Predicting longitudinal change in language production and comprehension in individuals with Down syndrome: hierarchical linear modeling

The Feasibility of an Online Language Program Delivered Through Music and the Impact of Dosage on Vocabulary Outcomes in Young Children With Down Syndrome

BACKGROUND

Few studies have explored the feasibility of online language interventions for young children with Down syndrome. Additionally, none have manipulated dose frequency or reported on the use of music as a medium through which language and sign can be learned.

PURPOSE

The purpose of this study was to (a) examine the feasibility and acceptability of an online language through music intervention for young children (1-3;6 years) with Down syndrome and (b) compare effectiveness at two intervention dose frequencies.

METHOD

The study was carried out in two phases using a mixed-methods design. Phase 1: Qualitative data were gathered from parents to examine feasibility when implementing a video-based language intervention. Phase 2: Seventy-six families participated in an online language intervention at home. Effectiveness was examined comparing two groups, randomly assigned to a high and low dose frequency. The Down Syndrome Education (DSE) checklists (combined) were the primary outcome measure. Process data were gathered to determine intervention acceptability in practice and to identify factors that would improve successful future implementation. Acceptability data were analyzed with reference to the theoretical framework of acceptability (Version 2).

RESULTS

Forty-three parents completed the Phase 1 scoping questionnaire, five of whom took part in focus groups. Once weekly morning sessions were indicated as the preferred scheduling choice. Phase 2 quantitative data were analyzed using beta regression adjusted for baseline scores and indicated no additional benefit to receiving the higher dose. However, exploratory interaction models suggested that the efficacy of the high-dose intervention was higher (than low-dose intervention) in participants with higher baseline DSE performance. Parents perceived the intervention to be effective and positive for the family.

CONCLUSION

The results add to our knowledge of real-world effective online interventions and suggest that a critical minimum language level is required for children with Down syndrome to benefit optimally from a higher intervention dose frequency.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.25979704.

Cross-Sectional Analysis of Caregiver-Reported Expressive Language Profiles and Associated Covariates in Individuals with Down Syndrome

OBJECTIVE

To describe the distribution of expressive language abilities of individuals with Down syndrome (DS) in a clinical sample and characterize demographic, environmental, and medical factors associated with varying expressive language profiles.

METHODS

Cross-sectional analysis was completed on a sample of 345 individuals with DS between the ages of 4 and 22 years who were enrolled into a longitudinal clinical database between March 2018 and August 2021. Expressive language-related items on a standardized caregiver-reported questionnaire assessing domains of functioning in neurodevelopmental disorders were used to conduct latent variable modeling and determine caregiver-reported expressive language (CREL) classes across the sample. Linear regression was used to explore associations between CREL classes and predictor variables.

RESULTS

Latent variable modeling revealed 3 distinct classes of CREL abilities representing higher, middle, and lower CREL. Individuals in the lower CREL class were more likely to be female, to use sign language or visual communication systems, have reduced pronunciation, attend private or residential school, and to be in a substantially separate classroom. Membership was not predicted by complex medical histories or co-occurring neurodevelopmental diagnoses.

CONCLUSION

Caregiver-reported expressive language abilities in a cohort of individuals with DS were variable, with most of the individuals belonging to higher or middle CREL classes, relative to one another. Additional studies are indicated to understand factors that predict higher expressive language ability and explore how to direct services to individuals who are at risk of more profound language delays.

BENDI: Improving Cognitive Assessments in Toddlers and Children with Down Syndrome Using Stealth Assessment

Cognitive assessment is a fundamental step in diagnosing intellectual and developmental disabilities, designing interventions, and evaluating their impact. However, developed and developing countries have different access to tools designed for these purposes. Our goal was to develop a battery for cognitive assessment mediated by digital technology that allows the exploration of cognitive domains (inhibitory control, attention, motor ability, and context memory) in children with Down Syndrome (DS) in Chile. Four tasks, based on established experimental paradigms modified to provide a game-like experience, were tested in 68 children with DS from 20 months to 12 years of age. We present evidence of reliability based on internal consistency and split-half analyses, with results ranging from adequate to excellent. Regarding validity, factorial and correlational analyses show evidence consistent with what was theoretically expected of internal structure, convergence, and divergence with other measures. Expected age trajectories were observed as well. Our data offer evidence that supports the use of tasks based on touch-screen devices for cognitive assessment in the population with DS. The tasks also have a low cultural load, so they could be validated and used in other contexts without the need for an adaptation process.

