Liquid to solid transition of elastin condensates.

Liquid-liquid phase separation of tropoelastin has long been considered to be an important early step in the complex process of elastin fiber assembly in the body and has inspired the development of elastin-like peptides with a wide range of industrial and biomedical applications. Despite decades of study, the material state of the condensed liquid phase of elastin and its subsequent maturation remain poorly understood. Here, using a model minielastin that mimics the alternating domain structure of full-length tropoelastin, we examine the elastin liquid phase. We combine differential interference contrast (DIC), fluorescence, and scanning electron microscopy with particle-tracking microrheology to resolve the material transition occurring within elastin liquids over time in the absence of exogenous cross-linking. We find that this transition is accompanied by an intermediate stage marked by the coexistence of insoluble solid and dynamic liquid phases giving rise to significant spatial heterogeneities in material properties. We further demonstrate that varying the length of the terminal hydrophobic domains of minielastins can tune the maturation process. This work not only resolves an important step in the hierarchical assembly process of elastogenesis but further contributes mechanistic insight into the diverse repertoire of protein condensate maturation pathways with emerging importance across biology.

Refining and extending measures for fricative spectra, with special attention to the high-frequency rangea).

Fricatives have noise sources that are filtered by the vocal tract and that typically possess energy over a much broader range of frequencies than observed for vowels and sonorant consonants. This paper introduces and refines fricative measurements that were designed to reflect underlying articulatory and aerodynamic conditions These show differences in the pattern of high-frequency energy for sibilants vs non-sibilants, voiced vs voiceless fricatives, and non-sibilants differing in place of articulation. The results confirm the utility of a spectral peak measure (FM) and low-mid frequency amplitude difference (AmpD) for sibilants. Using a higher-frequency range for defining FM for female voices for alveolars is justified; a still higher range was considered and rejected. High-frequency maximum amplitude (Fh) and amplitude difference between low- and higher-frequency regions (AmpRange) capture /f-θ/ differences in English and the dynamic amplitude range over the entire spectrum. For this dataset, with spectral information up to 15 kHz, a new measure, HighLevelD, was more effective than previously used LevelD and Slope in showing changes over time within the frication. Finally, isolated words and connected speech differ. This work contributes improved measures of fricative spectra and demonstrates the necessity of including high-frequency energy in those measures.

Comparing metrics for quantification of children's tongue shape complexity using ultrasound imaging.

Speech sound disorders can pose a challenge to communication in children that may persist into adulthood. As some speech sounds are known to require differential control of anterior versus posterior regions of the tongue body, valid measurement of the degree of differentiation of a given tongue shape has the potential to shed light on development of motor skill in typical and disordered speakers. The current study sought to compare the success of multiple techniques in quantifying tongue shape complexity as an index of degree of lingual differentiation in child and adult speakers. Using a pre-existing data set of ultrasound images of tongue shapes from adult speakers producing a variety of phonemes, we compared the extent to which three metrics of tongue shape complexity differed across phonemes/phoneme classes that were expected to differ in articulatory complexity. We then repeated this process with ultrasound tongue shapes produced by a sample of young children. The results of these comparisons suggested that a modified curvature index and a metric representing the number of inflection points best reflected small changes in tongue shapes across individuals differing in vocal tract size. Ultimately, these metrics have the potential to reveal delays in motor skill in young children, which could inform assessment procedures and treatment decisions for children with speech delays and disorders.

Dynamics in natural and designed elastins and their relation to elastic fiber structure and recoil.

