Phonetic variability in residual speech sound disorders: Exploration of subtypes

Neural Changes in Children With Residual Speech Sound Disorder After Ultrasound Biofeedback Speech Therapy

PURPOSE

Children with residual speech sound disorders (RSSD) have shown differences in neural function for speech production, as compared to their typical peers; however, information about how these differences may change over time and relative to speech therapy is needed. To address this gap, we used functional magnetic resonance imaging (fMRI) to examine functional activation and connectivity on adaptations of the syllable repetition task (SRT-Early Sounds and SRT-Late Sounds) in children with RSSD before and after a speech therapy program.

METHOD

Sixteen children with RSSD completed an fMRI experiment before (Time 1) and after (Time 2) a speech therapy program with ultrasound visual feedback for /ɹ/ misarticulation. Progress in therapy was measured via perceptual ratings of productions of untreated /ɹ/ word probes. To control for practice effects and developmental change in patterns of activation and connectivity, 17 children with typical speech development (TD) completed the fMRI at Time 1 and Time 2. Functional activation was analyzed using a region-of-interest approach and functional connectivity was analyzed using a seed-to-voxel approach.

RESULTS

Children with RSSD showed a range of responses to therapy. After correcting for multiple comparisons, we did not observe any statistically significant cross-sectional differences or longitudinal changes in functional activation. A negative relationship between therapy effect size and functional activation in the left visual association cortex was on the SRT-Late Sounds after therapy, but it did not survive correction for multiple comparisons. Significant longitudinal changes in functional connectivity were observed for the RSSD group on SRT-Early Sounds and SRT-Late Sounds, as well as for the TD group on the SRT-Early Sounds. RSSD and TD groups showed connectivity differences near the left insula on the SRT-Late Sounds at Time 2.

CONCLUSION

RSSD and treatment with ultrasound visual feedback may thus be associated with neural differences in speech motor and visual association processes recruited for speech production.

Variability, accuracy, and cross-linguistic transfer in bilingual children speaking Jamaican Creole and English

Due to the lack of normative data about bilingual speech development and limited availability of diagnostic tools optimised for this population, bilingual children under consideration for speech-language services are at an elevated risk of misdiagnosis. In the absence of validated assessment tools, speech-language pathologists may use measures of accuracy and variability of speech production to diagnose suspected speech sound disorders in bilingual children. Research in general motor development suggests that variability and accuracy may trade off in the course of maturation, whereby movement variability spikes before the transition to a more mature stage of motor control. Such variability-accuracy tradeoffs have been described in monolingual speech development but are understudied in bilingual populations, where cross-linguistic transfer occurs. This study aimed to examine variability, accuracy, and cross-linguistic transfer in the speech of 20 bilingual children speaking Jamaican Creole and English. We hypothesised that children who showed higher accuracy in their productions would also exhibit more variable speech, indicating a variability-accuracy tradeoff. The Word Inconsistency Assessment from the Diagnostic Evaluation of Articulation and Phonology was administered to measure accuracy and variability in the English context, where misdiagnosis is likely to occur. Contrary to our hypothesis, we observed that individuals with higher accuracy tended to be less variable in their productions. Future research should examine longitudinal trajectories of accuracy and variability and consider a more culturally-appropriate definition of 'accuracy' in documenting bilingual speech sound development.

The Effect of Practice on Variability in Childhood Apraxia of Speech: A Multidimensional Analysis

Purpose Variability has been interpreted in differing ways according to context (e.g., development, speech impairment, and learning). A challenge arises when interpreting variability in the context of learning for children with speech impairment characterized by high movement variability, as in childhood apraxia of speech (CAS). The objective of this study is to investigate changes in variability in CAS with practice in comparison to patterns seen in children with non-CAS speech sound disorders (SSD) and typical development. Method Speech production variability was examined in 24 children (5-6 years of age) with CAS, non-CAS SSD, and typical development in production of nonwords of varied motoric complexity. Multidimensional analyses were performed using measures of token-to-token speech consistency (percent word consistency), acoustic variability (acoustic spatiotemporal index), and movement variability (lip aperture spatiotemporal index). Changes in variability were examined in each group of children by comparing the first half to the last half of nonword tokens in the same data collection session. The impact of token complexity on practice effects was also explored across groups of children. Results All children displayed increased speech consistency within this practice period (p = .01). Only children with CAS displayed increased movement variability following practice (p = .01). Differences in acoustic and kinematic variability were observed across complexity levels in all groups, though these did not interact with practice effects. Discussion These findings suggest that increased movement variability in children with CAS might be facilitating perceptual consistency. It is believed that this finding reflects an inefficient strategy adapted by children with CAS in the absence of motor-based cueing and feedback to guide speech performance with practice.