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.

A biophysiological framework exploring factors affecting speech and swallowing in clinical populations: focus on individuals with Down syndrome

Speech and swallowing are complex sensorimotor behaviors accomplished using shared vocal tract anatomy. Efficient swallowing and accurate speech require a coordinated interplay between multiple streams of sensory feedback and skilled motor behaviors. Due to the shared anatomy, speech and swallowing are often both impacted in individuals with various neurogenic and developmental diseases, disorders, or injuries. In this review paper, we present an integrated biophysiological framework for modeling how sensory and motor changes alter functional oropharyngeal behaviors of speech and swallowing, as well as the potential downstream effects to the related areas of language and literacy. We discuss this framework with specific reference to individuals with Down syndrome (DS). Individuals with DS experience known craniofacial anomalies that impact their oropharyngeal somatosensation and skilled motor output for functional oral-pharyngeal activities such as speech and swallowing. Given the increased risk of dysphagia and "silent" aspiration in individuals with DS, it is likely somatosensory deficits are present as well. The purpose of this paper is to review the functional impact of structural and sensory alterations on skilled orofacial behaviors in DS as well as related skills in language and literacy development. We briefly discuss how the basis of this framework can be used to direct future research studies in swallowing, speech, and language and be applied to other clinical populations.

Expressive language sampling and outcome measures for treatment trials in fragile X and down syndromes: composite scores and psychometric properties

The lack of psychometrically sound outcome measures has been a barrier to evaluating the efficacy of treatments proposed for core symptoms of intellectual disability (ID). Research on Expressive Language Sampling (ELS) procedures suggest it is a promising approach to measuring treatment efficacy. ELS entails collecting samples of a participant's talk in interactions with an examiner that are naturalistic but sufficiently structured to ensure consistency and limit examiner effects on the language produced. In this study, we extended previous research on ELS by analyzing an existing dataset to determine whether psychometrically adequate composite scores reflecting multiple dimensions of language can be derived from ELS procedures administered to 6- to 23-year-olds with fragile X syndrome (n = 80) or Down syndrome (n = 78). Data came from ELS conversation and narration procedures administered twice in a 4-week test-retest interval. We found that several composites emerged from variables indexing syntax, vocabulary, planning processes, speech articulation, and talkativeness, although there were some differences in the composites for the two syndromes. Evidence of strong test-retest reliability and construct validity of two of three composites were obtained for each syndrome. Situations in which the composite scores would be useful in evaluating treatment efficacy are outlined.

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.

It's Never Too Late: Debunking Myths About Communication and Adults With Severe Disabilities

Communication infuses all dimensions and stages of life, influencing one's self-determination and quality of life. A number of empirical studies have demonstrated that people with severe disabilities continue to develop communication and language skills well into their adult years and make measurable gains when provided with appropriate communication services and supports. Several myths about age, ability, and experiences limit opportunities for persons with severe disabilities. In this paper, we confront and address these myths.

Morphosyntactic abilities in young children with Down syndrome: Evidence from the Greek language

Down syndrome is the most common genetic syndrome of intellectual disabilities with a distinct linguistic profile. Language research so far has come mainly from the English language, a language with different syntax and morphology from many other languages, including Greek, indicating a paucity of research findings in the Greek language. Given the rich morphology and distinct syntactic characteristics of the Greek language, the present study evaluated the performance of children with Down syndrome (N = 45) who are native Greek speakers in syntax and morphology and compared it with the performance of children with typical development (N = 45) matched for chronological age. The paper also analysed the items of each task in terms of the performance of the two groups in subject-verb agreement, noun conversion from singular to plural, and verb conversion from present to past and future tenses. All children were tested in four subscales of a standardized test, including morphosyntactic comprehension, morphosyntactic completion and articulation (parts 1 and 2). The results showed that children with Down syndrome lag behind in syntax and morphology compared with children of typical development and present difficulties in specific aspects of morphology and syntax inherent in the Greek language. WHAT THIS PAPER ADDS: What is already known on this subject Morphosyntactic skills are severely impaired in Down syndrome, and research so far has come mainly from the English language, a language with different syntax and morphology from many other languages. What this paper adds to existing knowledge This research adds more information about morphosyntactic skills in children with Down syndrome compared with typically developing children in the Greek language, a language with rich morphology and syntax. What are the potential or actual clinical implications of this work? Children with Down syndrome face difficulties in morphosyntactic skills in the Greek language, especially in subject-verb agreement and in converting nouns from singular to plural.

