Visual feedback technology with a focus on ultrasound : the effects of speech habilitation for adolescents with sensorineural hearing loss

Developments in instrumentation offer new possibilities in habilitation for speech-language pathology. The series of studies in this manuscript-style thesis represents an investigation of two articulatory feedback instruments, ultrasound and electropalatography, in speech habilitation for adolescents with hearing loss and related speech impairments. The first study in the dissertation investigated the outcomes for vowel intervention for three adolescents with hearing impairment. Acoustic analysis and expert transcription with perceptual anchors showed positive outcomes for all participants (Bacsfalvi et al., 2007).The next study focused on three adolescent cochlear implant users with long-term speech errors secondary to deafness. All students were successful in learning the articulatory gestures components of the target phoneme /[upside-down r]/, and one made significant progress in using the new phones in words. An additional finding of the first two papers concerned the tongue shapes and tongue-palate contacts of the speakers. Their tongue movements pre-treatment were similar to those of very young children (Green et al., 2000; Oh, 2005), who also show little or no differentiation of the parts of the tongue, lip and jaw during speech production. Post-therapy, these speakers showed a greater range of tongue movement, more similar to hearing speakers. Two longer-term outcomes studies followed. The first study examined the speech of the seven former participants 2-4 years post intervention. Perceptual judgements by expert listeners suggested that six out of seven speakers either maintained or continued to improve their level of immediate post-treatment performance. A qualitative study based on interview revealed the experiences of therapy with visual feedback technology for five of the clinical investigation participants and five related stakeholders. Key themes that emerged were: "better speech", "improvement", "visual feedback is helpful", "remembering what was learned", and "new information". The series of studies contribute to speech development research in speakers with severe hearing loss in addition to investigating advances in habilitation methods. The results show that ultrasound and electropalatography, as adjuncts to speech therapy, can increase speaker intelligibility, self-confidence and oral communication and have the potential to reduce treatment time and increase cost-effectiveness of treatment. Further large-scale investigation is warranted, for speakers with and without hearing impairment.Medicine, Faculty ofAudiology and Speech Sciences, School ofGraduat