Treating Complex Sentences in Children With DLD

AIMS For later-developing language skills, including those involving complex sentence forms, there are not only very few treatment studies, but effect sizes for the few that exist are quite modest. The investigators propose that the unexceptional treatment outcomes may be attributed to two issues: 1) the reliance on treatment methods that were developed primarily for preschoolers and that lie on the more explicit end of an implicit-to-explicit treatment continuum and 2) treatments that ignore the mapping of semantic roles to the main nouns that express the agent-patient relationship. The investigators hypothesize that explicit treatment methods in which children are taught to consciously apply a simple semantic mapping rule will result in strong in-treatment performance but at the cost of building implicit mental representations of semantic-syntactic mapping necessary to automatically and unconsciously apply this knowledge to untrained linguistic contexts.

The investigators will test this overarching hypothesis by using implicit and explicit intervention methods in two treatment studies. Two randomized clinical trials, one targeting subject-object relative sentences and the other targeting passive sentences, will test the degree to which results for the implicit and explicit therapy approaches replicate across different syntactic structures. Importantly, the investigators will hold critical aspects of treatment (e.g., dose number, session duration and spacing) and stimulus parameters constant across treatment methods to isolate effects to differences in treatment method. Finally, the clinical relevance of the previously modeled relationship between complex sentence comprehension and memory in the context of treatment outcomes that target these sentence types will be assessed. The two overarching aims are:

Aim 1. To determine whether explicit and implicit treatments will improve complex sentence knowledge and use in 8 to 11-year-old children with DLD.

Hypothesis 1a. Both treatments will be superior to no treatment. Hypothesis 1b. Children receiving the Explicit treatment will perform well on a proximal outcome measure that is structured similarly to the Explicit treatment format, but relatively poorly on distal outcome measures of language knowledge that require a strong mental representation of the syntactic form. Children receiving the Implicit treatment will show the opposite pattern of results.

Hypothesis 1c. The shift in mental representation for the syntactic template will affect children's ability to generalize the trained sentence form in a narrative context.