Cognitive, environmental, and linguistic predictors of syntax in fragile X syndrome and Down syndrome

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.

Communication in fragile X syndrome: Patterns and implications for assessment and intervention

Fragile X syndrome (FXS) is the most common cause of inherited intellectual disability and is associated with a high rate of autism diagnosis. Language delays have been noted in the areas of overall communication and the specific areas of receptive, expressive, and pragmatic language, as well as in development of speech sounds and literacy. It has been widely noted that those individuals with a diagnosis of both FXS and autism tend to have more significant intellectual disability and language disorder. In this study, the research exploring the FXS language phenotype is presented, and the roles of cognition, autistic symptomatology, and gender are highlighted as possible. Implications for assessment and intervention approaches based on the strengths and weaknesses of the FXS language phenotype are provided.

The Index of Productive Syntax: Psychometric Properties and Suggested Modifications

PURPOSE

The Index of Productive Syntax (IPSyn) is a well-known language sample analysis tool. However, its psychometric properties have not been assessed across a wide sample of typically developing preschool-age children and children with language disorders. We sought to determine the profile of IPSyn scores by age over early childhood. We additionally explored whether the IPSyn could be shortened to fewer items without loss of information and whether the required language sample could be shortened from a current required number of 100 utterances to 50.

METHOD

We used transcripts from the Child Language Data Exchange System, including 1,051 samples of adult-child conversational play with toys within the theoretical framework of item response theory. Samples included those from typically developing children as well as children with hearing loss, Down syndrome, and late language emergence.

RESULTS

The Verb Phrase and Sentence Structure subscales showed more stable developmental trajectories over the preschool years and greater differentiation between typical and atypical cohorts than did the Noun Phrase and Question/Negation subscales. A number of current IPSyn scoring items can be dropped without loss of information, and 50-utterance samples demonstrate most of the same psychometric properties of longer samples.

DISCUSSION

Our findings suggest ways in which the IPSyn can be automated and streamlined (proposed IPSyn-C) so as to provide useful clinical guidance with fewer items and a shorter required language sample. Reference values for the IPSyn-C are provided. Trajectories for one subscale (Question/Negation) appear inherently unstable and may require structured elicitation. Potential limitations, ramifications, and future directions are discussed.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.16915690.

Family Variables and Quality of Life in Children with Down Syndrome: A Scoping Review

The purpose of this scoping review was to identify the family and child quality of life variables that have been studied in relation to one another in children with Down syndrome, the frequency with which different relationships have been studied, and the extent to which family variables were the focus of the research aims. A literature search was conducted to find studies published between January 2007 and June 2018. The initial search yielded 2314 studies; of these, 43 were selected for a final review. Researchers most often addressed family resources and family problem-solving and coping concerning child personal development and physical well-being. Little attention to child emotional well-being was observed, with none considering family appraisal of child emotional well-being. The relationship between family variables and child QoL rarely was the primary focus of the study. Methodologically, most reviewed studies used cross-sectional designs, were conducted in North America and based on maternal report. From future research considering the issues found in this review, healthcare providers can obtain an in-depth understanding of relationships between children and family variables.

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.

A comprehensive examination of the memory profile of youth with Down syndrome in comparison to typically developing peers

Down syndrome (DS) is associated with significant memory deficits beyond overall global cognitive impairment. Although a number of studies have examined memory abilities in adults and teens with DS, very few studies have examined memory abilities in children with DS. Additionally, research has yet to examine prospective memory (i.e., remembering to carry out an action in the future) in youth with DS. Consequently, the current study aimed to comprehensively examine the memory profile, including learning, immediate recall, delayed recall and prospective memory, of youth with DS (n = 22, age M = 11.43) in comparison to typically developing, mental-age (MA) matched children (n = 20, age M = 5.04) Consistent with past research, the results indicated that youth with DS performed significantly below MA-expectations on tasks of immediate verbal recall, learning across trials, and prospective memory, and there was a trend toward youth with DS performing below MA-expectations on delayed recall tasks. However, youth with DS did not differ significantly from MA-matched peers on immediate visual recall, rate of learning across trials, or proportion of items recalled on verbal and visual memory tasks following a delay (i.e., proportion relative to their own recall performance prior to the delay). These results highlight the relative strengths and challenges experienced by youth with DS on different learning and memory tasks. The implications of these findings for educators and caregivers are discussed.

