Receptive Vocabulary, Expressive Vocabulary, and Speech Production of Boys With Fragile X Syndrome in Comparison to Boys With Down Syndrome

Opportunities to Respond During Dyadic Caregiver-Child and Naturalistic Family Interactions Among Children With Down Syndrome: A Preliminary Investigation

PURPOSE

Dyadic caregiver-child interactions are commonly used to examine children's language learning environments. However, children frequently interact with multiple caregivers and/or siblings if they come from homes with multiple caregivers and siblings. Thus, we examined if and how caregiver opportunities to respond (OTRs) varied when sampled across three interaction configurations.

METHOD

Twelve children with Down syndrome (Mage = 40.82 months) and their biological parents participated in the current study. We collected separate mother-child and father-child dyadic interactions and one family choice interaction (i.e., both caregivers present and occasionally siblings) in families' homes. We analyzed if differences in the caregiver's OTR frequency and type-explicit and implicit-existed among dyadic and family choice configurations.

RESULTS

We found that, during family choice interactions, children were exposed to fewer OTRs when combining the total number of father and mother OTRs compared to dyadic caregiver-child interactions. This effect was large for explicit OTRs (mother-dyadic vs. combined family choice: g = -1.99, confidence interval [CI] [-3.00, -1.00]; father-dyadic vs. combined family choice: g = -0.84, CI [-1.84, -0.11]). For implicit OTRs, effects were small for mother-dyadic versus combined family choice (g = -0.34, CI [-1.17, 0.48]) and negligible when comparing father-dyadic with combined family choice (g = -0.08, CI [-0.90, 0.73]).

CONCLUSION

Our preliminary findings highlight the need for a more nuanced understanding of children's language learning environments to better understand how caregivers support their children's language development.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.25579905.

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

Background

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

Objectives

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

Search Methods

The last electronic search was conducted in April 2022.

Selection Criteria

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

Data Collection and Analysis

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

Main Results

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

Authors’ Conclusions

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

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.

Neural Correlates of Auditory Hypersensitivity in Fragile X Syndrome

The mechanisms underlying the common association between autism spectrum disorders (ASD) and sensory processing disorders (SPD) are unclear, and treatment options to reduce atypical sensory processing are limited. Fragile X Syndrome (FXS) is a leading genetic cause of intellectual disability and ASD behaviors. As in most children with ASD, atypical sensory processing is a common symptom in FXS, frequently manifesting as sensory hypersensitivity. Auditory hypersensitivity is a highly debilitating condition in FXS that may lead to language delays, social anxiety and ritualized repetitive behaviors. Animal models of FXS, including Fmr1 knock out (KO) mouse, also show auditory hypersensitivity, providing a translation relevant platform to study underlying pathophysiological mechanisms. The focus of this review is to summarize recent studies in the Fmr1 KO mouse that identified neural correlates of auditory hypersensitivity. We review results of electroencephalography (EEG) recordings in the Fmr1 KO mice and highlight EEG phenotypes that are remarkably similar to EEG findings in humans with FXS. The EEG phenotypes associated with the loss of FMRP include enhanced resting EEG gamma band power, reduced cross frequency coupling, reduced sound-evoked synchrony of neural responses at gamma band frequencies, increased event-related potential amplitudes, reduced habituation of neural responses and increased non-phase locked power. In addition, we highlight the postnatal period when the EEG phenotypes develop and show a strong association of the phenotypes with enhanced matrix-metalloproteinase-9 (MMP-9) activity, abnormal development of parvalbumin (PV)-expressing inhibitory interneurons and reduced formation of specialized extracellular matrix structures called perineuronal nets (PNNs). Finally, we discuss how dysfunctions of inhibitory PV interneurons may contribute to cortical hyperexcitability and EEG abnormalities observed in FXS. Taken together, the studies reviewed here indicate that EEG recordings can be utilized in both pre-clinical studies and clinical trials, while at the same time, used to identify cellular and circuit mechanisms of dysfunction in FXS. New therapeutic approaches that reduce MMP-9 activity and restore functions of PV interneurons may succeed in reducing FXS sensory symptoms. Future studies should examine long-lasting benefits of developmental vs. adult interventions on sensory phenotypes.

Neuropsychological and ASD phenotypes in rare genetic syndromes: A critical review of the literature

OBJECTIVE

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition characterized by core deficits in social communication and restricted and repetitive behaviors and interests. Recent advances in clinical genetics have improved our understanding of genetic syndromes associated with ASD, which has helped clarify distinct etiologies of ASD and document syndrome-specific profiles of neurocognitive strengths and weaknesses. Pediatric neuropsychologists have the potential to be impactful members of the care team for children with genetic syndromes and their families.

METHOD

We provide a critical review of the current literature related to the neuropsychological profiles of children with four genetic syndromes associated with ASD, including Tuberous Sclerosis Complex (TSC), fragile X syndrome (FXS), 22q11.2 deletion syndrome, and Angelman syndrome. Recommendations for assessment, intervention, and future directions are provided.

RESULTS

There is vast heterogeneity in terms of the cognitive, language, and developmental abilities of these populations. The within- and across-syndrome variability characteristic of genetic syndromes should be carefully considered during clinical evaluations, including possible measurement limitations, presence of intellectual disability, and important qualitative differences in the ASD-phenotypes across groups.

CONCLUSIONS

Individuals with genetic disorders pose challenging diagnostic and assessment questions. Pediatric neuropsychologists with expertise in neurodevelopmental processes are well suited to address these questions and identify profiles of neurocognitive strengths and weaknesses, tailor individualized recommendations, and provide diagnostic clarification.

