envelope. Recent research in adults indicates that this neural tracking relates to linguistic knowledge and may be reduced in autism. Such reduced tracking, if present already in infancy, could impede language development. In the current study, we focused on children with a family history of autism, who often show a delay in first language acquisition. We investigated whether differences in tracking of sung nursery rhymes during infancy relate to language development and autism symptoms in childhood. We assessed speech-brain coherence at either 10 or 14 months of age in a total of 22 infants with high likelihood of autism due to family history and 19 infants without family history of autism. We analyzed the relationship between speech-brain coherence in these infants and their vocabulary at 24 months as well as autism symptoms at 36 months. Our results showed significant speech-brain coherence in the 10- and 14-month-old infants. We found no evidence for a relationship between speech-brain coherence and later autism symptoms. Importantly, speech-brain coherence in the stressed syllable rate (1-3 Hz) predicted later vocabulary. Follow-up analyses showed evidence for a relationship between tracking and vocabulary only in 10-month-olds but not in 14-month-olds and indicated possible differences between the likelihood groups. Thus, early tracking of sung nursery rhymes is related to language development in childhood.

Predictive language processing in young autistic children

Recent theories propose that domain-general deficits in prediction (i.e., the ability to anticipate upcoming information) underlie the behavioral characteristics associated with autism spectrum disorder (ASD). If these theories are correct, autistic children might be expected to demonstrate difficulties on linguistic tasks that rely on predictive processing. Previous research has largely focused on older autistic children and adolescents with average language and cognition. The present study used an eye-gaze task to evaluate predictive language processing among 3- to 4-year-old autistic children (n = 34) and 1.5- to 3-year-old, language-matched neurotypical (NT) children (n = 34). Children viewed images (e.g., a cake and a ball) and heard sentences with informative verbs (e.g., Eat the cake) or neutral verbs (e.g., Find the cake). Analyses of children's looking behaviors indicated that young autistic children, like their language-matched NT peers, engaged in predictive language processing. Regression results revealed a significant effect of diagnostic group, when statistically controlling for age differences. The NT group displayed larger difference scores between the informative and neutral verb conditions (in looks to target nouns) compared to the ASD group. Receptive language measures were predictive of looking behavior across time for both groups, such that children with stronger language skills were more efficient in making use of informative verbs to process upcoming information. Taken together, these results suggest that young autistic children can engage in predictive processing though further research is warranted to explore the developmental trajectory relative to NT development.

Naturalistic parent-child reading frequency and language development in toddlers with and without autism

BACKGROUND AND AIMS

The efficacy of parent-child reading for supporting language development has been well-established in the neurotypical (NT) literature. For children with autism spectrum disorder, (ASD) who may be at risk for delays in language development, prior research has shown promise for shared book-reading interventions. Yet there has been limited research on naturalistic parent-child reading with autistic children to date. The present study aimed to fill this missing link in the current literature.

METHODS

Fifty-seven autistic toddlers participated at two developmental time points: Time 1 (Mage = 30.4 months) and Time 2 (Mage = 43.8 months). An NT control group (N = 31) was matched on age to a subset of the ASD group (N = 33). We assessed group differences in parent-child reading frequency between age-matched NT and autistic groups. Using a one-year follow-up design, we evaluated the relationship between parent-child reading and autistic children's language development.

RESULTS

Cross-group comparisons revealed that parents of age-matched NT children reported significantly more frequent weekly parent-child reading than parents of autistic toddlers. After a one-year follow-up with the autistic group, within-group analyses revealed that greater frequency of parent-child reading (controlling for maternal education, books in the home, and autism symptom severity) was associated with larger growth in autistic toddlers' receptive and expressive language skills.

CONCLUSIONS AND IMPLICATIONS

These findings have important clinical implications as they emphasize the potential of parent-child reading for supporting autistic children's language development. Findings demonstrate that frequency of parent-child reading is associated with language development over one year. Findings also demonstrate that parents of autistic children engage in less frequent parent-child reading than parents of age-matched NT peers, suggesting these parents may face more barriers to implementing parent-child reading than parents of NT children.