Elastin fibers assemble in the extracellular matrix from the precursor protein tropoelastin and provide the flexibility and spontaneous recoil required for arterial function. Unlike many proteins, a structure-function mechanism for elastin has been elusive. We have performed detailed NMR relaxation studies of the dynamics of the minielastins 24x' and 20x' using solution NMR, and of purified bovine elastin fibers in the presence and absence of mechanical stress using solid state NMR. The low sequence complexity of the minielastins enables us to determine average dynamical timescales and degrees of local ordering in the cross-link and hydrophobic modules separately using NMR relaxation by taking advantage of their residue-specific resolution. We find an extremely high degree of disorder, with order parameters for the entirety of the hydrophobic domains near zero, resembling that of simple chemical polymers and less than the order parameters that have been observed in other intrinsically disordered proteins. We find that average backbone order parameters in natural, purified elastin fibers are comparable to those found in 24x' and 20x' in solution. The difference in dynamics, compared with the minielastins, is that backbone correlation times are significantly slowed in purified elastin. Moreover, when elastin is mechanically stretched, the high chain disorder in purified elastin is retained, showing that any change in local ordering is below that detectable in our experiment. Combined with our previous finding of a 10-fold increase in the ordering of water when fully hydrated elastin fibers are stretched by 50%, these results support the hypothesis that stretch induced solvent ordering, i.e., the hydrophobic effect, is a key player in the elastic recoil of elastin as opposed to configurational entropy loss.

Treatment generalization from trained /ɹ/ to untrained /l/: a case study of persisting distortion errors.

The extent to which treatment of speech errors that are phonetic in nature (i.e., distortions) produces generalization to untrained sounds is not well understood. This case study reports a child referred for treatment of a velarized distortion of American English /ɹ/, who also demonstrated an inconsistent velarized distortion of /l/. Acoustic analysis revealed evidence of a covert contrast between /ɹ/ and /l/ prior to treatment. Ultrasound biofeedback treatment and perceptual training targeted /ɹ/ only, but progress was tracked for both /ɹ/ and /l/. Substantial improvements in perceptually rated accuracy and significant changes in acoustic features were observed for both sounds, indicating generalization. These results highlight that generalization from trained to untrained sounds is possible for children with residual speech errors characterized by phonetic distortions.

Auditory-perceptual acuity in rhotic misarticulation: baseline characteristics and treatment response.

The rhotic sound /r/ is one of the latest-emerging sounds in English, and many children receive treatment for residual errors affecting /r/ that persist past the age of 9. Auditory-perceptual abilities of children with residual speech errors are thought to be different from their typically developing peers. This study examined auditory-perceptual acuity in children with residual speech errors affecting /r/ and the relation of these skills to production accuracy, both before and after a period of treatment incorporating visual biofeedback. Identification of items along an /r/-/w/ continuum was assessed prior to treatment. Production accuracy for /r/ was acoustically measured from standard/r/stimulability probes elicited before and after treatment. Fifty-nine children aged 9-15 with residual speech errors (RSE) affecting /r/ completed treatment, and forty-eight age-matched controls who completed the same auditory-perceptual task served as a comparison group. It was hypothesized that children with RSE would show lower auditory-perceptual acuity than typically developing speakers and that higher auditory-perceptual acuity would be associated with more accurate production before treatment. It was also hypothesized that auditory-perceptual acuity would serve as a mediator of treatment response. Results indicated that typically developing children have more acute perception of the /r/-/w/ contrast than children with RSE. Contrary to hypothesis, baseline auditory-perceptual acuity for /r/ did not predict baseline production severity. For baseline auditory-perceptual acuity in relation to biofeedback efficacy, there was an interaction between auditory-perceptual acuity and gender, such that higher auditory-perceptual acuity was associated with greater treatment response in female, but not male, participants.

Protocol for Correcting Residual Errors with Spectral, ULtrasound, Traditional Speech therapy Randomized Controlled Trial (C-RESULTS RCT).

