A comparison of language abilities in adolescents with Down syndrome and children with specific language impairment

Temporal-sampling theory and language in Down syndrome: An empirical study

BACKGROUND

Temporal-sampling theory argues that difficulties in the processing of syllable stress auditory markers and in lexical stress discrimination contribute to explaining the language problems of children with developmental language disorder and of those with dyslexia. The theory has not been tested in other developmental disabilities.

AIMS

This research sought to assess the potential of temporal-sampling theory as a framework to accounting for language difficulties in Down syndrome (DS).

METHODS AND PROCEDURES

Thresholds for auditory markers of lexical stress, lexical stress discrimination, and receptive vocabulary were studied in teenagers and young adults with DS and in peers with other intellectual disability (ID) of unknown origin matched on chronological age and non-verbal cognition.

OUTCOMES AND RESULTS

Frequency and intensity thresholds were higher in participants with DS, and their lexical stress discrimination and receptive vocabulary skills were lower than those of the group with other ID. Lexical stress discrimination was predicted by intensity thresholds and group, while receptive vocabulary was only predicted by lexical stress discrimination.

CONCLUSIONS AND IMPLICATIONS

The results suggest that temporal-sampling theory is useful to explain language difficulties in individuals with DS or with other ID. This opens up new window opportunities for the design of language intervention programs in such populations.

Frequency of Hebrew word usage by children with intellectual and developmental disabilities: implications for AAC core vocabulary

Appropriate vocabulary selection for augmentative and alternative communication (AAC) intervention is crucial to support communication and language development in children with intellectual and developmental disabilities (IDD). Core vocabulary lists are commonly used to guide this process, and there is a need for language-specific consideration. This paper aimed to develop a wordlist for selecting the core vocabulary for AAC intervention for young Hebrew-speaking children with IDD. Five children (age 3;5-8;4) were audio-recorded in naturalistic interactions with an interviewer and family members. Using Levy's clinical corpus in the Child Language Data Exchange System (CHILDES) and Child Phonology Analyzer (CPA) tools and preestablished codes, wordlists with usage frequencies were extracted and coded for lexeme, lexical categories and functions or content. The percentages of the 20, 50, 100, and 200 most frequent lexemes were calculated for each child and for the five children combined. The top 200 most frequently used lexemes constituted 85% of the composite lexicon. A comparison was made between this study list and a previous list derived from language samples of typically developing (TD). Lexemes representing function words dominated, albeit with a slight preference for content words in children with IDD. Among the content words, children with IDD used more adverbs, while children with TD used more verbs. Implications for AAC core vocabulary are discussed.

Everyday Executive Functioning Profiles in Adults with Down Syndrome

Research on everyday executive functions in individuals with Down Syndrome (DS) has focused mostly on children and adolescents. The current study examined everyday executive functions in DS adults. 27 DS adults (aged 22.00 to 42.00 years) were tested using the Behaviour Rating Inventory of Executive Function-Adult Informant Version (BRIEF-A). Findings revealed that DS adults exhibited greater impairments in Global Executive Composite (GEC), Working Memory, Plan/Organise, Task-Monitor and the Metacognition Index (MI) relative to typically developing adults in the normative sample. Substantial variabilities were found in all everyday executive function abilities among DS adults. Findings highlight the importance of making comprehensive assessments of everyday executive functions in DS individuals in order to identify problem areas and plan individualised support programmes.

Non-word repetition and vocabulary in Kuwaiti Arabic-speaking children with down syndrome and typically developing children

OVERVIEW

Non-word repetition (NWR) is one of the most effective predictors of language impairments in children as it has been found to correlate with various language measures and the association between NWR and vocabulary is well documented in typically developing (TD) studies. However, there is a dire need for investigations of language skills in Kuwaiti Arabic individuals with Down Syndrome, and this study set out to fill a gap in this field.

METHOD

In this paper, we compare the vocabulary and NWR skills of a group of 48 individuals with DS aged 6-20 years to a group of 44 TD children aged 3-10 years matched on nonverbal IQ. Furthermore, we investigate the correlations among these language measures in the two groups and examine whether NWR can predict receptive and expressive vocabulary in these two groups.

RESULT

Results found DS participants performed significantly less than the TD group on the three language measures (receptive vocabulary t(90)= -3.17, p < .01, expressive vocabulary t(90)= -3.27, p < .01, and NWR t(90)= -8.32, p < .01). Moreover, there were strong correlations between NWR and vocabulary (receptive and expressive) in the TD group but not the DS group.

CONCLUSION

Findings supported the working memory model and the phonological processing account for the TD group. On the other hand, the poor association between NWR and vocabulary in the DS group might be due to poor phonological discrimination difficulties and speech discrimination difficulties.

Oral language interventions can improve language outcomes in children with neurodevelopmental disorders: A systematic review and meta-analysis

Background

Young people who fail to develop language as expected face significant challenges in all aspects of life. Unfortunately, language disorders are common, either as a distinct condition (e.g., Developmental Language Disorder) or as a part of another neurodevelopmental condition (e.g., autism). Finding ways to attenuate language problems through intervention has the potential to yield great benefits not only for the individual but also for society as a whole.

Objectives

This meta-analytic review examined the effect of oral language interventions for children with neurodevelopmental disorders.

Search Methods

The last electronic search was conducted in April 2022.

Selection Criteria

Intervention studies had to target language skills for children from 2 to 18 years of age with Developmental Language Disorder, autism, intellectual disability, Down syndrome, Fragile X syndrome, and Williams syndrome in randomised controlled trials or quasi-experimental designs. Control groups had to include business-as-usual, waiting list, passive or active conditions. However, we excluded studies in which the active control group received a different type, delivery, or dosage of another language intervention. Eligible interventions implemented explicit and structured activities (i.e., explicit instruction of vocabulary, narrative structure or grammatical rules) and/or implicit and broad activities (i.e., shared book reading, general language stimulation). The intervention studies had to assess language skills in receptive and/or expressive modalities.

Data Collection and Analysis

The search provided 8195 records after deduplication. Records were screened by title and abstract, leading to full-text examinations of 448 records. We performed Correlated and Hierarchical Effects models and ran a retrospective power analysis via simulation. Publication bias was assessed via p-curve and precision-effect estimate.

Main Results

We examined 38 studies, with 46 group comparisons and 108 effects comparing pre-/post-tests and eight studies, with 12 group comparisons and 21 effects at follow-up. The results showed a mean effect size of d = 0.27 at the post-test and d = 0.18 at follow-up. However, there was evidence of publication bias and overestimation of the mean effects. Effects from the meta-analysis were significantly related to these elements: (1) receptive vocabulary and omnibus receptive measures showed smaller effect sizes relative to expressive vocabulary, grammar, expressive and receptive discourse, and omnibus expressive tests; and (2) the length of the intervention, where longer sessions conducted over a longer period of time were more beneficial than brief sessions and short-term interventions. Neither moderators concerning participants' characteristics (children's diagnosis, diagnostic status, age, sex, and non-verbal cognitive ability and severity of language impairment), nor those regarding of the treatment components and implementation of the language interventions (intervention content, setting, delivery agent, session structure of the intervention or total number of sessions) reached significance. The same occurred to indicators of study quality. The risk of bias assessment showed that reporting quality for the studies examined in the review was poor.

Authors’ Conclusions

In sum, the current evidence base is promising but inconclusive. Pre-registration and replication of more robust and adequately powered trials, which include a wider range of diagnostic conditions, together with more long-term follow-up comparisons, are needed to drive evidence-based practice and policy.

The relationship between mean length of utterance (MLU), Persian developmental sentence score (PDSS), and photographic expressive Persian grammar test (PEGT) in typically developing children and those with developmental language disorder (DLD)

PURPOSE

This study investigated the relationship between three practical measures for evaluating Persian grammar expression skills, MLU, PDSS, and PEGT, in preschool children with developmental language disorder (DLD) and their typically developing (TD) peers.