Language profiles of Welsh-English bilingual children with Down syndrome

PURPOSE

Given that children with Down syndrome (DS) have language learning difficulties, concerns have been raised about the capacity of these children to acquire two (or more) languages. This research examines the language profiles of bilingual children with DS and typically developing (TD) children in comparison to monolinguals, with a view towards identifying the factors associated with language abilities within these populations.

METHOD

Four groups of children were recruited: Welsh-English bilinguals with DS (n=10), English monolinguals with DS (n=10), TD Welsh-English bilinguals (n=10) and TD English monolinguals (n=10). Children were individually matched on nonverbal cognitive ability (NVCA) to each child in the bilingual DS group and the four groups were matched on socioeconomic status and gender. Bilinguals were matched on current and lifetime exposure to Welsh and age of first exposure to their L2. Within DS and TD groups, chronological age was statistically controlled for. Language abilities were assessed via standardised assessments and specially designed tasks. Bilinguals were assessed in both of their languages.

RESULTS

Results show no effect of language status on measures of expressive and receptive language abilities or phonological awareness. Language impairments were evident for both DS groups, particularly for expressive morphosyntax. Welsh receptive vocabulary scores of the bilinguals with DS were comparable to the TD bilinguals. Working memory, phonological awareness and chronological age were the strongest predictors of receptive language outcomes in both DS groups, explaining 90% of the variability.

CONCLUSIONS

In conclusion, we report no adverse outcomes on language development for bilinguals with DS. To our knowledge, this is the first group study of bilingualism in children with DS within the UK. Findings align with and add to the growing body of literature that reports that bilingualism does not negatively impact the language development of children with developmental disabilities. Clinical and educational implications are discussed.

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

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

Differences and Similarities in Predictors of Expressive Vocabulary Development between Children with Down Syndrome and Young Typically Developing Children

The purpose of this study was to examine potential differences in the predictors of expressive vocabulary development between children with Down syndrome and typically developing children to support preparation for intervention development. An age cohort of 43 children with Down syndrome and 57 typically developing children with similar nonverbal mental age levels were assessed at three time points. Linear mixed models were used to investigate the predictors of expressive vocabulary over time. Both groups achieved progress in expressive vocabulary. The typically developing children had steeper growth than the children with Down syndrome (1.38 SD vs. 0.8 SD, p < 0.001). In both groups, receptive vocabulary, auditory memory, and the home literacy environment were significant predictors of development. In the children with Down syndrome, the phonological awareness and oral motor skills were also significant. Group comparisons showed that receptive vocabulary, auditory memory and oral motor skills were stronger predictors in the children with Down syndrome than in the typically developing children. These results indicate that children with Down syndrome are more vulnerable when it comes to risk factors that are known to influence expressive vocabulary than typically developing children. Children with Down syndrome therefore require early broad-based expressive vocabulary interventions.

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.

Language across the Lifespan in Fragile X Syndrome: Characteristics and Considerations for Assessment

While it is widely acknowledged that language development is delayed for the majority of individuals with fragile X syndrome (FXS), there has been limited research into how best to assess this area. This study aimed to deepen the understanding of standardized language assessment in FXS by addressing the three following objectives: (1) Examine the feasibility and validity of widely-used, standardized assessments in participants with FXS; (2) describe linguistic and cognitive profiles for a large sample of individuals with FXS; and (3) Compare results obtained from objective testing in clinic to those obtained using caregiver report. Results indicate that previous results indicating strong correlations between cognition and language results hold true across a wide range of ages as well as across multiple assessments, with an exception in very young children. Caregiver report tended to give lower estimates of language ability than what was found using an objectively administered assessment. Appropriate assessments remain difficult to find as a significant percentage of individuals scored at floor when scaled scores were calculated. Further, a sub-group of participants were coded for behavioral response to testing demands, the majority being able to complete a standardized assessment. These results speak to the need for assessments that provide a wider range of items so individuals can both achieve a valid score and demonstrate progress in their attainment of language skills.

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.

Expressive language abilities of boys with idiopathic autism spectrum disorder and boys with fragile X syndrome + autism spectrum disorder: Cross-context comparisons

BACKGROUND AND AIMS

Understanding the unique expressive language profiles of children with phenotypically similar, but distinct neurodevelopmental disorders, such as idiopathic autism spectrum disorder and fragile X syndrome with a co-diagnosis of autism spectrum disorder (fragile X syndrome + autism spectrum disorder), has both clinical and theoretical implications. However, comparative studies of these two clinical groups have been limited, and results have been inconsistent, partially as a result of different assessment methods being utilized. Thus, the current study compared the expressive language profiles of boys with idiopathic autism spectrum disorder and boys with fragile X syndrome + autism spectrum disorder and examined whether a similar linguistic profile emerged across different language sampling contexts: a semi-structured conversation and the Autism Diagnostic Observation Schedule.

METHODS

Eighteen boys with autism spectrum disorder (M_age  = 13.25 years) and 19 boys with fragile X syndrome + autism spectrum disorder (M_age  = 12.19 years), matched on autism spectrum disorder symptom severity and similar in terms of chronological age and mean length of utterance, participated in this study. Boys produced two language samples: one semi-structured conversation and one taken from the Autism Diagnostic Observation Schedule. Language samples were coded for talkativeness, lexical diversity, mean length of utterance, intelligibility, and repetitive or perseverative language.

RESULTS

Analyses revealed that boys with autism spectrum disorder produced language samples that were more lexically diverse and intelligible, and that included less topic perseveration compared to boys with fragile X syndrome + autism spectrum disorder. With regards to sampling context, boys in both groups were more talkative and produced longer and more intelligible utterances in their conversation sample compared to their Autism Diagnostic Observation Schedule sample. However, boys with autism spectrum disorder and fragile X syndrome + autism spectrum disorder used a higher proportion of topic perseveration during the conversation sample.