BACKGROUND: Speech sound disorder in childhood poses a barrier to academic and social participation, with potentially lifelong consequences for educational and occupational outcomes. While most speech errors resolve by the late school-age years, between 2 and 5% of speakers exhibit residual speech errors (RSE) that persist through adolescence or even adulthood. Previous findings from small-scale studies suggest that interventions incorporating visual biofeedback can outperform traditional motor-based treatment approaches for children with RSE, but this question has not been investigated in a well-powered randomized controlled trial. METHODS/DESIGN: This project, Correcting Residual Errors with Spectral, ULtrasound, Traditional Speech therapy Randomized Controlled Trial (C-RESULTS RCT), aims to treat 110 children in a parallel randomized controlled clinical trial comparing biofeedback and non-biofeedback interventions for RSE affecting the North American English rhotic sound /ɹ/. Eligible children will be American English speakers, aged 9-15 years, who exhibit RSE affecting /ɹ/ but otherwise show typical cognitive-linguistic and hearing abilities. Participants will be randomized, with stratification by site (Syracuse University or Montclair State University) and pre-treatment speech production ability, to receive either a motor-based treatment consistent with current best practices in speech therapy (40% of participants) or treatment incorporating visual biofeedback (60% of participants). Within the biofeedback condition, participants will be assigned in equal numbers to receive biofeedback in the form of a real-time visual display of the acoustic signal of speech or ultrasound imaging of the tongue during speech. The primary outcome measure will assess changes in the acoustics of children's production of /ɹ/ during treatment, while a secondary outcome measure will use blinded listeners to evaluate changes in the perceived accuracy of /ɹ/ production after the completion of all treatment. These measures will allow the treatment conditions to be compared with respect to both efficacy and efficiency. DISCUSSION: By conducting the first well-powered randomized controlled trial comparing treatment with and without biofeedback, this study aims to provide high-quality evidence to guide treatment decisions for children with RSE. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT03737318, November 9, 2018.

Protocol for the Connected Speech Transcription of Children with Speech Disorders: An Example from Childhood Apraxia of Speech.

OBJECTIVE: While it is known that connected speech has different features to single-word speech, there are currently few recommendations regarding connected speech transcription. This research therefore aimed to develop a clinically feasible protocol for connected speech transcription. The protocol was then used to assist with description of the connected speech of children with childhood apraxia of speech (CAS), as little is known about their connected speech characteristics. PARTICIPANTS AND METHODS: Following a literature review, the Connected Speech Transcription Protocol (CoST-P) was iteratively developed and trialled. The CoST-P was then used to transcribe 50 connected utterances produced by 12 children (aged 6-13 years) with CAS. The characteristics of participants' connected speech were analysed to capture independent and relational analyses. RESULTS: The CoST-P was developed, trialled, and determined to have adequate reliability and fidelity. The frequency of inter-word segregation (mean = 29) was higher than intra-word segregation (mean = 4). Juncture accuracy was correlated with intelligibility metrics such as percentage of consonants correct. CONCLUSION: Connected speech transcription is challenging. The CoST-P may be a useful resource for speech-language pathologists and clinical researchers. Use of the CoST-P assisted in displaying CAS speech characteristics unique to connected speech (e.g., inter-word segregation and juncture).

Tongue shapes for rhotics in school-age children with and without residual speech errors.

Speakers of North American English use variable tongue shapes for rhotic sounds. However, quantifying tongue shapes for rhotics can be challenging, and little is known about how tongue shape complexity corresponds to perceptual ratings of rhotic accuracy in children with residual speech sound errors (RSE). In this study, 16 children aged 9-16 with RSE and 14 children with typical speech (TS) development made multiple productions of 'Let Robby cross Church Street'. Midsagittal ultrasound images were collected once for children with TS and twice for children in the RSE group (once after 7 h of speech therapy, then again after another 7 h of therapy). Tongue contours for the rhotics in the four words were traced and quantified using a new metric of tongue shape complexity: the number of inflections. Rhotics were also scored for accuracy by four listeners. During the first assessment, children with RSE had fewer tongue inflections than children with TS. Following 7 h of therapy, there were increases in the number of inflections for the RSE group, with the cluster items cross and Street reaching tongue complexity levels of those with TS. Ratings of rhotic accuracy were correlated with the number of inflections. Therefore, the number of inflections in the tongue, an index of tongue shape complexity, was associated with perceived accuracy of rhotic productions.

Modelling category goodness judgments in children with residual sound errors.