Defining Expressive Language Benchmarks for Children with Down Syndrome

Establishing expressive language benchmarks (ELBs) for children with Down syndrome (DS), as developed by Tager-Flusberg et al. for children with autism, is critically needed to inform the development of novel treatments, identify individualized treatment targets, and promote accurate monitoring of progress. In the present study, we assessed ELB assignments in three language domains (phonology, vocabulary, and grammar) for 53 young children with DS (CA range: 2.50–7.99 years) using standardized assessments. The participants were classified into one of four ELB levels (preverbal, first words, word combinations, and sentences) in each language domain. Associations with additional measures of language, chronological age, nonverbal cognition, and verbal short-term memory were considered. Analyses of individual ELB profiles indicated substantial variability across the three language domains, with six different patterns of variation across domains emerging. At the same time, the ELB categories were significantly associated with independent language measures and broader developmental domains. Moreover, ELB changes were observed in a small sample of children with DS reassessed 18–24 months after the initial visit. Results from the present study suggest the procedures outlined by Tager-Flusberg et al. for defining ELBs are a potentially useful tool for describing the language abilities of children with DS.

Language Intervention in Down Syndrome: A Systematic Literature Review

Language is one of the most affected areas in people with Down syndrome and is one of the most influential throughout their development. That is why the linguistic difficulties presented by this group are susceptible to treatment through different specific interventions. However, little emphasis has been placed on the effectiveness and importance of this type of intervention in improving their language skills. Therefore, this work aimed to carry out a systemic literature review of language intervention programs that have been carried out in the last 20 years. To this end, a total of 18 articles were analyzed in which the effectiveness of different types of treatment related to oral language, written language and communication, in general, was studied, using the guidelines of the PRISMA Statement and the COSMIN methodology. The results highlight that language intervention improves linguistic levels in people with Down Syndrome. Most of the research focuses on early interventions and interventions carried out through individual sessions. Nevertheless, the data are unanimous in considering the efficacy and effectiveness of the proposed treatments for improving the language skills of people with Down syndrome. Thus, linguistic intervention is a fundamental area of work throughout the lives of people with Down syndrome.

Syntactic development and verbal short-term memory of children with autism spectrum disorders having intellectual disabilities and children with down syndrome

BACKGROUND AND AIMS

Previous studies suggest that syntactic development in children with intellectual disabilities (ID) is positively correlated with verbal short-term memory (VSTM). This study investigated the characteristics of syntactic development and their relationships of VSTM in children with ID based on type.

METHODS

The participants were children with ID (N = 34), including 14 children with autism spectrum disorders (ASD), 20 with Down syndrome (DS), with chronological ages from 8 years 10 months to 18 years 4 months and nonverbal mental ages (MA) of over 4 years, and typically developing (TD) children (N = 21) with chronological ages from 5 years 0 months to 5 years 10 months. They were assessed using VSTM, syntactic comprehension, and expression tasks.

RESULTS

The results showed that both the ASD and DS groups performed significantly lower on the syntactic comprehension task and the syntactic expression task than the TD group with the same nonverbal MA in the complex aspect of grammatical structure. In the VSTM task, the ASD group showed significantly lower performance in sentence and story repetition tasks than the TD group of the same nonverbal MA. The DS group showed significantly lower performance in forward digit span, and word, nonword, sentence, and story repetition tasks than the TD group of the same nonverbal MA.

CONCLUSIONS

These results suggest that children with ASD have difficulty in understanding and remembering linguistic information with complex semantic structures, and children with DS have a small capacity for VSTM, affecting their syntactic development.

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.

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.

Exploring different aspects of emotion understanding in adults with Down Syndrome

BACKGROUND

Adults with Down Syndrome (DS) present difficulties in emotion understanding, although research has mainly focused on emotion recognition (external aspects), and little is known about their performance in other complex components (mental and reflective aspects).

AIMS

This study aims to examine different aspects of emotion understanding in adults with DS, including a codification of their error pattern, and also to determine the association with other variables that are commonly impaired in adults with DS.

METHODS AND PROCEDURES

Twenty-two adults with DS and twenty-two children with typical development (TD) matched for vocabulary level were assessed with the Test of Emotion Comprehension (TEC), along with other non-verbal reasoning (NVR), structural language and working memory (WM) tasks.