Syntactic Ability of Girls With Fragile X Syndrome: Phonological Memory and Discourse Demands on Complex Sentence Use

This study was designed to establish the extent of delay in complex sentence use by females with fragile X syndrome (FXS) and to identify sources of variability among individuals. Females with FXS (n = 16; 10;2-15;7) and younger typically developing girls (n = 17; 4;1-8;11) were group-wise matched on nonverbal cognition and receptive syntax. Language samples (conversation and narration) yielded syntactic complexity in terms of mean length of C-unit (MLCU) and Developmental Level sentence coding (DLevel; Rosenberg & Abbeduto, 1987 ). Complex syntax was not weaker than developmental expectations; however, MLCU was lower than expected for age. Phonological memory and verbal working memory correlated with measures of syntactic complexity in narration. Discourse demands may play an important role in the language produced by females with FXS.

A Multimethod Analysis of Pragmatic Skills in Children and Adolescents With Fragile X Syndrome, Autism Spectrum Disorder, and Down Syndrome

PURPOSE

Pragmatic language skills are often impaired above and beyond general language delays in individuals with neurodevelopmental disabilities. This study used a multimethod approach to language sample analysis to characterize syndrome- and sex-specific profiles across different neurodevelopmental disabilities and to examine the congruency of 2 analysis techniques.

METHOD

Pragmatic skills of young males and females with fragile X syndrome with autism spectrum disorder (FXS-ASD, n = 61) and without autism spectrum disorder (FXS-O, n = 40), Down syndrome (DS, n = 42), and typical development (TD, n = 37) and males with idiopathic autism spectrum disorder only (ASD-O, n = 29) were compared using variables obtained from a detailed hand-coding system contrasted with similar variables obtained automatically from the language analysis program Systematic Analysis of Language Transcripts (SALT).

RESULTS

Noncontingent language and perseveration were characteristic of the pragmatic profiles of boys and girls with FXS-ASD and boys with ASD-O. Boys with ASD-O also initiated turns less often and were more nonresponsive than other groups, and girls with FXS-ASD were more nonresponsive than their male counterparts. Hand-coding and SALT methods were largely convergent with some exceptions.

CONCLUSION

Results suggest both similarities and differences in the pragmatic profiles observed across different neurodevelopmental disabilities, including idiopathic and FXS-associated cases of ASD, as well as an important sex difference in FXS-ASD. These findings and congruency between the 2 language sample analysis techniques together have important implications for assessment and intervention efforts.

Specificity: A Phenotypic Comparison of Communication-Relevant Domains Between Youth With Down Syndrome and Fragile X Syndrome

Despite the shared presence of an intellectual disability (ID), there is a growing literature documenting important phenotypic differences between Down syndrome (DS) and fragile X syndrome (FXS). These conclusions, however, are based on a synthesis across studies, each of which typically includes only measures of a limited number of constructs, and with differing participant characteristics. Firmer conclusions regarding specific phenotypes require a single comprehensive multi-domain assessment of participants with the syndrome groups being well matched on chronological age (CA) and cognitive functioning. The current study was designed to fill this gap by assessing several important cognitive and behavioral domains relevant to communication, such as: structural language skills, false belief understanding, as well as pragmatics and behavioral difficulties, in 30 adolescents of both sexes with DS and 39 males with FXS, matched on CA and nonverbal (NV) cognition. After statistically controlling for NV cognition, we did not find significant syndrome differences in expressive and receptive structural language or false belief understanding. In contrast, participants with DS displayed less stereotyped language and fewer behavioral difficulties compared to males with FXS. Within-syndrome associations among the targeted domains are described. Finally, females with DS were less impaired than males with DS in almost all structural language domains, whereas no significant sex-related differences were observed in NV cognition, false belief understanding, pragmatics, or behavior. Clinical and methodological implications of the findings are discussed.

