Developmental deglutition and intrinsic tongue muscle maturation phenotypes in the Ts65Dn mouse model of Down syndrome

Introduction

Down syndrome (DS) is associated with difficulties with feeding during infancy and childhood. Weaning, or transitioning from nursing to independent deglutition, requires developmental progression in tongue function. However, little is known about whether postnatal tongue muscle maturation is impacted in DS. This study tested the hypothesis that the Ts65Dn mouse model of DS has developmental delays in deglutition, comprised of differences in eating and drinking behaviors relative to euploid controls, coinciding with atypical measures of intrinsic tongue muscle microanatomy.

Methods

The Ts65Dn mouse model of DS and euploid controls were evaluated at 7 days of age (p7; nursing), p21 (weaning), and p35 (mature deglutition) (n = 13-18 mice per group). Eating behavior, drinking behavior, and body weight changes were quantified in p21 and p35 mice through the use of automated monitoring over 24 h. Intrinsic tongues of mice at all three ages were sectioned and stained to permit quantification of the sizes of the four major intrinsic tongue muscles. Transverse intrinsic tongue muscles were evaluated for myofiber size (average myofiber cross sectional area (CSA) of all fibers, MyHC2a fibers, MyHC 2b fibers, and minimum Feret fiber diameter), and percentage of MyHC isoforms (%MyHC2a + fibers, and %MyHC 2b + fibers) in anterior, middle, and posterior regions.

Results

Ts65Dn showed significant differences from euploid in deglutition measures. Compared to euploid, Ts65Dn also showed differences in intrinsic tongue muscle microanatomy and biology. Specifically, Ts65Dn intrinsic tongues had smaller transverse muscle myofiber size measures than control in the anterior and middle tongue, but not in the posterior tongue.

Conclusion

Differences in intrinsic tongue muscles coincide with feeding phenotypes in the Ts65Dn mouse model of DS.

Adaptation and validation of the word complexity measure for Persian-speaking toddlers

This study aimed to adapt and validate the Word Complexity Measure (WCM) for Persian-speaking toddlers. The WCM is a tool for assessing phonological complexity, originally proposed by Stoel-Gammon. The study was conducted in two phases: (1) adapting the WCM parameters to the Persian language and (2) conducting a validation study with 60 monolingual Persian-speaking toddlers aged 18–35 months. The toddlers’ language productions were collected through a picture-naming task, and the researchers derived the Proportion of Word Complexity Measure-Persian (PWCM-P) and Proportion of Consonant Correct (PCC) scores. Parents completed the Persian adapted version of the MacArthur-Bates Communication Development Inventories-II (CDI-II) to obtain receptive and expressive vocabulary scores for each child. Statistical analyses showed a significant difference in PWCM-P scores between age groups, with younger children producing fewer phonologically complex words. In addition, PWCM-P scores were positively and significantly correlated with PCC scores, receptive and expressive vocabulary size. Overall, the successful adaptation and validation of the WCM for Persian provides a reliable tool for assessing phonological development in young children and sheds light on the importance of phonological complexity in vocabulary acquisition. This research can further deepen our understanding of phonological development during early childhood and its implications for language learning.

Developmental Changes in Coarticulation Degree Relate to Differences in Articulatory Patterns: An Empirically Grounded Modeling Approach

PURPOSE

Coarticulatory effects in speech vary across development, but the sources of this variation remain unclear. This study investigated whether developmental differences in intrasyllabic coarticulation degree could be explained by differences in children's articulatory patterns compared to adults.

METHOD

To address this question, we first compared the tongue configurations of 3- to 7-year-old German children to those of adults. The observed developmental differences were then examined through simulations with Task Dynamics Application, a Task Dynamics simulation system, to establish which articulatory modifications could best reproduce the empirical results. To generate syllables simulating the lack of tongue gesture differentiation, we tested three simulation scenarios.

RESULTS

We found that younger speakers use less differentiated articulatory patterns to achieve alveolar constrictions than adults. The simulations corresponding to undifferentiated control of tongue tip and tongue body resulted in (a) tongue shapes similar to those observed in natural speech and (b) higher degrees of intrasyllabic coarticulation in children when compared to adults.

CONCLUSIONS

Results provide evidence that differences in articulatory patterns contribute to developmental differences in coarticulation degree. This study further shows that empirically informed modeling can advance our understanding of changes in coarticulatory patterns across age.

