Characterising the social interaction style of autism in young adult males with fragile X syndrome

BACKGROUND

The characterisation of autism in fragile X syndrome (FXS) has been a source of controversy due to the complexity of disentangling autism traits from common features of the FXS phenotype. Autism in FXS is significantly underdiagnosed in the community, which may be partly due to insufficient clinical description of the social interaction profile of autism within the FXS phenotype. In this study, we applied a classic framework for characterising social interaction styles in autism to a sample of young adult males with FXS and co-occurring autism to enhance understanding of how the social challenges associated with autism manifest within FXS.

METHODS

Participants were 41 males (M age = 18 years) with FXS and co-occurring autism. Interaction samples were coded for expression of predominately 'active' (characterised by a desire to make social approaches) or 'passive' (characterised by lack of initiation of social approach towards others) interaction profiles. Differences in the expression of phenotypic features of FXS, including anxiety, attention-deficit/hyperactivity disorder, cognitive, adaptive and language impairments and autism symptom severity, were examined across those with passive and active interaction styles.

RESULTS

Approximately half of the sample was classified as active and half as passive, demonstrating diversity in the social phenotype of autism associated with FXS. The two subtypes did not differ in autism severity, anxiety or attention-deficit/hyperactivity disorder symptoms or in cognitive, adaptive or language abilities.

CONCLUSIONS

This study enhances understanding of FXS-associated autism by documenting phenotypic variability in the social interaction profile in this group, with active and passive social interaction styles represented. The two social interaction styles were not associated with differential expression of common phenotypic features of FXS, suggesting similar support needs.

The FMR1 Premutation Phenotype and Mother-Youth Synchrony in Fragile X Syndrome

A subset of mothers who carry the FMR1 premutation may express a unique phenotype. The relationship between the FMR1 phenotype and mother-child interaction in families with fragile X-associated disorders has not been well characterized, despite the importance of high-quality mother-child interaction for child development. This study examined the association between the FMR1 phenotype and the quality of interactions between mothers and their adolescent/young adult sons with fragile X syndrome. Mother-youth synchrony was coded from a dyadic interaction. Maternal anxiety and depression symptoms, executive function deficits, and pragmatic language difficulties were evaluated. Results indicated that pragmatic language was associated with mother-youth synchrony. These findings highlight the importance of family-centered intervention practices for families with fragile X-associated disorders.

Prevalence and Predictors of Anxiety Disorders in Adolescent and Adult Males with Autism Spectrum Disorder and Fragile X Syndrome

Anxiety disorders affect ~ 15-20% of youths without neurodevelopmental disorders, with persons having autism spectrum disorder (ASD) and fragile X syndrome (FXS) at elevated risk for anxiety disorders. Few studies have compared rates and predictors of anxiety disorders in adolescents with FXS or ASD. This study directly compares rates, predictors, and medication of anxiety disorders between age-matched, male adolescents with FXS (n = 31) or ASD (n = 20). Results indicate that 51.6% of FXS and 50.0% of ASD adolescents met criteria for an anxiety disorder. Cognitive scores and ASD severity did not predict anxiety. Of those with anxiety, ~ 40% of the FXS and 20% of the ASD participants were prescribed medications for anxiety.

The Emergence of Effortful Control in Young Boys With Fragile X Syndrome

Effortful control, or the ability to suppress a dominant response to perform a subdominant response, is an early-emerging temperament trait that is linked with positive social-emotional development. Fragile X syndrome (FXS) is a single-gene disorder characterized by hallmark regulatory impairments, suggesting diminished effortful control. This study compared the development of effortful control in preschool boys with FXS ( n = 97) and typical development ( n = 32). Unlike their typical peers, the boys with FXS did not exhibit growth in effortful control over time, which could not be accounted for by adaptive impairments, FMR1 molecular measures, or autism symptoms. These results contribute to our understanding of the childhood phenotype of FXS that may be linked to the poor social-emotional outcomes seen in this group.