CONCLUSIONS

Overall, we found similarities as well as distinctions in the expressive language profiles of boys with fragile X syndrome + autism spectrum disorder and boys with idiopathic autism spectrum disorder. Moreover, the Autism Diagnostic Observation Schedule sample elicited a relatively different language profile than the conversation sample for boys in both groups.

IMPLICATIONS

These findings help to further elucidate the unique language phenotypes of boys with idiopathic autism spectrum disorder and boys with fragile X syndrome + autism spectrum disorder. Moreover, our findings indicate that multiple language samples may be needed to obtain a comprehensive account of a child's expressive language ability.

Developmental Trajectory of Communication Repair in Children with Fragile X Syndrome

BACKGROUND & AIMS

The development of communicative competence requires both language and social skills. The ability to repair following a communication breakdown is critical for continued conversational interchange and to ensure comprehension of bids for communication. Repair demonstrates adequate language and social skills. Children with Fragile X Syndrome (FXS) have difficulty with language development and social skills, which may result in delays or deficits in repair. Repair may be additionally impaired in children with FXS and co-morbid autism. This study examined the development of repair in children with FXS from toddlerhood into middle childhood.

METHODS

Fifty-five children with FXS and their biological mothers participated. Data were collected during in-home visits approximately every 18 months. Videotaped mother-child interactions were collected, as well as standardized assessments of language, social skills, and autism symptomology.

RESULTS

Children with FXS acquired the ability to repair at 90% mastery by three-and-a-half years of age. Multilevel logistic regressions predicting probability of repair indicated marginally significant effects of mean length of utterance and number of different words, and significant effects of global social skills and autism symptomology. Effect sizes were small to moderate.

CONCLUSIONS

Ability to repair was measured in a naturalistic setting, which allowed children with FXS to utilize repairs in their daily interactions. Although children with FXS may have delayed development of repair relative to typically developing expectations, in general they nonetheless catch up and demonstrate a robust ability to repair by three-and-a-half years of age. However, this study provides evidence that individual differences in language and social skills may influence ability to repair in children with FXS. Finally, the relationship between autism symptoms and repair remains unclear, necessitating further exploration.

IMPLICATIONS

Given the noted delay in repair in young children with FXS, clinicians working with this population should target development of this skill as early as possible to maximize successful social interactions. This may be particularly necessary for children with FXS and co-morbid autism.

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.

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.

Inferential language use by school-aged boys with fragile X syndrome: Effects of a parent-implemented spoken language intervention

This study examined the impact of a distance-delivered parent-implemented narrative language intervention on the use of inferential language during shared storytelling by school-aged boys with fragile X syndrome, an inherited neurodevelopmental disorder. Nineteen school-aged boys with FXS and their biological mothers participated. Dyads were randomly assigned to an intervention or a treatment-as-usual comparison group. Transcripts from all pre- and post-intervention sessions were coded for child use of prompted and spontaneous inferential language coded into various categories. Children in the intervention group used more utterances that contained inferential language than the comparison group at post-intervention. Furthermore, children in the intervention group used more prompted inferential language than the comparison group at post-intervention, but there were no differences between the groups in their spontaneous use of inferential language. Additionally, children in the intervention group demonstrated increases from pre- to post-intervention in their use of most categories of inferential language. This study provides initial support for the utility of a parent-implemented language intervention for increasing the use of inferential language by school aged boys with FXS, but also suggests the need for additional treatment to encourage spontaneous use.

Language Skills of Males with Fragile X Syndrome or Nonsyndromic Autism Spectrum Disorder

Despite the similarities observed between the fragile X syndrome (FXS) and autism spectrum disorder (ASD) phenotypes, few studies have compared their behavioral profiles outside of ASD symptomatology. In the present study, we sought to compare lexical and grammatical abilities in these two conditions. Comparisons of language abilities in both of these conditions are particularly interesting because both conditions are characterized by difficulties navigating social interactions. Results suggest that although both FXS and ASD are associated with language difficulties, there are important differences between the two conditions in terms of the language profiles observed and the factors influencing language when considering children of similar developmental levels. Theoretical implications are discussed.

Investigating the Receptive-Expressive Vocabulary Profile in Children with Idiopathic ASD and Comorbid ASD and Fragile X Syndrome

Previous work has noted that some children with autism spectrum disorder (ASD) display weaknesses in receptive vocabulary relative to expressive vocabulary abilities. The current study extended previous work by examining the receptive-expressive vocabulary profile in boys with idiopathic ASD and boys with concomitant ASD and fragile X syndrome (ASD + FXS). On average, boys with ASD + FXS did not display the same atypical receptive-expressive profile as boys with idiopathic ASD. Notably, there was variation in vocabulary abilities and profiles in both groups. Although we did not identify predictors of receptive-expressive differences, we demonstrated that nonverbal IQ and expressive vocabulary positively predicted concurrent receptive vocabulary knowledge and receptive vocabulary predicted expressive vocabulary. We discuss areas of overlap and divergence in subgroups of ASD.

Noncomprehension Signaling in Males and Females With Fragile X Syndrome

Purpose

This study used a prospective longitudinal design to evaluate the trajectory and predictors of noncomprehension signaling in male and female youth with fragile X syndrome (FXS).

Method

A direction-following task in which some of the directions were inadequate was administered. Participants were 52 youth (36 boys, 16 girls) with FXS. Upon study entry, participants ranged from 10 to 16 years. The average number of annual assessments per participant was 3.65 (range = 1-4), providing 198 data points for analysis.