OUTCOMES AND RESULTS

Adults with DS showed lower emotion competence than children with TD in different components of the TEC, and also a different pattern of errors was observed. Structural language, NVR and WM predicted distinct emotion understanding skills in different ways.

CONCLUSIONS AND IMPLICATIONS

It is important to plan interventions aimed at improving particular aspects of emotion understanding skills for adults with DS, taking into account the different components, the type of error and the different cognitive and linguistic skills involved in each emotion understanding skill.

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.

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.

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.

Do Infants With Down Syndrome Show an Early Receptive Language Advantage?

Purpose The study explored longitudinally the course of vocabulary and general language development in a group of infants with Down syndrome (DS) compared to a group of typically developing (TD) infants matched on nonverbal mental ability (NVMA). Method We compared the vocabulary and general language trajectories of the two groups in two ways: (a) at three time points during a 12-month period and (b) at two time points when the groups had made equal progress in NVMA (a period of 6 months for the TD infants vs. 12 months for the infants with DS). Results The TD group had overtaken the DS group on all general language and vocabulary measures by the end of the 12-month period. However, expressive communication and expressive vocabulary were developing at the same rate and level in the two groups when examined over a period in which the two groups were matched in gains in NVMA. Furthermore, the infants with DS showed a receptive language advantage over the TD group; this group's auditory comprehension and receptive vocabulary scores were superior to those of the TD group at both time points when NVMA was accounted for. Conclusion The results shed light on the widely reported discrepancy between expressive and receptive language in individuals with DS. Although infants with DS appear to be developing language skills more slowly than chronological age TD peers, when NVMA is taken into account, infants with DS do not have expressive language delays, and they seem to show a receptive language advantage.

An investigation into maternal use of telegraphic input to children with Down syndrome

Maternal input influences language development in children with Down syndrome (DS) and typical development (TD). Telegraphic input, or simplified input violating English grammatical rules, is controversial in speech-language pathology, yet no research to date has investigated whether mothers of children with DS use telegraphic input. This study investigated the quality of linguistic input to children with DS compared to age-matched children with TD, and the relationship between maternal input and child language abilities. Mothers of children with DS simplified their input in multiple ways, by using a lower lexical diversity, shorter utterances, and more telegraphic input compared to mothers of children with TD. Telegraphic input was not significantly correlated with other aspects of maternal input or child language abilities. Since children with DS demonstrate specific deficits in grammatical compared to lexical abilities, future work should investigate the long-term influence of maternal telegraphic input on language development in children with DS.

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.

Improving Cognitive Visual-Motor Abilities in Individuals with Down Syndrome

Down syndrome causes a reduction in cognitive abilities, with visual-motor skills being particularly affected. In this work, we have focused on this skill in order to stimulate better learning. The proposal relies on stimulating the cognitive visual-motor skills of individuals with Down Syndrome (DS) using exercises with a gestural interaction platform based on the KINECT sensor named TANGO:H, the goal being to improve them. To validate the proposal, an experimental single-case study method was designed using two groups: a control group and an experimental one, with similar cognitive ages. Didactic exercises were provided to the experimental group using visual cognitive stimulation. These exercises were created on the TANGO:H Designer, a platform that was designed for gestural interaction using the KINECT sensor. As a result, TANGO:H allows for visual-motor cognitive stimulation through the movement of hands, arms, feet and head. The "Illinois Test of Psycholinguistic Abilities (ITPA)" was applied to both groups as a pre-test and post-test in its four reference sections: visual comprehension, visual-motor sequential memory, visual association, and visual integration. Two checks were made, one using the longitudinal comparison of the pre-test/post-test of the experimental group, and another that relied on comparing the difference of the means of the pre-test/post-test. We also used an observational methodology for the working sessions from the experimental group. Although the statistical results do not show significant differences between the two groups, the results of the observations exhibited an improvement in visual-motor cognitive skills.

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.

Modeling the Relations Among Sustained Attention, Short-Term Memory, and Language in Down Syndrome

Sustained attention (SA) and short-term memory (STM) contribute to language function in Down syndrome (DS). We proposed models in which relations of SA to language in DS are mediated by STM. Thirty-seven youth with DS aged 10-22 years (M = 15.59) completed SA, STM, and language tasks. Cross-sectional mediation analyses were run with the bootstrapping method. We found significant indirect effects of SA separately on vocabulary and syntax through auditory STM with point estimates of -.30 and -.31, respectively. Results suggest lapses in SA compromise auditory STM, which in turn impacts vocabulary and syntax in youth with DS; however, further research is needed to confirm causality. Addressing SA and STM in language therapy with youth with DS could lead to improved outcomes.