METHOD

Secondary data were obtained by re-analyzing language samples collected in previous studies. Previously audiotaped language samples of 25 monolingual 5-7 years-old Persian children with DLD and 25 TD children were transcribed and reanalyzed to calculate MLU in words (MLU-w) and PDSS for comparison with the results of PEGT.

RESULTS

Children with DLD had lower scores in PEGT, PDSS, and MLU-w than TD children (p < 0.001). In addition, there was a strong correlation between PDSS and MLU-w in both DLD (r = 0.91) and TD groups (r = 0.79). There was a significant correlation between PEGT and MLU (r = 0.76) and PDSS (r = 0.78) in the DLD group, while these correlations were not significant in TD group.

CONCLUSIONS

Considering the positive and significant correlation between MLU, PDSS, and PEGT in children with DLD, the use of PEGT, as a valid, reliable, and accurate test of grammar, which can be implemented quickly and easily, is suggested for clinical purposes of identification and screening of Persian children with DLD.

Distinct neuroanatomical and neuropsychological features of Down syndrome compared to related neurodevelopmental disorders: a systematic review

Objectives

We critically review research findings on the unique changes in brain structure and cognitive function characteristic of Down syndrome (DS) and summarize the similarities and differences with other neurodevelopmental disorders such as Williams syndrome, 22q11.2 deletion syndrome, and fragile X syndrome.

Methods

We conducted a meta-analysis and systematic literature review of 84 studies identified by searching PubMed, Google Scholar, and Web of Science from 1977 to October 2022. This review focuses on the following issues: (1) specific neuroanatomic and histopathological features of DS as revealed by autopsy and modern neuroimaging modalities, (2) language and memory deficits in DS, (3) the relationships between these neuroanatomical and neuropsychological features, and (4) neuroanatomic and neuropsychological differences between DS and related neurodevelopmental syndromes.

Results

Numerous post-mortem and morphometric neuroimaging investigations of individuals with DS have reported complex changes in regional brain volumes, most notably in the hippocampal formation, temporal lobe, frontal lobe, parietal lobe, and cerebellum. Moreover, neuropsychological assessments have revealed deficits in language development, emotional regulation, and memory that reflect these structural changes and are more severe than expected from general cognitive dysfunction. Individuals with DS also show relative preservation of multiple cognitive, linguistic, and social domains compared to normally developed controls and individuals with other neurodevelopmental disorders. However, all these neurodevelopment disorders exhibit substantial heterogeneity among individuals.

Conclusion

People with Down syndrome demonstrate unique neurodevelopmental abnormalities but cannot be regarded as a homogenous group. A comprehensive evaluation of individual intellectual skills is essential for all individuals with neurodevelopment disorders to develop personalized care programs.

Morphosyntactic development in German-speaking individuals with Down syndrome-longitudinal data

Introduction

The present study provides longitudinal data on the development of receptive and expressive grammar in children and adolescents with Down syndrome and addresses the role of nonverbal cognitive abilities and verbal short-term memory for morphosyntactic development.

Method

Seventeen German-speaking individuals with Down syndrome (aged 4;6-17;1 years at first testing (T1)) were assessed twice, 4;4-6;6 years apart. For a subset of five participants, there was also a third assessment 2 years after the second. Receptive grammar, nonverbal cognition, and verbal short-term memory were tested using standardized measures. For expressive grammar, elicitation tasks were used to assess the production of subject-verb agreement and of wh-questions.

Results

At group level, the participants showed a significant increase in grammar comprehension from T1 to T2. However, progress diminished with increasing chronological age. Notable growth could not be observed beyond the age of 10 years.With respect to expressive grammatical abilities, progress was limited to those participants who had mastered verbal agreement inflection around age 10 years. Individuals who did not master verbal agreement by late childhood achieved no progress in producing wh-questions, either.There was an increase in nonverbal cognitive abilities in the majority of participants. Results for verbal short-term memory followed a similar pattern as those for grammar comprehension. Finally, neither nonverbal cognition nor verbal short-term memory were related to changes in receptive or expressive grammar.

Discussion

The results point to a slowdown in the acquisition of receptive grammar which starts before the teenage years. For expressive grammar, improvement in wh-question production only occurred in individuals with good performance in subject-verb agreement marking, which suggests that the latter might have a trigger function for further grammatical development in German-speaking individuals with Down syndrome. The study provides no indication that nonverbal cognitive abilities or verbal short-term memory performance determined the receptive or expressive development. The results lead to clinical implications for language therapy.

Acquisition of cognitive and communication milestones in infants with Down syndrome

BACKGROUND

Understanding the timing of developmental milestones in typical and clinical populations facilitates intervention planning and the early detection of risk for co-occurring conditions. Normative timing of developmental milestone achievement has been established for typically developing children. However, there is little information regarding the timing of cognitive and communication skill acquisition in young children with Down syndrome (DS). The objectives of this study are to (1) provide foundational information regarding the timing of cognitive and communication skill acquisition in infants with DS and (2) facilitate the early identification of infants with risk for co-occurring conditions.

METHOD

Seventy-four infants with DS (age range: 4-18 months) completed the Bayley Scales of Infant Development-III (Bayley 2006). Individual items from the cognitive and communication scales were selected for analysis. Parents provided information regarding their infant's developmental and family history.

RESULTS

The percentage of infants who attained each skill was calculated within 2-month age bands. For infants who did not show skill acquisition within each age band, the rates of prematurity, heart defects, corrective heart surgery and significant illness were calculated as well.

CONCLUSIONS

This study provides foundational information that can contribute to the formulation of a developmental schedule for cognitive and language milestone acquisition in infants with DS.

Positive Predictive Values Associated With Adapting the Redmond Sentence Recall Measure Into a Kindergarten Screener for Developmental Language Disorder

PURPOSE

Researchers estimate the prevalence of developmental language disorder (DLD) in 5-year-olds to be between 7% and 12%. Current identification systems in public schools typically favor referral identification formats over targeted or universal screenings. Public schools face unique challenges when assessing the value of screening measures for DLD that include real-world considerations such as administration, time, and resource constraints. This study used the positive predictive value (PPV) of the Redmond Sentence Recall (RSR) to assess its fidelity when administered by special education paraprofessionals. Our obtained PPV was compared across three areas: (a) previous studies that have utilized the RSR, (b) rates extrapolated from the participating school district's preexisting referral system from a previous study, and (c) expectations based on DLD prevalence.

METHOD

Language screenings were conducted in two elementary schools using the RSR administered by school-based paraprofessionals trained on the screener protocol. One hundred sixty-four kindergarten students (age range: 5-6 years) were screened. Confirmatory testing was completed on all students who failed the screener.

RESULTS

Of the 164 students screened, 19 failed the RSR (11.5%), and 14 met criteria (8.5%) for DLD (PPV = .74). Our PPV was similar to previously published studies that utilized the RSR using research assistants and was higher than the PPV associated with teacher-based referrals from the participating school district.

CONCLUSION

The RSR represents a potentially useful screener for identifying children at risk for previously unidentified language disorders in public schools.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.22044479.

Embedding key word sign prompts in a shared book reading activity: The impact on communication between children with Down syndrome and their parents

BACKGROUND

Children with Down syndrome have speech and language difficulties that are disproportionate to their overall intellectual ability and relative strengths in the use of gesture. Shared book reading between parents and their children provides an effective context in which language development can be facilitated. However, children with Down syndrome often take a passive role in shared book reading and the use of key word signing (KWS) as a shared book reading technique has never been investigated.

AIMS

This study aimed to compare children with Down syndrome's participation and use of KWS across two methods of shared book reading - one in which a book had key-word sign prompts embedded (signed condition) and the other in which a book was read as normal (unsigned condition). Measures of child and parent communicative behaviour were taken in each condition to establish if differences emerged.

