Language profiles in children with Down syndrome and children with language impairment: implications for early intervention.

This study investigated early language profiles in two groups of children with developmental disability: children with Down Syndrome (DS, n=13) and children with Language Impairment (LI, n=16). Vocabulary and grammatical skills in the two groups were assessed and compared to language skills of typically developing (TD) children matched on size of either their receptive or expressive vocabulary (n=58). The study aimed to establish if language development in these groups is delayed or fundamentally different than the TD groups, and if the group with DS showed a similar language profile to the group with LI. There is a clinical motivation to identify possible key risk characteristics that may distinguish children who are likely to have LI from the variation observed in TD children. Three clear findings emerged from the data. Firstly, both receptive and expressive vocabulary compositions did not significantly differ in the clinical groups (DS and LI) after being matched to the vocabulary size of TD children. This provides further support for the idea that word learning for the children in the clinical groups is delayed rather than deviant. Secondly, children with LI showed a significantly larger gap between expressive and receptive word knowledge, but children with DS showed a pattern comparable to TD children. Thirdly, children with LI who understood a similar number of words as the TD children still had significantly poorer grammatical skills, further underlining the dissociation between lexical and grammatical skills in children with LI. Grammatical skills of children with DS were commensurate with their lexical skills. The findings suggest that language intervention should be specifically tailored to etiology rather than focused on general communication strategies, particularly in children with LI.