Diagnosing inconsistent phonological disorder: quantitative and qualitative measures.

Studies of children's consistency of word production allow identification of speech sound disorder. Inconsistent errors are reported for two groups of children: childhood apraxia of speech (CAS) due to difficulty with the motoric precision and consistency of speech movements; and inconsistent phonological disorder (IPD) attributed to impaired phonological planning. This paper describes the inconsistent productions of children with IPD in comparison to typically developing children. In two studies of suspected SSD (N = 135), 22 children pronounced ≥40% of 25 words inconsistently on three repeated trials. No participant had symptoms of CAS. They were monolingual and spoke Australian- or Irish-English. Assessment determined the proportions of words said consistently (i.e. the same across productions: all correct or with the same error) or inconsistently (i.e. differently across productions: at least one correct and one error or different errors in productions). Qualitative analyses examined error types and explored the effect of target words' characteristics on inconsistency. Children with IPD produced 52% of words with different errors. While 56% of all phoneme errors were developmental (age appropriate or delayed), atypical errors typified inconsistency: default sounds and word structure errors. Words with more phonemes, syllables and consonant clusters were vulnerable to inconsistency, but their frequency of occurrence had no effect. TD children and those with IPD had different quantitative and qualitative error profiles, confirming IPD as a diagnostic category of SSD. Qualitative analyses supported the hypothesised deficit in phonological planning of words' production for children with IPD.

Preschool children's consistency of word production.

Consistency of word production contributes to carers' ability to understand children's speech. Reports of the proportion of words produced consistently by typically developing preschool children, however, vary widely from 17% to 87%. This paper examines the quantitative (consistency count) and qualitative (e.g. phonemic analysis) characteristics of word consistency in 96 children aged 36-60 months. Children named 15 pictures twice, in separate trials, in the same assessment session. The mean consistency of the production for the whole group was 82%. Older children were more consistent than younger children. Girls were more consistent than boys. Words produced correctly in one trial and in error in another may indicate resolving error patterns. Words produced in error in two different ways provided useful evidence about the nature of inconsistent word production in typically developing children. The clinical and theoretical implications are discussed.

Differentiating phonological delay from phonological disorder: Executive function performance in preschoolers.

BACKGROUND: The conversational speech of most children can be understood by people outside the family by the time they reach 4 years. However, for some children, speech sound disorders (SSDs) persist into their early school years, and beyond, despite adequate hearing, oromotor function, and language learning opportunities. One explanation for children's SSDs are domain-general cognitive-linguistic deficits that impair the child's ability to correctly derive rules governing how speech sounds legally combine to form words in a specific language. AIMS: To explore whether there are differences in performance on executive function tasks between children who make speech errors characteristic of phonological delay and those who make speech errors characteristic of phonological disorder. METHODS & PROCEDURES: Twenty-six children aged from 3;6 to 5;2 (13 with phonological delay and 13 with phonological disorder), matched pairwise for age and sex (nine males), were assessed on tasks measuring cognitive flexibility (rule abstraction and cognitive shift) and phonological working memory. OUTCOME & RESULTS: For the cognitive flexibility tasks, the performance of children with phonological delay was significantly better than that for children with phonological disorder, but there were no group differences for the phonological working memory task. CONCLUSIONS & IMPLICATIONS: Children with phonological disorders might benefit from intervention programmes that incorporate training in cognitive flexibility. WHAT IS ALREADY KNOWN ON THE SUBJECT: Children with phonological delay and phonological disorder comprise the two largest SSD subgroups that present to speech-language therapy clinics. Evidence suggests domain-general cognitive processes (e.g., phonological working memory, ability to revise faulty underlying representations, rule abstraction, and cognitive shift) influence phonological development. Differences between the two subgroups in the types of speech errors, linguistic abilities, developmental trajectories, and responses to intervention have been reported, yet little is known about the underlying cognitive-linguistic deficits. WHAT THIS PAPER ADDS TO EXISTING KNOWLEDGE: The results of this study suggest that children with phonological delay and phonological disorder have distinct patterns of performance on executive function tasks: Children with phonological disorder showed deficits in domain general rule-abstraction and cognitive shift when compared to children with phonological delay. WHAT ARE THE POTENTIAL OR ACTUAL CLINICAL IMPLICATIONS OF THIS WORK?: The findings draw attention to: (1) the importance of differential diagnosis of phonological delay and phonological disorder; (2) the role of domain-general cognitive processes in explaining why children make particular types of errors; and (3) the need to develop innovative and tailored intervention techniques that target specific underlying deficits.

