Browsing by Subject "Speech-Language-Hearing Sciences"
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Item A comparison between nonlinguistic cognitive processing treatment and traditional language treatment for bilingual children with primary language impairment(2011-07) Ebert, Kerry DanahyBackground: Children with Primary Language Impairment (PLI) show subtle weaknesses in nonlinguistic cognitive processing (NCP) skills such as attention, memory, and speed of processing. It is possible that these weaknesses contribute causally to the language delays that characterize PLI. For bilingual children with PLI, NCP weaknesses would underlie language learning ability for both languages. The purpose of this study was to explore the relationship between NCP skills and language skills in bilingual children with PLI by treating processing speed and attention. Methods: A total of 24 participants in three groups (NCP treatment, English language treatment, and delayed treatment control) completed the study protocol. All participants were Spanish-English bilingual children with PLI between the ages of 6 and 10 years. All participants completed an extensive battery of assessments indexing NCP, English language, and Spanish language skills both before and after a treatment cycle. Analyses examined change for individuals, for each group separately, and for the three groups in comparison to one another. Results: Children who completed the NCP treatment showed significant change in processing speed and in overall English language skills. However, children who completed the English language treatment tended to make greater gains, both in English and in NCP skills. Few comparisons between the three groups reached significance, in part because the delayed treatment control group tended to make positive change and in part because of the small sample size. Individual variability was apparent across all three groups, but particularly pronounced for Spanish. Conclusions: The results support a connection between NCP and language skills in children with PLI. Language-based treatment programs may effectively alter NCP skills, and NCP treatment programs may alter language skills.Item Dual language development among Vietnamese-English bilingual children:modeling trajectories and cross-linguistic associations within a dynamic systems framework.(2011-06) Pham, Giang ThuyThe purpose of this longitudinal study was to mathematically model first and second language trajectories and interactions among developing sequential bilingual school-age children. Language data were collected in four waves, with a one-year interval between each wave. Participants (N = 34, mean age of 7.3 at Wave 1) lived in the US, spoke Vietnamese as a first and home language (L1) and began learning the majority community language, English (L2), in early childhood. Children completed measures in the L1 and L2 at lexical, grammatical, and discourse subsystems each year for four consecutive years. Multivariate hierarchical linear models were calculated to examine the shape and rates of change for the two languages nested within individual children. Associations within and between languages were examined across different language subsystems at each wave and over time in a series of correlational and longitudinal analyses. Results showed (a) positive growth across all language subsystems for the L1 and L2 with relatively more rapid gains in the L2, (b) moderate to strong positive associations between languages at each wave and over time, (c) bidirectional cross-linguistic transfer, and (d) changes in the nature of L1-L2 relationships with age. Findings are interpreted within a Dynamic Systems framework in which a child's language system emerges from multiple interactions across cognitive, social and language systems as well as interactions within and between languages (de Bot, Lowie, & Verspoor, 2007; Kohnert, 2007).Item The Effects of Listener Bias on the Perception of Accuracy in Children’s Speech(2009-04-08) Meyer, Marie K.Phonetic transcription is a tool that has long been used by speech-language pathologists (SLPs) to record children's productions of speech sounds. Transcription employs a level of of detail that allows SLPs to assess whether children produce speech sounds accurately, and to track progress during the treatment of production errors. Transcription has generally been considered to be an objective method, and not subject to bias when used by clinicians with professional training. In contrast, previous work (Schellinger, Edwards, Munson, and Beckman, 2008a,b,c) suggested that listener's expectations about a child's age and development can affect his or her rating and subsequent transcription of the child's production. Schellinger et al. found only a small biasing effect in their experiment. The goal of this UROP project was to further investigate the strength of listener bias, and to explore the factors that influence bias. In the Spring 2009, I ran three experiments in which subjects rated the accuracy of 200 productions of the "s" sound by preschool children. Listeners were led to believe they were produced either by an older, typically developing child, or a younger child with speech-production errors. I examined whether the adult listeners shifted their criteria for a correct "s" as a function of their assumptions about the child's age/ability level. The three experiments differed slightly in the expectations about the child that were given to the subjects. This allowed us to better understand why listeners are biased by expectations. The results of the project will help us develop more objective clinical assessments.Item Spectral resolution and speech recognition in noise by cochlear implant users.(2011-07) Anderson, Elizabeth SusanFor cochlear implant (CI) users, the relationship between spectral resolution and speech perception in noise has remained ambiguous. An even more fundamental question has been how to measure spectral resolution in CI listeners. This dissertation describes work exploring the relationships among different measures of spectral resolution, and between each of those measures and speech recognition in quiet and in noise. Spectral ripple discrimination was found to correlate strongly with spatial tuning curves, when the measures were matched in frequency region. Broadband spectral ripple discrimination correlated well with sentence recognition in quiet, but not in background noise. Spectral ripple detection correlated strongly with speech recognition in quiet, but its validity as a measure of spectral resolution was not empirically supported. Spectral ripple discrimination thresholds were compared to sentence recognition in noise, using spectrally-limited maskers that did not overlap with the entire speech spectrum. Speech reception thresholds were measured in the presence of four low- or high-frequency maskers, all bandpass-filtered from speech-shaped noise, and a broadband masker encompassing most of the speech spectrum. The findings revealed substantial between-subject variability in susceptibility to masking by each of these noises and in spectral release from masking, which cannot be explained simply in terms of energetic masking and does not appear to be strongly related to spectral resolution. Better CI users appeared to show stronger relationships between spectral resolution and speech perception than did poorer users, implying that advanced CI processing strategies designed to maximize the number of spectral channels may not benefit all CI users equally.