This study investigates category goodness judgments of /r/ in adults and children with and without residual speech errors (RSEs) using natural speech stimuli. Thirty adults, 38 children with RSE (ages 7-16) and 35 age-matched typically developing (TD) children provided category goodness judgments on whole words, recorded from 27 child speakers, with /r/ in various phonetic environments. The salient acoustic property of /r/ - the lowered third formant (F3) - was normalized in two ways. A logistic mixed-effect model quantified the relationships between listeners' responses and the third formant frequency, vowel context and clinical group status. Goodness judgments from the adult group showed a statistically significant interaction with the F3 parameter when compared to both child groups (p < 0.001) using both normalization methods. The RSE group did not differ significantly from the TD group in judgments of /r/. All listeners were significantly more likely to judge /r/ as correct in a front-vowel context. Our results suggest that normalized /r/ F3 is a statistically significant predictor of category goodness judgments for both adults and children, but children do not appear to make adult-like judgments. Category goodness judgments do not have a clear relationship with /r/ production abilities in children with RSE. These findings may have implications for clinical activities that include category goodness judgments in natural speech, especially for recorded productions.

Motor-based treatment with and without ultrasound feedback for residual speech-sound errors.

BACKGROUND: There is a need to develop effective interventions and to compare the efficacy of different interventions for children with residual speech-sound errors (RSSEs). Rhotics (the r-family of sounds) are frequently in error American English-speaking children with RSSEs and are commonly targeted in treatment. One treatment approach involves the use of ultrasound visual feedback of the tongue. AIMS: Although prior studies have shown that children with RSSEs acquire rhotics and generalize to untrained words with ultrasound visual feedback treatment, predictions from schema-based motor learning theory suggest that visual feedback might impede generalization. Therefore, the primary aim was to compare the generalization of rhotics treated with and without ultrasound in children with RSSEs. METHODS & PROCEDURES: Twelve children aged 10-16 years with RSSEs affecting rhotics participated in a multiple-baseline single-case design with two treatment phases. For each participant, rhotics in one syllable position were treated for 7 h-long sessions with ultrasound visual feedback and rhotics in a different syllable position were treated without ultrasound in a second treatment phase. The order of treatment conditions was counterbalanced across participants. A treatment framework incorporating the principles of motor learning through chaining procedures was implemented across both treatment phases; thus the primary distinction between conditions was the use of ultrasound visual feedback. OUTCOMES & RESULTS: On average, both treatments resulted in an approximately 30% increase in accuracy of untreated words in seven sessions. However, variability in response suggested some children showed a preferential response to one treatment over another, some responded well to both interventions, and some responded minimally to both interventions. CONCLUSIONS & IMPLICATIONS: Motor-based treatment with and without ultrasound visual feedback of the tongue may aid in speech-sound acquisition for children with RSSEs. Both approaches may be viable options for some children. Future research is necessary to determine which children are the best candidates for interventions with and without ultrasound visual feedback.

Risk and Protective Factors for Late Talking: An Epidemiologic Investigation.

OBJECTIVE: To identify risk and protective factors for late talking in toddlers between 24 and 30 months of age in a large community-based cohort. STUDY DESIGN: A prospective, longitudinal pregnancy cohort of 1023 mother-infant pairs in metropolitan Calgary, Canada, were followed across 5 time points: before 25 weeks gestation, between 34-36 weeks gestation, and at 4, 12, and 24 months postpartum. Toddlers who scored ≤10th percentile on The MacArthur-Bates Communicative Development Inventories: Words and Sentences between 24 and 30 months of age were identified as late talkers. Thirty-four candidate characteristics theoretically and/or empirically linked to language development and/or language impairment were collected using survey methodology. RESULTS: The prevalence of late talking was 12.6%. Risk factors for late talking in the multivariable model included: male sex (P = .017) and a family history of late talking and/or diagnosed speech or language delay (P = .002). Toddlers were significantly less likely to be late talkers if they engaged in informal play opportunities (P = .013), were read to or shown picture books daily (P < .001), or cared for primarily in child care centers (P = .001). CONCLUSIONS: Both biological and environmental factors were associated with the development of late talking. Biological factors placed toddlers at risk for late talking, and facets of the environment played a protective role. Enveloping infants and toddlers in language-rich milieus that promote opportunities for playing, reading, and sharing books daily may decrease risk for delayed early vocabulary.