Cortisol profiles differentiated in adolescents and young adult males with fragile X syndrome versus autism spectrum disorder

BACKGROUND

Fragile X syndrome (FXS) and non-syndromic autism spectrum disorder (ASD) are distinct disorders with overlapping behavioral features. Both disorders are also highly associated with anxiety with abnormal physiological regulation implied mechanistically. Some reports suggest atypical hypothalamus-pituitary-adrenal (HPA) axis function, indexed via aberrant cortisol reactivity, in both FXS and non-syndromic ASD. However, no study has compared cortisol reactivity across these two disorders, or its relationship to ASD symptom severity.

METHODS

Cortisol reactivity (prior to and following a day of assessments) was measured in 54 adolescent/young adult males with FXS contrasted to 15 males with non-syndromic ASD who had low cognitive abilities.

RESULTS

Greater ASD symptom severity was related to increased cortisol reactivity and higher levels at the end of the day, but only in the non-syndromic ASD group. Elevated anxiety was associated with increased HPA activation in the group with FXS alone.

CONCLUSIONS

Taken together, findings suggest a unique neuroendocrine profile that distinguishes adolescent/young adult males with FXS from those with non-syndromic ASD. Severity of ASD symptoms appears to be related to cortisol reactivity in the non-syndromic ASD sample, but not in FXS; while anxiety symptoms are associated with HPA activation in the FXS sample, but not in ASD despite a high prevalence of ASD, anxiety and physiological dysregulation characteristic in both populations.

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.

Reading and phonological skills in boys with fragile X syndrome

Although reading skills are critical for the success of individuals with intellectual disabilities, literacy has received little attention in fragile X syndrome (FXS). This study examined the literacy profile of FXS. Boys with FXS (n = 51; mean age 10.2 years) and mental age-matched boys with typical development (n = 35) participated in standardized assessments of reading and phonological skills. Phonological skills were impaired in FXS, while reading was on-par with that of controls. Phonological awareness predicted reading ability and ASD severity predicted poorer phonological abilities in FXS. Boys with FXS are capable of attaining reading skills that are commensurate with developmental level and phonological awareness skills may play a critical role in reading achievement in FXS.

Phonological awareness and reading in boys with fragile X syndrome

BACKGROUND

Reading delays are well documented in children with fragile X syndrome (FXS), but few studies have examined linguistic precursors of reading in this population. This study examined the longitudinal development of phonological awareness and its relationship with basic reading in boys with FXS. Individual differences in genetic, social-behavioral and environmental factors were also investigated as predictors of phonological awareness.

METHODS

Participants included 54 boys with FXS and 53 typically developing (TD) mental age-matched peers who completed assessments of phonological awareness, nonverbal intelligence, and reading annually for up to 4 years. FMRP level and autism symptomatology were also measured within the FXS group. Hierarchical linear modeling was used to examine change in phonological awareness over time and its predictors. Linear regression was used to examine phonological awareness as a predictor of word reading.

RESULTS

Boys with FXS exhibited slower growth than TD peers in phonological awareness only when nonverbal cognitive abilities were not controlled. The rate of change in phonological awareness decreased significantly after age 10 in boys with FXS. Phonological awareness accounted for 18% unique variance in basic reading ability after controlling for nonverbal cognition, with similar relationships across groups.

CONCLUSION

Phonological awareness skills in the boys with FXS were commensurate with their nonverbal cognitive abilities, with similar relationships between phonological awareness and reading as observed in the TD mental age-matched peers. More research is needed to examine potential causal relationships between phonological awareness, other language skills, and reading abilities in individuals with FXS and other neurodevelopmental disorders.

Therapy service use among individuals with fragile X syndrome: findings from a US parent survey

BACKGROUND

Fragile X syndrome (FXS) is known to be associated with a range of developmental challenges, yet the occurrence and intensity of therapy services along with associated factors have not been determined.

METHOD

In a US national survey, caregivers provided information regarding the therapy services received by their sons (n = 1013) and daughters (n = 283) with FXS (from birth to 63 years; mean = 15.6 years, SD = 10.6). Caregivers reported (1) type, (2) amount, (3) location, and (4) overall satisfaction with services. Associations with other child variables and family income were also examined.

