Auditory Speech Processing in Hearing Impaired Children

点击翻译按钮获取中文摘要

DESCRIPTION (provided by applicant): To learn to communicate, children must abstract and store the meanings and names of words. Auditory input dominates this early lexical learning, which raises an issue about lexical development in children with hearing loss (HL) who use aural/oral communication. Our goal is to explicate the development of word representations and processes in normal hearing (NH) children and children with HL. We hypothesize that HL degrades and filters auditory input, resulting in 1) less rich semantic categorical knowledge, 2) less well specified phonological representations, and 3) slower & less efficient processing. Visual speech assumes a more important role in the acquisition of words, particularly for phonological knowledge. The research will apply a cross modal picture-word task using early-learned words and phonemes to assess the influence of semantically- or phonologically-related speech word-distractors on picture naming. If a to-be-ignored speech distractor slows down or speeds up picture naming, performance is assumed to reflect informational crosstalk between the comprehension and production systems. The patterns of crosstalk provide a basis for hypothesizing about the nature of the representations and processes underlying performance. The timing relation between the onsets of the distractors and pictures, termed stimulus onset asynchrony (SOA), also varies. The patterns of interference/facilitation across SOAs allow one to make inferences about the time course of lexical semantic or phonological processing. Previous results found that 1) some children with HL had a protracted time course of semantic interference and 2) a lack of phonological effects even for discriminated phoneme contrasts, implying prolonged lexical semantic activation and less fine grained or less auditorily based phonological representations. Previous results were constrained, however, by an inability to fully map out 1) the time course of phonological activation, 2) the influence of participant characteristics and distractor recognition/phoneme discrimination abilities on naming, and 3) the role of visual speech as a source of phonological knowledge. The proposed research corrects these constraints. We will apply auditory and audiovisual versions of the picture-word task to address 3 specific aims: namely, to determine 1) developmental change in the patterns of interference/facilitation in NH children between 3-4 yrs of age, which will inform interpretation of results in children with HL, 2) developmental change in the patterns of interference/facilitation in children with HL, and 3) the influence of auditory only versus audiovisual input on the patterns of interference/facilitation in children, NH & HL. By joining together the resources of UTD and CID, we have a unique opportunity to explore the nature of lexical semantic and phonological representations and the dynamics of the speech processing system in children, NH & HL. Such knowledge should lead to improved intervention strategies, expanding social, educational, and vocational opportunities for children with HL.