The Effectiveness of Ultrasound Visual Biofeedback in Articulation Therapy for Children and Adolescents With Speech Sound Disorders: A Systematic Review and Meta-Analysis.

backgroundSpeech sound disorders (SSD) may compromise speech intelligibility in children and adolescents, impacting communication, social interactions and academic performance. Ultrasound visual biofeedback (U-VBF) has emerged as a promising tool for articulation therapy, providing real-time tongue movement visualization, yet its evidence base requires updating given methodological advancements.

aimsThis systematic review and meta-analysis updates the evidence for the effectiveness of the use of U-VBF in improving articulation accuracy for paediatric SSD, synthesizing recent studies with robust designs to quantify outcomes and inform clinical adoption.

methodsFollowing PRISMA guidelines, a preregistered review (PROSPERO: CRD42024627408) involved searching PubMed, Web of Science, CINAHL Plus, Cochrane Library and Linguistics and Language Behaviour Abstracts (January 2000-July 2025) for studies on U-VBF in children and adolescents (≤18 years) with SSD, using all designs with articulation accuracy outcomes. Three reviewers used Covidence for study selection, data extraction and risk of bias assessment. Busk and Serlin's d2 effect sizes at the study level were calculated where possible for random-effects meta-analysis. MAIN CONTRIBUTION: From 545 references, 35 studies (192 unique participants, aged 4-18) were included (16 for meta-analysis). The pooled d2 was 1.32 (95% CI [0.54, 2.10]), indicating substantial improvements in accuracy despite high heterogeneity (Q = 494.36, p < 0.001; I

conclusionsEvidence indicates that U-VBF is promising for SSD articulation therapy, supported by stronger designs post-2019. Future RCTs, non-English studies and standardized reporting are essential to mitigate bias and refine individualized applications. WHAT THIS PAPER ADDS: What is already known on this subject A 2019 systematic review qualitatively synthesized early evidence for ultrasound visual biofeedback (U-VBF) in speech sound disorders (SSDs), highlighting its promise as an adjunct for persistent errors but limited by small samples, few RCTs and no effect size pooling. Subsequent studies have introduced more robust designs and quantitative data, necessitating an update to quantify U-VBF's impact amid growing clinical interest. What this paper adds to existing knowledge This review updates the evidence with 35 studies (192 unique participants) and a novel meta-analysis of 16 studies, yielding a large pooled effect on articulation accuracy despite high heterogeneity. It identifies SSD subtype-specific variability and intensity influences, revealing reporting gaps that limit subgroup analyses. These findings provide the first quantitative benchmark, enabling future power calculations and stratified research. What are the potential or actual clinical implications of this work? U-VBF offers a viable tool for personalized SSD therapy, with enhanced intensity reporting guiding tailored protocols. Clinicians should integrate U-VBF judiciously, mindful of English-centric evidence and potential bias inflating effects. Future research should prioritize RCTs and non-English trials to refine applicability across diverse populations.