Is children's speech development changing? Preliminary evidence from Australian English-speaking 3-year-olds.

Purpose: Around 9% of children have difficulty acquiring intelligible speech despite typical sensory, neuro-motor and cognitive function. Speech-language pathologists (SLPs) rely on descriptions of children's speech errors to identify speech sound disorder (SSD) and determine intervention targets and goals. Existing normative data, however, need re-evaluation to reflect changes in populations and the language learning environment. This research evaluates whether developmental phonological patterns widely accepted as describing typical acquisition predict speech errors in a recent sample of pre-school children.Method: In 2015, 99 neurotypical children aged 3;0-3;8 years;months were assessed using the Diagnostic Evaluation of Articulation and Phonology (DEAP). Their performance was compared to studies describing speech development by children of the same age for phone repertoire and phonological patterns.Result: There were differences for both measures. Phone repertoire differences were marginal, but changes in phonological pattern use were unexpected. Suppression of three developmental phonological patterns (stopping of fricatives, final consonant deletion and voicing contrasts) was delayed compared to previous norms. Atypical consonant cluster reduction, sometimes considered a marker for disorder, was observed in 10% of children.Conclusion: There were qualitative differences in the speech development of the 2015 cohort of children compared to previous developmental norms. Valid and current normative data are necessary for the accurate identification of children needing intervention. The differences we found reinforce the need for regular updating of assessment tools, as well as greater understanding of how children's language learning environments are changing and potentially influencing speech development.

Re-Evaluating Evidence for Best Practice in Paediatric Speech-Language Pathology.

BACKGROUND: Systematic reviews of treatment trials for children with speech and language difficulties often exemplify the limited clinical usefulness of the evidence base, reflecting recent literature in evidence-based medicine. Other studies report that clinicians often fail to seek information about best practice, across the health professions. Consequently, clinical researchers, including those in speech-language pathology, have sought alternative methodologies for determining best practice. SUMMARY: Some approaches focus on "pragmatic trials," usually as part of existing health services. Others place case management of individuals at the centre of intervention presenting studies of one or more cases, including N-of-1 randomized controlled trials and cross-over group designs. Clinical case studies can provide important theoretical data contributing to our understanding of the development of typical and atypical communication. Precision medicine (also known as personalized medicine) is an emerging approach to building the clinical evidence base that acknowledges the importance of individual genetic and environmental differences between people. With increasing knowledge of aetiological heterogeneity, even within children presenting with the same diagnosis (e.g., childhood apraxia of speech), data reinforce the edict that children are not all born equal. Key Message: This review argues that to understand response to treatment, it is critical to examine child-related factors as well as the variables of the intervention itself.

Which measure of socioeconomic status best predicts bilingual lexical abilities and how? A focus on four-year-olds exposed to two majority languages.

This study evaluates the ability of different measures of socioeconomic status (SES) to predict lexical outcomes for preschoolers raised in a context of nationwide bilingualism. The participants were 58 children aged 3;11-4;3 from Maltese-dominant homes who attended state preschools. Receptive picture name judgement and picture naming, in Maltese and English, were employed to measure receptive and expressive lexical abilities, respectively. Lexical outcomes for four individual SES variables and a single composite SES measure were similar but not directly interchangeable. The composite SES variable emerged as most strongly predictive of children's lexical performance. Receptive judgement of phonological accuracy improved similarly in both languages with higher composite SES. Naming skills increased significantly in English but not in Maltese, suggesting differences in English input related to parental SES. A focus on SES in relation to lexical skills in two majority languages is novel and adds to current understanding of normative bilingual acquisition.

Speech development in preschool children: evaluating the contribution of phonological short-term and phonological working memory.