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.

Distance delivery of a spoken language intervention for school-aged and adolescent boys with fragile X syndrome

A small randomized group design (N = 20) was used to examine a parent-implemented intervention designed to improve the spoken language skills of school-aged and adolescent boys with FXS, the leading cause of inherited intellectual disability. The intervention was implemented by speech-language pathologists who used distance video-teleconferencing to deliver the intervention. The intervention taught mothers to use a set of language facilitation strategies while interacting with their children in the context of shared story-telling. Treatment group mothers significantly improved their use of the targeted intervention strategies. Children in the treatment group increased the duration of engagement in the shared story-telling activity as well as use of utterances that maintained the topic of the story. Children also showed increases in lexical diversity, but not in grammatical complexity.

Public Health Literature Review of Fragile X Syndrome

OBJECTIVES

The purpose of this systematic literature review is to describe what is known about fragile X syndrome (FXS) and to identify research gaps. The results can be used to help inform future public health research and provide pediatricians with up-to-date information about the implications of the condition for individuals and their families.

METHODS

An electronic literature search was conducted, guided by a variety of key words. The search focused on 4 areas of both clinical and public health importance: (1) the full mutation phenotype, (2) developmental trajectories across the life span, (3) available interventions and treatments, and (4) impact on the family. A total of 661 articles were examined and 203 were included in the review.

RESULTS

The information is presented in the following categories: developmental profile (cognition, language, functional skills, and transition to adulthood), social-emotional profile (cooccurring psychiatric conditions and behavior problems), medical profile (physical features, seizures, sleep, health problems, and physiologic features), treatment and interventions (educational/behavioral, allied health services, and pharmacologic), and impact on the family (family environment and financial impact). Research gaps also are presented.

CONCLUSIONS

The identification and treatment of FXS remains an important public health and clinical concern. The information presented in this article provides a more robust understanding of FXS and the impact of this complex condition for pediatricians. Despite a wealth of information about the condition, much work remains to fully support affected individuals and their families.

Addressing phonological memory in language therapy with clients who have Down syndrome: Perspectives of speech-language pathologists

BACKGROUND

Phonological memory (PM) plays a significant role in language development but is impaired in individuals with Down syndrome (DS). Without formal recommendations on how to address PM limitations in clients with DS, it is possible speech-language pathologists (SLPs) find ways to do so in their practices.

AIMS

This study asked if and how SLPs address PM in language therapy with clients who have DS. It also asked about SLPs' opinions of the importance, practicality and difficulty of addressing PM in clients with DS.

METHODS & PROCEDURES

SLPs participated in an online survey that asked if they address PM in clients with DS and, if so, how often and with which techniques. The survey also asked SLPs to rate their opinions of addressing PM in clients with DS with Likert scales. To contrast clients with DS, SLPs were asked about their practices and opinions with clients who have specific language impairment (SLI) and autism spectrum disorders (ASD). SLPs were recruited through e-mails sent from state organizations and researchers. To compare SLPs' practices and opinions across client types, frequency analyses and analyses of variance (ANOVAs) were run.

OUTCOMES & RESULTS

In all, 290 SLPs from 28 states completed the survey. Nearly all SLPs were currently practising at the time data were collected, and all worked with at least one of the three client types. Findings indicated SLPs less often addressed PM and used less variety when addressing PM with clients who have DS compared with clients who have SLI or ASD. Further, SLPs considered it less important, less practical and more difficult to address PM in clients who have DS when compared with clients who have SLI, whereas a similar pattern was found with clients who have ASD.

CONCLUSIONS & IMPLICATIONS

SLPs' opinions could be one reason they under-address PM with clients who have DS. Other reasons include there are no evidence-based practice (EBP) guidelines on this topic, and there is not enough familiarity with the DS phenotype among SLPs. Future research on ways to address PM in clients with DS successfully are essential so that EBP guidelines can be established and language therapy can be made more effective.