Results

Participants with FXS were less likely to signal noncomprehension than younger, typically developing, cognitively matched children. The average rate of change in noncomprehension signaling was not significantly different from 0 for either boys or girls, suggesting a plateau. Both FMRP and nonverbal IQ were significant independent predictors of noncomprehension signaling for boys. Variability in noncomprehension signaling among girls was not explained by any of the predictors, but trends similar to those observed for boys were observed.

Conclusions

Noncomprehension signaling appears to be an area of weakness for individuals with FXS. Because the failure to signal noncomprehension can have negative, cumulative effects on comprehension, the results suggest a need for interventions targeting the requisite cognitive skills.

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.

Habituation is altered in neuropsychiatric disorders-A comprehensive review with recommendations for experimental design and analysis

Abnormalities in the simplest form of learning, habituation, have been reported in a variety of neuropsychiatric disorders as etiologically diverse as Autism Spectrum Disorder, Fragile X syndrome, Schizophrenia, Parkinson's Disease, Huntington's Disease, Attention Deficit Hyperactivity Disorder, Tourette's Syndrome, and Migraine. Here we provide the first comprehensive review of what is known about alterations in this form of non-associative learning in each disorder. Across several disorders, abnormal habituation is predictive of symptom severity, highlighting the clinical significance of habituation and its importance to normal cognitive function. Abnormal habituation is discussed within the greater framework of learning theory and how it may relate to disease phenotype either as a cause, symptom, or therapy. Important considerations for the design and interpretation of habituation experiments are outlined with the hope that these will aid both clinicians and basic researchers investigating how this simple form of learning is altered in disease.

Management of swallowing and communication difficulties in Down syndrome: A survey of speech-language pathologists

PURPOSE

To explore speech pathology services for people with Down syndrome across the lifespan.

METHOD

Speech-language pathologists (SLPs) working in Australia were invited to complete an online survey, which enquired about the speech pathology services they had provided to client/s with Down syndrome in the past 12 months. The data were analysed using descriptive statistics.

RESULT

A total of 390 SLPs completed the survey; 62% reported seeing a client with Down syndrome in the past 12 months. Most commonly, SLPs provided assessment and individual intervention for communication with varying levels of family involvement. The areas of dysphagia and/or communication addressed by SLPs, or in need of more services differed according to the age of the person with Down syndrome. SLPs reported a number of reasons why services were restricted.

CONCLUSION

There is a need to re-assess the way that SLPs currently provide services to people with Down syndrome. More research is needed to develop and evaluate treatment approaches that can be used to better address the needs of this population.

Matrix metalloproteinase-9 deletion rescues auditory evoked potential habituation deficit in a mouse model of Fragile X Syndrome

Sensory processing deficits are common in autism spectrum disorders, but the underlying mechanisms are unclear. Fragile X Syndrome (FXS) is a leading genetic cause of intellectual disability and autism. Electrophysiological responses in humans with FXS show reduced habituation with sound repetition and this deficit may underlie auditory hypersensitivity in FXS. Our previous study in Fmr1 knockout (KO) mice revealed an unusually long state of increased sound-driven excitability in auditory cortical neurons suggesting that cortical responses to repeated sounds may exhibit abnormal habituation as in humans with FXS. Here, we tested this prediction by comparing cortical event related potentials (ERP) recorded from wildtype (WT) and Fmr1 KO mice. We report a repetition-rate dependent reduction in habituation of N1 amplitude in Fmr1 KO mice and show that matrix metalloproteinase-9 (MMP-9), one of the known FMRP targets, contributes to the reduced ERP habituation. Our studies demonstrate a significant up-regulation of MMP-9 levels in the auditory cortex of adult Fmr1 KO mice, whereas a genetic deletion of Mmp-9 reverses ERP habituation deficits in Fmr1 KO mice. Although the N1 amplitude of Mmp-9/Fmr1 DKO recordings was larger than WT and KO recordings, the habituation of ERPs in Mmp-9/Fmr1 DKO mice is similar to WT mice implicating MMP-9 as a potential target for reversing sensory processing deficits in FXS. Together these data establish ERP habituation as a translation relevant, physiological pre-clinical marker of auditory processing deficits in FXS and suggest that abnormal MMP-9 regulation is a mechanism underlying auditory hypersensitivity in FXS.

SIGNIFICANCE

Fragile X Syndrome (FXS) is the leading known genetic cause of autism spectrum disorders. Individuals with FXS show symptoms of auditory hypersensitivity. These symptoms may arise due to sustained neural responses to repeated sounds, but the underlying mechanisms remain unclear. For the first time, this study shows deficits in habituation of neural responses to repeated sounds in the Fmr1 KO mice as seen in humans with FXS. We also report an abnormally high level of matrix metalloprotease-9 (MMP-9) in the auditory cortex of Fmr1 KO mice and that deletion of Mmp-9 from Fmr1 KO mice reverses habituation deficits. These data provide a translation relevant electrophysiological biomarker for sensory deficits in FXS and implicate MMP-9 as a target for drug discovery.

Symptoms of Autism in Males with Fragile X Syndrome: A Comparison to Nonsyndromic ASD Using Current ADI-R Scores

Symptoms of autism are frequent in males with fragile X syndrome (FXS), but it is not clear whether symptom profiles differ from those of nonsyndromic ASD. Using individual item scores from the Autism Diagnostic Inventory-Revised, we examined which current symptoms of autism differed in boys with FXS relative to same-aged boys diagnosed with nonsyndromic ASD. In addition, different subsamples of participants were matched on autism diagnostic status and severity of autism symptoms. Between-group comparisons revealed that boys with FXS showed significantly less impairment in Social Smiling than did age-, diagnostic-, and severity-matched boys with nonsyndromic ASD. Severity-matched boys with FXS showed more impairment in complex mannerisms than did boys with nonsyndromic ASD. Behavioral differences between FXS and nonsyndromic ASD may be of theoretical importance in understanding the causes and correlates of ASD in FXS and in developing and implementing appropriate treatments.