Emerging evidence suggests domain-general processes, including working memory, may contribute to reduced speech production skills in young children. This study compared the phonological short-term (pSTM) and phonological working memory (pWM) abilities of 50 monolingual English-speaking children between 3;6 and 5;11 with typical speech production skills and percentage consonant correct (PCC) standard scores of 12 and above (n = 22) and typical speech production skills and PCC standard scores of between 8 and 11 (n = 28). A multiple hierarchical regression was also conducted to determine whether pSTM and/or pWM could predict PCC. Children with typical speech production skills and PCC standard scores of 12 and above had better pWM abilities than children with typical speech production skills and PCC standard scores of between 8 and 11. pSTM ability was similar in both groups. pWM accounted for 5.3% variance in overall phonological accuracy. Implications of phonological working memory in speech development are discussed.

Computer Adaptive Test Stopping Rules Applied to The Flexilevel Shoulder Functioning Test.

Computerized adaptive testing (CAT) is an attractive alternative to traditional paper-and-pencil testing because it can provide accurate trait estimates while administering fewer items than a linear test form. A stopping rule is an important factor in determining an assessments efficiency. This simulation compares three variable-length stopping rules-standard error (SE) of .3, minimum information (MI) of .7 and change in trait (CT) of .02 - with and without a maximum number of items (20) imposed. We use fixed-length criteria of 10 and 20 items as a comparison for two versions of a linear assessment. The MI rules resulted in longer assessments with more biased trait estimates in comparison to other rules. The CT rule resulted in more biased estimates at the higher end of the trait scale and larger standard errors. The SE rules performed well across the trait scale in terms of both measurement precision and efficiency.

Comparing computer adaptive testing stopping rules under the generalized partial-credit model.

An important consideration of any computer adaptive testing (CAT) program is the criterion used for ending item administration-the stopping rule, which ensures that all examinees are assessed to the same standard. Although various stopping rules exist, none of them have been compared under the generalized partial-credit model (Muraki in Applied Psychological Measurement, 16, 159-176, 1992). In this simulation study we compared the performance of three variable-length stopping rules-standard error (SE), minimum information (MI), and change in theta (CT)-both in isolation and in combination with requirements of minimum and maximum numbers of items, as well as a fixed-length stopping rule. Each stopping rule was examined under two termination criteria-one a more lenient requirement (SE = 0.35, MI = 0.56, CT = 0.05), and one more stringent (SE = 0.30, MI = 0.42, CT = 0.02). The simulation design also included content-balancing and exposure controls, aspects of CAT that have been excluded in previous research comparing variable-length stopping rules. The minimum-information stopping rule produced biased theta estimates and varied greatly in measurement quality across the theta distribution. The absolute-change-in-theta stopping rule had strong performance when paired with a lower criterion and a minimum test length. The standard error stopping rule consistently provided the best balance of measurement precision and operational efficiency and was based on the fewest number of administered items necessary to obtain accurate and precise theta estimates, particularly when it was paired with a maximum-number-of-items stopping rule.

Articulation or phonology? Evidence from longitudinal error data.

Children's speech difficulties can be motor (phone misarticulation) or linguistic (impaired knowledge of phonological contrasts and constraints). These two difficulties sometimes co-occur. This paper reports longitudinal data from the Early Language in Victoria Study (ELVS) at 4 and 7 years of age. Of 1494 participants, 93 made non-age appropriate speech errors on standardised assessments at 4 years, and were able to be reassessed at 7 years. At 4 years, 85% of these children only made phonological errors, 14% made both articulation and phonological errors and one child only made articulation errors (a lateral lisp). In total, 8 of 13 children making both articulation and phonological errors at 4 years had resolved by 7 years. Unexpectedly, eight children who had demonstrated articulation of fricatives at 4 years, acquired distorted production of ≥ 50% of occurrences of/s, z/ by 7 years. In total, then, 22 children (24% of children with speech difficulties) made articulatory errors at one or both assessments. Case data for all children are presented. Theoretical and clinical implications are considered.

Language-General Auditory-Visual Speech Perception: Thai-English and Japanese-English McGurk Effects.

