Language development in school-age girls with fragile X syndrome

Language Skills Influence Transition Planning in Adolescents With Fragile X Syndrome

Individuals with fragile X syndrome (FXS) and their parents have a range of experiences navigating the crucial transition period between adolescence and adulthood. Semistructured interviews of 47 mothers of adolescents with FXS (mean child age = 15.89 years) were analyzed to identify mothers' changing expectations during the adolescent period and parent goals related to work and postsecondary education. Mothers' work and education goals were explored in relation to child factors such as language skills and autism characteristics. Lower language skills were associated with lower likelihood of reporting vocational goals. Results suggest that adolescents with FXS with lower language ability are less likely to have vocational plans for adulthood during this critical period and may need greater transition planning assistance.

Comparison of Linguistic Error Production in Conversational Language Among Boys With Fragile X Syndrome + Autism Spectrum Disorder and Autistic Boys

PURPOSE

Expressive language impairments are common among school-age boys with fragile X syndrome (FXS) and autistic boys. Given the high co-occurrence of autism spectrum disorder (ASD) among individuals with FXS, cross-condition comparisons can elucidate the specificity of such impairments as they relate to ASD. Language samples can provide fruitful information regarding individuals' grammatical skills in less structured formats relative to standardized measures. This study examined grammatical errors produced during a conversational language sample among 20 boys with FXS and co-occurring ASD (FXS + ASD) and 19 autistic boys matched on ASD severity.

METHOD

Language samples were coded for omissions and errors at the word and utterance levels. Participants' grammatical errors were also compared to separate mental age-matched and mean length of utterance-matched boys from a reference database.

RESULTS

Boys with FXS + ASD and autistic boys produced similar rates of errors across all categories. Relative to their matched comparison groups, boys with FXS + ASD and autistic boys produced significantly more omissions during conversation.

CONCLUSIONS

These findings suggest that omissions may be a unique grammatical marker associated with the ASD phenotype. Further examination of omissions across diagnostic groups would aid in clarifying the specificity of omissions in the language phenotype of ASD.

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.

Language in young females with fragile X syndrome: Influence on the neurocognitive profile and adaptive behavior

Fragile X syndrome (FXS) is the leading cause of inherited intellectual disability. The objective of this research is to analyze the relationship between linguistic functions and performance of the following neuropsychological functions: executive, quantitative reasoning, social perception, behavior, social skills, and adaptive behavior. A neuropsychological and behavioral evaluations were carried out with a group of 26 girls with FXS, and 14 girls without FXS as a control group, using standardized tests. The two groups were homogeneous in age and IQ. Significant differences were found between groups in the relationship between some language processes: inhibition, auditory working memory, cognitive flexibility, level of social adaptation, self-direction, conceptual adaptation, academic skills, leadership ability, theory of mind, and arithmetic. In the group of girls with FXS, it was found that different aspects of language influence some of the executive functions evaluated, in addition to some specific aspects of social perception, adaptive behavior, and quantitative reasoning, in different ways. Future research should incorporate the study of the influence of other cognitive variables such as visual perception and executive function on behavioral, social, and adaptive aspects to know the real influence of all the cognitive variables on the behavior of girls with FXS.

Language Development From Early Childhood to Adolescence in Youths With Fragile X Syndrome

Purpose The aim of this study was to investigate language growth in individuals with fragile X syndrome (FXS) from early childhood to adolescence and the influence of maternal responsivity on language growth. Method We conducted a longitudinal analysis of language development in 55 youths (44 males, 11 females) with FXS. Data collection spanned the ages of 11-216 months. We measured expressive and receptive vocabulary with standardized tests. The number of different words and mean length of utterance were obtained from language sample analyses of mother-child interactions. We also measured maternal comments (responsivity indicator) produced during the language samples and child nonverbal IQ. Results Growth models indicated that rates of number of different words and receptive vocabulary were related to maternal commenting. Mean length of utterance did not change significantly over time. Expressive vocabulary measured with a standardized test grew, but the growth was not related to maternal commenting. Nonverbal IQ was related to all language outcomes at age of 10 years and to changes over time in vocabulary. Visual analysis indicated that the highest scores on standardized tests were produced by girls; however, measures derived from language sample analyses appeared similar for boys and girls. Language models for boys only were similar to the total sample models with lower scores at age of 10 years for some outcomes. Conclusion Results of persistent language impairments for most youths with FXS suggest the need for continued, focused interventions aimed at improved language productions in addition to a responsive environment. Supplemental Material https://doi.org/10.23641/asha.13022825.