RESULTS

Key findings included that 72% of males and 47% of females were currently receiving at least one type of therapy service; the most common services for both males and females were speech-language therapy (ST) and occupational therapy (OT). Overall, males were more likely to receive therapy services as well as a greater number of services than females. Autism status was significantly associated with both males and females receiving ST and males receiving OT and behaviour management therapy. Therapies were provided in a variety of locations, and parents were generally satisfied with the amount and quality of therapy services. Age-related declines were evident in the use of services for both males and females, with very few individuals receiving any therapy services after 20 years of age.

CONCLUSIONS

This study provides a baseline description of the current state of therapy services for children with FXS, laying a foundation for future research and recommendations for service provision and policy.

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.

Mapping developmental trajectories of attention and working memory in fragile X syndrome: Developmental freeze or developmental change?

Fragile X syndrome (FXS) has a characteristic cognitive “signature” that by late childhood includes core weaknesses in attention and working memory (WM), but their earlier developmental trajectories remain uncharted. Using a combined cross-sectional and prospective longitudinal design, we tested whether early profiles of attention and WM impairment in FXS indicate developmental freeze or developmental change. In Study 1, 26 young boys with FXS and 55 typically developing (TD) boys completed two experimental paradigms designed to assess cognitive aspects of attention and WM, in addition to behavioral indices of inattention and hyperactivity. Study 2 mapped longitudinal changes in 21 children with FXS and 21 TD children. In Study 1, significant weaknesses emerged for boys with FXS, with no substantial improvement over chronological age. Mapping performance against mental age level revealed delay, but it also yielded a similar attention and WM profile to TD boys. In Study 2, longitudinal improvements for boys with FXS paralleled those in TD children. In conclusion, cognitive attention and WM, although delayed in FXS, reveal developmental change, rather than “arrest.” Our findings underscore the need for going beyond cross-sectional group comparisons and gross behavioral indices to map cognitive changes longitudinally in developmental disorders.

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.

A long-term open-label extension study assessing cognition and behavior, tolerability, safety, and efficacy of adjunctive levetiracetam in children aged 4 to 16 years with partial-onset seizures

The objective of this study was to assess cognition and behavior in children (4-16 years; n = 103) with partial-onset seizures using the Leiter-R International Performance Scale and Achenbach Child Behavior Checklist. The study was a multicenter, open-label, noncomparative 48-week extension study (NCT00152516) of adjunctive levetiracetam (20-100 mg/kg/d, mean 50.2 mg/kg/d). Improvement from baseline in Leiter-R Memory Screen composite score at weeks 24 and 48 (mean [SD] change, +4.8 [12.6] and +4.5 [15.3]) was similar to changes observed with levetiracetam and placebo in a prior study. Child Behavior Checklist Syndrome scores improved from baseline at weeks 24 and 48 (total problems mean [SD] change, -9.3 [22.2] and -10.4 [23.4]). Adjunctive levetiracetam was well tolerated (most frequently reported central nervous system-related treatment-emergent adverse events: headache [24.3%], aggression [7.8%], irritability [7.8%]). Of the patients, 4.9% discontinued because of treatment-emergent adverse events. Levetiracetam provided good and sustained seizure control (median percentage reduction from baseline in partial-onset seizure frequency/wk during maintenance: 86.4%); 24.7% of patients had continuous seizure freedom from all seizure types for ≥40 weeks. In children, adjunctive levetiracetam was associated with long-term stability in cognitive functioning and improvement in emotional/behavioral functioning over time.

