Verb comprehension and use in children and adults with Down syndrome.

PURPOSE Expressive syntax is a particular area of difficulty for individuals with Down syndrome (DS). In order to better understand the basis for sentence formulation deficits often observed in children and adults with DS, the authors explored the use and comprehension of verbs differing in argument structure. METHOD The authors examined verb and argument structure retrieval in 18 individuals, 9 with DS, age 11;11 (years;months) to 32;10 and 9 receptive vocabulary age-matched typically developing (TD) children, age 3;2 to 13;6. Participants completed verb and noun comprehension tasks, a working memory assessment, verb and noun naming tasks, grammaticality judgments, and narrative tasks. RESULTS Neither single verb comprehension nor single verb naming differentiated the DS and TD groups. Individuals with DS performed significantly worse than individuals who are TD when asked to judge sentence grammaticality. Individuals with DS omitted verbs in elicited narratives significantly more often than individuals who are TD, specifically when productions of 2-place and 3-place verbs were attempted. Individuals with DS also omitted other necessary elements of argument structure, such as subjects, in sentences containing 2-place and 3-place verbs significantly more often than individuals who are TD. Performance was not related to working memory skills. CONCLUSIONS Results indicate that individuals with DS do display a specific expressive deficit in verb and argument structure retrieval (but not comprehension) that varies as a function of verb type (1 place, 2 place, and 3 place).