Development of Neural Response to Novel Sounds in Fragile X Syndrome: Potential Biomarkers

Auditory processing abnormalities in fragile X syndrome (FXS) may contribute to difficulties with language development, pattern identification, and contextual updating. Participants with FXS (N = 41) and controls (N = 27) underwent auditory event-related potentials during presentation of an oddball paradigm. Data was adequate for analysis for 33 participants with FXS and 27 controls (age 4-51 y, 13 females [FXS]; 4-54 y, 11 females [control]). Participants with FXS showed larger N1 and P2 amplitudes, abnormal lack of modulation of P1 and P2 amplitudes and P2 latency in response to oddball stimuli ) relative to controls: Females with FXS were more similar to controls. Participants with FXS showed a marginal speeding of the P2 latency, suggesting potentiation to oddball stimuli rather than habituation. Participants with FXS showed a heightened N1 habituation effect compared to controls. Gamma power was significantly higher for participants with FXS. Groups did not differ on mismatch negativity. Both controls and participants with FXS showed similar developmental trajectories in P1 and N1 amplitude, P2 latency, and gamma power, but not for P2 amplitude. One month retest analyses performed in 14 participants suggest strong test-retest reliability for most measures. Individuals with FXS show previously demonstrated increased response amplitude and high frequency neural activity. Despite an overall normal developmental trajectory for most measures, individuals with FXS show age-independent but gender-dependent decreases in complex processing of novel stimuli. Many markers show strong retest reliability even in children and thus are potential biomarkers for clinical trials in FXS.

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.

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

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

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.

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.

Vocabulary comprehension in adults with fragile X syndrome (FXS)

BACKGROUND

Receptive and expressive vocabulary in adult and adolescent males with fragile X syndrome (FXS) have been shown as significantly lower than their chronological age; however, receptive vocabulary has been considered a strength relative to mental age. This has not been formally examined, however, and data are needed to compare receptive vocabulary with other language skills and with mental age in individuals with FXS. This is especially important as vocabulary measures are sometimes used as a proxy to estimate language ability.

METHODS

This preliminary study examined receptive vocabulary, global language, and cognitive skills in 42 adults (33 males and 9 females) with FXS as a portion of the baseline evaluation prior to randomization in a clinical trial of ampakine CX516. The battery of standardized tests addressed receptive vocabulary with the Peabody Picture Vocabulary Test, Third Edition (PPVT-III), receptive and expressive language (termed henceforth as global language) via the Preschool Language Scale, Fourth Edition or the Clinical Evaluation of Language Fundamentals, Third Edition, and non-verbal cognition via the Stanford-Binet Intelligence Scales, Fourth Edition (SB-IV).

RESULTS

Results showed (1) significantly higher receptive vocabulary than global language, (2) significantly better receptive vocabulary than non-verbal cognition, (3) equivalent non-verbal cognition and global language, and (4) severity of autism symptomatology was not correlated to receptive vocabulary or global language once non-verbal cognition was removed as factor. The scores from the PPVT-III did not represent the global language skills in our sample of adults with FXS.

CONCLUSIONS

Findings from this investigation strongly suggest that the PPVT-III should not be used as a screening tool for language levels or cognitive function in clinical studies since the scores from the PPVT-III were not representative of global language or non-verbal cognitive skills in adults with intellectual disabilities. This finding is critical in order to understand how to evaluate, as well as to treat, language in individuals with FXS. Development of efficient and appropriate tools to measure language, cognition, and behavior in individuals with FXS is essential.

A Description of the Educational Setting Among Individuals With Fragile X Syndrome

Children with fragile X syndrome (FXS) display wide-ranging intellectual and behavioral abilities that affect daily life. We describe the educational setting of students with FXS and assess the relationships between school setting, co-occurring conditions, and functional ability using a national survey sample ( n = 982). The majority of students with FXS in this sample have formal individualized education plans, spend part of the day outside regular classrooms, and receive modifications when in a regular classroom. Males with FXS and certain co-occurring conditions (autism, aggression, and self-injurious behavior) are more likely to spend the entire day outside regular classrooms, compared to males without these co-occurring conditions. Students who spend more time in regular classrooms are more likely to perform functional tasks without help.

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.

Maternal Responsiveness to Gestures in Children With Down Syndrome

PURPOSE

This study compared gesture use in young children with Down syndrome (DS) and typical development (TD) as well as how mothers respond to child gestures based on child age and diagnosis.

METHOD

Twenty-two mother-child dyads with DS and 22 mother-child dyads with TD participated. The child participants were between 22 and 63 months and were matched on chronological age. We coded child gesture use and whether mothers recoded child gestures (i.e., provided a verbal translation) during naturalistic interactions.

