Developmental language disorder (DLD; aka specific language impairment) affects approximately 7% of children at the time they enter kindergarten, with longstanding adverse academic, social, and communicative consequences. While there is no question that language deficits feature prominently in children diagnosed with DLD, there are other cognitive and motor capacities affected?such as pattern induction, rhythmic grouping, and sequential organization. Previous findings show that the capacity for deploying sequentially patterned information mediates language and motor production. Sequential patterning is a central component of phonology and morphosyntax--domains of language difficulty presented in children with DLD. It has become apparent that this broad profile of deficits cannot be explained by a general motor co-morbidity, but rather forms a core component of DLD. Therefore, it is crucial to determine whether learning and generalization would be facilitated by the inclusion of these more basic cognitive operations. Indeed, an exclusive focus on language (especially morphosyntactic) factors in intervention has resulted in slow and laborious learning in children with DLD with only small gains observed. The central aim of the current project is to implement a novel framework for applying domain general cognitive mechanisms to learning and generalization; specifically all of the proposed experiments have in common the hypothesis that children with DLD will learn more effectively and generalize more broadly when targets are selected to emphasize the regularity of sequential patterns. The outcome of this work has the potential to inform early identification of very young children--when sequence learning (but not grammatical) deficits may be identified--and to alter the substance of intervention to incorporate broad cognitive, language, and motor mechanisms that underlie DLD. The planned studies consist of learning paradigms conducted over multiple sessions that manipulate sequential pattern learning in the spoken language and manual domains. Behavioral measures (e.g., of production accuracy) will be combined with motor measures of oral and manual movement to evaluate when in a learning sequence children acquire more stable patterns or are able to predict the element that comes next. As a control, a separate cohort of children will engage in similar learning experiences, with the critical difference being that the stimuli they are exposed to will not contain sequential patterns. The over-arching goal of Aims 1 and 2 is to determine whether and how sequential pattern regularities incorporated in the input and in production practice facilitate the acquisition and generalization of phonological regularities in words and signs (Aim 1) and grammatical regularities in sentences and rhythmic musical sequences (Aim 2).
In Aim 3, modifications of the serial reaction time task will be used to determine how manipulations of sequential patterns influence learning when language and cognitive demands are reduced.
Developmental language disorder (DLD) affects 7% of young school age children. Children with DLD have deficits that limit their language and their motor development, with poor academic and social outcomes. In this project children with DLD will participate in a series of complex language and motor activities that are designed to enhance learning and generalization. The goal is to translate recent scientific discoveries about language production and motor action into learning approaches that are broad, effective, and sustained. This research will lead to new knowledge that will influence the treatment of disabilities, and thus is consistent with the mission of the NIH.