METHODS & PROCEDURES

A total of 36 children with Down syndrome (aged between 18 and 61 months) and their mothers took part in the study. Parent-child dyads were videoed at home reading two books, one in a signed and one in an unsigned condition. Child measures included total number of signs produced in each condition and levels of attention and initiation as measured by the Pivotal Behaviour Rating Scale. Parent measures included total number of utterances, mean length of utterance (MLU) in morphemes and vocabulary diversity (VOCD). Parental measures were transcribed using the Codes for Human Analysis Transcripts (CHAT) software and analysed by the Computerised Language Analysis software (CLAN). Contrasts in outcomes between the signed and unsigned conditions were estimated using Poisson and linear mixed-effects models, determined by the type of data.

OUTCOMES & RESULTS

Results showed that children attempted to sign significantly more in the signed than unsigned condition, as well as showing significant increases in their levels of attention and initiation. There was also a significant increase in the total number of utterances used by parents in the signed versus unsigned condition and a decrease in MLU. VOCD was similar in both conditions.

CONCLUSIONS & IMPLICATIONS

This study shows that the simple act of embedding key word signs into commercially available books, during shared book reading between parents and young children with Down syndrome, positively affects children's participation (initiation and attention) and use of KWS. The use of KWS as a core shared book reading technique may therefore be a fruitful avenue to facilitate growth in the language abilities of young children with Down syndrome.

WHAT THIS PAPER ADDS

What is already known on this subject Most children with Down syndrome have significant speech and language difficulties, with relative strengths in the use of gesture. Shared book reading is an activity reported to positively affect language. However, children with Down syndrome are reported to take a passive role in shared book reading and are therefore more dependent on their parents to use techniques that facilitate their levels of participation, in order to maximise potential benefits. To the best of our knowledge, the communicative effects of embedding key word signing (KWS) in shared book reading have never been examined with children with Down syndrome. What this paper adds to existing knowledge This is the first study to investigate the communicative impact of parents embedding KWS in a shared book reading activity with their young children with Down syndrome. Our findings show that this relatively simple manipulation resulted in Increase in children's sign attempts. Increase in children's overall participation in shared book reading (indicated by levels of attention and initiation). Increase in the number of utterances produced by parents (primarily as a result of repetitions). Decrease in parental mean length of utterance. These findings suggest that embedding KWS in shared book reading is likely to facilitate increased language abilities in this cohort. What are the potential or actual clinical implications of this work? Shared book reading is part of the daily routine for many parents and their children with Down syndrome. Integrating KWS is a relatively simple adaptation to this activity which is likely to enhance children's language skills. Therapists can encourage parents to do this at home to support work carried out at school and in a clinical setting.

The association between expressive language skills and adaptive behavior in individuals with Down syndrome

The primary goal of this study was to determine whether expressive language skills contribute to adaptive behavior (e.g., socialization and daily living skills) in children, adolescents, and young adults with Down syndrome (DS) whilst controlling for age and nonverbal cognitive ability. Expressive language was assessed using the psychometrically validated Expressive Language Sampling (ELS) conversation and narration procedures. The language produced was transcribed and analyzed to yield measures of expressive vocabulary, syntax, and intelligibility. Socialization and daily living skills of participants with DS were measured with the Vineland Adaptive Behavior Scales, 2nd edition (VABS-2) parent/caregiver rating form. Our results show that the three ELS measures were significantly correlated with multiple measures from the VABS-2 when controlling for age. Several correlations remained significant even when nonverbal cognitive ability was included as a control variable. Our results suggest that expressive language skills contribute to adaptive behavior in children, adolescents, and young adults with DS regardless of age and some of these associations are not explained solely by overall cognitive delays. Further studies including longitudinal data are needed to extend our results.

Online Comprehension of Verbal Number Morphology in Children With Developmental Language Disorder: An Eye-Tracking Study

PURPOSE

Previous studies have raised the possibility of preserved language comprehension in children with developmental language disorder (DLD) in online tasks and within simple sentence structures. Consequently, we evaluated the capacity of children with DLD to comprehend verbal number agreement in simple sentence structures (i.e., verb-object-subject and verb-subject).

METHOD

Using an eye-tracking methodology, we conducted two psycholinguistic experiments with 96 Spanish- and Catalan-speaking participants. The sample was distributed into four groups: 24 children with DLD (age range: 4;6-12;6 [years;months]; average age = 7;8 [years;months]), 24 children with the same chronological age (4;6-12;2, 7;8), 24 children with the same linguistic level (4;6-9;4, 6;8), and 24 university students as language experts (18-30, 22;5).

RESULTS

The experimental data indicate that children with DLD can comprehend verbal number agreement at least under the present experimental conditions.

CONCLUSION

The empirical outcomes suggest that number morphology comprehension by children with DLD might be more typical than what it is generally considered to be.

Structural magnetic resonance imaging demonstrates volumetric brain abnormalities in down syndrome: Newborns to young adults

Down syndrome (DS) is a genetic disorder caused by the presence of an extra full or partial copy of chromosome 21 and characterized by intellectual disability. We hypothesize that performing a retrospective analysis of 73 magnetic resonance imaging (MRI) examinations of participants with DS (aged 0 to 22 years) and comparing them to a large cohort of 993 brain MRI examinations of neurotypical participants (aged 0 to 32 years), will assist in better understanding what brain differences may explain phenotypic developmental features in DS, as well as to provide valuable confirmation of prospective literature findings clinically. Measurements for both absolute volumes and volumes corrected as a percentage of estimated total intracranial volume (%ETIV) were extracted from each examination. Our results presented novel findings such as volume increases (%ETIV) in the perirhinal cortex, entorhinal cortex, choroid plexus, and Brodmann's areas (BA) 3a, 3b, and 44, as well as volume decreases (%ETIV) in the white matter of the cuneus, the paracentral lobule, the postcentral gyrus, and the supramarginal gyrus. We also confirmed volumetric brain abnormalities previously discussed in the literature. Findings suggest the presence of volumetric brain abnormalities in DS that can be detected clinically with MRI.

Capacity of the CCC-2 to Discriminate ASD from Other Neurodevelopmental Disorders

The Children’s Communication Checklist (CCC-2) has demonstrated its usefulness as an instrument to assess discrepancies between the use of structural dimensions of language and the pragmatic and sociointeractive uses of language. The aims of the present paper are: (1) to test the capacity of the Galician adaptation of the CCC-2 to discriminate the linguistic profiles of children with different disorders and (2) to test whether the capacity of the CCC-2 to discriminate the linguistic abilities of children with different disorders is the same at different ages: earlier development and later development. The sample is of 117 children previously diagnosed with different disorders: autism spectrum disorder (ASD), developmental language disorder (DLD), attention deficit with hyperactivity disorder (ADHD), Down syndrome children (DS) and typically developing children (TD). The children were divided into two different age groups: from 4 to 6 and from 7 to 16 years of age. The results indicate that the Galician CCC-2 (1) accurately identified children with and without communicative impairments, (2) distinguished between profiles with a predominance of pragmatic (ASD and ADHD) and structural disorders (DS and DLD) and (3) distinguished between different profiles of pragmatic impairment. The CCC-2 equally identified these profiles at both earlier and later ages. The Galician CCC-2 seems to be a useful instrument for differentiating among different clinical groups and for assessing pragmatic disorders from an early age, which can be valuable for planning early intervention.

Maternal Use of Decontextualized and Contextualized Talk: An In-Depth Investigation of Early Parent-Child Interactions in Down Syndrome

Purpose The goal of this study was to characterize and quantify maternal use of decontextualized and contextualized input during mother-child interactions including young children with Down syndrome (DS). Method Participants included 22 mother-child dyads with DS (M age = 42.8 months) and 22 mother-child dyads with typical development (M age = 44.0 months). Parent-child language samples were collected during free-play, book reading, and snack time, and coded for maternal decontextualized (i.e., pretend, explanatory, and narrative talk) and contextualized input (i.e., descriptions, conversation, praise, questions, and directives). Results Mothers of children with DS used a larger proportion of pretend talk compared to other types of decontextualized input and also used a larger proportion of questions, conversation, and descriptions compared to other types of contextualized language. Mothers of children with DS generally used a smaller proportion of decontextualized input compared to mothers of children with typical development, with the exception of pretend talk. Maternal decontextualized input was not related to children's age or language ability in DS. Conclusions Findings shed new light on the early language environments of children with DS, providing important insight into the ways that mothers of children with DS are incorporating decontextualized and contextualized talk into early mother-child conversations. Additional implications and future directions are discussed.