Métodos de avaliação da apraxia de fala na infância: revisão sistemática

RESUMO Objetivos Revisar sistematicamente os protocolos e/ou avaliações que contribuem para o diagnóstico de apraxia de fala na infância (AFI) e classificá-los de acordo com a dimensão clínica avaliada. Estratégia de pesquisa Estudo de revisão sistemática da literatura nas bases de dados MEDLINE (acessado via PubMed), LILACS, Scopus e SciELO, com os descritores Apraxias, Childhood apraxia of speech, Evaluation, Assessment, Validation Studies, Evaluation Studies, Language Therapy, Rehabilitation of Speech and Language Disorders, Child e Child, Preschool. Critérios de seleção A busca nas bases de dados foi conduzida por três pesquisadores independentes. Foram incluídos estudos que avaliavam, de forma clara, sujeitos com suspeita ou diagnóstico de AFI. Os revisores realizaram a coleta de dados no que diz respeito às características metodológicas, intervenções e desfechos dos estudos, por meio de planilhas previamente elaboradas especificamente para o presente estudo. O dado principal coletado foi referente aos procedimentos de avaliação da AFI para crianças. Resultados A maior parte dos estudos (14 dos 21 incluídos) realizou a associação entre a avaliação de habilidades motoras e/ou articulatórias e segmentais. Cinco realizaram avaliação de todos os aspectos elencados: motor e/ou articulatória, segmental e suprassegmental e dois realizaram apenas avaliação motora e/ou articulatória. A idade dos sujeitos variou de 3 a 12 anos. Conclusão A maioria das pesquisas considerou a associação entre habilidades motoras e/ou articulatórias e segmentais para avaliação da apraxia de fala na infância. Sugere-se a realização de mais estudos, a fim de buscar evidências de validade.

Retrospective video analysis of the early speech sound development of infants and toddlers later diagnosed with lateralisation errors

Purpose: Although lateralisation errors (LEs) are a common speech sound disorder, no studies have examined their early development. The purpose of this exploratory small-scale investigation was to compare the early (birth-24 months) speech sound development between children later diagnosed with LEs and typically developing children.Method: This was a between-group case-controlled design with six monolingual English-speaking participants. Participants were White, non-Hispanic girls with at least one college-educated parent. As children, three had been diagnosed with lateralisation speech sound errors and three demonstrated typical speech sound development. Participants' parents provided home video-recordings of the participants as infants/toddlers between birth and age 2. These videos were then analysed for the amount, type and diversity of sounds, and canonical babbling onset.Result: There was no statistically significant between-group difference in the volubility (i.e. combined frequency of non-resonant and resonant utterances) or in the age at which [s] or [z] emerged. However, infants/toddlers who were later diagnosed with LEs showed reduced frequency/minute in production of resonant utterances and consonants (including [s, z]), used fewer different consonants/minute, and used fewer syllable shapes/minute compared to typically developing infants/toddlers. At 7-12 months, none of the infants/toddlers later diagnosed with LEs, but all participants in the comparison group had reached the canonical babbling stage.Conclusion: Children who have LEs may have had a less robust speech sound system as infants/toddlers than their typically developing peers. However, these findings must be considered with caution due to the significant limitations of this investigation.

Assessment of Childhood Apraxia of Speech: A Review/Tutorial of Objective Measurement Techniques

Background With respect to the clinical criteria for diagnosing childhood apraxia of speech (commonly defined as a disorder of speech motor planning and/or programming), research has made important progress in recent years. Three segmental and suprasegmental speech characteristics-error inconsistency, lengthened and disrupted coarticulation, and inappropriate prosody-have gained wide acceptance in the literature for purposes of participant selection. However, little research has sought to empirically test the diagnostic validity of these features. One major obstacle to such empirical study is the fact that none of these features is stated in operationalized terms. Purpose This tutorial provides a structured overview of perceptual, acoustic, and articulatory measurement procedures that have been used or could be used to operationalize and assess these 3 core characteristics. Methodological details are reviewed for each procedure, along with a short overview of research results reported in the literature. Conclusion The 3 types of measurement procedures should be seen as complementary. Some characteristics are better suited to be described at the perceptual level (especially phonemic errors and prosody), others at the acoustic level (especially phonetic distortions, coarticulation, and prosody), and still others at the kinematic level (especially coarticulation, stability, and gestural coordination). The type of data collected determines, to a large extent, the interpretation that can be given regarding the underlying deficit. Comprehensive studies are needed that include more than 1 diagnostic feature and more than 1 type of measurement procedure.