The effect of acute exercise on the performance of verbal fluency in adolescents and young adults with Down syndrome: a pilot study

BACKGROUND

The high prevalence of cognitive dysfunction is well documented in individuals with Down syndrome. However, only a few studies have focused on the effect of exercise on cognitive performance in this population. In particular, verbal fluency has been shown to be relevant to the early onset of Alzheimer's disease in individuals with Down syndrome. Thus, this study was aimed at investigating the relationship between acute exercise and verbal fluency in this population.

METHODS

It was a pre-post design. Twenty-eight participants (aged 14-31) were assigned to high-intensity exercise (i.e. 70-85% of predicted maximum heart rate) (N = 8), moderate-intensity exercise (i.e. 50-69% of predicted maximum heart rate) (N = 10) or attentional control (N = 10) groups. Two exercise groups walked on a treadmill using an incremental walking protocol, and the attentional control group watched a video for 20 min. Measures of verbal fluency (i.e. semantic fluency and phonetic fluency) were tested pre-intervention and post-intervention.

RESULTS

The result showed a quadric trend between semantic fluency and intensity of exercise. The improvement in cognitive performance on semantic fluency test was observed in the moderate-intensity exercise. However, neither a linear trend nor a quadric trend was seen in phonetic fluency.

CONCLUSIONS

The result showed an inverted-U relationship between exercise intensity and semantic fluency. A larger sample size, testing time and more reliable psychophysiological measures (e.g. VO₂ max and neuroimaging technology), should be considered to explore the underlying mechanisms in this population.

Use of electropalatography in the treatment of speech disorders in children with Down syndrome: a randomized controlled trial

BACKGROUND

Electropalatography (EPG) records details of the location and timing of tongue contacts with the hard palate during speech. It has been effective in treating articulation disorders that have failed to respond to conventional therapy approaches but, until now, its use with children and adolescents with intellectual/learning disabilities and speech disorders has been limited.

AIMS

To evaluate the usefulness of EPG in the treatment of speech production difficulties in children and adolescents with Down syndrome (DS) aged 8-18 years.

METHODS & PROCEDURES

A total of 27 children with DS were assessed on a range of cognitive and speech and language measures and underwent additional EPG assessment. Participants were randomly allocated to one of three age-matched groups receiving either EPG therapy, EPG-informed conventional therapy or 'treatment as usual' over a 12-week period. The speech of all children was assessed before therapy using the Diagnostic Evaluation of Articulation and Phonology (DEAP) and reassessed immediately post- and 3 and 6 months post-intervention to measure percentage consonants correct (PCC). EPG recordings were made of the DEAP assessment items at all time points. Per cent intelligibility was also calculated using the Children's Speech Intelligibility Measure (CSIM).

OUTCOMES & RESULTS

Gains in accuracy of production immediately post-therapy, as measured by PCC, were seen for all groups. Reassessment at 3 and 6 months post-therapy revealed that those who had received therapy based directly on EPG visual feedback were more likely to maintain and improve on these gains compared with the other groups. Statistical testing showed significant differences between groups in DEAP scores across time points, although the majority did not survive post-hoc evaluation. Intelligibility across time points, as measured by CSIM, was also highly variable within and between the three groups, but despite significant correlations between DEAP and CSIM at all time points, no statistically significant group differences emerged.

CONCLUSIONS & IMPLICATIONS

EPG was an effective intervention tool for improving speech production in many participants. This may be because it capitalizes on the relative strength of visual over auditory processing in this client group. The findings would seem to warrant an increased focus on addressing speech production difficulties in current therapy.

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.

Cognitive Functioning in Children with Down Syndrome: Current Knowledge and Future Directions

Infants and children with Down syndrome (DS) can look forward toward bright futures, as individuals with DS are living healthier, more productive lives than ever due to medical advances, opportunities for early and continued intervention, and inclusive education. Despite these advances, infants and children with DS experience challenges in specific domains of cognitive functioning relative to their typically developing (TD) peers. Over the long term, individuals with DS are also more likely to develop Alzheimer's disease relative to the general population. Understanding cognitive functioning early in life may be important in charting cognitive decline over time. This chapter synthesizes the literature on cognitive functioning in infants and children with DS specific to general intelligence or IQ, language development, recall memory, and executive functioning, with additional focus on critical issues and future directions. These research findings provide important information for understanding cognitive competencies and intervention opportunities for children with DS and also serves to provide a foundation from which to plan longitudinal studies examining stability and change in cognitive functioning over time.