Print-Speech Convergence Predicts Future Reading Outcomes in Early Readers.

Becoming a skilled reader requires building a functional neurocircuitry for printed-language processing that integrates with spoken-language-processing networks. In this longitudinal study, functional MRI (fMRI) was used to examine convergent activation for printed and spoken language (print-speech coactivation) in selected regions implicated in printed-language processing (the reading network). We found that print-speech coactivation across the left-hemisphere reading network in beginning readers predicted reading achievement 2 years later beyond the effects of brain activity for either modality alone; moreover, coactivation effects accounted for variance in later reading after controlling for initial reading performance. Within the reading network, effects of coactivation were significant in bilateral inferior frontal gyrus (IFG) and left inferior parietal cortex and fusiform gyrus. The contribution of left and right IFG differed, with more coactivation in left IFG predicting better achievement but more coactivation in right IFG predicting poorer achievement. Findings point to the centrality of print-speech convergence in building an efficient reading circuitry in children.

Using ultrasound visual feedback to remediate velar fronting in preschool children: A pilot study.

Anecdotally, velar fronting can be difficult to remediate in some children. This pilot study examined the use of ultrasound visual feedback in remediating velar fronting in typically developing children. A single-case, multiple-baseline across-subjects experimental design was used to examine acquisition, retention and generalisation of velar treatment targets. Two otherwise typically developing children (P1, aged 4;0; P3, aged 4;11) completed the study. The productions of /k/ and /É¡/ at syllable level were targeted during treatment. P1 improved her productions of /k/ and /É¡/ at syllable level during the treatment period and achieved correct production at word level during follow-up. P3 made no improvements in his productions of velar targets. This study suggests that ultrasound visual feedback may be an option for remediating velar fronting in some preschoolers. Further study is required.

Limited acquisition and generalisation of rhotics with ultrasound visual feedback in childhood apraxia.

Ultrasound visual feedback of the tongue is one treatment option for individuals with persisting speech sound errors. This study evaluated children's performance during acquisition and generalisation of American English rhotics using ultrasound feedback. Three children aged 10-13 with persisting speech sound errors associated with childhood apraxia of speech (CAS) were treated for 14 one-hour sessions. Two of the participants increased the accuracy of their rhotic production during practise trials within treatment sessions, but none demonstrated generalisation to untreated words. Lack of generalisation may be due to a failure to acquire the target with sufficient accuracy during treatment, or to co-existing linguistic weaknesses that are not addressed in a motor-based treatment. Results suggest a need to refine the intervention procedures for CAS and/or a need to identify appropriate candidates for intervention to optimise learning.

Glutamate and choline levels predict individual differences in reading ability in emergent readers.

Reading disability is a brain-based difficulty in acquiring fluent reading skills that affects significant numbers of children. Although neuroanatomical and neurofunctional networks involved in typical and atypical reading are increasingly well characterized, the underlying neurochemical bases of individual differences in reading development are virtually unknown. The current study is the first to examine neurochemistry in children during the critical period in which the neurocircuits that support skilled reading are still developing. In a longitudinal pediatric sample of emergent readers whose reading indicators range on a continuum from impaired to superior, we examined the relationship between individual differences in reading and reading-related skills and concentrations of neurometabolites measured using magnetic resonance spectroscopy. Both continuous and group analyses revealed that choline and glutamate concentrations were negatively correlated with reading and related linguistic measures in phonology and vocabulary (such that higher concentrations were associated with poorer performance). Correlations with behavioral scores obtained 24 months later reveal stability for the relationship between glutamate and reading performance. Implications for neurodevelopmental models of reading and reading disability are discussed, including possible links of choline and glutamate to white matter anomalies and hyperexcitability. These findings point to new directions for research on gene-brain-behavior pathways in human studies of reading disability.

Perception of Speech Sounds in School-Aged Children with Speech Sound Disorders.

