Tara McAllister Byun

Retroflex Versus Bunched in Treatment for Rhotic Misarticulation: Evidence From Ultrasound Biofeedback Intervention

PURPOSE To document the efficacy of ultrasound biofeedback treatment for misarticulation of the North American English rhotic in children. Because of limited progress in the first cohort, a series of two closely related studies was conducted in place of a single study. The studies differed primarily in the nature of tongue-shape targets (e.g., retroflex, bunched) cued during treatment. METHOD Eight participants received 8 weeks of individual ultrasound biofeedback treatment targeting rhotics. In Study 1, all 4 participants were cued to match a bunched tongue-shape target. In Study 2, participants received individualized cues aimed at eliciting the tongue shape most facilitative of perceptually correct rhotics. RESULTS Participants in Study 1 showed only minimal treatment effects. In Study 2, all participants demonstrated improved production of rhotics in untreated words produced without biofeedback, with large to very large effect sizes. CONCLUSIONS The results of Study 2 indicate that with proper parameters of treatment, ultrasound biofeedback can be a highly effective intervention for children with persistent rhotic errors. In addition, qualitative comparison of Studies 1 and 2 suggests that treatment for the North American English rhotic should include opportunities to explore different tongue shapes, to find the most facilitative variant for each individual speaker.

Functional Segregation of Cortical Regions Underlying Speech Timing and Articulation

Spoken language is a central part of our everyday lives, but the precise roles that individual cortical regions play in the production of speech are often poorly understood. To address this issue, we focally lowered the temperature of distinct cortical regions in awake neurosurgical patients, and we relate this perturbation to changes in produced speech sequences. Using this method, we confirm that speech is highly lateralized, with the vast majority of behavioral effects seen on the left hemisphere. We then use this approach to demonstrate a clear functional dissociation between nearby cortical speech sites. Focal cooling of pars triangularis/pars opercularis (Brocas region) and the ventral portion of the precentral gyrus (speech motor cortex) resulted in the manipulation of speech timing and articulation, respectively. Our results support a class of models that have proposed distinct processing centers underlying motor sequencing and execution for speech.

Enhancing generalisation in biofeedback intervention using the challenge point framework: A case study

Abstract Biofeedback intervention can help children achieve correct production of a treatment-resistant error sound, but generalisation is often limited. This case study suggests that generalisation can be enhanced when biofeedback intervention is structured in accordance with a “challenge point” framework for speech-motor learning. The participant was an 11-year-old with residual /r/ misarticulation who had previously attained correct /r/ production through a structured course of ultrasound biofeedback treatment but did not generalise these gains beyond the word level. Treatment difficulty was adjusted in an adaptive manner following predetermined criteria for advancing, maintaining, or moving back a level in a multidimensional hierarchy of functional task complexity. The participant achieved and maintained virtually 100% accuracy in producing /r/ at both word and sentence levels. These preliminary results support the efficacy of a semi-structured implementation of the challenge point framework as a means of achieving generalisation and maintenance of treatment gains.

Positional velar fronting: an updated articulatory account.

