Limited acquisition and generalisation of rhotics with ultrasound visual feedback in childhood apraxia

ABSTRACT

Ultrasound visual feedback of the tongue is one treatment option for individuals with persisting speech sound errors. This study evaluated children’s performance during acquisition and generalisation of American English rhotics using ultrasound feedback. Three children aged 10–13 with persisting speech sound errors associated with childhood apraxia of speech (CAS) were treated for 14 one-hour sessions. Two of the participants increased the accuracy of their rhotic production during practise trials within treatment sessions, but none demonstrated generalisation to untreated words. Lack of generalisation may be due to a failure to acquire the target with sufficient accuracy during treatment, or to co-existing linguistic weaknesses that are not addressed in a motor-based treatment. Results suggest a need to refine the intervention procedures for CAS and/or a need to identify appropriate candidates for intervention to optimise learning.

KEYWORDS:

• Childhood apraxia of speech
• feedback
• rhotics
• ultrasound

Declaration of interest

The authors declare that funding was provided by NIH grant R03DC012152.

Notes

¹ Although some studies also evaluate tongue shape changes over the course of treatment, the aim of this study was to evaluate ecologically valid outcomes related to listeners’ judgments of correct and incorrect /ɹ/.

² Multiple vowel contexts were used with the cluster targets to ensure a sufficiently large number of items that could be trained and extended into longer words and phrases (see Session Structure below).

³ Inferential statistics are not reported as this study was not designed to meet the assumptions of such analyses (Kratochwill et al., 2010).