The Association between Difficulties with Speech Fluency and Language Skills in a National Age Cohort of Children with Down Syndrome

The present study (a) addressed difficulties in speech fluency in children with Down syndrome and typically developing children at a similar non-verbal level and (b) examined the association between difficulties with speech fluency and language skills in children with Down syndrome. Data from a cross-sectional parent survey that included questions about children's difficulties with speech fluency, as well as clinical tests from a national age cohort of 43 six-year-olds with Down syndrome and 57 young typically developing children, were collected. Fisher's exact test, Student's t-test, linear regression, and density ellipse scatter plots were used for analysis. There was a significantly higher occurrence of parent-reported difficulties with speech fluency in the children with Down syndrome. Higher language scores were significantly associated with a lower degree of difficulties; this association was strongest for vocabulary and phonological skills. Although difficulties with speech fluency were not reported for all children with Down syndrome, a substantially higher occurrence of such difficulties was reported compared to that for typically developing children. The significant association between difficulties with speech fluency and the level of language functioning suggests that speech fluency and language skills should be taken into consideration when planning treatment for children with Down syndrome.

Efficacy of the Treatment of Developmental Language Disorder: A Systematic Review

Background. Language disorder is the most frequent developmental disorder in childhood and it has a significant negative impact on children’s development. The goal of the present review was to systematically analyze the effectiveness of interventions in children with developmental language disorder (DLD) from an evidence-based perspective. Methods. We considered systematic reviews, meta-analyses of randomized controlled trials (RCTs), control group cohort studies on any type of intervention aimed at improving children’s skills in the phono-articulatory, phonological, semantic-lexical, and morpho-syntactic fields in preschool and primary school children (up to eight years of age) that were diagnosed with DLD. We identified 27 full-length studies, 26 RCT and one review. Results. Early intensive intervention in three- and four-year-old children has a positive effect on phonological expressive and receptive skills and acquisitions are maintained in the medium term. Less evidence is available on the treatment of expressive vocabulary (and no evidence on receptive vocabulary). Intervention on morphological and syntactic skills has effective results on expressive (but not receptive) skills; however, a number of inconsistent results have also been reported. Only one study reports a positive effect of treatment on inferential narrative skills. Limited evidence is also available on the treatment of meta-phonological skills. More studies investigated the effectiveness of interventions on general language skills, which now appears as a promising area of investigation, even though results are not all consistent. Conclusions. The effectiveness of interventions over expressive and receptive phonological skills, morpho-syntactic skills, as well as inferential skills in narrative context underscores the importance that these trainings be implemented in children with DLD.

Real-time comprehension of Spanish prepositions and prepositional locutions in bilingual children with developmental language disorder: A study based on eye-movement evidence

BACKGROUND

Function words, and more specifically prepositions and prepositional locutions, are considered to be one of the most important difficulties for children with DLD.

AIMS

To examine the capacity of bilingual children with developmental language disorder (DLD) to comprehend different Spanish prepositions and prepositional locutions in a simple sentence structure, for example, El gato está sobre la mesa/El gato está bajo la mesa (The cat is on the table/The cat is under the table).

METHODS & PROCEDURES

We used simple sentence structures to reduce lexical difficulties in order to focus our evaluation strictly on the grammatical morphemes under study. A total of 96 Spanish and Catalan-speaking participants, divided into four groups, were evaluated in an eye-tracking psycholinguistic experiment: 24 children with DLD (average age = 7.8 years, age range = 4.6-12.6), 24 children with the same chronological age (average age = 7.8 years, age range = 4.6-12.2), 24 children with the same linguistic level (average age = 6.8 years, age range = 4.6-9.4) and 24 adults (average age = 22.5 years, age range = 18-30).

OUTCOMES & RESULTS

The empirical data show that, despite some differences, bilingual children with and without DLD can comprehend Spanish prepositions and prepositional locutions under the current experimental conditions.

CONCLUSIONS & IMPLICATIONS

Our results suggest that the capacity of bilingual children with DLD to comprehend Spanish prepositions and prepositional locutions in real time and within simple sentence structures is preserved. What this paper adds What is already known on the subject The empirical literature indicates that children with DLD show important errors in the production of functional words in general, and prepositions in particular. However, unlike other grammatical morphemes (such as clitic pronouns and articles), prepositions have been less studied, and the few existing studies have focused on the dimension of language production, not comprehension. What this paper adds to existing knowledge The present study, composed of two experimental tasks, seeks to determine to what extent the observable difficulty in the linguistic production of prepositions is also present in the comprehension of children with DLD. The empirical results suggest a less atypical comprehension in comparison with our initial hypothesis, and the differences that appear between the two tasks, allow us to formulate a theoretical interpretation regarding the mechanisms of their understanding. Thus far, we are not aware of other studies that have evaluated in real time the comprehension of prepositions and prepositional locutions in parallel. Clinical implications of this study Results suggest the presence of a more preserved comprehension of prepositions and prepositional locutions, at least in real-time experimental conditions (eye-tracking) and in simple sentence structures. A less atypical comprehension raises the possibility of a better prognosis for children with DLD. Working with comprehension of simple sentences and the gradual addition of more difficult grammatical morphemes could help to enhance the comprehension of a growing complex grammar.

Diagnosis of Autism Spectrum Disorder Across the Lifespan

Although autism spectrum disorder (ASD) is one of the most common neurodevelopmental disorders it is also one of the most heterogeneous conditions, making identification and diagnosis complex. The importance of a stable and consistent diagnosis cannot be overstated. An accurate diagnosis is the basis for understanding the individual and establishing an individualized treatment plan. We present those elements that should be included in any assessment for ASD and describe the ways in which ASD typically manifests itself at various developmental stages. The implications and challenges for assessment at different ages and levels of functioning are discussed.

Neuropsychological profile of adults with Down syndrome and moderate intellectual disability

BACKGROUND

The neuropsychological profile of individuals with Down syndrome (DS) has been described as being characterized by dissociations between verbal and visual abilities, as well as between verbal comprehension and production abilities (higher visual than verbal abilities and higher verbal comprehension than verbal production abilities). However, the studies that reached these conclusions based these conclusions mainly on inter-group differences in children but not on intra-group differences.

AIMS

The study explores dissociations in adults with DS, taking inter-group and intra-group differences into account.

METHOD AND PROCEDURES

The sample was composed of 40 adults with DS and 38 adults with moderate intellectual disability (ID) but without DS, matched for chronological age, sex, and intellectual level.

OUTCOMES AND RESULTS

The participants with DS, unlike the other group, exhibited similar performance in their verbal and visual abilities, as well as in their verbal comprehension and production abilities (intra-group differences). In addition, they showed worse performance in verbal general measures and verbal comprehension abilities but similar performance in visual general measures and verbal production abilities (inter-group differences) compared with those without DS with similar intellectual levels on standardized measures.

CONCLUSIONS AND IMPLICATIONS

The observed intra-group differences highlight that a lack of dissociation between verbal and visual abilities, as well as between verbal comprehension and production abilities, seems to be a specific feature of adults with DS.