The Psychometric Evaluation of a Speech Production Test Battery for Children: The Reliability and Validity of the Computer Articulation Instrument

Purpose The aims of this study were to assess the reliability and validity of the Computer Articulation Instrument (CAI), a speech production test battery assessing phonological and speech motor skills in 4 tasks: (1) picture naming, (2) nonword imitation, (3) word and nonword repetition, and (4) maximum repetition rate (MRR). Method Normative data were collected in 1,524 typically developing Dutch-speaking children (aged between 2;0 and 7;0 [years;months]). Parameters were extracted on segmental and syllabic accuracy (Tasks 1 and 2), consistency (Task 3), and syllables per second (Task 4). Interrater reliability and test-retest reliability were analyzed using subgroups of the normative sample and studied by estimating intraclass correlation coefficients (ICCs). Construct validity was investigated by determining age-related changes of test results and factor analyses of the extracted speech measures. Results ICCs for interrater reliability ranged from sufficient to good, except for percentage of vowels correct of picture naming and nonword imitation and for the MRRs for bisyllabic and trisyllabic items. The ICCs for test-retest reliability were sufficient (picture naming, nonword imitation) to insufficient (word and nonword repetition, MRR) due to larger-than-expected normal development and learning effects. Continuous norms showed developmental patterns for all CAI parameters. The factor analyses revealed 5 meaningful factors: all picture-naming parameters, the segmental parameters of nonword imitation, the syllabic structure parameters of nonword imitation, (non)word repetition consistency, and all MRR parameters. Conclusion Its overall sufficient to good psychometric properties indicate that the CAI is a reliable and valid instrument for the assessment of typical and delayed speech development in Dutch children in the ages of 2-7 years.

A Psycholinguistic Framework for Diagnosis and Treatment Planning of Developmental Speech Disorders

BACKGROUND

Differential diagnosis and treatment planning of developmental speech disorders (DSD) remains a major challenge in paediatric speech-language pathology. Different classification systems exist, in which subtypes are differentiated based on their theoretical cause and in which the definitions generally refer to speech production processes. Accordingly, various intervention methods have been developed aiming at different parts of the speech production process. Diagnostic classification in these systems, however, is primarily based on a description of behavioural speech symptoms rather than on underlying deficits.

PURPOSE

In this paper, we present a process-oriented approach to diagnosis and treatment planning of DSD. Our framework comprises two general diagnostic categories: developmental delay and developmental disorder. Within these categories, treatment goals/targets and treatment methods are formulated at the level of processes and rules/representations.

CONCLUSION

A process-oriented approach to diagnosis and treatment planning holds important advantages, offering direct leads for treatment aimed at the underlying impairment, tailored to the specific needs of the individual and adjusted to the developmental trajectory.

A Standardized Protocol for Maximum Repetition Rate Assessment in Children

BACKGROUND/AIMS

Maximum repetition rate (MRR) is often used in the assessment of speech motor performance in older children and adults. The present study aimed to evaluate a standardized protocol for MRR assessment in young children in Dutch.

METHODS

The sample included 1,524 children of 2-7 years old with no hearing difficulties and Dutch spoken in their nursery or primary school and was representative for children in the Netherlands. The MRR protocol featured mono-, tri-, and bisyllabic sequences and was computer-implemented to maximize standardization.

RESULTS

Less than 50% of the 2-year-olds could produce >1 monosyllabic sequence correctly. Children who could not correctly produce ≥2 monosyllabic sequences could not produce any of the multisyllabic sequences. The effect of instruction ("faster" and "as fast as possible") was small, and multiple attempts yielded a faster MRR in only 20% of the cases. MRRs did not show clinically relevant differences when calculated over different numbers of repeated syllables.

