Children with speech sound disorder show diminished accuracy and intelligibility in spoken communication and may thus be perceived as less capable or intelligent than peers, with negative consequences for both socioemotional and socioeconomic outcomes. While most speech errors resolve by the late school-age years, between 2-5% of speakers exhibit residual speech errors (RSE) that persist through adolescence or even adulthood, reflecting about 6 million cases in the US. Both affected children/families and speech-language pathologists (SLPs) have highlighted the critical need for research to identify more effective forms of treatment for children with RSE. In a series of single-case experimental studies, research has found that treatment incorporating technologically enhanced sensory feedback (visual-acoustic biofeedback, ultrasound biofeedback) can improve speech in individuals with RSE who have not responded to previous intervention. Further research is needed to understand heterogeneity across individuals in the magnitude of response to biofeedback treatment.

The overall objective of this proposal is to conduct clinical research that will guide the evidence-based management of RSE while also providing novel insights into the sensorimotor underpinnings of speech. The central hypothesis is that individual deficit profiles will predict relative response to visual-acoustic vs ultrasound biofeedback. From the larger population of children with RSE evaluated as part of C-RESULTS-RCT (Correcting Residual Errors With Spectral, Ultrasound, Traditional Speech Therapy Randomized Controlled Trial), a subset of 8 children will be selected who show a deficit in one domain (auditory or somatosensory) and intact perception in the other. Single-case methods will be used to test the hypothesis that sensory deficit profiles differentially predict response to visual-acoustic vs ultrasound biofeedback.

Single-Case Randomization Component: At the group level, speakers with RSE show poorer auditory and oral somatosensory acuity than typically developing (TD) speakers, but individuals differ in the extent to which each sensory domain is impacted. The objective of this aim is to evaluate how distinct sensory profiles mediate relative response to different types of biofeedback, with the goal of optimizing treatment through personalized learning. This study will test the working hypothesis that visual-acoustic biofeedback will produce larger gains in children whose deficit primarily affects the specification of the auditory target, while ultrasound biofeedback will produce larger gains in children with a primary somatosensory deficit. The main approach to testing this hypothesis is to select, from the larger population of children with RSE evaluated as part of C-RESULTS-RCT, a subset of 8 children who show asymmetric sensory profiles (strong auditory and weak somatosensory acuity, or vice versa). These children will be enrolled in a single-case experimental design where individual treatment sessions are randomly assigned to feature visual-acoustic or ultrasound biofeedback. Participants will complete 20 hrs of treatment (10 days, 2 sessions per day) over a 5 week period. Acoustic measures will be used to evaluate /r/ production accuracy within each session. Randomization tests will be used to evaluate differences in accuracy between ultrasound and visual-acoustic biofeedback treatment conditions.

Inclusion Criteria:

• Must be between 9;0 and 15;11 years of age at the time of enrollment.
• Must speak English as the dominant language (i.e., must have begun learning English by age 2, per parent report).
• Must speak a rhotic dialect of English.
• Must pass a pure-tone hearing screening at 20 decibels (dB) Hearing Level (HL).
• Must pass a brief examination of oral structure and function.
• Must exhibit less than thirty percent accuracy, based on trained listener ratings, on a probe list eliciting /r/ in various phonetic contexts at the word level.
• Must show 0-5% accuracy in production of /r/ at the syllable level, based on treating clinicians' perceptual ratings, during an initial Dynamic Assessment phase consisting of 2 hours of traditional (non-biofeedback) instruction.
• Must fit one of two profiles: (1) primary auditory deficit (scores outside the normative predictive interval for auditory measures assessing identification and discrimination of synthetic speech stimuli, but within the normative predictive interval for measures of oral stereognosis and articulator placement awareness or (2) primary somatosensory deficit, with the reverse profile of spared/impaired sensory function.

Exclusion Criteria:

• Must not receive a T score more than 1.3 standard deviations (SD) below the mean on the Wechsler Abbreviated Scale of Intelligence-2 (WASI-2) Matrix Reasoning.
• Must not receive a standard score below 80 on the Core Language Index of the Clinical Evaluation of Language Fundamentals-5 (CELF-5).
• Must not exhibit voice or fluency disorder of a severity judged likely to interfere with the ability to participate in study activities.
• Must not have an existing diagnosis of developmental disability, major neurobehavioral syndrome such as cerebral palsy, Down Syndrome, or Autism Spectrum Disorder, or major neural disorder (e.g., epilepsy, agenesis of the corpus callosum) or insult (e.g., traumatic brain injury, stroke, or tumor resection).
• Must not show clinically significant signs of apraxia of speech or dysarthria.

6 weeks

The definition of adverse event and serious adverse event used to collect adverse event information does not differ from that of clinicaltrials.gov.

Single-case randomization designs are limited in that gains from one treatment condition may carry over to the next.

All perceptual ratings will be obtained from blinded, naive listeners recruited through online crowdsourcing. Following protocols refined in previous published research, binary rating responses will be aggregated over at least 9 unique listeners per token.