This program of research is designed to explore the status of the lexicon in young children with specific language impairment (SLI). The research plan is based on the premises that: (1) the lexical production problems of children with SLI are rooted in deficits in lexical storage; (2) comparisons between children with and without SLI can be used to characterize the nature of lexical storage deficits associated with SLI and (3) a more complete understanding of these lexical storage deficits will lead to more efficacious treatment for lexical production in children with SLI. Participants are 20 preschoolers who have SLI, their 40 normally-developing age-matched cohorts and their 40 normally- developing, younger, language-matched cohorts. These experiments are motivated by Levelt's (1991) speech production model, and, in particular, his notion of lemma and lexeme representation and access. Specifically, it is hypothesized that the lemma is particularly underdeveloped in children with SLI and that this proble may be traced back to atypical semantic mapping during early word learning. Four experiments are designed to investigate the organization and elaboration of the semantic lexicon. A fifth experiment is designed to determine what semantic information is initially stored when children with SLI and their cohorts map new words. A sixth experiment will test the efficacy of intervention aimed at improving lexical production for children with SLI by enhancing their semantic knowledge.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
1R29DC003698-01
Application #
2593435
Study Section
Sensory Disorders and Language Study Section (CMS)
Project Start
1998-06-01
Project End
2003-05-31
Budget Start
1998-06-01
Budget End
1999-05-31
Support Year
1
Fiscal Year
1998
Total Cost
Indirect Cost
Name
Northwestern University at Chicago
Department
Other Health Professions
Type
Schools of Arts and Sciences
DUNS #
City
Evanston
State
IL
Country
United States
Zip Code
60201
Hashimoto, Naomi; McGregor, Karla K; Graham, Anne (2007) Conceptual organization at 6 and 8 years of age: evidence from the semantic priming of object decisions. J Speech Lang Hear Res 50:161-76
Newman, Robyn M; McGregor, Karla K (2006) Teachers and laypersons discern quality differences between narratives produced by children with or without SLI. J Speech Lang Hear Res 49:1022-36
Capone, Nina C; McGregor, Karla K (2005) The effect of semantic representation on toddlers' word retrieval. J Speech Lang Hear Res 48:1468-80
McGregor, Karla K; Sheng, Li; Smith, Bruce (2005) The precocious two-year-old: status of the lexicon and links to the grammar. J Child Lang 32:563-85
McGregor, Karla K; Capone, Nina C (2004) Genetic and environmental interactions in determining the early lexicon: evidence from a set of tri-zygotic quadruplets. J Child Lang 31:311-37
Capone, Nina C; McGregor, Karla K (2004) Gesture development: a review for clinical and research practices. J Speech Lang Hear Res 47:173-86
McGregor, Karla K; Newman, Robyn M; Reilly, Renee M et al. (2002) Semantic representation and naming in children with specific language impairment. J Speech Lang Hear Res 45:998-1014
McGregor, Karla K; Appel, Alison (2002) On the relation between mental representation and naming in a child with specific language impairment. Clin Linguist Phon 16:1-20
McGregor, Karla K; Friedman, Rena M; Reilly, Renee M et al. (2002) Semantic representation and naming in young children. J Speech Lang Hear Res 45:332-46