CONCLUSIONS

The MRR protocol is suitable for children of 3 years and older. If children cannot produce at least 2 of the monosyllabic sequences, the multisyllabic tasks should be omitted. Furthermore, all fast attempts of each sequence should be analyzed to determine the fastest MRR.

Error Consistency in Acquired Apraxia of Speech With Aphasia: Effects of the Analysis Unit

PURPOSE

Diagnostic recommendations for acquired apraxia of speech (AOS) have been contradictory concerning whether speech sound errors are consistent or variable. Studies have reported divergent findings that, on face value, could argue either for or against error consistency as a diagnostic criterion. The purpose of this study was to explain discrepancies in error consistency results based on the unit of analysis (segment, syllable, or word) to help determine which diagnostic recommendation is most appropriate.

METHOD

We analyzed speech samples from 14 left-hemisphere stroke survivors with clinical diagnoses of AOS and aphasia. Each participant produced 3 multisyllabic words 5 times in succession. Broad phonetic transcriptions of these productions were coded for consistency of error location and type using the word and its constituent syllables and sound segments as units of analysis.

RESULTS

Consistency of error type varied systematically with the unit of analysis, showing progressively greater consistency as the analysis unit changed from the word to the syllable and then to the sound segment. Consistency of error location varied considerably across participants and correlated positively with error frequency.

CONCLUSIONS

Low to moderate consistency of error type at the word level confirms original diagnostic accounts of speech output and sound errors in AOS as variable in form. Moderate to high error type consistency at the syllable and sound levels indicate that phonetic error patterns are present. The results are complementary and logically compatible with each other and with the literature.

Underlying manifestations of developmental phonological disorders in French-speaking pre-schoolers

This study examined the psycholinguistic profiles of Quebec French-speaking children with developmental phonological disorders (DPD). The purpose was to determine whether the endophenotypes that have been identified in English-speaking children with DPD are similarly associated with speech impairment in French-speaking children. Seventy-two children with DPD and ten children with normally developing speech, aged four to six years, received a comprehensive assessment battery that included measures at the phenotype level (i.e. measures of overt speech production skills) and endophenotype level (i.e. measures of potential underlying core deficits such as phonological processing or oral motor impairments). The majority of the children with DPD presented with a psycholinguistic profile indicative of difficulties with phonological processing. Phonological processing skills also explained unique variance in speech production accuracy, indicating that French-speaking children with DPD, who produce different surface speech errors than English-speaking children with DPD, are nonetheless very similar with regards to their underlying psycholinguistic profile.

Variable Practice to Enhance Speech Learning in Ultrasound Biofeedback Treatment for Childhood Apraxia of Speech: A Single Case Experimental Study

PURPOSE

The purpose of this study was to evaluate the role of practice variability, through prosodic variation during speech sound training, in biofeedback treatment for children with childhood apraxia of speech. It was hypothesized that variable practice would facilitate speech sound learning.

METHOD

Six children ages 8-16 years with persisting speech sound errors due to childhood apraxia of speech participated in a single-subject experimental design. For each participant, 2 speech sound targets were treated with ultrasound visual feedback training: one with prosodic variation (i.e., practicing sound targets in words and phrases spoken fast, slow, loud, as a question, command, and declarative), and one without prosodic variation. Each target was treated for half of the 1-hr session for 14 treatment sessions.

RESULTS

As measured by standardized effect sizes, all participants showed greater change on generalization probes for sound targets treated under the prosodic variation condition with mean effect sizes (d2) of 14.5 for targets treated with prosodic variation and 8.3 for targets treated without prosodic variation. The average increase in generalization scores was 38% in the prosodic variation condition compared to 31% without.

CONCLUSIONS

Ultrasound visual feedback may facilitate speech sound learning and learning may be enhanced by treating speech sounds with explicit prosodic variation.

SUPPLEMENTAL MATERIALS

https://doi.org/10.23641/asha.5150119.

Effect of gap detection threshold on consistency of speech in children with speech sound disorder

BACKGROUND AND AIMS

The present study examined the relationship between gap detection threshold and speech error consistency in children with speech sound disorder.