RESULTS

The children with DS used more gestures than peers with TD. After controlling for expressive language ability, the two groups were not significantly different on child gesture use. Regardless of child diagnosis, mothers recoded approximately the same percentage of child gestures. There was a significant interaction between child diagnosis and child age when predicting the percentage of maternal gesture recodes; mothers of children with DS did not demonstrate differences in the percentage of maternal gesture recodes based on child age, but there was a negative relationship between the percentage of maternal gesture recodes and child age for the children with TD.

CONCLUSIONS

Young children with DS gesture more than chronological age-matched children with TD, therefore providing numerous opportunities for caregivers to recode child gestures and support language development. Early intervention should focus on increasing parent responsiveness to child gestures earlier in life in order to provide additional word-learning opportunities for children with DS.

Genetic and maternal predictors of cognitive and behavioral trajectories in females with fragile X syndrome

Background

Fragile X syndrome (FXS) is caused by a mutation in the FMR1 gene on the X chromosome, leading to decreased levels of FMR1 protein (FMRP), which causes the array of neuropsychological impairments that define FXS. Because FXS is an X-linked condition, fewer females display FXS and females with FXS are more mildly affected than males, on average. However, there is a considerable variability in terms of severity of affectedness among females with FXS. The current study was designed to investigate potential genetic (FMRP level and ratio of affected to total chromosomes) and environmental factors (maternal psychological distress and closeness in the mother–child relationship) influencing the cognitive (fluid and crystallized intelligence) and behavioral (anxiety and withdrawal) phenotype of females with FXS.

Methods

We conducted a prospective 3-year longitudinal study of 16 females with FXS (with up to four assessments, each separated by a year) using an accelerated longitudinal design so that we had coverage of the age range of 10–15 years at study start and 13–18 at study end. We focused on both the level of functioning related to chronological age expectations (standard scores) and absolute change in skill (raw scores) over the 3-year period.

Results

At a cross-sectional level, fluid intelligence and crystallized intelligence were both predicted by a closer mother–child relationship and lower maternal psychological distress. However, only fluid intelligence was predicted by a lower ratio of affected to total chromosomes. Anxiety and withdrawal were predicted by a higher ratio of affected to total chromosomes. Withdrawal was also predicted by lower closeness in the mother–child relationship and higher maternal distress. In terms of longitudinal change, gains were observed in fluid and crystallized intelligence, whereas anxious and withdrawn behaviors remained stable over visits. Gains in fluid intelligence were solely predicted by FXS biomarkers (higher FMRP level and lower ratio of affected to total chromosomes), while gains in crystallized intelligence were not predicted by any of the biological and environmental variables.

Conclusions

Our results show that FXS biomarkers and maternal variables contribute differentially to the cognitive and behavioral features of the adolescent female with FXS. These findings can help in the design of treatment studies aimed at enhancing cognitive and behavioral abilities in the FXS population.

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.

Growth of Expressive Syntax in Children With Fragile X Syndrome

PURPOSE

This research explored syntactic growth in children with fragile X syndrome (FXS) over a 5-year period, and variability in growth in relation to autism symptoms, nonverbal cognition, maternal responsivity, and gender.

METHOD

Language samples at 4 time points from 39 children with FXS, 31 boys and 8 girls, were analyzed using the Index of Productive Syntax (Scarborough, 1990) and mean length of utterance (Brown, 1973). The degree of autism symptoms was evaluated using the Childhood Autism Rating Scale (Schopler, Reichler, & Renner, 1988) at the first time point. Maternal responsivity estimates were averaged across time points.

RESULTS

Children with FXS showed significant syntactic growth over time and a significant plateau (quadratic trend) in the later observations. Children who exhibited more autism symptoms at Time 1 had significantly lower syntactic abilities over time than children who exhibited fewer autism symptoms. Nonverbal cognition significantly predicted mean length of utterance scores but not Index of Productive Syntax scores. Maternal responsivity was not a significant predictor of syntactic outcomes. Girls with FXS generally demonstrated better expressive syntax than boys with FXS with notable individual differences.

CONCLUSION

Despite significant growth over time, expressive syntax is a vulnerable domain for children with FXS, especially for those with severe autism symptoms. Clinical implications arising from the current findings are discussed.

The impact of autism spectrum disorder symptoms on gesture use in fragile X syndrome and Down syndrome

BACKGROUND & AIMS

This study compared gesture rate and purpose in participants with Down syndrome (DS) and fragile X syndrome (FXS), and the impact of autism spectrum disorder (ASD) symptoms on each syndrome.