Predictors of receptive and expressive vocabulary development in children with Down syndrome

PURPOSE

There is a lack of longitudinal data on predictors of vocabulary development in children with Down syndrome (DS). In typically developing children, many internal and external predictors of vocabulary development have been determined before. The purpose of the present study was to investigate the role of these variables in the receptive and expressive vocabulary development of children with DS.

METHOD

The present study used a longitudinal design in young children with DS to study the vocabulary development over a period of 1.6 years and investigated the possible predictive role of child-related and environmental variables.

RESULT

Receptive vocabulary development was best predicted by the adaptive level of functioning and early receptive vocabulary skills. Expressive vocabulary development was best predicted by the adaptive level of functioning, receptive vocabulary, maternal educational level, level of communicative intent of the child, attention skills and phonological/phonemic awareness.

CONCLUSION

A wide range of internal and external predictors for vocabulary development of children with DS was found. Predictors resemble those predicting vocabulary development in peers with typical development between 1 and 6 years of age, as identified in other studies.

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.

A case report of the neurocognitive and behavioral phenotype of mosaic trisomy 14

Mosaic trisomy 14 is associated with impaired intellectual functioning, although no study has examined the cognitive-behavioral profile associated with the syndrome. This study provides the first case description of the cognitive-behavioral phenotype associated with mosaic trisomy 14 by contrasting the performance an adolescent female (T14) with a group of females with Down syndrome (DS; n=9). T14 performed below age expectations on most direct assessments and demonstrated weaknesses relative to the DS group on aspects of language, adaptive functioning, and executive functioning. T14 also demonstrated strengths in delayed visual recall and social skills relative to the DS group.

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.

Developmental trajectories of children with Down syndrome by socio-economic status: the case of Latin America

BACKGROUND

Several studies show that socio-economic status (SES) is related to the developmental trajectories of children with typical development (TD). However, few studies have analysed this relationship regarding children with neurodevelopmental disorders such as Down syndrome (DS). In this paper, we analyse the impact of SES in the neurodevelopmental trajectories of children with DS in comparison with children with TD.

METHOD

Cognitive, language, motor and socio-emotional development were assessed in 31 children with DS between the ages of 15 and 80 months from high to low SES backgrounds. Data from this group were compared with data from a sample of 72 children with TD randomly selected from the Longitudinal Survey of Early Childhood. We analyse and compare these two groups using the developmental trajectories method RESULTS: The results show delayed onsets for the four abilities measured in children with DS compared with children with TD from high to low SES. In the comparison of the developmental trajectories, we found that the differences between the neurodevelopmental trajectories in DS and TD vary according to SES. High SES show differences only in language development, while low SES show significant differences in cognitive, language and socio-emotional development.

CONCLUSIONS

The results indicate that SES is a factor that could impact the developmental trajectories of children with DS. Although the differences between children with DS and with TD are similar at the beginning regardless of SES, the developmental trajectories are slower in children with DS of low SES than in children of high SES. We argue that the differences are related to the complex interaction of several biological and cultural factors associated with SES. Some specific hypotheses about nutrition, health care access, quality of education and parenting practices are presented, but more research in this area is needed to fully understand these results.

Simple Mindreading Abilities Predict Complex Theory of Mind: Developmental Delay in Autism Spectrum Disorders

Theory of mind (ToM) is impaired in individuals with autism spectrum disorders (ASD). The aims of this study were to: (i) examine the developmental trajectories of ToM abilities in two different mentalizing tasks in children with ASD compared to TD children; and (ii) to assess if a ToM simple test known as eyes-test could predict performance on the more advanced ToM task, i.e. comic strip test. Based on a sample of 37 children with ASD and 55 TD children, our results revealed slower development at varying rates in all ToM measures in children with ASD, with delayed onset compared to TD children. These results could stimulate new treatments for social abilities, which would lessen the social deficit in ASD.

