Investigating intervention : phonological therapy in a psycholinguistic framework.

This thesis investigates intervention for school-aged children with speech and literacy difficulties. Many previous studies have used phonological analysis as a theoretical basis, while others have used psycho linguistic models. The present study combines these approaches to assessment, intervention and evaluation of outcomes using a single case pre-post design for five children, aged 5;6 - 8;6 years.
The research aimed to determine if intervention could result in (a) specific and (b) generalised improvements in the speech processing skills of children with severe and persisting difficulties. Assessment took place at two levels. First, the macro level focused on global change in each child's speech processing skills using psycho linguistic speech profiling, phonological analyses and intelligibility evaluations. Second, the micro level assessment focused on specific, treated and matched control stimuli, and was used to evaluate generalisation for each child. Changes at each level are used to contribute to the clinical evidence base and to inform theory of children's speech processing.
Key areas highlighted by individual cases include stimuli selection; connected speech; production and perception of consonant clusters, and links between speech and spelling difficulties. Themes emerging across the cases are the links between theory and therapy, the integration of developmental and information-processing perspectives, the complementary relationship between profiling and sub-grouping approaches as a means of dealing with the heterogeneity of the population and intelligibility as a clinical outcome measure.
Intervention brought about significant improvements in each child's speech processing at the micro level. The extent of generalisation varied across children. For some, change extended to the macro level including significantly increased intelligibility. For others, change was limited to the micro level. The fundamentally different nature of the children's speech processing profiles is considered together with ways in which speech-processing models might be developed. The case studies collectively contribute towards the development of a theory of therapy grounded in a psycho linguistic framework.