Adaptive behaviour of Chinese boys with fragile X syndrome

BACKGROUND

Adaptive behaviour is closely related to quality of life in children with intellectual disability (ID), but little is known about the adaptive behaviour of children with fragile X syndrome (FXS) in China.

METHOD

In boys with FXS, the adaptive behaviours in six domains, including self-dependence, locomotion, work skills, communication, socialisation and self-management, were assessed by the Infants-Junior Middle School Students Social-life Abilities Scale. In addition, we compared the adaptive skills of boys with FXS to those of three control groups of boys, including boys with Down syndrome (DS) and typically developing (TD) boys matched by chronological age (CA) or mental age (MA). The profile of the adaptive behaviour of boys with FXS is discussed in detail.

RESULTS

Compared to boys with DS, boys with FXS obtained lower scores in three domains in adaptive behaviour, including work skills, socialisation and self-management skills; boys with FXS had better scores in self-dependence and locomotion skills than boys matched for MA; as expected, boys with FXS had significantly poorer adaptive skills in all six domains assessed compared to CA boys.

CONCLUSION

The development of adaptive skills in boys with FXS was worse than that of boys with DS. The profile of the adaptive behaviour of boys with FXS establishes a basis for the development of targeted interventions to promote social development in this population.

Speech production in children with Down's syndrome: The effects of reading, naming and imitation

People with DS are known to have difficulties with expressive language, and often have difficulties with intelligibility. They often have stronger visual than verbal short-term memory skills and, therefore, reading has often been suggested as an intervention for speech and language in this population. However, there is as yet no firm evidence that reading can improve speech outcomes. This study aimed to compare reading, picture naming and repetition for the same 10 words, to identify if the speech of eight children with DS (aged 11-14 years) was more accurate, consistent and intelligible when reading. Results show that children were slightly, yet significantly, more accurate and intelligible when they read words compared with when they produced those words in naming or imitation conditions although the reduction in inconsistency was non-significant. The results of this small-scale study provide tentative support for previous claims about the benefits of reading for children with DS. The mechanisms behind a facilitatory effect of reading are considered, and directions are identified for future research.

Auditory processing in fragile x syndrome

Fragile X syndrome (FXS) is an inherited form of intellectual disability and autism. Among other symptoms, FXS patients demonstrate abnormalities in sensory processing and communication. Clinical, behavioral, and electrophysiological studies consistently show auditory hypersensitivity in humans with FXS. Consistent with observations in humans, the Fmr1 KO mouse model of FXS also shows evidence of altered auditory processing and communication deficiencies. A well-known and commonly used phenotype in pre-clinical studies of FXS is audiogenic seizures. In addition, increased acoustic startle response is seen in the Fmr1 KO mice. In vivo electrophysiological recordings indicate hyper-excitable responses, broader frequency tuning, and abnormal spectrotemporal processing in primary auditory cortex of Fmr1 KO mice. Thus, auditory hyper-excitability is a robust, reliable, and translatable biomarker in Fmr1 KO mice. Abnormal auditory evoked responses have been used as outcome measures to test therapeutics in FXS patients. Given that similarly abnormal responses are present in Fmr1 KO mice suggests that cellular mechanisms can be addressed. Sensory cortical deficits are relatively more tractable from a mechanistic perspective than more complex social behaviors that are typically studied in autism and FXS. The focus of this review is to bring together clinical, functional, and structural studies in humans with electrophysiological and behavioral studies in mice to make the case that auditory hypersensitivity provides a unique opportunity to integrate molecular, cellular, circuit level studies with behavioral outcomes in the search for therapeutics for FXS and other autism spectrum disorders.

Matching variables for research involving youth with Down syndrome: Leiter-R versus PPVT-4

Much of what is known about the cognitive profile of Down syndrome (DS) is based on using either receptive vocabulary (e.g., PPTV-4) or nonverbal ability (e.g., Leiter-R) as a baseline to represent cognitive developmental level. In the present study, we examined the relation between these two measures in youth with DS, with non-DS intellectual disability (ID), and with typical development (TD). We also examined the degree to which these two measures produce similar results when used as a group matching variable. In a cross-sectional developmental trajectory analysis, we found that the relation between PPVT-4 and Leiter-R was largely similar across groups. However, when contrasting PPVT-4 and Leiter-R as alternate matching variables, the pattern of results was not always the same. When matched on Leiter-R or PPVT-4, the group with DS performed below that of the groups with ID and TD on receptive grammar and below the group with TD on category learning. When matched on the PPVT-4, the group with ID performed below that of the group with TD on receptive grammar and category learning, but these differences between the groups with ID and TD were not found when matched on the Leiter-R. The results of the study suggest that the PPVT-4 and Leiter-R are interchangeable at least for some outcome measures for comparing youth with DS and TD, but they may produce different results when comparing youth with ID and TD.

Effect of sustained maternal responsivity on later vocabulary development in children with fragile X syndrome

PURPOSE

This research explored whether sustained maternal responsivity (a parent–child interaction style characterized by warmth, nurturance, and stability as well as specific behaviors, such as contingent positive responses to child initiations) was a significant variable predicting vocabulary development of children with fragile X syndrome through age 9 years.

METHOD

Fifty-five mother–child dyads were followed longitudinally when children were between 2 and 10 years of age. Measures of maternal responsivity and child vocabulary were obtained at regular intervals starting at age 2.9 years. Sustained responsivity was indicated by the average responsivity measured over Observations 2–5. Responsivity at the 1st time period, autism symptoms, and cognitive development were used as control variables.

