Off-campus UNL users: To download campus access dissertations, please use the following link to log into our proxy server with your NU ID and password. When you are done browsing please remember to return to this page and log out.
Non-UNL users: Please talk to your librarian about requesting this dissertation through interlibrary loan.
Perceptual skills underlying phonological deficits in children: Evidence from behavioral and electrophysiological measures of speech perception
Deficits in phonology, which are related to the organization and retrieval of speech sounds in the mental lexicon are associated with two distinct clinical disorders, dyslexia (DYS) and speech-sound disorder (SSD). Three studies were conducted to identify the relationship between speech perception and phonological functioning in these children. Thirty-eight children (7;6–9;6 years) with DYS, SSD, DYS/SSD and their typically-developing (TD) peers participated in this investigation. The first study presented children with three syllable discrimination tasks to determine their sensitivity to specific acoustic-phonetic contrasts. All children performed discriminated /bα – wα/, an early-developing acoustic contrast, equally well. Children with phonological impairments had more difficulty discriminating a spectro-temporal cue distinguishing place of articulation, /dα – gα/ than TD children. Children with SSD performed poorly discriminating a spectro-temporal cue for a speech production error, /rα – wα/. However, children with DYS/SSD discriminated this same contrast with no difficulty, despite the fact children in both groups exhibited a similar speech production error. The second study evaluated the importance of non-linguistic characteristics of speech on children with phonological deficits and their TD peers during word recognition. All children performed equally well on the word recognition tasks. However, exploratory analysis revealed children with SSD exhibit particular weakness for the processing of fine spectral cues during word recognition. The third study evaluated underlying neural processes during speech identification of three syllable contrasts. Findings showed that children with phonological deficits exhibited electrophysiological processing differences as compared to their TD peers. Children with DYS or SSD exhibited delayed and inefficient neural processing for /dα – gα/, whereas children with DYS/SSD exhibited further delayed and more inefficient neural processing for this same contrast. Children with SSD and DYS/SSD discriminated /rα – wα/ at a significantly later stage of neural processing than their peers. These findings suggest children with disorders of phonology exhibit less efficient and less automatic neural processes for speech perception. Taken together, these studies provide evidence that measures of speech perception distinguish children with differing deficits in phonology. Further research is warranted to determine the utility of these measures for early identification for children at risk for long-term effects of these deficits.
Cabbage, Kathryn L, "Perceptual skills underlying phonological deficits in children: Evidence from behavioral and electrophysiological measures of speech perception" (2013). ETD collection for University of Nebraska - Lincoln. AAI3556519.