METHODS

Twenty individuals with fragile X syndrome and 20 individuals with Down syndrome between nine and 22 years of age participated in this study. We coded gesture rate and purpose from an autism spectrum disorder evaluation, the Autism Diagnostic Observation Schedule - Second Edition.

RESULTS

We did not find between-group differences (Down syndrome compared to fragile X syndrome) in gesture rate or purpose. Notably, as autism spectrum disorder symptoms increased, the group with Down syndrome produced a lower rate of gestures, but used gestures for the same purpose. Gesture rate did not change based on autism spectrum disorder symptoms in the participants with fragile X syndrome, but as autism spectrum disorder symptoms increased, the participants with fragile X syndrome produced a larger proportion of gestures to regulate behavior and a smaller proportion for joint attention/social interaction.

CONCLUSIONS

Overall, the amount or purpose of gestures did not differentiate individuals with Down syndrome and fragile X syndrome. However, the presence of autism spectrum disorder symptoms had a significant and unique impact on these genetic disorders. In individuals with Down syndrome, the presence of more autism spectrum disorder symptoms resulted in a reduction in the rate of gesturing, but did not change the purpose. However, in fragile X syndrome, the rate of gestures remained the same, but the purpose of those gestures changed based on autism spectrum disorder symptoms.

IMPLICATIONS

Autism spectrum disorder symptoms differentially impact gestures in Down syndrome and fragile X syndrome. Individuals with Down syndrome and more autism spectrum disorder symptoms are using gestures less frequently. Therefore, clinicians may need to consider children with Down syndrome demonstrating symptoms of autism spectrum disorder as distinctly different from children with Down syndrome and few to no symptoms of autism spectrum disorder when implementing interventions or therapy techniques. Severity of autism spectrum disorder symptoms in fragile X syndrome affects qualitative gesture use and motivation to communicate through social gestures, which may be an appropriate goal to target in children with fragile X syndrome and heightened autism spectrum disorder symptoms.

Signaling of noncomprehension in communication breakdowns in fragile X syndrome, Down syndrome, and autism spectrum disorder

The ability to indicate a failure to understand a message is a critical pragmatic (social) language skill for managing communication breakdowns and supporting successful communicative exchanges. The current study examined the ability to signal noncomprehension across different types of confusing message conditions in children and adolescents with fragile X syndrome (FXS), Down syndrome (DS), autism spectrum disorder (ASD), and typical development (TD). Controlling for nonverbal mental age and receptive vocabulary skills, youth with comorbid FXS and ASD and those with DS were less likely than TD controls to signal noncomprehension of confusing messages. Youth with FXS without ASD and those with idiopathic ASD did not differ from controls. No sex differences were detected in any group. Findings contribute to current knowledge of pragmatic profiles in different forms of genetically-based neurodevelopmental disorders associated with intellectual disability, and the role of sex in the expression of such profiles.

LEARNING OUTCOMES

Upon completion of this article, readers will have learned about: (1) the social-communicative profiles of youth with FXS, DS, and ASD, (2) the importance of signaling noncomprehension in response to a confusing message, and (3) the similarities and differences in noncomprehension signaling in youth with FXS (with and without ASD), DS, idiopathic ASD, and TD.

Language comprehension profiles of young adolescents with fragile X syndrome

PURPOSE

In this study, the authors sought to characterize the language phenotype of fragile X syndrome (FXS), focusing on the extent of impairment in receptive syntax, within-syndrome variability in those impairments in relation to gender, and the syndrome specificity of those impairments.

METHOD

The Test for Reception of Grammar, Version 2 ( Bishop, 2003), was used to examine the overall receptive syntactic skills of adolescents with FXS ( n = 35; 30 males, 5 females), adolescents with Down syndrome (DS; n = 28; 18 males, 10 females), and younger typically developing (TD) children ( n = 23; 14 males, 9 females) matched on nonverbal cognition. Performance on specific grammatical constructions and error types was examined for a subset of matched participants.

RESULTS

Participants with FXS had overall receptive syntax scores that were lower than those of the TD participants but higher than those of the participants with DS; however, there was no difference in performance between the FXS and DS groups when females were excluded. Grammatical constructions that were especially difficult for participants with FXS and those with DS were identified, especially relative clause constructions and reversible constructions requiring attention to word order encoded by syntactic features.

CONCLUSION

The current findings have implications for understanding the nature of the language learning difficulties of individuals with FXS and for language interventions.