RESULTS

After controlling for development and autism symptoms, the authors found significant effects for sustained responsivity on receptive vocabulary, expressive vocabulary, and the rate of different words children produced through age 9.

CONCLUSIONS

Maternal responsivity, which is typically a variable of interest during early childhood, continues to be a significant variable, predicting vocabulary development through the middle childhood period. Thus, responsivity is a potential target for language interventions through this age period.

The use of nouns and verbs by children with Down syndrome in two different situations

PURPOSE

To verify the use of nouns and verbs by children with Down syndrome and to compare this use between conditions of interaction with the mother and the Speech-language pathologist (SLP).

METHODS

Participants were 21 children aged between 5 and 11 years, divided into three groups, according to chronological and mental age as established by the results of the Primary Tests of Nonverbal Intelligence. The speech sample was obtained through free interaction situations that were videotaped during session of 30 minutes and transcribed in specific protocols. The first 100 utterances from the first five minutes were used. The interval between each situation ranged from 7 to 15 days. T-test and analysis of variance were used for statistical analysis and the significance level adopted was of 5%.

RESULTS

More verbs than nouns were used in both conditions; however, a higher number of nouns were observed during the interaction with the SLP. The between-group comparison in the interaction with the SLP shows significant differences for verbs and nouns, but during the interaction with the mother, there was tendency for difference only for the verbs.

CONCLUSION

The data indicate the growing development on using of nouns and verbs according to the increase of age. There was a higher use of verbs when compared with nouns mainly in the condition of interaction with the SLP.

Early grammatical development in Spanish children with Down syndrome

The objective of this work was to analyze morphosyntactic development in a wide sample of children with Down syndrome (DS) (n = 92) and children with typical development (TD) (n = 92) with a mental age (MA) of 20 to 29 months. Children were individually matched for gender and MA (Analysis 1) and for vocabulary size (Analysis 2). Information about morphosyntax was obtained using an adaptation of the CDI for children with DS. In both analyses, the number of children with DS and with TD who combined words was similar. Analysis 1 showed that children with DS produced shorter utterances, with less morphosyntactic complexity and less morphological suffixes than children with TD, despite having the same mental age. The developmental pattern was similar, although slower in children with DS. Analysis 2 showed that the performance of children with DS was lower than the performance of children with TD in relation to morphosyntactic complexity and morphological suffixes.

Investigating word learning in fragile X syndrome: a fast-mapping study

Fast-mapping paradigms have not been used previously to examine the process of word learning in boys with fragile X syndrome (FXS), who are likely to have intellectual impairment, language delays, and symptoms of autism. In this study, a fast-mapping task was used to investigate associative word learning in 4- to 10-year-old boys with FXS relative to younger typically developing boys and age-matched boys with autism spectrum disorders (ASD). Task performance exceeded chance levels for all groups; however, boys with FXS outperformed boys with ASD, despite having lower levels of nonverbal cognition. Memory task demands significantly impacted performance only for boys with typical development. For boys with FXS or ASD, fast-mapping uniquely accounted for small but significant variance in concurrent levels of vocabulary comprehension as did chronological age and nonverbal IQ, but not autism severity. Understanding the fast-mapping process has implications for designing interventions to support word learning and language acquisition in these populations.

Longitudinal profiles of expressive vocabulary, syntax and pragmatic language in boys with fragile X syndrome or Down syndrome

BACKGROUND

Fragile X syndrome (FXS) and Down syndrome (DS) are the two leading genetic causes of intellectual disability, and FXS is the most common known genetic condition associated with autism. Both FXS and DS are associated with significant language impairment, but little is known about expressive language across domains over time or the role of autism in language development in FXS.

AIMS

To compare three domains of language production (vocabulary, syntax, pragmatics) over time within and across groups of boys with FXS with and without autism spectrum disorder (FXS-ASD, FXS-O), boys with DS, and typically developing (TD) boys.

METHODS & PROCEDURES

Twenty-nine boys with FXS-O, 40 boys with FXS-ASD, 34 boys with DS, and 48 younger TD boys of similar non-verbal mental age living in the United States participated in the study. The Antonyms, Syntax Construction and Pragmatic Judgment subtests of the Comprehensive Assessment of Spoken Language were administered annually over 3 years.

OUTCOMES & RESULTS

TD boys scored higher than all other groups on all three subtests; boys with FXS-O and FXS-ASD scored higher than boys with DS in Syntax Construction; and boys with FXS-O scored higher than boys with FXS-ASD in Pragmatic Judgment. Within-group patterns varied between groups. Overall, the TD group showed significantly more change over time than all other groups.

CONCLUSIONS & IMPLICATIONS

Findings suggest that expressive language skills and growth across various domains are more impaired in boys with FXS and DS than would be expected based on non-verbal mental age, that for boys with DS syntax is more impaired than would be expected based on intellectual disability, and that autism status affects pragmatic language in boys with FXS. Findings suggest that language production across domains should be addressed during assessment and intervention for boys with FXS and boys with DS, with differing group profiles also suggesting potentially different areas of focus.

Cognitive flexibility among individuals with Down syndrome: assessing the influence of verbal and nonverbal abilities

The influences of verbal mental age (VMA) and performance mental age (PMA) on cognitive flexibility were examined among a group of participants with Down syndrome (DS), in order to disentangle the relative contributions of each. The impaired cognitive flexibility typically observed among individuals with DS in combination with uneven VMA and PMA development suggests an opportunity to further understand the developmental relationship between VMA, PMA, and cognitive flexibility. We examined the performance of 22 participants with DS on the Flexible Item Selection Task (FIST), used for measuring cognitive flexibility among preschoolers. Partial correlations revealed that only VMA was related to the FIST after controlling for PMA, highlighting the role of verbal abilities in the development of cognitive flexibility.