Children with speech sound disorders may perceive speech differently than children with typical speech development. The nature of these speech differences is reviewed with an emphasis on assessing phoneme-specific perception for speech sounds that are produced in error. Category goodness judgment, or the ability to judge accurate and inaccurate tokens of speech sounds, plays an important role in phonological development. The software Speech Assessment and Interactive Learning System, which has been effectively used to assess preschoolers' ability to perform goodness judgments, is explored for school-aged children with residual speech errors (RSEs). However, data suggest that this particular task may not be sensitive to perceptual differences in school-aged children. The need for the development of clinical tools for assessment of speech perception in school-aged children with RSE is highlighted, and clinical suggestions are provided.

Development of an audiovisual speech perception app for children with autism spectrum disorders.

Perception of spoken language requires attention to acoustic as well as visible phonetic information. This article reviews the known differences in audiovisual speech perception in children with autism spectrum disorders (ASD) and specifies the need for interventions that address this construct. Elements of an audiovisual training program are described. This researcher-developed program delivered via an iPad app presents natural speech in the context of increasing noise, but supported with a speaking face. Children are cued to attend to visible articulatory information to assist in perception of the spoken words. Data from four children with ASD ages 8-10 are presented showing that the children improved their performance on an untrained auditory speech-in-noise task.

Neural correlates of language and non-language visuospatial processing in adolescents with reading disability.

Despite anecdotal evidence of relative visuospatial processing strengths in individuals with reading disability (RD), only a few studies have assessed the presence or the extent of these putative strengths. The current study examined the cognitive and neural bases of visuospatial processing abilities in adolescents with RD relative to typically developing (TD) peers. Using both cognitive tasks and functional magnetic resonance imaging (fMRI) we contrasted printed word recognition with non-language visuospatial processing tasks. Behaviorally, lower reading skill was related to a visuospatial processing advantage (shorter latencies and equivalent accuracy) on a geometric figure processing task, similar to findings shown in two published studies. FMRI analyses revealed key group by task interactions in patterns of cortical and subcortical activation, particularly in frontostriatal networks, and in the distributions of right and left hemisphere activation on the two tasks. The results are discussed in terms of a possible neural tradeoff in visuospatial processing in RD.

Artificial Intelligence-Assisted Speech Therapy for /ɹ/: A Single-Case Experimental Study.

PURPOSE: This feasibility trial describes changes in rhotic production in residual speech sound disorder following ten 40-min sessions including artificial intelligence (AI)-assisted motor-based intervention with ChainingAI, a version of Speech Motor Chaining that predicts clinician perceptual judgment using the PERCEPT-R Classifier (Perceptual Error Rating for the Clinical Evaluation of Phonetic Targets). The primary purpose is to evaluate /ɹ/ productions directly after practice with ChainingAI versus directly before ChainingAI and to evaluate how the overall AI-assisted treatment package may lead to perceptual improvement in /ɹ/ productions compared to a no-treatment baseline phase. METHOD: Five participants ages 10;7-19;3 (years;months) who were stimulable for /ɹ/ participated in a multiple (no-treatment)-baseline ABA single-case experiment. Prepractice activities were led by a human clinician, and drill-based motor learning practice was automated by ChainingAI. Study outcomes were derived from masked expert listener perceptual ratings of /ɹ/ from treated and untreated utterances recorded during baseline, treatment, and posttreatment sessions. RESULTS: Listeners perceived significantly more rhoticity in practiced utterances after 30 min of ChainingAI, without a clinician, than directly before ChainingAI. Three of five participants showed significant generalization of /ɹ/ to untreated words during the treatment phase compared to the no-treatment baseline. All five participants demonstrated statistically significant generalization of /ɹ/ to untreated words from pretreatment to posttreatment. PERCEPT-clinician rater agreement (i.e., F1 score) was largely within the range of human-human agreement for four of five participants. Survey data indicated that parents and participants felt hybrid computerized-clinician service delivery could facilitate at-home practice. CONCLUSIONS: This study provides evidence of participant improvement for /ɹ/ in untreated words in response to an AI-assisted treatment package. The continued development of AI-assisted treatments may someday mitigate barriers precluding access to sufficiently intense speech therapy for individuals with speech sound disorders. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.26662807.