Visualising articulation: real-time ultrasound visual biofeedback and visual articulatory models and their use in treating speech sound disorders associated with submucous cleft palate
Background: Ultrasound Tongue Imaging (UTI) is growing increasingly popular for assessing and treating Speech Sound Disorders (SSDs) and has more recently been used to qualitatively investigate compensatory articulations in speakers with cleft palate (CP). However, its therapeutic application for speakers with CP remains to be tested. A different set of developments, Visual Articulatory Models (VAMs), provide an offline dynamic model with context for lingual patterns. However, unlike UTI, they do not provide real-time biofeedback. Commercially available VAMs, such as Speech Trainer 3D, are available on iDevices, yet their clinical application remains to be tested. Aims: This thesis aims to test the diagnostic use of ultrasound, and investigate the effectiveness of both UTI and VAMs for the treatment of SSDs associated with submucous cleft palate (SMCP). Method: Using a single-subject multiple baseline design, two males with repaired SMCP, Andrew (aged 9;2) and Craig (aged 6;2), received six assessment sessions and two blocks of therapy, following a motor-based therapy approach, using VAMs and UTI. Three methods were used to measure therapy outcomes. Firstly, percent target consonant correct scores, derived from phonetic transcriptions provide outcomes comparable to those used in typical practice. Secondly, a multiplephonetically trained listener perceptual evaluation, using a two-alternative multiple forced choice design, to measure listener agreement provides a more objective measure. Thirdly, articulatory analysis, using qualitative and quantitative measures provides an additional perspective able to reveal covert errors. Results and Conclusions: There was overall improvement in the speech for both speakers, with a greater rate of change in therapy block one (VAMs) and listener agreement in the perceptual evaluation. Articulatory analysis supplemented phonetic transcriptions and detected covert articulations and covert contrast as well as supporting the improvements in auditory outcome scores. Both VAMs and UTI show promise as a clinical tool for the treatment of SSDs associated with CP.