An investigation of narrative ability in boys with autism and fragile X syndrome

Whereas pragmatic language difficulties are characteristic of both autism and Fragile X syndrome, it is unclear whether such deficits are qualitatively similar or whether certain skills are differentially affected. This study compared narrative competence in boys with autism, Fragile X syndrome, Down syndrome, and typical development. Results revealed that an interaction between diagnosis and nonverbal mental age predicted narrative microstructure (e.g., complex syntax) but not macrostructure (e.g., thematic maintenance). Correlations with FMR1-related variation were investigated in children with Fragile X syndrome. While CGG repeat length was associated with many language characteristics, nonverbal IQ appeared to mediate these relationships. These findings are an important step toward understanding narrative abilities in boys with and without the FMR1 mutation.

Discriminating Down Syndrome and Fragile X syndrome based on language ability

ABSTRACT This study compared the receptive and expressive language profiles of verbally expressive children and adolescents with Down Syndrome (DS) and those with Fragile X syndrome (FXS) and examined the extent to which these profiles reliably differentiate the diagnostic groups. A total of twenty-four verbal participants with DS (mean age: 12 years), twenty-two verbal participants with FXS (mean age: 12 years), and twenty-seven participants with typical development (TD; mean age = 4 years) completed standardized measures of receptive and expressive vocabulary and grammar, as well as a conversational language sample. Study results indicate that there are distinct DS and FXS language profiles, which are characterized by differences in grammatical ability. The diagnostic groups were not differentiated based on vocabulary performance. This study supports the existence of unique language profiles associated with DS and FXS.

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

PURPOSE

To examine which cognitive, environmental, and speech-language variables predict expressive syntax in boys with fragile X syndrome (FXS), boys with Down syndrome (DS), and typically developing (TD) boys, and whether predictive relationships differed by group.

METHOD

We obtained Index of Productive Syntax ( Scarborough, 1990) scores for 18 boys with FXS only, 20 boys with both FXS and an autism spectrum disorder, 27 boys with DS, and 25 younger TD boys of similar nonverbal mental age. Predictors included group (diagnosis), nonverbal cognition, phonological working memory (PWM), maternal education, speech intelligibility, and expressive vocabulary. The research questions were addressed via hierarchical linear regression.

RESULTS

Diagnostic group, nonverbal cognition, and PWM predicted 56% of the variance in syntactic ability, with approximately three-fourths of the predicted variance explained by group membership alone. The other factors did not contribute any additional significant variance in this final model. There was no evidence that predictor effects differed by group.

CONCLUSIONS

Nonverbal cognition and PWM have an effect on expressive syntax beyond that of diagnostic group. These effects are estimated to be the same in boys with FXS, boys with DS, and TD boys. Explanations for residual variance and the relative role of different predictors are discussed.

Language development in school-age girls with fragile X syndrome

BACKGROUND

Girls with fragile X syndrome (FXS) have a wide range of cognitive and language abilities. The range of language outcomes experienced by girls with FXS, however, has been relatively unexplored. The purpose of this exploratory study was to examine receptive and expressive language, with a focus on vocabulary and syntax, in a group of school-age girls with FXS.

METHOD

Twenty-one girls with FXS aged 7-15 years participated in the study. The girls completed a receptive vocabulary test, non-verbal IQ test and an expressive language sample.

RESULTS

The mean IQ for this group of girls was at the cut-off for intellectual disability. Vocabulary was an area of strength relative to non-verbal cognition. Age and non-verbal IQ were significant predictors of vocabulary performance.

CONCLUSIONS

The data suggest that a substantial portion of the sample would qualify for speech and language services. This study highlights the need for continued research in the area of language and cognitive development in girls with the full mutation of fragile X.

Perseveration in the connected speech of boys with Fragile X syndrome with and without autism spectrum disorder

Verbal perseveration is a frequently reported language characteristic of males with Fragile X syndrome and may be a defining feature or hallmark of the syndrome. We compared the verbal perseveration of boys with Fragile X syndrome with (n  =  29) and without (n  =  30) autism spectrum disorder, boys with Down syndrome (n  =  27), and typically developing boys (n  =  25) at similar nonverbal mental ages. During a social interaction, boys with both Fragile X syndrome and autism spectrum disorder produced significantly more topic perseveration than all other groups. In social interaction as compared to narration, boys with Fragile X syndrome (regardless of autism status) produced significantly more topic perseveration. These findings suggest that autism status, as well as language sampling context, affect perseveration in boys with Fragile X syndrome.

Social communication and theory of mind in boys with autism and fragile x syndrome

Impairments in the social use of language, or pragmatics, constitute a core characteristic of autism. Problems with pragmatic language have also been documented in fragile X syndrome (FXS), a monogenic condition that is the most common known genetic cause of autism. Evidence suggests that social cognitive ability, or theory of mind, may also be impaired in both conditions, and in autism, may importantly relate to pragmatic language ability. Given the substantial overlap observed in autism and FXS, this study aimed to better define those social-communicative phenotypes that overlap in these two conditions by comparing pragmatic language ability and theory of mind in children with idiopathic autism and children with FXS, with and without autism, as well as children with Down syndrome and typically developing controls. We further examined correlations between these cognitive-behavioral phenotypes and molecular genetic variation related to the Fragile X Mental Retardation-1 gene (FMR1) in the FXS group. Results indicated that children with idiopathic autism and those with FXS and autism performed comparably on direct-assessment measures of pragmatic language and theory of mind, whereas those with FXS only did not differ from controls. Theory of mind was related to pragmatic language ability in all groups. Pragmatic language and theory of mind also correlated with genetic variation at the FMR1 locus (Cytosine-Guanine-Guanine repeats and percent methylation). These results point toward substantial overlap in the social and language phenotypes in autism and FXS and suggest a molecular genetic basis to these phenotypic profiles.

