Visual biofeedback shows faster early progress than motor-based therapy for children with residual speech sound disorder
This randomized controlled trial compared visual biofeedback treatment to motor-based treatment in 108 children aged 9-15 years with residual speech sound disorder affecting American English /ɹ/. The biofeedback intervention was subdivided into ultrasound and visual-acoustic types, while the comparator was motor-based treatment consistent with current best practices in speech therapy. The primary outcome was rate of progress in the first three sessions, quantified by an acoustic measure of distance between the second and third formants.
The study found a statistically significant interaction between treatment type and session, with the rate of progress significantly faster in the biofeedback condition compared to motor-based treatment. However, no statistically significant difference was observed between the ultrasound and visual-acoustic biofeedback types. Secondary outcomes included generalization learning after treatment completion, but results for this endpoint were not reported in the available data.
Safety and tolerability data were not reported. The study's limitations include that previous research in this area has had inconclusive results due to study design limitations and small sample sizes. While this trial with 108 participants provides more robust evidence, the findings should be interpreted cautiously as they primarily address early treatment progress rather than long-term outcomes or generalization. The results support previous small-scale research suggesting biofeedback can help children with residual speech sound disorder acquire American English /ɹ/, but do not establish superiority over standard care for all treatment outcomes.