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.

Use of the ADOS for assessing spontaneous expressive language in young children with ASD: a comparison of sampling contexts

PURPOSE

The current study compared the spontaneous expressive language of children with autism spectrum disorder (ASD) across multiple language sampling contexts: the Autism Diagnostic Observation Schedule (ADOS; Lord, Rutter, DiLavore, & Risi, 1999) and play with an examiner or parent.

METHOD

Participants were children with ASD (n = 63; 55 boys) with a mean age of 45 months (SD = 3.94, range = 37-53). The number of utterances produced; percentage of intelligible utterances; number of different words; mean length of utterance; and the number of requests, comments, and instances of turn-taking were calculated for the ADOS, examiner-child play, and parent-child play. Children were categorized into Tager-Flusberg et al.'s (2009) developmental language phases for each context.

RESULTS

Effects of sampling context were identified for all variables examined. The ADOS resulted in fewer utterances and lower structural and pragmatic language performance than examiner-child play and/or parent-child play. Categorization of children into language phases differed across contexts.

CONCLUSIONS

Use of the ADOS as a language sampling context may lead to underestimating the abilities of young children with ASD relative to play with an examiner or parent. Researchers and clinicians should be aware of context effects, particularly for assessments designed to observe autism symptoms.

Outcome measures for clinical trials in fragile X syndrome

OBJECTIVE

Progress in basic neuroscience has led to identification of molecular targets for treatment in fragile X syndrome (FXS) and other neurodevelopmental disorders; however, there is a gap in translation to targeted therapies in humans. One major obstacle to the demonstration of efficacy in human trials has been the lack of generally accepted endpoints to assess improvement in function in individuals with FXS. To address this problem, the National Institutes of Health convened a meeting of leading scientists and clinicians with the goal of identifying and standardizing outcome measures for use as potential endpoints in clinical trials in FXS.

METHODS

Participants in the meeting included FXS experts, experts in the design and implementation of clinical trials and measure development, and representatives from advocacy groups, industry, and federal agencies.

RESULTS

The group generated recommendations for optimal outcome measures in cognitive, behavioral, and biomarker/medical domains, including additional testing and validation of existing measures and development of new measures in areas of need. Although no one endpoint or set of endpoints could be identified that met all criteria as an optimal measure, recommendations are presented in this report.

CONCLUSION

The report is expected to guide the selection of measures in clinical trials and lead to the use of a more consistent battery of measures across trials. Furthermore, this will help to direct research toward gaps in the development of validated FXS-specific outcome measures and to assist with interpretation of clinical trial data by creating templates for measurement of treatment efficacy.

Genetic insights into the functional elements of language

Language disorders cover a wide range of conditions with heterologous and overlapping phenotypes and complex etiologies harboring both genetic and environmental influences. Genetic approaches including the identification of genes linked to speech and language phenotypes and the characterization of normal and aberrant functions of these genes have, in recent years, unraveled complex details of molecular and cognitive mechanisms and provided valuable insight into the biological foundations of language. Consistent with this approach, we have reviewed the functional aspects of allelic variants of genes which are currently known to be either causally associated with disorders of speech and language or impact upon the spectrum of normal language ability. We have also reviewed candidate genes associated with heritable speech and language disorders. In addition, we have evaluated language phenotypes and associated genetic components in developmental syndromes that, together with a spectrum of altered language abilities, manifest various phenotypes and offer details of multifactorial determinants of language function. Data from this review have revealed a predominance of regulatory networks involved in the control of differentiation and functioning of neurons, neuronal tracks and connections among brain structures associated with both cognitive and language faculties. Our findings, furthermore, have highlighted several multifactorial determinants in overlapping speech and language phenotypes. Collectively this analysis has revealed an interconnected developmental network and a close association of the language faculty with cognitive functions, a finding that has the potential to provide insight into linguistic hypotheses defining in particular, the contribution of genetic elements to and the modular nature of the language faculty.