Growth and Decline in Language and Phonological Memory Over Two Years Among Adolescents With Down Syndrome

Forty-two adolescents with Down syndrome (DS) ages 10 to 21 years completed a battery of language and phonological memory measures twice, 2 years apart. Individual differences were highly stable across two years. Receptive vocabulary scores improved, there was no change in receptive or expressive grammar scores, and nonword repetition scores declined. Digit memory and expressive vocabulary scores improved among younger adolescents, but generally held steady among older adolescents. These patterns may reveal key points in development at which interventions may be best applied. Further research is needed to understand specific processes in tasks that appear to be slowing or declining during adolescence. They may be important for understanding early aging and dementia in DS.

Speech therapy in adolescents with Down syndrome: In pursuit of communication as a fundamental human right

PURPOSE

The achievement of speech intelligibility by persons with Down syndrome facilitates their participation in society. Denial of speech therapy services by virtue of low cognitive skills is a violation of their fundamental human rights as proclaimed in the Universal Declaration of Human Rights in general and in Article 19 in particular. Here, we describe the differential response of an adolescent with Down syndrome to three speech therapy interventions and demonstrate the use of a single subject randomisation design to identify effective treatments for children with complex communication disorders.

METHOD

Over six weeks, 18 speech therapy sessions were provided with treatment conditions randomly assigned to targets and sessions within weeks, specifically comparing auditory-motor integration prepractice and phonological planning prepractice to a control condition that included no prepractice. All treatments involved high intensity practice of nonsense word targets paired with tangible referents.

RESULT

A measure of generalisation from taught words to untaught real words in phrases revealed superior learning in the auditory-motor integration condition.

CONCLUSION

The intervention outcomes may serve to justify the provision of appropriate supports to persons with Down syndrome so that they may achieve their full potential to receive information and express themselves.

Verbal short-term memory shows a specific association with receptive but not productive vocabulary measures in Down syndrome

BACKGROUND

Verbal short-term memory (STM) capacity has been considered to support vocabulary learning in typical children and adults, but evidence for this link is inconsistent for studies in individuals with Down syndrome (DS). The aim of this study was explore the role of processing demands on the association between verbal STM and vocabulary measures in DS, by comparing receptive vocabulary measures with high STM processing demands to productive vocabulary measures with low STM processing demands.

METHOD

Forty-seven adults with Down syndrome were administered receptive vocabulary and productive vocabulary tasks, as well as measures of verbal STM abilities and intellectual efficiency.

RESULTS

Bayesian regression analyses showed that verbal STM abilities were strongly and specifically associated with receptive vocabulary measures but not productive lexical abilities after controlling for intellectual efficiency, and this is despite the fact that vocabulary abilities as measured by receptive and productive vocabulary tasks were closely associated.

CONCLUSIONS

In Down syndrome, verbal STM abilities may be predictive of specific task demands associated with receptive vocabulary tasks rather than of vocabulary development per se.

A population-based study of communicative participation in preschool children with speech-language impairments

AIM

To develop statistical models of communicative participation development of preschool children and explore variations by level of function.

METHOD

This was a secondary analysis of data from a longitudinal study of preschool children with speech and language impairments (n=46 872; age range 18-67mo, mean age [SD] 41.76mo [11.92]; 67% male) accessing publicly funded services in Ontario, Canada. Two measures were used: Focus on the Outcomes of Communication Under Six (FOCUS), measuring changes in communicative participation skills, and the Communication Function Classification System (CFCS), classifying communicative function into one of five levels. We used mixed effects modeling to fit growth curves for children in each CFCS level. Models allowed for variation in initial FOCUS score at 18 months, rate of growth with age, and rate of acceleration/deceleration with age.

RESULTS

Starting FOCUS score (18mo) varied inversely with CFCS level at entry to the program. Growth was initially rapid and then leveled off for children in Levels I to III. Growth was less rapid for children in Level IV, but leveled off, and was slow but continual for children in Level V.

INTERPRETATION

This work can help us to move beyond traditional impairment-based thinking and shows that children can make meaningful communicative changes regardless of their function.

Language comprehension in children, adolescents, and adults with Down syndrome

BACKGROUND

There is conflicting evidence as to whether receptive language abilities of individuals with Down syndrome (DS) continue to improve into adulthood, reach a plateau in late adolescence, or even start to decline.

AIM

The study aims to shed light on the question whether receptive syntactic skills change from childhood/adolescence to adulthood and provides a detailed qualitative analysis of the receptive abilities of adults with DS.

METHODS

58 individuals with DS participated in the study: 31 children/adolescents (aged: 4;6-19;0 years) and 27 adults (aged: 20;8-40;3 years). They completed measures of grammar comprehension, nonverbal cognition, and phonological working memory.