METHODS AND PROCEDURES

The participants were children five to six years of age who were categorized into three groups of typical speech, consistent speech disorder (CSD) and inconsistent speech disorder (ISD).The phonetic gap detection threshold test was used for this study, which is a valid test comprised six syllables with inter-stimulus intervals between 20-300ms. The participants were asked to listen to the recorded stimuli three times and indicate whether they heard one or two sounds.

OUTCOMES AND RESULTS

There was no significant difference between the typical and CSD groups (p=0.55), but there were significant differences in performance between the ISD and CSD groups and the ISD and typical groups (p=0.00). The ISD group discriminated between speech sounds at a higher threshold.

CONCLUSIONS AND IMPLICATIONS

Children with inconsistent speech errors could not distinguish speech sounds during time-limited phonetic discrimination. It is suggested that inconsistency in speech is a representation of inconsistency in auditory perception, which causes by high gap detection threshold.

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.

Predictors of token-to-token inconsistency in preschool children with typical speech-language development

The purpose of this study was to examine potential concurrent predictors and replicate rates of token-to-token inconsistency (inconsistency in repeated productions of the same word) in 43 children with typical speech-language development, ages 2;6 to 4;2. A standard linear regression was used to determine which variables, if any, among age, expressive and receptive vocabulary, and speech sound production abilities predicted token-to-token inconsistency. Inconsistency rates in children from one research site, reported elsewhere, were compared to rates in children from a second research site. The results revealed that expressive vocabulary was the only significant predictor of token-to-token inconsistency in these children. Furthermore, inconsistency rates were similarly high across the two research sites. The findings are discussed in terms of their implications for our theoretical understanding of token-to-token inconsistency and its role in the differential diagnosis of speech sound disorders in children.

Lexical and phonological variability in preschool children with speech sound disorder

PURPOSE

The authors of this study examined relationships between measures of word and speech error variability and between these and other speech and language measures in preschool children with speech sound disorder (SSD).

METHOD

In this correlational study, 18 preschool children with SSD, age-appropriate receptive vocabulary, and normal oral motor functioning and hearing were assessed across 2 sessions. Experimental measures included word and speech error variability, receptive vocabulary, nonword repetition (NWR), and expressive language. Pearson product–moment correlation coefficients were calculated among the experimental measures.

RESULTS

The correlation between word and speech error variability was slight and nonsignificant. The correlation between word variability and receptive vocabulary was moderate and negative, although nonsignificant. High word variability was associated with small receptive vocabularies. The correlations between speech error variability and NWR and between speech error variability and the mean length of children's utterances were moderate and negative, although both were nonsignificant. High speech error variability was associated with poor NWR and language scores.

CONCLUSION

High word variability may reflect unstable lexical representations, whereas high speech error variability may reflect indistinct phonological representations. Preschool children with SSD who show abnormally high levels of different types of speech variability may require slightly different approaches to intervention.

How should children with speech sound disorders be classified? A review and critical evaluation of current classification systems

BACKGROUND

Children with speech sound disorders (SSD) form a heterogeneous group who differ in terms of the severity of their condition, underlying cause, speech errors, involvement of other aspects of the linguistic system and treatment response. To date there is no universal and agreed-upon classification system. Instead, a number of theoretically differing classification systems have been proposed based on either an aetiological (medical) approach, a descriptive-linguistic approach or a processing approach.

AIMS

To describe and review the supporting evidence, and to provide a critical evaluation of the current childhood SSD classification systems.

METHODS & PROCEDURES

Descriptions of the major specific approaches to classification are reviewed and research papers supporting the reliability and validity of the systems are evaluated.

MAIN CONTRIBUTION

Three specific paediatric SSD classification systems; the aetiologic-based Speech Disorders Classification System, the descriptive-linguistic Differential Diagnosis system, and the processing-based Psycholinguistic Framework are identified as potentially useful in classifying children with SSD into homogeneous subgroups. The Differential Diagnosis system has a growing body of empirical support from clinical population studies, across language error pattern studies and treatment efficacy studies. The Speech Disorders Classification System is currently a research tool with eight proposed subgroups. The Psycholinguistic Framework is a potential bridge to linking cause and surface level speech errors.

CONCLUSIONS & IMPLICATIONS

There is a need for a universally agreed-upon classification system that is useful to clinicians and researchers. The resulting classification system needs to be robust, reliable and valid. A universal classification system would allow for improved tailoring of treatments to subgroups of SSD which may, in turn, lead to improved treatment efficacy.