Lexical access in school-aged children with and without specific language impairment.
Item
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Title
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Lexical access in school-aged children with and without specific language impairment.
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Identifier
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AAI3159256
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identifier
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3159256
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Creator
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Seiger, Liat.
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Contributor
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Adviser: Richard G. Schwartz
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Date
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2005
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Language
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English
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Publisher
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City University of New York.
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Subject
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Health Sciences, Speech Pathology
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Abstract
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One of the hallmarks of school-aged children with Specific Language Impairment (SLI) is word-finding difficulty. Semantic or phonological deficits were postulated to underlie this difficulty. The present study was designed to investigate the process of lexicalization during language production in children with and without SLI using the Cross Modal Picture - Word Interference Paradigm. Picture presentations were manipulated in time relative to the presentation of auditory interfering stimuli (i.e., Stimulus Asynchrony-SA). Interfering stimuli appeared before (SA-150ms), with (SA0ms), and after (SA+150, +300, & +500ms) the presentation of the pictures. The interfering stimuli were either related semantically or phonologically to the target pictures, or unrelated. Subjects were instructed to name the pictures as quickly as possible while ignoring the interfering stimuli. Reaction times to naming were measured.;Fourteen children with SLI (ages 8--10), 20 children with Typical Language Development (TLD) (ages 8--10), and 20 adults participated in the study. Results revealed similar temporal patterns of lexical access in the adult and TLD groups, supporting the notion of similar underlying mechanisms of lexicalization in children and adults. Qualitative differences in the process of lexical access were apparent in the SLI group compared to the TLD and the Adult groups. Persistent semantic inhibition effects over time and the presence of a late semantic inhibition effect at SA +300 in the SLI group suggested a breakdown at the semantic level. A strong phonological facilitation effect suggested that children with SLI are capable of utilizing phonological primes to ease lexical access. Reaction times on a simple naming task (in the absence of distractors) revealed no differences between the SLI and the TLD groups. However, slower reaction times in the presence of distractors in the SLI group suggested that these children's deficits are localized to the lexical system and not to a general slowing mechanism. The children's data support the predictions of the time course of lexical access made by the interactive model, Cascaded Processing Model. Clinical implications of the results of this study are discussed.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
