Language Performance in Preschool-Aged Boys with Nonsyndromic Autism Spectrum Disorder or Fragile X Syndrome

Short-term and Long-term Stability of the Autism Diagnostic Observation Schedule (ADOS-2) Calibrated Comparison Scores (CCS) and Classification Scores in Youth with Down Syndrome or Fragile X Syndrome with Intellectual Disability

Autism diagnosis in individuals with fragile X syndrome (FXS) or Down syndrome (DS) with co-occurring intellectual disability is complex since clinicians often must consider other co-occurring behavioral features. Understanding how best to assess the features of autism in individuals with these conditions is crucial. In this study, we consider the short-term and long-term psychometric consistency of the Autism Diagnostic Observation Schedule-2 (ADOS-2) calibrated comparison scores (CCSs) and ASD classifications in individuals with FXS or DS. 76 individuals with DS (39 males; Mage = 15.27) and 90 individuals with FXS (71 males; Mage = 14.52 years) completed an assessment battery (ADOS-2, abbreviated IQ assessment and semi-structured language sample) at three timepoints (initial visit, short-term stability visit, long-term stability visit). All CCSs were found to have short-and long-term consistency for both groups, with lowest reliability scores for the repetitive behaviors (RRB) CCSs. Decreased reliability of RRB CCSs was found in the DS group than the FXS group. Variable short- and long-term ASD classifications were observed in both groups, with significantly higher variability in the DS group. Across groups, participants with variable classifications had lower ADOS-2 CCSs and higher language scores than those with stable ASD classifications. In the FXS group, those with variable classifications earned higher cognitive scores than did participants with stable ASD classifications. These findings highlight the high incidence of autism symptomatology in individuals with DS or FXS and co-occurring intellectual disability, while elucidating the short- and long-term variability of symptom expression in the context of structured observational tasks such as the ADOS-2.

Studies assessing domains pertaining to structural language in autism vary in reporting practices and approaches to assessment: A systematic review

LAY ABSTRACT

Under the Diagnostic and Statistical Manual of Mental Disorders (5th ed.), language impairment can co-occur with autism. It is not yet clear how research defines, reports, and characterizes structural language abilities of autistic individuals eligible for school-based special education services (aged 3-21 years) in the United States. In the United States, students typically must be formally diagnosed to be eligible for services and supports. However, the quality of diagnosis is only as good as the research evidence on which diagnosis depends. To evaluate evidence quality, we examined how studies of school-aged autistic individuals report assessments of language ability. This systematic review included 57 studies using English language age-referenced assessments used to measure structural language. Findings showed many differences across studies in how language abilities were measured and reported. Also, none of the studies fully reported the variables relevant to characterizing language impairment. Outcomes were similar across versions of the Diagnostic and Statistical Manual of Mental Disorders. Findings indicate that researchers and clinicians should pay attention to reporting diagnostic and grouping criteria. Carefully interpreting research evidence is critical for ensuring that diagnostic criteria and supports are representative of and accessible to autistic individuals and relevant parties.

Adaptive, behavioral, and cognitive outcomes in individuals with fragile X syndrome with varying autism severity

This study aimed to determine the association between severity of autism spectrum disorder (ASD) and cognitive, behavioral, and molecular measures in individuals with fragile X syndrome (FXS). Study inclusion criteria included individuals with FXS and (1) age 6-40 years, (2) full-scale IQ < 84, and (3) language ≥3-word phrases. ASD symptom severity was determined by Autism Diagnostic Observation Schedule-2 (ADOS-2). Other measures identified non-verbal IQ, adaptive skills, and aberrant behaviors. Molecular measures included blood FMR1 and CYFIP1 mRNA levels, FMRP and MMP9 levels. Analysis of variance (ANOVA) and Spearman's correlations were used to compare ASD severity groups. Data from 54 individuals was included with no/mild (N = 7), moderate (N = 18), and severe (N = 29) ASD. Individuals with high ASD severity had lower adaptive behavior scores (47.48 ± 17.49) than the no/mild group (69.00 ± 20.45, p = 0.0366); they also had more challenging behaviors, lethargy, and stereotypic behaviors. CYFIP1 mRNA expression levels positively correlated with the ADOS-2 comparison score(r2  = 0.33, p = 0.0349), with no significant correlations with other molecular markers. In conclusion, autism symptom severity is associated with more adverse cognitive and adaptive skills and specific behaviors in FXS, whereas CYFIP1 mRNA expression levels may be a potential biomarker for severity of ASD in FXS.