Cross-language McGurk Effects are used to investigate the locus of auditory-visual speech integration. Experiment 1 uses the fact that [], as in 'sing', is phonotactically legal in word-final position in English and Thai, but in word-initial position only in Thai. English and Thai language participants were tested for 'n' perception from auditory [m]/visual [] (A[m]V[]) in word-initial and -final positions. Despite English speakers' native language bias to label word-initial [] as 'n', the incidence of 'n' percepts to A[m]V[] was equivalent for English and Thai speakers in final and initial positions. Experiment 2 used the facts that (i) [ð] as in 'that' is not present in Japanese, and (ii) English speakers respond more often with 'tha' than 'da' to A[ba]V[ga], but more often with 'di' than 'thi' to A[bi]V[gi]. English and three groups of Japanese language participants (Beginner, Intermediate, Advanced English knowledge) were presented with A[ba]V[ga] and A[bi]V[gi] by an English (Experiment 2a) or a Japanese (Experiment 2b) speaker. Despite Japanese participants' native language bias to perceive 'd' more often than 'th', the four groups showed a similar phonetic level effect of [a]/[i] vowel context × 'th' vs. 'd' responses to A[b]V[g] presentations. In Experiment 2b this phonetic level interaction held, but was more one-sided as very few 'th' responses were evident, even in Australian English participants. Results are discussed in terms of a phonetic plus postcategorical model, in which incoming auditory and visual information is integrated at a phonetic level, after which there are post-categorical phonemic influences.

The phonological memory profile of preschool children who make atypical speech sound errors.

Previous research indicates that children with speech sound disorders (SSD) have underlying phonological memory deficits. The SSD population, however, is diverse. While children who make consistent atypical speech errors (phonological disorder/PhDis) are known to have executive function deficits in rule abstraction and cognitive flexibility, little is known about their memory profile. Sixteen monolingual preschool children with atypical speech errors (PhDis) were matched individually to age-and-gender peers with typically developing speech (TDS). The two groups were compared on forward recall of familiar words (pointing response), reverse recall of familiar words (pointing response), and reverse recall of digits (spoken response) and a receptive vocabulary task. There were no differences between children with TDS and children with PhDis on forward recall or vocabulary tasks. However, children with TDS significantly outperformed children with PhDis on the two reverse recall tasks. Findings suggest that atypical speech errors are associated with impaired phonological working memory, implicating executive function impairment in specific subtypes of SSD.

Comparing Imputation Methods for Trait Estimation Using the Rating Scale Model.

This study examined the performance of four methods of handling missing data for discrete response options on a questionnaire: (1) ignoring the missingness (using only the observed items to estimate trait levels); (2) nearest-neighbor hot deck imputation; (3) multiple hot deck imputation; and (4) semi-parametric multiple imputation. A simulation study examining three questionnaire lengths (41-, 20-, and 10-item) crossed with three levels of missingness (10, 25, and 40 percent) was conducted to see which methods best recovered trait estimates when data were missing completely at random and the polytomous items were scored with Andrich's (1978) rating scale model. The results showed that ignoring the missingness and semi-parametric imputation best recovered known trait levels across all conditions, with the semi-parametric technique providing the most precise trait estimates. This study demonstrates the power of specific objectivity in Rasch measurement, as ignoring the missingness leads to generally unbiased trait estimates.

Who to Refer for Speech Therapy at 4 Years of Age Versus Who to "Watch and Wait"?

OBJECTIVE: To examine predictors of speech disorder resolution versus persistence at age 7 years in children with speech errors at age 4 years. STUDY DESIGN: Participants were drawn from a longitudinal, community cohort. Assessment at age 4 years (N?=?1494) identified children with speech errors. Reassessment at age 7 years allowed categorization into resolved or persistent categories. Logistic regression examined predictors of speech outcome, including family history, sex, socioeconomic status, nonverbal intelligence, and speech error type (delay vs disorder). RESULTS: At age 7 years, persistent errors were seen in over 40% of children who had errors at age 4 years. Speech symptomatology was the only significant predictor of outcome (P?=?.02). Children with disordered errors at age 4 years were twice as likely to have poor speech outcomes at age 7 years compared with those with delayed errors. CONCLUSIONS: Children with speech delay at age 4 years seem more likely to resolve, and this might justify a "watch and wait" approach. In contrast, those with speech disorder at age 4 years appear to be at greater risk for persistent difficulties, and could be prioritized for therapy to offset long-term impacts.