Narrative Abilities of Adults' With Down Syndrome as a Window to Their Morphosyntactic, Socio-Cognitive, and Prosodic Abilities

Down syndrome (DS) is the most common developmental disorder characterized by mild to moderate intellectual disability. Several studies have reported poor language and prosodic skills and contradictory results regarding individuals’ with DS socio-cognitive skills, whereas most of them have focused on children with DS. The present study attempts to explore adults’ with DS language, socio-cognitive and prosodic abilities via the use of story-retellings. Twenty adults with DS and two groups of TD children, one matched to their expressive vocabulary (TD-EVT) and the other matched to their non-verbal mental age (TD-RCPM), took part in the present study. Participants listened to a story while viewing a wordless picture PowerPoint presentation on a computer screen, and then, they were instructed to retell the story while viewing the pictures for a second time. Each participant listened to two stories, one with “lively” and one with “flat” prosody. Results revealed that adults’ with DS performance was comparable with the one presented by the TD-RCPM group, whereas the TD-EVT group performed significantly better in almost all variables. Individuals’ with DS re-narrations, however, contained significantly less complement clauses and internal state terms (related or not related to Theory of Mind–ToM) compared to the re-narrations of both control groups. In contrast, the group with DS performed similarly to both control groups in comprehension questions related to main characters’ internal state terms and significantly better compared to the TD-RCPM group in questions related to ToM. In terms of prosody, all three groups performed significantly better on story structure and comprehension questions when prosody was “lively” compared “flat” prosody. DS group’s re-narrations did not contain enough internal state terms, not due to their inability in recognizing them, but due to their poor morphosyntactic abilities, which did not allow them to find the proper means to express the main characters’ internal states. Prosody facilitated participants with DS in the comprehension and re-narration. This suggests that intervention programs based on prosody could support the language skills of adults with DS.

Language characterization in 16p11.2 deletion and duplication syndromes

Expressive language impairment is one of the most frequently associated clinical features of 16p11.2 copy number variations (CNV). However, our understanding of the language profiles of individuals with 16p11.2 CNVs is still limited. This study builds upon previous work in the Simons Variation in Individuals Project (VIP, now known as Simons Searchlight), to characterize language abilities in 16p11.2 deletion and duplication carriers using comprehensive assessments. Participants included 110 clinically ascertained children and family members (i.e., siblings and cousins) with 16p11.2 BP4-BP5 deletion and 58 with 16p11.2 BP4-BP5 duplication between the ages of 2-23 years, most of whom were verbal. Regression analyses were performed to quantify variation in language abilities in the presence of the 16p11.2 deletion and duplication, both with and without autism spectrum disorder (ASD) and cognitive deficit. Difficulties in pragmatic skills were equally prevalent in verbal individuals in both deletion and duplication groups. NVIQ had moderate quantifiable effects on language scores in syntax and semantics/pragmatics (a decrease of less than 1 SD) for both groups. Overall, language impairments persisted even after controlling for ASD diagnosis and cognitive deficit. Language impairment is one of the core clinical features of individuals with 16p11.2 CNVs even in the absence of ASD and cognitive deficit. Results highlight the need for more comprehensive and rigorous assessment of language impairments to maximize outcomes in carriers of 16p11.2 CNVs.

Expressive language development in adolescents with Down syndrome and fragile X syndrome: change over time and the role of family-related factors

BACKGROUND

It is well known that individuals with Down syndrome (DS) or fragile X syndrome (FXS) demonstrate expressive language difficulties beginning early in childhood. It is less clear, however, whether expressive language skills change during the adolescent period in these individuals, and if any of these changes are syndrome specific. Studying this, as well as the role of maternal and family-related factors in expressive language development, may provide the foundation for efficacious interventions for adolescents with DS or FXS.

METHODS

In this study, we examined expressive language trajectories, assessed through conversation and narration, in 57 adolescent males with intellectual disability (ID) (20 DS and 37 FXS) in relation to the diagnostic group (DS vs. FXS) and family-related factors (maternal IQ, maternal psychological distress, closeness in the mother-child relationship, family income, and maternal and paternal education) after adjusting for chronological age (CA) and nonverbal cognition.

RESULTS

Changes over repeated annual assessments for males with DS or FXS were observed only during conversation, such as an increase in talkativeness, but a decrease in syntax complexity and lexical diversity. We found a diagnosis-related effect in the change over time in conversational talkativeness favoring those with FXS. Finally, a closer mother-child relationship predicted less decrease over time in lexical diversity during conversation, and participants of mothers who graduated college showed a greater increase in conversational talkativeness over time compared to those of mothers with a high school education.

CONCLUSIONS

Our results suggest that, during the adolescent period for males with DS or FXS, there is an increase in the amount of talk produced in conversational contexts, but also a decrease in the quality of the language produced. In addition, our results indicate syndrome-specificity for aspects of expressive language development and reinforce the protective role of family-related factors.

Children with Down syndrome can benefit from language interventions; Results from a systematic review and meta-analysis

Language disorder is a cardinal challenge for children with Down syndrome, and their learning capacity has been debated. The aim of the current study was to conduct a systematic review and meta-analysis of existing language interventions for children with Down syndrome to reveal knowledge about the effects of these interventions and identify any common characteristics specific to effective or ineffective interventions. A systematic search was conducted in databases relevant for education, speech and language therapy, and psychology. Based on a set of predefined inclusion criteria, the hits were screened and coded. Eight studies were synthesised in a systematic review and four in a meta-analysis. The overall effect of the interventions was large (g = 1.01), but significant transfer effects to untrained aspects of language were rarely found. Interventions showing significant effects varied with regards to numerous characteristics including the age of the target group, the intervention approach, the dosage, and the implementer. The common characteristic across the effective interventions was simply the aim of improving language skills in children with Down syndrome. Overall, there was a moderate to high risk of bias across all studies. To conclude, children with Down syndrome have the potential to respond to language intervention. However, more interventions that reach transfer effects are needed to maximise children's language outcomes. Based on the limited number of studies and a moderate to high risk of bias across the studies, there is a great need for more robust intervention studies to ensure that future interventions are informed by high-quality research.

Comparing Tense and Agreement Productivity in Boys With Fragile X Syndrome, Children With Developmental Language Disorder, and Children With Typical Development

Purpose This study compared and characterized the tense and agreement productivity of boys with fragile X syndrome (FXS), children with developmental language disorder (DLD), and children with typical development (TD) matched on mean length of utterance. Method Twenty-two boys with FXS (M age = 12.22 years), 19 children with DLD (M age = 4.81 years), and 20 children with TD (M age = 3.23 years) produced language samples that were coded for their productive use of five tense markers (i.e., third-person singular, past tense -ed, copula BE, auxiliary BE, and auxiliary DO) using the tense and agreement productivity score. Children also completed norm-referenced cognitive and linguistic assessments. Results Children with DLD generally used tense and agreement markers less productively than children with TD, particularly third-person singular and auxiliary BE. However, boys with FXS demonstrated a more complicated pattern of productivity, where they were similar to children with DLD and TD, depending on the tense marker examined. Results revealed that children with DLD and TD showed a specific developmental sequence of the individual tense markers that aligns with patterns documented by previous studies, whereas boys with FXS demonstrated a more even profile of productivity. Conclusions These findings help to further clarify areas of overlap and discrepancy in tense and agreement productivity among boys with FXS and children with DLD. Additional clinical implications of these results are discussed.

Diagnosis of Autism Spectrum Disorder Across the Lifespan

Although autism spectrum disorder (ASD) is one of the most common neurodevelopmental disorders it is also one of the most heterogeneous conditions, making identification and diagnosis complex. The importance of a stable and consistent diagnosis cannot be overstated. An accurate diagnosis is the basis for understanding the individual and establishing an individualized treatment plan. We present those elements that should be included in any assessment for ASD and describe the ways in which ASD typically manifests itself at various developmental stages. The implications and challenges for assessment at different ages and levels of functioning are discussed.