This study develops the hypothesis that the child-specific phenomenon of positional velar fronting can be modeled as the product of phonologically encoded articulatory limitations unique to immature speakers. Children have difficulty executing discrete tongue movements, preferring to move the tongue and jaw as a single unit. This predisposes the child to produce undifferentiated linguopalatal contact, neutralizing the coronal-velar contrast. Adopting a phonetically sensitive model of phonology, I propose that childrens difficulty with discrete tongue movement can be encoded in a violable constraint, Move.as-Unit. The positional nature of fronting reflects the fact that discrete lingual movement is penalized more heavily in the motorically challenging context of a larger gesture. This analysis is supported with a longitudinal study of one child (3 ; 9 to 4 ; 4) whose fronting was conditioned by both segmental and prosodic factors. Adopting Move.as-Unit in a Harmonic Grammar framework makes it possible to reframe disparate-seeming conditioning factors as a unified grammatical system.This study develops the hypothesis that the child-specific phenomenon of positional velar fronting can be modeled as the product of phonologically encoded articulatory limitations unique to immature speakers. Children have difficulty executing discrete tongue movements, preferring to move the tongue and jaw as a single unit. This predisposes the child to produce undifferentiated linguopalatal contact, neutralizing the coronal-velar contrast. Adopting a phonetically sensitive model of phonology, I propose that childrens difficulty with discrete tongue movement can be encoded in a violable constraint, Move.as-Unit. The positional nature of fronting reflects the fact that discrete lingual movement is penalized more heavily in the motorically challenging context of a larger gesture. This analysis is supported with a longitudinal study of one child (3 ; 9 to 4 ; 4) whose fronting was conditioned by both segmental and prosodic factors. Adopting Move.as-Unit in a Harmonic Grammar framework makes it possible to reframe disparate-seeming conditioning factors as a unified grammatical system.

Social, Emotional, and Academic Impact of Residual Speech Errors in School-Aged Children: A Survey Study

Children with residual speech errors face an increased risk of social, emotional, and/or academic challenges relative to their peers with typical speech. Previous research has shown that the effects of speech sound disorder may persist into adulthood and span multiple domains of activity limitations and/or participation restrictions, as defined by the World Health Organizations International Classification of Functioning, Disability and Health model. However, the nature and extent of these influences varies widely across children. This study aimed to expand the evidence base on the social, emotional, and academic impact of residual speech errors by collecting survey data from parents of children receiving treatment for /r/ misarticulation. By examining the relationship between an overall measure of impact (weighted summed score) and responses to 11 survey items, the present study offers preliminary suggestions for factors that could be considered when making decisions pertaining to treatment allocation in this population.

A gestural account of a child-specific neutralisation in strong position

The child-specific phenomenon of preferential neutralisation in initial position, which reverses a positional bias attested across adult grammars, represents a long-standing problem for formal models of developmental phonology. In a phonetically based model of phonology, child-specific phonological patterns may emerge as the consequence of physical differences between child and adult speech. This paper presents new case-study data suggesting that a child-specific pattern of fricative neutralisation in initial position has its roots in childrens articulatory limitations. Coarticulated fricative and vowel gestures are shown to require independent control of the tongue and jaw, known to be problematic for developing speakers. Substitution errors affecting fricatives are analysed as a phonologised reflex of this phonetic pressure to avoid overlapping vowel and fricative gestures. The positional asymmetry emerges as the consequence of the differing degrees of gestural overlap permitted in syllable-initial vs . syllable-final position, as encoded in the framework of Articulatory Phonology (Browman & Goldstein 1986 ).

Bidirectional perception–production relations in phonological development: evidence from positional neutralization

Many children who neutralize phonemic contrasts in production exhibit diminished perception of the same contrasts. It is usually difficult to determine whether the perception deficit caused the production error, or vice versa; however, the direction of causation has implications for treatment planning. This study examines perception–production relationships in the phenomenon of neutralization in strong position, where children neutralize only in perceptually salient contexts. To test a hypothesis that this phenomenon arises from a child-specific pattern of perceptual sensitivity, a non-word discrimination task was administered to a 4-year-old boy with neutralization in strong position in production. Contrary to the perceptual hypothesis, his discrimination accuracy was greatest for contrasts in initial/strong position, where his production errors occurred. Independent of position, however, his perception of a phonemic contrast he neutralized was decreased relative to other contrasts. This case is argued to constitute evidence that a primary production deficit can cause decreased perceptual ability.

Covert contrast in velar fronting: An acoustic and ultrasound study.