Speech production in Mandarin-speaking children with cochlear implants: a systematic review

OBJECTIVE

This study aimed to systematically review and critically appraise the literature describing the phonetic characteristics and accuracy of the consonants, vowels and tones produced by Mandarin-speaking children with cochlear implants (CIs).

DESIGN

The protocol in this review was designed in conformity with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. EBSCOhost, PubMed, Scopus, PsycINFO, ProQuest Central databases were searched for relevant articles which met the inclusion criteria.

STUDY SAMPLE

A total of 18 journal papers were included in this review.

RESULTS

The results revealed that Mandarin-speaking children with CIs perform consistently more poorly in their production of consonants, in particular on fricatives, have a smaller and less well-defined vowel space, and exhibit greater difficulties in tone realisation, notably T2 and T3, when compared to their normal-hearing (NH) peers. The results from acoustic and accuracy analyses are negatively correlated with CI implantation age, but largely positively correlated with hearing age.

CONCLUSIONS

Findings of this review highlight the factors that influence consonant, vowel and tone production in Mandarin-speaking children with CIs, thereby providing critical information for clinicians and researchers working with this population.

Neural Changes Induced by a Speech Motor Treatment in Childhood Apraxia of Speech: A Case Series

We report a case series of children with childhood apraxia of speech, by describing behavioral and white matter microstructural changes following 2 different treatment approaches.Five children with childhood apraxia of speech were assigned to a motor speech treatment (PROMPT) and 5 to a language, nonspeech oral motor treatment. Speech assessment and brain MRI were performed pre- and post-treatment. The ventral (tongue/larynx) and dorsal (lips) corticobulbar tracts were reconstructed in each subject. Mean fractional anisotropy and mean diffusivity were extracted. The hand corticospinal tract was assessed as a control pathway. In both groups speech improvements paralleled changes in the left ventral corticobulbar tract fractional anisotropy. The PROMPT treated group also showed fractional anisotropy increase and mean diffusivity decrease in the left dorsal corticobulbar tract. No changes were detected in the hand tract. Our results may provide preliminary support to the possible neurobiologic effect of a multimodal speech motor treatment in childhood apraxia of speech.

The Acquisition of Articulatory Timing for Liquids: Evidence From Child and Adult Speech

Purpose Liquids are among the last sounds to be acquired by English-speaking children. The current study considers their acquisition from an articulatory timing perspective by investigating anticipatory posturing for /l/ versus /ɹ/ in child and adult speech. Method In Experiment 1, twelve 5-year-old, twelve 8-year-old, and 11 college-aged speakers produced carrier phrases with penultimate stress on monosyllabic words that had /l/, /ɹ/, or /d/ (control) as singleton onsets and /æ/ or /u/ as the vowel. Short-domain anticipatory effects were acoustically investigated based on schwa formant values extracted from the preceding determiner (= the) and dynamic formant values across the /ə#LV/ sequence. In Experiment 2, long-domain effects were perceptually indexed using a previously validated forward-gated audiovisual speech prediction task. Results Experiment 1 results indicated that all speakers distinguished /l/ from /ɹ/ along F3. Adults distinguished /l/ from /ɹ/ with a lower F2. Older children produced subtler versions of the adult pattern; their anticipatory posturing was also more influenced by the following vowel. Younger children did not distinguish /l/ from /ɹ/ along F2, but both liquids were distinguished from /d/ in the domains investigated. Experiment 2 results indicated that /ɹ/ was identified earlier than /l/ in gated adult speech; both liquids were identified equally early in 5-year-olds' speech. Conclusions The results are interpreted to suggest a pattern of early tongue-body retraction for liquids in /ə#LV/ sequences in children's speech. More generally, it is suggested that children must learn to inhibit the influence of vowels on liquid articulation to achieve an adultlike contrast between /l/ and /ɹ/ in running speech.

A comparison of the nutritive sucking performance of full term and preterm neonates at hospital discharge: A prospective study

BACKGROUND

Studies show that 40% to 70% of premature infants exhibit both immature and atypical feeding ability. To establish thresholds of performance and develop efficacious treatments for initiating and advancing oral feedings, we must first identify the nutritive sucking performance measures impacted by preterm birth.

AIMS

To compare objective measures of neonatal nutritive sucking between full term and preterm infants at hospital discharge.

