Delineation of Sensorimotor Subtypes Underlying Residual Speech Errors

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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Correcting Residual Errors With Spectral, Ultrasound, and Traditional Speech Therapy: Delineation of Sensorimotor Subtypes

Conditions
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Speech Sound Disorder

Intervention / Treatment
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* Behavioral: Visual-acoustic biofeedback
* Behavioral: Ultrasound biofeedback


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 9 Years
Maximum Age: 15 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: In this single-case randomization design, each participant will receive an equal number of sessions of visual-acoustic and ultrasound biofeedback, with randomized allocation of treatment types to individual sessions. Treatment will last 20 hrs (10 days) over a 5 week period. Randomization will be blocked, with each day of treatment serving as a block; within each day, one hour of treatment will be randomly assigned to feature visual-acoustic and one to feature ultrasound treatment. A congruent condition and an incongruent condition will be defined for each participant based on their sensory profile, where the congruent condition is the biofeedback type that is expected to be more effective and the incongruent condition is the type expected to be less effective. Visual-acoustic biofeedback is defined as the congruent condition for individuals with a primary auditory deficit and ultrasound biofeedback is defined as congruent for individuals with a primary somatosensory deficit.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Visual-acoustic biofeedback<br>Visual-acoustic biofeedback treatment targeting /r/ distortions. | Behavioral: Visual-acoustic biofeedback<br>* In visual-acoustic biofeedback treatment, the elements of traditional articulatory treatment (i.e., auditory models and verbal descriptions of articulator placement) are enhanced with a dynamic display of the speech signal in the form of the real-time LPC spectrum. Because correct vs incorrect productions of /r/ contrast acoustically in the frequency of the third formant (F3), participants will be cued to make their real-time LPC spectrum match a visual target characterized by a low F3 frequency. I<br>|
| Experimental: Ultrasound biofeedback<br>Ultrasound biofeedback treatment targeting /r/ distortions. | Behavioral: Ultrasound biofeedback<br>* In ultrasound biofeedback, the elements of traditional articulatory treatment are enhanced with a real-time ultrasound display of the shape and movements of the tongue. One or two target tongue shapes will be selected for each participant, and a trace of the selected target will be superimposed over the ultrasound screen. Participants will be cued to reshape the tongue to match this target during /r/ production.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Normalized F3-F2 Distance, an Acoustic Measure That Correlates With Perceptual Accuracy of /r/, Measured From /r/ Sounds Produced in Treatment Sessions. | During treatment, one trial in each block of 10 was flagged for measurement and the first three formants (F1, F2, F3) were extracted from the center of the /r/ interval. The distance between the second and third formants (F3-F2) was converted to z-scores relative to normative data from age-matched children with typical speech (Lee et al., 1999). A z-score of 0 represents the mean F3-F2 distance for typical children; a z-score of 1 indicates one standard deviation of the normative sample above the sample mean. Because F3-F2 is small in perceptually accurate /r/, larger values indicate lower accuracy; z-scores above 2 are considered clinically atypical. Summary statistics report the mean and standard deviation of normalized F3-F2 distance for each treatment condition, pooled across participants and sessions. A two-tailed paired-samples t-test (superiority criterion) was used to compare mean normalized F3-F2 distance for each treatment condition across subjects. | Acoustic accuracy was measured in all ten sessions of each type of treatment, which were administered over five weeks. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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speech, articulation, motor development