RESULTS

There was no significant correlation between comprehension performance and chronological age in the overall sample. Separate correlational analyses for the subgroups of children/adolescents and adults yielded a significant positive result for the former subgroup but not for the latter. We also found significant positive correlations between grammar comprehension scores and nonverbal mental age as well as measures of phonological working memory. Qualitative analyses showed various limitations in the receptive syntactic abilities of adults with DS. Difficulties increase with sentence length and grammatical complexity, but are also apparent in simple sentences.

CONCLUSION

The results suggest that syntactic comprehension abilities of individuals with DS continue to improve through childhood and adolescence and that thereafter a plateau is reached and maintained. Language comprehension in adults with DS is impaired for a variety of grammatical structures and receptive performance seems to be related to nonverbal cognitive abilities, phonological working memory, and grammatical complexity.

A Spoken-Language Intervention for School-Aged Boys With Fragile X Syndrome

Using a single case design, a parent-mediated spoken-language intervention was delivered to three mothers and their school-aged sons with fragile X syndrome, the leading inherited cause of intellectual disability. The intervention was embedded in the context of shared storytelling using wordless picture books and targeted three empirically derived language-support strategies. All sessions were implemented through distance videoteleconferencing. Parent education sessions were followed by 12 weekly clinician coaching and feedback sessions. Data were collected weekly during independent homework and clinician observation sessions. Relative to baseline, mothers increased their use of targeted strategies, and dyads increased the frequency and duration of story-related talking. Generalized effects of the intervention on lexical diversity and grammatical complexity were observed. Implications for practice are discussed.

Syntactic comprehension and working memory in children with specific language impairment, autism or Down syndrome

This study examined syntactic assignment for predicates and reflexives as well as working memory effects in the sentence comprehension of children with Specific Language Impairment (SLI), Down syndrome (DS), high functioning Autism (HFA) and Typical Language Development (TLD). Fifty-seven children (35 boys and 22 girls) performed a computerised picture-selection sentence comprehension task. Predicate attachment and reflexive antecedent assignment (with working memory manipulations) were investigated. The results showed that SLI, HFA and DS children exhibited poorer overall performance than TLD children. Children with SLI exhibited similar performance to the DS and HFA children only when working memory demands were higher. We conclude that children with SLI, HFA and DS differ from children with TLD in their comprehension of predicate and reflexive structures where the knowledge of syntactic assignment is required. Working memory manipulation had different effects on syntactic comprehension depending on language disorder. Intelligence was not an explanatory factor for the differences observed in performance.

Pronoun comprehension in individuals with Down syndrome: the role of age

BACKGROUND

A number of studies have suggested that language in individuals with Down syndrome (DS) may not be simply delayed compared with language in typically developing (TD) children, but deviant. The deviance has been detected in the comprehension of pronouns, and it has triggered proposals for the existence of a specific syntactic deficit in individuals with DS. However, the developmental path of pronoun comprehension in individuals with DS is unknown as there are no studies examining individuals of different ages.

AIMS

To perform a pilot study examining pronoun comprehension in adolescents and adults with DS in comparison with TD children. Research questions include: Are some pronoun types more difficult than others for each of the two groups (DS and TD)? Is there a difference in performance between the two groups? Does performance correlate with chronological age in the DS group?

METHODS & PROCEDURES

Using a manual picture selection task, we examined the comprehension of different types of pronouns in 14 Greek-speaking individuals with DS, ranging from 10 to 34 years of age. We also tested a control group of TD children as well as a typical adult group. The TD and DS groups were recruited and tested in pre-schools and schools/centres for individuals with learning disabilities, respectively. Within- and between-group comparisons were performed for all conditions. For the DS group, correlations between chronological age and performance in each condition were also explored.

OUTCOMES & RESULTS

Results reveal a significant positive correlation of age with performance in the DS group, but only in structures that also presented difficulties to TD children. Structures that presented difficulties only to individuals with DS do not appear to be less problematic for older participants.

CONCLUSIONS & IMPLICATIONS

These findings provide support to the deviance hypothesis by suggesting that the syntactic deficit in the comprehension of pronouns in individuals with DS is present in individuals of a wide age range. At the same time, the results, if corroborated by large-scale studies, suggest that some aspects of grammatical development in individuals with DS may continue even after adolescence and well into adulthood. We argue that these findings can contribute towards more targeted intervention practices by increasing our knowledge of the behavioural phenotype of DS.