The Development of MST Test Information for the Prediction of Test Performances.

The current study proposes novel methods to predict multistage testing (MST) performance without conducting simulations. This method, called MST test information, is based on analytic derivation of standard errors of ability estimates across theta levels. We compared standard errors derived analytically to the simulation results to demonstrate the validity of the proposed method in both measurement precision and classification accuracy. The results indicate that the MST test information effectively predicted the performance of MST. In addition, the results of the current study highlighted the relationship among the test construction, MST design factors, and MST performance.

Feasibility of Technology Enabled Speech Disorder Screening.

One in twenty Australian children suffers from a speech disorder. Early detection of such problems can significantly improve literacy and academic outcomes for these children, reduce health and educational burden and ongoing social costs. Here we present the development of a prototype and feasibility tests of a screening and decision support tool to assess speech disorders in young children. The prototype incorporates speech signal processing, machine learning and expert knowledge to automatically classify phonemes of normal and disordered speech. We discuss these results and our future work towards the development of a mobile tool to facilitate broad, early speech disorder screening by non-experts.

Marginalized Maximum Likelihood Estimation for the 1PL-AG IRT Model.

Marginal maximum likelihood estimation based on the expectation-maximization algorithm (MML/EM) is developed for the one-parameter logistic model with ability-based guessing (1PL-AG) item response theory (IRT) model. The use of the MML/EM estimator is cross-validated with estimates from NLMIXED procedure (PROC NLMIXED) in Statistical Analysis System. Numerical data are provided for comparisons of results from MML/EM and PROC NLMIXED.

A comparison of stopping rules for computerized adaptive screening measures using the rating scale model.

The current study evaluates three stopping rules for computerized adaptive testing (CAT): the predicted standard error reduction (PSER), the fixed-length, and the minimum SE using Andrich's rating scale model with a survey to identify at-risk students. PSER attempts to reduce the number of items administered and increase measurement precision of the trait. Several variables are manipulated, such as trait distribution and item pool size, in order to evaluate how these conditions interact and potentially help improve the correct classification of students. The findings indicate that the PSER stopping rule may be preferred when wanting to correctly diagnose or classify students at-risk and at the same time alleviate test burden for those taking screening measures based on the rating scale model with smaller item pools.

Concept map analysis in the assessment of speech-language pathology students' learning in a problem-based learning curriculum: a longitudinal study.

The aim of this study was to track students' critical thinking performance longitudinally through concept map analysis in a problem-based learning (PBL) curriculum. Concept map analysis has been employed in the assessment of students' critical thinking in medical education. Little is known concerning concept mapping (CM) in speech-language pathology (SLP) education. In this quantitative study, students in a 4-year SLP education program (N = 38) were followed until the completion of a fully-integrated PBL curriculum from Years 1 to 3. Students' concept maps were analyzed using a tool developed for this study, the Concept Map Assessment Profile (CMAP). There was an increase in concept map scores across the 3 years at the beginning of the academic year. The CM performance over the 3 years predicted 21.0% to 33.6% of variance in three measures of learning outcomes. The CMAP is a reliable measure, with strong inter-rater and intra-rater reliability (r = 0.85 and r = 0.96, respectively). In addition to its use as an assessment tool, the CMAP might be used to facilitate students' learning as feedback concerning strengths and weaknesses in the development of critical thinking can be provided.

Early lexical expression in typically developing Maltese children: implications for the identification of language delay.

Limited word production may be the first indicator of impaired language development. The unavailability of normative data and standardized assessments for young Maltese children hinders the identification of early language delays. This study aimed to document Maltese children's expressive vocabulary growth and accompanying range of variation, to assist identification of children at risk for language impairment. The expressive vocabularies of 44 typically developing children aged 12-30 months were measured through caregiver report. Mean scores at each age point were characterized by substantial individual variation. Gender was not related to mean growth in vocabulary production. Minimum scores were compared to clinical thresholds for English-speaking children. Results emphasized the assessment- and language-specific nature of identification criteria. Nevertheless, established thresholds may be referred to when normative data for particular languages/language pairs are limited. In such contexts, the consideration of other risk markers gains importance in supplementing findings on lexical expression.