Speech technology
What is biofeedback for the R sound, and does it work?
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The short answer
Biofeedback lets a child see what’s happening as they practise: an ultrasound image of their tongue, or a live picture of the sound they’re making. In a 2026 randomized trial of 108 children aged 9 to 15 with lingering R errors, children learned R faster, and carried it into more untreated words, with biofeedback than with standard motor-based therapy. It’s delivered by trained clinicians with clinic equipment, and the evidence is for older children working on R.
Two kinds of biofeedback
- Ultrasound biofeedback shows a real-time image of the tongue’s shape, so the child can compare correct and incorrect attempts (Preston et al., 2017).
- Visual-acoustic biofeedback shows a live display of the sound’s acoustics, which the child tries to match to a target. It works best when the clinician and child understand the display and targets are well chosen (Hitchcock et al., 2023).
What the research shows
- A 2019 systematic review of 29 ultrasound biofeedback studies found mostly small studies (on average about 4 participants, average age about 11), mostly on R. It concluded that ultrasound biofeedback may be an effective add-on for some people whose errors persist (Sugden et al., 2019).
- In the 2026 C-RESULTS randomized trial, 108 children aged 9 to 15 with residual R errors received motor-based treatment or biofeedback. Over the first three sessions, the biofeedback group progressed significantly faster; ultrasound and visual-acoustic biofeedback didn’t differ significantly (McAllister et al., 2026).
- Across 20 sessions, children who had biofeedback carried R into more untreated words: median accuracy rose from about 6% to 49%, compared with about 9% to 43% with motor-based treatment (Preston et al., 2026).
Who it’s for, and the limits
- The trial included children aged 9 to 15 who were getting R right no more than 30% of the time.
- It needs clinic equipment (an ultrasound unit, or acoustic analysis software) and a clinician trained to use it.
- The authors describe it as an efficacy trial under idealized conditions, with a session schedule that’s hard to match in typical school settings, and no long-term follow-up yet.
- It studied American English R only. Comparisons between ultrasound and visual-acoustic biofeedback were mixed.
If your child is older and still working on R, it’s reasonable to ask their speech-language pathologist whether biofeedback is available and suitable. See also how long R therapy takes.
Common questions
Is biofeedback better than regular speech therapy?
In one large trial of 9 to 15-year-olds with R errors, children learned R faster and generalized it more with biofeedback. Both groups improved, and there’s no long-term follow-up yet.
Can younger children have biofeedback?
Most of the research is in older children. The largest trial included ages 9 to 15, and a review of ultrasound studies found an average participant age of about 11.
Does it work for sounds other than R?
Most studies have been on R: in the 2019 review, about 80% of participants were working on R-type sounds. Evidence for other sounds is more limited.
Sources
- Preston, J. L., McAllister Byun, T., Boyce, S. E., Hamilton, S., Tiede, M., Phillips, E., Rivera-Campos, A., & Whalen, D. H. (2017). Ultrasound images of the tongue: A tutorial for assessment and remediation of speech sound errors. Journal of Visualized Experiments, 119, e55123.
- Hitchcock, E. R., Ochs, L. C., Swartz, M. T., Leece, M. C., Preston, J. L., & McAllister, T. (2023). Tutorial: Using visual-acoustic biofeedback for speech sound training. American Journal of Speech-Language Pathology, 32(1), 18–36.
- Sugden, E., Lloyd, S., Lam, J., & Cleland, J. (2019). Systematic review of ultrasound visual biofeedback in intervention for speech sound disorders. International Journal of Language & Communication Disorders, 54(5), 705–728.
- McAllister, T., Preston, J. L., Benway, N. R., Hill, J., Lara, M. P., Leece, M. C., Liang, W., & Hitchcock, E. R. (2026). Rhotic acquisition is more rapid in biofeedback than motor-based treatment for residual speech sound disorder: Primary outcome of a randomized controlled trial. Journal of Speech, Language, and Hearing Research, 69(4), 1342–1361.
- Preston, J. L., Hitchcock, E. R., Leece, M. C., Benway, N. R., Hill, J., & McAllister, T. (2026). Rhotic generalization is more rapid in biofeedback than motor-based treatment for residual speech sound disorder: Secondary outcomes of a randomized controlled trial. Journal of Speech, Language, and Hearing Research, 69(4), 1362–1378.