Contributions of phonological and verbal working memory to language development in adolescents with fragile X syndrome

Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability. Although language delays are frequently observed in FXS, neither the longitudinal course of language development nor its cognitive predictors are well understood. The present study investigated whether phonological and working memory skills are predictive of growth in vocabulary and syntax in individuals with FXS during adolescence. Forty-four individuals with FXS (mean age = 12.61 years) completed assessments of phonological memory (nonword repetition and forward digit recall), verbal working memory (backward digit recall), vocabulary, syntax, and nonverbal cognition. Vocabulary and syntax skills were reassessed at a 2-year follow-up. In a series of analyses that controlled for nonverbal cognitive ability and severity of autism symptoms, the relative contributions of phonological and working memory to language change over time were investigated. These relationships were examined separately for boys and girls. In boys with FXS, phonological memory significantly predicted gains in vocabulary and syntax skills. Further, verbal working memory was uniquely associated with vocabulary gains among boys. In girls with FXS, phonological and working memory skills showed no relationship with language change across the 2-year time period. Our findings indicate that, for adolescent boys with FXS, acquisition of vocabulary and syntax may be constrained by the ability to maintain and manipulate phonological representations online. Implications for the identification and treatment of language disorders in this population are discussed. The present study is the first to identify specific cognitive mechanisms contributing to language growth over time in individuals with FXS.

Gender differences in neurodevelopmental disorders: autism and fragile x syndrome

Gender is an important factor to consider in understanding the clinical presentation, management, and developmental trajectory of children with neuropsychiatric disorders. While much is known about the clinical and neurobehavioural profiles of boys with neuropsychiatric disorders, surprisingly little is known about girls. The aim of this chapter was to review our understanding of gender by considering the most prevalent childhood onset neuropsychiatric disorders, autism and Fragile X syndrome. This chapter highlights findings which suggest that girls with autism and Fragile X syndrome show some unique differences in cognitive and clinical profiles when compared to boys with these conditions; this may indicate the need for innovative assessment and management approaches which take gender into consideration. Our understanding of how differences emerge in boys and girls with neuropsychiatric disorders is unclear, future research needs to focus on the role of biological maturation rates, sex hormones, and psychosocial factors in order to progress this field.

Memory skills of boys with fragile X syndrome

Multiple aspects of memory were examined in 42 boys with fragile X syndrome and a comparison group of 42 typically developing boys matched on MA. Working memory, incidental memory, and deliberate memory were assessed with a battery that included both free-recall and recognition tasks. Findings indicated that boys with fragile X syndrome performed more poorly than their matches on most measures. The exception was free recall, in which their accuracy was equal to that of the control participants. Results from analyses of a subset of boys with fragile X syndrome who exhibit characteristics of autism and their MA matches, though preliminary, support the conclusion that memory deficits are especially marked in boys who have fragile X syndrome and evidence autistic behaviors.

Ethical, legal, and social concerns about expanded newborn screening: fragile X syndrome as a prototype for emerging issues

Technology will make it possible to screen for fragile X syndrome and other conditions that do not meet current guidelines for routine newborn screening. This possibility evokes at least 8 broad ethical, legal, and social concerns: (1) early identification of fragile X syndrome, an "untreatable" condition, could lead to heightened anxiety about parenting, oversensitivity to development, alterations in parenting, or disrupted bonding; (2) because fragile X syndrome screening should be voluntary, informed consent could overwhelm parents with information, significantly burden hospitals, and reduce participation in the core screening program; (3) screening will identify some children who are or appear to be phenotypically normal; (4) screening might identify children with other conditions not originally targeted for screening; (5) screening could overwhelm an already limited capacity for genetic counseling and comprehensive care; (6) screening for fragile X syndrome, especially if carrier status is disclosed, increases the likelihood of negative self-concept, societal stigmatization, and insurance or employment discrimination; (7) screening will suggest risk in extended family members, raising ethical and legal issues (because they never consented to screening) and creating a communication burden for parents or expanding the scope of physician responsibility; and (8) screening for fragile X syndrome could heighten discrepancies in how men and women experience genetic risk or decide about testing. To address these concerns we recommend a national newborn screening research network; the development of models for informed decision-making; materials and approaches for helping families understand genetic information and communicating it to others; a national forum to address carrier testing and the disclosure of secondary or incidental findings; and public engagement of scientists, policy makers, ethicists, practitioners, and other citizens to discuss the desired aims of newborn screening and the characteristics of a system needed to achieve those aims.