STUDY DESIGN AND METHODS

This was a prospective observational study including full term (FT; N = 32) and preterm (PT; N = 44) infants. Nutritive sucking performance at discharge was assessed. The outcome measures of interest were means and coefficients of variability of nutritive sucking peak amplitude, frequency, duration, and smoothness, and feeding-related length of stay.

RESULTS

There was a significant difference in sucking performance between groups; FT infants demonstrated significantly lower mean suck frequency, with longer suck duration and greater suck smoothness as compared to PT. PT infants had significantly less variability in suck amplitude and frequency as compared to FT, while FT infants had significantly less variability in suck smoothness as compared to PT. Post hoc regression analyses found suck frequency alone accounted for 28% of the variance in feeding length of stay for PT; suck smoothness alone accounted for 34% of the variance in feeding length of stay for FT.

CONCLUSIONS

Suck frequency may be an important intervention target for PT infants having difficulty transitioning to oral feeding. Suck smoothness may be a sensitive marker for identifying infants at high risk for feeding challenges.

Praxia não verbal na fonoaudiologia: revisão de literatura

RESUMO A Fala é definida como representação motora da Linguagem, em que há a coordenação de três processos neurológicos: organização de conceitos, formulação e expressão simbólica; programação do ato motor envolvido na produção da fala; e sua própria produção motora. O Controle Motor da Fala, que ordena a contração muscular para a sua execução, inclui o planejamento, a preparação de movimentos e a execução de planos para resultar em contrações musculares e deslocamentos de estruturas que culminarão na articulação da Fala. Os estudos científicos nacionais e internacionais vislumbram um novo campo de atuação fonoaudiológica para o trabalho com a fala alterada, com a estimulação da Praxias Não Verbais. O objetivo deste trabalho é revisar, na bibliografia, o tratamento dado às praxias orais e não verbais e pontuar suas aplicações clínicas no âmbito fonoaudiológico. Realizou-se uma busca nas bases de dados PubMed, Lilacs e Scielo. As 40 citações selecionadas foram avaliadas de forma crítica. Os artigos mostraram que a Praxia Não Verbal pode ser estimulada para o trabalho clínico com a Fala, no entanto, não há descrição do trabalho fonoaudiológico, tampouco um detalhamento dos exercícios em sequência que poderiam ser utilizados. Nenhum artigo apontou para o modo como as Praxias Não Verbais deveriam ser trabalhadas, nem mesmo como estimular a programação motora para a Fala. Este estudo propõe a necessidade clínica de criar instrumentos de intervenção fonoaudiológica que incluam a estimulação das Praxias Não Verbais para o trabalho com a articulação da Fala.

Children's acquisition of English onset and coda /l/: articulatory evidence

PURPOSE

The goal of this study was to better understand how and when onset /l/ (leap) and coda /l/ (peel) are acquired by children by examining both the articulations involved and adults' perceptions of the produced segments.

METHOD

Twenty-five typically developing Australian English-speaking children aged 3;0 (years;months) to 7;11 participated in an elicited imitation task, during which audio, video, and lingual ultrasound images were collected. Transcribers perceptually rated audio, whereas video and ultrasound images were visually examined for the presence of adult-like articulations.

RESULTS

Data from this study establish that for Australian English-learning children, coda /l/s are acquired later than onset /l/s, and older children produce greater proportions of adultlike /l/s in both onset and coda positions, roughly following established norms for American English-speaking children. However, although perceptibility of coda /l/s was correlated with their articulations, onset /l/s were nearly uniformly perceived as adultlike despite substantial variation in the articulations used to produce them.

CONCLUSIONS

The disparity in the production and perception of children's singleton onset /l/s is linked to both physiological and phonological development. Suggestions are made for future research to tease these factors apart.

Sagittal area of the vocal tract in young female children

OBJECTIVE

To measure the sagittal areas of the front and back cavities of the vocal tract in children acquiring speech.

PATIENTS AND METHODS

Ten female children were selected from the Serial Experimental collection of the Burlington Growth Centre in Toronto, Canada. Each of the 10 children was seen annually from ages 3 through 8. Data collections included lateral cephalograms in occlusion. We traced those cephalograms and identified landmarks to delineate the front and back cavities. The sagittal areas of the front and back cavities were calculated. A measure of the angle of the head to the cervical vertebrae was made.

RESULTS

Front cavities were larger and grew faster. For both front and back cavities, age, angle measure, and the interaction of age and angle measure were significant.

CONCLUSION

Space available for the tongue to maneuver is greater anteriorly than posteriorly even when the jaw is maximally elevated.