Relations between Everyday Executive Functioning and Language in Youth with Down Syndrome and Youth with Autism Spectrum Disorder

Language and executive functioning are major impairments in many neurodevelopmental disorders, but little is known about the relations between these constructs, particularly using parent-report. Thus, the current research sought to examine relations between executive function and language in two groups - Down syndrome (DS; n=41; Mage = 11.2) and autism spectrum disorder (ASD; n=91; Mage = 7.7). Results were as follows: in DS, executive function predicted pragmatic, but not structural language after covarying for age, sex, and social functioning; in ASD, executive function predicted both. Findings highlight the interrelatedness of language and executive functioning and may have implications for intervention development.

Language growth in very young siblings at risk for autism spectrum disorder

BACKGROUND

Children with autism spectrum disorder (ASD) show substantial variability in their language development. Language problems are highly prevalent in these children. In addition, the quality of early language abilities contributes to the overall development of these children and is highly predictive of their adult outcome. Yet, little is known about language development in children at risk of ASD during the first years of life.

AIMS

To compare early receptive language (RL) and expressive language (EL) development in children at risk of ASD and determine predictors of language development.

METHODS & PROCEDURES

Developmental trajectories of RL and EL were investigated from 10 to 36 months of age in younger siblings of typically developing children (LR-sibs, N = 30) and in younger siblings of children with ASD (HR-sibs, N = 31) using the Mullen Scales of Early Learning. Furthermore, both child and demographic characteristics were examined as possible predictors of language development.

OUTCOMES & RESULTS

Both groups showed similar growth curves for RL and EL and the majority of the children showed average (within ±1.5 SD of the mean) or above-average language abilities. Nevertheless, the mean growth of EL was lower and the variation in growth of both RL and EL was higher in HR-sibs than in LR-sibs. Furthermore, early child characteristics were predictive of language development in both groups. Yet, some child characteristics seemed to be of more importance in HR-sibs than in LR-sibs. Consequently, lower non-verbal abilities at 10 months in both groups and a higher degree of ASD characteristics at 14 months in HR-sibs may be indicative of difficulties in language development.

CONCLUSIONS & IMPLICATIONS

HR-sibs show more variation in their language development than LR-sibs during the first 3 years of life. The majority of HR-sibs, however, did not present with below-average language abilities. Yet, early characteristics of ASD may be a red flag for difficulties in the language development of HR-sibs.

Psycholinguistic profile of young adults with Down syndrome

BACKGROUND

The phenotype of Down syndrome (DS) is usually characterized by relative strengths in visual skills and severe deficits in auditory processing; this has consequences for language and communication. To date, it is not known whether this pattern characterizes the psycholinguistic profile of young adults with DS.

AIMS

This study aimed to assess whether, relative to their cognitive level, young adults with DS present a specific and homogeneous phenotype for both auditory and visual psycholinguistic skills.

METHODS AND PROCEDURES

Fifty young adults with DS and 50 peers with other intellectual disability (ID) were equated in chronological age and nonverbal cognition and were compared regarding their performance in auditory and visual psycholinguistic functions.

OUTCOMES AND RESULTS

Participants with DS showed more phenotypic-specific deficits in auditory psycholinguistic skills than in those involved in visual processing. However, phenotypic-specific impairments in visual psycholinguistic skills were also observed, while no significant between-group differences were found for some auditory psycholinguistic skills.

CONCLUSIONS AND IMPLICATIONS

The psycholinguistic pattern of young adults with DS is not homogeneous with respect to auditory and visual processing. The profile of specific deficits suggests that the educative support for young adults with DS may need to be specific.

What predicts nonword repetition performance?

Despite the widespread use of nonword repetition in child neuropsychological research and clinical practice, the specific cognitive, linguistic and motor processes that contribute to variability in performance are unclear. The aim of this work was to determine the role of phonological memory, word reading, oromotor sequencing, and oromotor control on nonword repetition performance in the context of children's speech and language abilities. Ninety one children between the ages of 9 and 11 years, with a broad range of speech and language abilities participated in the study. Hierarchical regression was used to a) evaluate the contribution of phonological memory, word reading, oromotor sequencing and oromotor control to nonword repetition and b) determine whether speech and/or language ability moderated the relationship between these specific skills and nonword repetition performance. Results showed all four predictor variables were related to nonword repetition performance, accounting for 59% of variance. The variable with the strongest association with nonword repetition was phonological memory, followed by oromotor sequencing ability, word reading, and oromotor control. Contrary to expectations, neither speech nor language ability were significantly associated with the degree to which these specific skills were drawn upon to perform the nonword repetition task. These findings underline the multidimensional nature of the nonword repetition task and provide further evidence of the major contributions made by phonological memory, word reading, speech sequencing and control to performance on this task. Further, findings suggest that speech and language ability, as measured here, do not significantly influence the skills employed for nonword repetition performance.

Verb-mediated anticipatory eye movements in people with Down syndrome

BACKGROUND

Children and adults with neurotypical development employ linguistic information to predict and anticipate information. Individuals with Down syndrome (DS) have weaknesses in language production and the domain of grammar but relative strengths in language comprehension and the domain of semantics. What is not clear is the extent to which they can use linguistic information, as it unfolds in real time, to anticipate upcoming information correctly.

AIMS

To investigate whether children and young people with DS employ verb information to predict and anticipate upcoming linguistic information.

METHODS & PROCEDURES

A preferential looking task was performed, using an eye-tracker, with children and teenagers with DS and a typically developing (TD) control group matched by sex and mental age (average = 5.48 years). In each of 10 trials, two images were presented, a target and a distractor, while participants heard a phrase that contained a semantically informative verb (e.g., 'eat') or an uninformative verb (e.g., 'see').

OUTCOMES & RESULTS

Both DS and TD control participants could anticipate the target upon hearing an informative verb, and prediction skills were positively correlated with mental age in those with DS.

CONCLUSIONS & IMPLICATIONS

This work demonstrates for the first time that children and teenagers with DS can predict linguistic information based on semantic cues from verbs, and that sentence processing is driven by predictive relationships between verbs and arguments, as in children with typical development. Clinicians can take advantage of these prediction skills, using them in therapy to support weaker areas.

Assessing general cognitive and adaptive abilities in adults with Down syndrome: a systematic review

BACKGROUND

Measures of general cognitive and adaptive ability in adults with Down syndrome (DS) used by previous studies vary substantially. This review summarises the different ability measures used previously, focusing on tests of intelligence quotient (IQ) and adaptive behaviour (AB), and where possible examines floor effects and differences between DS subpopulations. We aimed to use information regarding existing measures to provide recommendations for individual researchers and the DS research community.

RESULTS

Nineteen studies reporting IQ test data met inclusion for this review, with 17 different IQ tests used. Twelve of these IQ tests were used in only one study while five were used in two different studies. Eleven studies reporting AB test data met inclusion for this review, with seven different AB tests used. The only AB scales to be used by more than one study were the Vineland Adaptive Behaviour Scale (VABS; used by three studies) and the Vineland Adaptive Behavior Scale 2nd Edition (VABS-II; used by two studies). A variety of additional factors were identified which make comparison of test scores between studies problematic, including different score types provided between studies (e.g. raw scores compared to age-equivalent scores) and different participant inclusion criteria (e.g. whether individuals with cognitive decline were excluded). Floor effects were common for IQ tests (particularly for standardised test scores). Data exists to suggest that floor effects may be minimised by the use of raw test scores rather than standardised test scores. Raw scores may, therefore, be particularly useful in longitudinal studies to track change in cognitive ability over time.

CONCLUSIONS

Studies assessing general ability in adults with DS are likely to benefit from the use of both IQ and AB scales. The DS research community may benefit from the development of reporting standards for IQ and AB data, and from the sharing of raw study data enabling further in-depth investigation of issues highlighted by this review.

Acquisition of Reading and Intellectual Development Disorder

We propose a review of the literature of the studies investigating reading acquisition in intellectual deficiency (ID), with particular focus on the explanatory factors for reading difficulties. Indeed, we explore the role of intellectual efficiency, perceptual abilities, oral language development, phonological processing and memory. The study of reading acquisition in ID is a challenge because of a high degree of heterogeneity in the results which, together with other variables influencing learning and development. This review has allowed us to understand that there are multiple reasons why individuals with ID have difficulty learning to read. More specifically, there is a link between reading skills and certain cognitive skills, such as perception, oral language, phonological processing and working memory.

