Visualising articulation: real-time ultrasound visual biofeedback and visual articulatory models and their use in treating speech sound disorders associated with submucous cleft palate
Abstract
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.