Autistic behavior in children with fragile X syndrome: prevalence, stability, and the impact of FMRP

We examined autistic behavior in a cross-sectional sample of 179 children with fragile X syndrome (FXS) and a longitudinal subset of 116 children using the Childhood Autism Rating Scale (CARS) to (a) determine a prevalence of autistic behavior in FXS, (b) examine the stability of autistic ratings over time, and (c) assess the association between the fragile X mental retardation protein (FMRP) and autistic behavior. Approximately 21% of the sample of 129 children (25.9% of boys) scored at or above the cutoff for autism. CARS scores increased slowly, yet significantly, over time, and low levels of FMRP were associated with higher mean levels of autistic behavior as measured by the CARS.

Patterns of Nonverbal Cognitive Functioning in Young Children with Autism Spectrum Disorders

Previous research demonstrates an uneven pattern of cognitive abilities in children with autism spectrum disorders (ASDs). This study examined whether this uneven pattern exists within the nonverbal domain in young children. We hypothesized relative strengths in perceptual abilities and weaknesses in nonverbal conceptual abilities in preschoolers with ASDs compared to groups with non-autism developmental delays and typical development. Profiles were examined using the Leiter International Performance Scale-Revised. The ASD group displayed clear relative strengths in visuospatial disembedding and detail-focused processing, with relative weaknesses in abstraction and concept formation. This contrasted with patterns of roughly equivalent abilities in both comparison groups. These findings have implications for subsequent development and may represent key features of the cognitive profile of autism.

Mapping nonverbal IQ in young boys with fragile X syndrome

This study examines the developmental changes in nonverbal intellectual functioning evident in males with fragile X syndrome (FXS) measured by the Leiter International Performance Scales-Revised (Leiter-R). The Leiter-R provides both IQ scores and associated growth scores which permit the examination of both age-based IQ scores and overall intellectual growth. Participants were 45 males with full mutation FXS and ranged in age from 4.0 to 13.8 years. Each child was assessed annually using the Leiter-R as part of a larger longitudinal battery for an average of 3.5 assessments per child and a range of 2-6 assessments, representing a total of 156 assessment occasions. Longitudinal analyzes of Leiter scores consisted primarily of hierarchical linear modeling, with the impact of chronological age, maternal education, fragile X mental retardation 1 protein (FMRP), autistic behaviors also being assessed. Findings revealed a significant linear decline in nonverbal IQ scores, with no effects of maternal education, autistic behaviors, or FMRP on mean level or rate of change in IQ scores over time. The decline slowed significantly around 8 years of age, but scores continued to decline into the 12th year of age. In contrast, a significant linear increase was observed in Leiter-R growth scores, which was negatively influenced by autistic behaviors. The rate of increase did not change over time, and neither mean level nor rate of increase was influenced by maternal education or FMRP levels. These findings suggest that declines in IQ are the result of steady, but suboptimal intellectual growth, rather than a true deterioration in overall intellectual functioning.

Performance of young people with Down syndrome on the Leiter-R and British picture vocabulary scales

BACKGROUND

The British picture vocabulary scales (BPVS-II) and the Leiter international performance scales (Leiter-R), both restandardised in 1997, are often used in experimental studies to match individuals with intellectual impairment. Both provide a brief measure of mental age, and cover a wide ability range using a simple format. The BPVS-II assesses verbal comprehension and the Leiter nonverbal abilities. The issue is which to choose. People with Down syndrome (DS), for example, have particular problems in language and so the BPVS may provide an underestimation of ability.

METHOD

The present study investigated this by comparing the performance of 46 young people with DS (21 females, 25 males, mean age 19 years 10 months) on the BPVS-II (verbal mental age - VMA) and the Leiter-R brief IQ (nonverbal mental age - NVMA).

RESULTS

Contrary to expectations VMAs were significantly higher than NVMAs (6 years 6 months and 5 years 2 months, respectively). There was a significant correlation of 0.61 between the VMA and NVMA, and both discriminated participants at all levels of ability. However, the Leiter-R brief IQ scores provided poor discrimination at the bottom end of the IQ range (IQ 36).

CONCLUSION

Both the BPVS-II and the Leiter-R provide mental age equivalent scores that are useful for plotting developmental progress, although absolute mental ages may differ.