Participation in Social Skills Therapy is Associated With Enhanced Recall Memory by Children With Down Syndrome: An Exploratory Study

Participation in social skills therapy (SST) facilitates cognitive functioning in children with developmental disabilities. The present pilot study examined whether participation in SST was associated with enhanced encoding and 1-month delayed recall in children with Down syndrome (DS). Children were presented with novel three-step event sequences in an elicited imitation procedure. Immediate imitation was permitted as an index of encoding; long-term memory was assessed 1 month later. Parents completed questionnaires inquiring about children's participation in SST. Participation in SST was associated with enhanced encoding of temporal order information and 1-month delayed recall of individual target actions. In addition, encoding mediated the relation between group and 1-month delayed recall. The conducted research indicates that involvement in SST may be beneficial for children with DS despite their noted strengths in imitation and social learning. As such, additional experimental work is warranted to determine causality.

The understanding of complex syntax in children with Down syndrome

Background: Down syndrome (DS) is associated with poor language skills that seem disproportionate to general nonverbal ability, but the nature and causes of this deficit are unclear. We assessed how individuals with DS understand complex linguistic constructions, and considered how cognitive ability and memory and impact the ability of those with DS to process these sentence types. Methods: There were three groups participating in the study: children with DS (n = 33) and two control groups composed of children with cognitive impairment of unknown aetiology (CI) (n = 32) and children with typical development (n = 33). The three groups did not differ on raw scores on a test of non-verbal cognitive ability. Using a newly devised animation task, we examined how well individuals with DS (n = 33) could understand relative clauses, complement clauses and adverbial clauses compared to children with CI and typically developing controls. Participants also completed the Test for the Reception of Grammar-2, three measures of memory (forward and backward digit recall, visuo-spatial memory) and a hearing screen. Results: Results indicated that (1) with the exception of intransitive subject relative clauses, children with DS performed at floor on all other complex sentences, (2) they performed at a significantly lower level than both control groups, and (3) DS status accounted for a significant proportion of the variance over and above memory skills. Conclusions: Our findings suggest that children with DS have a disproportionate difficulty understanding complex sentences compared to two control groups matched on mental age. Furthermore, their understanding of syntax is not completely explained by poor cognitive or memory skills, rather it appears to be a specific deficit that may distinguish children with DS from other neurodevelopmental disorders.

The understanding of complex syntax in children with Down syndrome

Background: Down syndrome (DS) is associated with poor language skills that seem disproportionate to general nonverbal ability, but the nature and causes of this deficit are unclear. We assessed how individuals with DS understand complex linguistic constructions, and considered how cognitive ability, memory and hearing level impact the ability of those with DS to process these sentence types. Methods: There were three groups participating in the study: children with DS (n = 33) and two control groups composed of children with cognitive impairment of unknown aetiology (CI) (n = 32) and children with typical development (n = 33). Both groups were matched to those with DS on cognitive ability. Using a newly devised animation task, we examined how well individuals with DS (n = 33) could understand relative clauses, complement clauses and adverbial clauses compared to children with CI and typically developing controls. Participants also completed the Test for the Reception of Grammar-2, three measures of memory (forward and backward digit recall, visuo-spatial memory) and a hearing screen. Results: Results indicated that (1) with the exception of intransitive subject relative clauses, children with DS performed at floor on all other complex sentences, (2) they performed at a significantly lower level than both control groups, and (3) DS status accounted for a significant proportion of the variance over and above memory skills. Conclusions: Our findings suggest that children with DS have a disproportionate difficulty understanding complex sentences compared to two control groups matched on mental age. Furthermore, their understanding of syntax is not completely explained by poor cognitive or memory skills, rather it appears to be a specific deficit that may distinguish children with DS from other neurodevelopmental disorders.

Parent-mediated interventions for promoting communication and language development in young children with Down syndrome

BACKGROUND

Communication and language development are areas of particular weakness for young children with Down syndrome. Caregivers' interaction with children influences language development, so many early interventions involve training parents how best to respond to their children and provide appropriate language stimulation. Thus, these interventions are mediated through parents, who in turn are trained and coached in the implementation of interventions by clinicians. As the interventions involve a considerable commitment from clinicians and families, we undertook this review to synthesise the evidence of their effectiveness.

OBJECTIVES

To assess the effects of parent-mediated interventions for improving communication and language development in young children with Down syndrome. Other outcomes are parental behaviour and responsivity, parental stress and satisfaction, and children's non-verbal means of communicating, socialisation and behaviour.

SEARCH METHODS

In January 2018 we searched CENTRAL, MEDLINE, Embase and 14 other databases. We also searched three trials registers, checked the reference lists of relevant reports identified by the electronic searches, searched the websites of professional organizations, and contacted their staff and other researchers working in the field to identify other relevant published, unpublished and ongoing studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs that compared parent-mediated interventions designed to improve communication and language versus teaching/treatment as usual (TAU) or no treatment or delayed (wait-listed) treatment, in children with Down syndrome aged between birth and six years. We included studies delivering the parent-mediated intervention in conjunction with a clinician-mediated intervention, as long as the intervention group was the only group to receive the former and both groups received the latter.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures for data collection and analysis.

MAIN RESULTS

We included three studies involving 45 children aged between 29 months and six years with Down syndrome. Two studies compared parent-mediated interventions versus TAU; the third compared a parent-mediated plus clinician-mediated intervention versus a clinician-mediated intervention alone. Treatment duration varied from 12 weeks to six months. One study provided nine group sessions and four individualised home-based sessions over a 13-week period. Another study provided weekly, individual clinic-based or home-based sessions lasting 1.5 to 2 hours, over a six-month period. The third study provided one 2- to 3-hour group session followed by bi-weekly, individual clinic-based sessions plus once-weekly home-based sessions for 12 weeks. Because of the different study designs and outcome measures used, we were unable to conduct a meta-analysis.We judged all three studies to be at high risk of bias in relation to blinding of participants (not possible due to the nature of the intervention) and blinding of outcome assessors, and at an unclear risk of bias for allocation concealment. We judged one study to be at unclear risk of selection bias, as authors did not report the methods used to generate the random sequence; at high risk of reporting bias, as they did not report on one assessed outcome; and at high risk of detection bias, as the control group had a cointervention and only parents in the intervention group were made aware of the target words for their children. The sample sizes of each included study were very small, meaning that they are unlikely to be representative of the target population.The findings from the three included studies were inconsistent. Two studies found no differences in expressive or receptive language abilities between the groups, whether measured by direct assessment or parent reports. However, they did find that children in the intervention group could use more targeted vocabulary items or utterances with language targets in certain contexts postintervention, compared to those in the control group; this was not maintained 12 months later. The third study found gains for the intervention group on total-language measures immediately postintervention.One study did not find any differences in parental stress scores between the groups at any time point up to 12 months postintervention. All three studies noted differences in most measures of how the parents talked to and interacted with their children postintervention, and in one study most strategies were maintained in the intervention group at 12 months postintervention. No study reported evidence of language attrition following the intervention in either group, while one study found positive outcomes on children's socialisation skills in the intervention group. One study looked at adherence to the treatment through attendance data, finding that mothers in the intervention group attended seven out of nine group sessions and were present for four home visits. No study measured parental use of the strategies outside of the intervention sessions.A grant from the Hospital for Sick Children Foundation (Toronto, Ontario, Canada) funded one study. Another received partial funding from the National Institute of Child Health and Human Development and the Department of Education in the USA. The remaining study did not specify any funding sources.In light of the serious limitations in methodology, and the small number of studies included, we considered the overall quality of the evidence, as assessed by GRADE, to be very low. This means that we have very little confidence in the results, and further research is very likely to have an important impact on our confidence in the estimate of treatment effect.