Effects of sampling context on spontaneous expressive language in males with fragile X syndrome or Down syndrome

PURPOSE

In this study, the authors examined the impact of sampling context on multiple aspects of expressive language in male participants with fragile X syndrome in comparison to male participants with Down syndrome or typical development.

METHOD

Participants with fragile X syndrome ( n = 27), ages 10-17 years, were matched groupwise on nonverbal mental age to adolescents with Down syndrome ( n = 15) and typically developing 3- to 6-year-olds ( n = 15). Language sampling contexts were an interview-style conversation and narration of a wordless book, with scripted examiner behavior. Language was assessed in terms of amount of talk, mean length of communication unit (MLCU), lexical diversity, fluency, and intelligibility.

RESULTS

Participants with fragile X syndrome had lower MLCU and lexical diversity than did participants with typical development. Participants with Down syndrome produced yet lower MLCU. A differential effect of context among those with fragile X syndrome, Down syndrome, and typical development emerged for the number of attempts per minute, MLCU, and fluency. For participants with fragile X syndrome, autism symptom severity related to the number of utterances produced in conversation. Aspects of examiner behavior related to participant performance.

CONCLUSION

Sampling context characteristics should be considered when assessing expressive language in individuals with neurodevelopmental disabilities.

Profiles of receptive and expressive language abilities in boys with comorbid fragile X syndrome and autism

Abstract The authors examined receptive and expressive language profiles for a group of verbal male children and adolescents who had fragile X syndrome along with varying degrees of autism symptoms. A categorical approach for assigning autism diagnostic classification, based on the combined use of the Autism Diagnostic Interview-Revised and the Autism Diagnostic Observation Schedule (ADOS), and a continuous approach for representing autism symptom severity, based on ADOS severity scores, were used in 2 separate sets of analyses. All analyses controlled for nonverbal IQ and chronological age. Nonverbal IQ accounted for significant variance in all language outcomes with large effect sizes. Results of the categorical analyses failed to reveal an effect of diagnostic group (fragile X syndrome-autism, fragile X syndrome-no autism) on standardized language test performance. Results of the continuous analyses revealed a negative relationship between autism symptom severity and all of the standardized language measures. Implications for representing autism symptoms in fragile X syndrome research are considered.

Exploring the zebra finch Taeniopygia guttata as a novel animal model for the speech-language deficit of fragile X syndrome

Fragile X syndrome (FXS) is the most common cause of inherited intellectual disability and presents with markedly atypical speech-language, likely due to impaired vocal learning. Although current models have been useful for studies of some aspects of FXS, zebra finch is the only tractable lab model for vocal learning. The neural circuits for vocal learning in the zebra finch have clear relationships to the pathways in the human brain that may be affected in FXS. Further, finch vocal learning may be quantified using software designed specifically for this purpose. Knockdown of the zebra finch FMR1 gene may ultimately enable novel tests of therapies that are modality-specific, using drugs or even social strategies, to ameliorate deficits in vocal development and function. In this chapter, we describe the utility of the zebra finch model and present a hypothesis for the role of FMRP in the developing neural circuitry for vocalization.

Language and verbal short-term memory skills in children with Down syndrome: a meta-analytic review

This study presents a meta-analytic review of language and verbal short-term memory skills in children with Down syndrome. The study examines the profile of strengths and weaknesses in children with Down syndrome compared to typically developing children matched for nonverbal mental age. The findings show that children with Down syndrome have broad language deficits (that are not restricted to measures of expressive language) and associated verbal short-term memory deficits. The profile of language skills in children with Down syndrome shows similarities to that seen in children with Specific Language Impairment. The practical and theoretical implications of these findings are discussed.

Functional magnetic resonance imaging of cognitive processing in young adults with Down syndrome

The authors used functional magnetic resonance imaging (fMRI) to investigate neural activation during a semantic-classification/object-recognition task in 13 persons with Down syndrome and 12 typically developing control participants (age range  =  12-26 years). A comparison between groups suggested atypical patterns of brain activation for the individuals with Down syndrome. Correlation analyses between an index of visual spatial ability and brain activation depicted a positive relationship between (a) this index and brain activation in regions of the occipital and parietal lobes for the typically developing individuals and (b) the middle and dorsal frontal gyri in the individuals with Down syndrome. These findings supported the authors' hypothesis that persons with Down syndrome demonstrate atypical neural activation compared with typically developing individuals matched for chronological age.

The development of vocabulary in Spanish children with Down syndrome: comprehension, production, and gestures

BACKGROUND

Our main purpose was to compare the lexical development of Spanish children with Down syndrome (DS) and children with typical development (TD) to investigate the relationship between cognitive and vocabulary development in comprehension and oral and gestural production.

METHOD

Participants were 186 children with DS and 186 children with TD, with a mental age (MA) of 8-29 months and matched on gender and MA. Information about vocabulary was obtained using a new Spanish adaptation of the MacArthur-Bates CDI for children with DS.

RESULTS

No significant differences in oral production were found. Lexical comprehension and gestural production of children with DS were superior. Similar to children with TD, gestural production in children with DS decreased as oral production increased.

CONCLUSION

Our study provides evidence to support that lexical comprehension and gesture production are strengths in children with DS. With respect to oral production, our results do not support a specific dissociation between cognitive and lexical development.