ABSTRACT There is growing evidence that speech sound acquisition is a gradual process, with instrumental measures frequently revealing covert contrast in errors perceived to involve phonemic substitution. Ultrasound imaging has the potential to expand our understanding of covert contrast by showing whether a child uses different tongue shapes while producing sounds that are perceived as neutralised. This study used an ultrasound measure (Dorsum Excursion Index) and acoustic measures (VOT and spectral moments of the burst) to investigate overt and covert contrast between velar and alveolar stops in child speech. Participants were two children who produced a perceptually overt velar-alveolar contrast and two children who neutralised the contrast via velar fronting. Both acoustic and ultrasound measures revealed significant differences between perceptually distinct velar and alveolar targets. One child with velar fronting demonstrated covert contrast in one acoustic and one ultrasound measure; the other showed no evidence of contrast. Clinical implications are discussed in this article.

Differential Effects of Visual-Acoustic Biofeedback Intervention for Residual Speech Errors.

Recent evidence suggests that the incorporation of visual biofeedback technologies may enhance response to treatment in individuals with residual speech errors. However, there is a need for controlled research systematically comparing biofeedback versus non-biofeedback intervention approaches. This study implemented a single-subject experimental design with a crossover component to investigate the relative efficacy of visual-acoustic biofeedback and traditional articulatory treatment for residual rhotic errors. Eleven child/adolescent participants received ten sessions of visual-acoustic biofeedback and 10 sessions of traditional treatment, with the order of biofeedback and traditional phases counterbalanced across participants. Probe measures eliciting untreated rhotic words were administered in at least three sessions prior to the start of treatment (baseline), between the two treatment phases (midpoint), and after treatment ended (maintenance), as well as before and after each treatment session. Perceptual accuracy of rhotic production was assessed by outside listeners in a blinded, randomized fashion. Results were analyzed using a combination of visual inspection of treatment trajectories, individual effect sizes, and logistic mixed-effects regression. Effect sizes and visual inspection revealed that participants could be divided into categories of strong responders (n = 4), mixed/moderate responders (n = 3), and non-responders (n = 4). Individual results did not reveal a reliable pattern of stronger performance in biofeedback versus traditional blocks, or vice versa. Moreover, biofeedback versus traditional treatment was not a significant predictor of accuracy in the logistic mixed-effects model examining all within-treatment word probes. However, the interaction between treatment condition and treatment order was significant: biofeedback was more effective than traditional treatment in the first phase of treatment, and traditional treatment was more effective than biofeedback in the second phase. This is consistent with existing theory and data suggesting that detailed knowledge of performance feedback is most effective in the early stages of motor learning. Further research is needed to confirm that an initial phase of biofeedback has a facilitative effect, and to determine the optimal duration of biofeedback treatment. In addition, there is a strong need for correlational studies to examine which individuals with residual speech errors are most likely to respond to treatment.

Enhancing Intervention for Residual Rhotic Errors Via App-Delivered Biofeedback: A Case Study

Purpose Recent research suggests that visual-acoustic biofeedback can be an effective treatment for residual speech errors, but adoption remains limited due to barriers including high cost and lack of familiarity with the technology. This case study reports results from the first participant to complete a course of visual-acoustic biofeedback using a not-for-profit iOS app, Speech Therapists App for /r/ Treatment. Method App-based biofeedback treatment for rhotic misarticulation was provided in weekly 30-min sessions for 20 weeks. Within-treatment progress was documented using clinician perceptual ratings and acoustic measures. Generalization gains were assessed using acoustic measures of word probes elicited during baseline, treatment, and maintenance sessions. Results Both clinician ratings and acoustic measures indicated that the participant significantly improved her rhotic production accuracy in trials elicited during treatment sessions. However, these gains did not transfer to generalization probes. Conclusions This study provides a proof-of-concept demonstration that app-based biofeedback is a viable alternative to costlier dedicated systems. Generalization of gains to contexts without biofeedback remains a challenge that requires further study. App-delivered biofeedback could enable clinician-research partnerships that would strengthen the evidence base while providing enhanced treatment for children with residual rhotic errors. Supplemental Material https://doi.org/10.23641/asha.5116318.