AUTHORS' CONCLUSIONS

There is currently insufficient evidence to determine the effects of parent-mediated interventions for improving the language and communication of children with Down syndrome. We found only three small studies of very low quality. This review highlights the need for well-designed studies, including RCTs, to evaluate the effectiveness of parent-mediated interventions. Trials should use valid, reliable and similar measures of language development, and they should include measures of secondary outcomes more distal to the intervention, such as family well-being. Treatment fidelity, in particular parental dosage of the intervention outside of prescribed sessions, also needs to be documented.

Regular and irregular inflection in down syndrome - New evidence from German

The study aims to explore whether regular inflectional morphology is affected in children/adolescents with Down syndrome (DS). German past participle forms were elicited for ten regular and ten irregular inflected verbs as well as for five novel verbs. Data were collected from a group of 21 monolingual German children and adolescents with DS (chronological age M = 11;03 years) and a group of 21 typically developing monolingual German children (chronological age M = 4;03 years) matched in chronological age to the nonverbal mental age of the DS group (mental age DS group M = 4;05 years). Data analysis indicated that eight children/adolescents with DS displayed a deficit in acquiring the regular participle marker -t and in applying it as default inflection in German participle formation. In contrast, a group of 13 individuals with DS performed similar to the typically developing control children. They had successfully acquired the regular participle affix -t and readily applied it as default inflection to produce participles for irregular verbs and novel verbs. The data indicate that the acquisition of regular inflectional morphology is not outside the scope of individuals with DS and succeeded in many affected individuals. However, a substantial number of individuals with DS displayed a selective deficit with regular default inflection. The occurrence of a selective deficit with regular default inflection in individuals with DS supports dualistic views to inflection, according to which two different cognitive components are involved in regular and irregular inflection that can be selectively affected in language disorders.

Morphosyntax Production of Preschool Children With Hearing Loss: An Evaluation of the Extended Optional Infinitive and Surface Accounts

Purpose

The first aim of this study was to explore differences in profiles of morphosyntax production of preschool children with hearing loss (CHL) relative to age- and language-matched comparison groups. The second aim was to explore the potential of extending 2 long-standing theoretical accounts of morphosyntax weakness in children with specific language impairment to preschool CHL.

Method

This study examined conversational language samples to describe the accuracy and type of inaccurate productions of Brown's grammatical morphemes in 18 preschool CHL as compared with an age-matched group (±3 months, n = 18) and a language-matched group (±1 raw score point on an expressive language subtest, n = 18). Age ranged from 45 to 62 months. Performance across groups was compared. In addition, production accuracy of CHL on morphemes that varied by tense and duration was compared to assess the validity of extending theoretical accounts of children with specific language impairment to CHL.

Results

CHL exhibited particular difficulty with morphosyntax relative to other aspects of language. In addition, differences across groups on accuracy and type of inaccurate productions were observed. Finally, a unified approach to explaining morphosyntax weakness in CHL was more appropriate than a linguistic- or perceptual-only approach.

Conclusions

Taken together, the findings of this study support a unified theoretical account of morphosyntax weakness in CHL in which both tense and duration of morphemes play a role in morphosyntax production accuracy, with a more robust role for tense than duration.

Verbal Agreement Inflection in German Children With Down Syndrome

PURPOSE

The study aims to explore whether finite verbal morphology is affected in children/adolescents with Down syndrome (DS), whether observed deficits in this domain are indicative of a delayed or deviant development, and whether they are due to phonetic/phonological problems or deficits in phonological short-term memory.

METHOD

An elicitation task on subject-verb agreement, a picture-naming task targeting stem-final consonants that also express verbal agreement, a nonword repetition task, and a test on grammar comprehension were conducted with 2 groups of monolingual German children: 32 children/adolescents with DS (chronological age M = 11;01 [years;months]) and a group of 16 typically developing children (chronological age M = 4;00) matched on nonverbal mental age.

RESULTS

Analyses reveal that a substantial number of children/adolescents with DS are impaired in marking verbal agreement and fail to reach an acquisition criterion. The production of word-final consonants succeeds, however, when these consonants do not express verbal agreement. Performance with verbal agreement and nonword repetition are related.

CONCLUSIONS

Data indicate that a substantial number of children/adolescents with DS display a deficit in verbal agreement inflection that cannot be attributed to phonetic/phonological problems. The influence of phonological short-term memory on the acquisition of subject-verb agreement has to be further explored.

The emergence of multiword utterances in children with Down syndrome

Morphosyntax is one of the most impaired aspects of language development in children with Down syndrome. The present study aimed to assess the emergence of multiword utterances in this population. Sixteen Italian-speaking children with Down syndrome were followed from 36 to 48 months of age. Data derived from an analysis of their spontaneous productions showed that although the mean productivity of multiword utterances increased over the three time points (36, 42 and 48 months), different growth patterns of early syntactic development could be identified: (1) null or marginal development; (2) a gradual increase in multiword production over time; (3) an increase in the production of more complex multiword utterances and a decrease or inverted U-shaped profile in the production of simpler multiword productions; (4) an inverted U-shaped profile in multiword productions. In addition, children showed an improvement in their ability to express different semantic functions by word combinations. Significant relationships were found between early syntactic skills and both the child's vocabulary size and developmental age. A better knowledge of the acquisition pace and content of word combinations could allow more effective rehabilitative treatment during the first steps of children's syntactic development.

Effectiveness of intervention with visual templates targeting tense and plural agreement in copula and auxiliary structures in school-aged children with complex needs: a pilot study

This pilot study aims to evaluate the effectiveness of a school-based intervention using visual strategies for improving accurate use of auxiliary and copula marking in singular and plural, past and present tense by students with moderate learning disability and complex needs. Eleven students, aged 10-14 years, in a specialist school based in the UK, participated in the study. A within participants design was used which included testing at baseline, pre- and post-intervention to consider progress with intervention as compared with progress during a baseline period of similar length. The experimental intervention consisted of eight, bi-weekly, 20 minute sessions, over a four week period, in small groups, in a classroom setting. Half of the participants focused on the auxiliary and half on the copula, but all were tested on both. Techniques included the use of visual templates and rules (the Shape Coding^TM system) to support explicit instruction. Eight participants made greater progress during the intervention term than during the baseline term and this was significant at a group level (d = 0.92). A comparison of progress to zero was not significant during the baseline period (d = 0.15) but was during the intervention period (d = 1.07). Progress also appeared to generalise from the targeted to non-targeted structure. This pilot study therefore provides preliminary evidence that older students with complex needs can make progress with morphology when intervention includes explicit instruction and visual templates and that generalisation may be observed.

Receptive Language Skills in Slovak-Speaking Children With Intellectual Disability: Understanding Words, Sentences, and Stories

PURPOSE

The study aims to describe receptive language skills in children with intellectual disability (ID) and to contribute to the debate on deviant versus delayed language development. This is the 1st study of receptive skills in children with ID who speak a Slavic language, providing insight into how language development is affected by disability and also language typology.

METHOD

Twenty-eight Slovak-speaking children participated in the study (14 children with ID and 14 typically developing [TD] children matched on nonverbal reasoning abilities). The children were assessed by receptive language tasks targeting words, sentences, and stories, and the groups were compared quantitatively and qualitatively.

RESULTS

The groups showed similar language profiles, with a better understanding of words, followed by sentences, with the poorest comprehension for stories. Nouns were comprehended better than verbs; sentence constructions also showed a qualitatively similar picture, although some dissimilarities emerged. Verb comprehension was strongly related to sentence comprehension in both groups and related to story comprehension in the TD group only.

CONCLUSION

The findings appear to support the view that receptive language skills follow the same developmental route in children with ID as seen in younger TD children, suggesting that language development is a robust process and does not seem to be differentially affected by ID even when delayed.