Studies pertaining to language impairment in school-age autistic individuals underreport participant socio-demographics: A systematic review

LAY ABSTRACT

Although exclusion of racially and ethnically minoritized autistic individuals from research is a long-standing issue, we have yet to determine how exclusion impacts areas of autism research important for identifying language impairment. Diagnosis depends on the quality of the evidence (i.e. research) and is often the pathway to gaining access to services. As a first step, we examined how research studies related to language impairment in school-age autistic individuals report participant socio-demographics. We analyzed reports using age-referenced assessments in English (n = 60), which are commonly used by both practitioners and researchers to diagnose or identify language impairment. Findings showed only 28% of studies reported any information on race and ethnicity; in these studies, most (at least 77%) of the participants were white. In addition, only 56% of studies reported gender or sex and specified what they were reporting (gender, sex, or gender identity). Just 17% reported socio-economic status using multiple indicators. Altogether, findings indicate broad issues with underreporting and exclusion of racially and ethnically minoritized individuals, which might overlay with other aspects of identity including socio-economic status. It is impossible to determine the extent and precise nature of exclusion without intersectional reporting. To ensure that language in autism research is representative of the autistic population, future research must implement reporting guidelines and broaden inclusion of who participates in research studies.

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.

Research Gaps in Fragile X Syndrome: An Updated Literature Review to Inform Clinical and Public Health Practice

OBJECTIVE

The phenotypic impact of fragile X syndrome (FXS) has been well-documented since the discovery of the fragile X messenger ribonucleoprotein 1 gene 30 years ago. However, gaps remain in clinical and public health research. The purpose of this literature review was to determine the extent to which these gaps have been addressed and identify targeted areas of future research.

METHODS

We conducted an electronic search of several scientific databases using a variety of key words. The search focused on 5 areas identified as research gaps by an earlier review: (1) diagnosis, (2) phenotypic presentation, (3) familial impact, (4) interventions and treatments, and (5) life span perspectives. Inclusion criteria included publication between 2014 and 2020, focus on human subjects, and publication in English. A total of 480 articles were identified, 365 were reviewed, and 112 are summarized in this review.

RESULTS

Results are organized into the following categories: (1) FXS phenotype and subtypes (FXS subtypes, medical profile, cognitive/developmental profile, social and behavioral profile); (2) needs of adults; (3) public health needs (clinical diagnosis and newborn screening, health care needs, and access); (4) treatment (treatment priorities, pharmacological treatments, and behavioral and educational interventions); and (5) families (economic burden and mother-child relationship).

CONCLUSION

Despite the progress in many areas of FXS research, work remains to address gaps in clinical and public health knowledge. We pose 3 main areas of focused research, including early detection and diagnosis, determinants of health, and development and implementation of targeted interventions.

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.

Linear discriminant analysis of phenotypic data for classifying autism spectrum disorder by diagnosis and sex

Autism Spectrum Disorder (ASD) is a developmental condition characterized by social and communication differences. Recent research suggests ASD affects 1-in-44 children in the United States. ASD is diagnosed more commonly in males, though it is unclear whether this diagnostic disparity is a result of a biological predisposition or limitations in diagnostic tools, or both. One hypothesis centers on the ‘female protective effect,’ which is the theory that females are biologically more resistant to the autism phenotype than males. In this examination, phenotypic data were acquired and combined from four leading research institutions and subjected to multivariate linear discriminant analysis. A linear discriminant model was trained on the training set and then deployed on the test set to predict group membership. Multivariate analyses of variance were performed to confirm the significance of the overall analysis, and individual analyses of variance were performed to confirm the significance of each of the resulting linear discriminant axes. Two discriminant dimensions were identified between the groups: a dimension separating groups by the diagnosis of ASD (LD1: 87% of variance explained); and a dimension reflective of a diagnosis-by-sex interaction (LD2: 11% of variance explained). The strongest discriminant coefficients for the first discriminant axis divided the sample in domains with known differences between ASD and comparison groups, such as social difficulties and restricted repetitive behavior. The discriminant coefficients for the second discriminant axis reveal a more nuanced disparity between boys with ASD and girls with ASD, including executive functioning and high-order behavioral domains as the dominant discriminators. These results indicate that phenotypic differences between males and females with and without ASD are identifiable using parent report measures, which could be utilized to provide additional specificity to the diagnosis of ASD in female patients, potentially leading to more targeted clinical strategies and therapeutic interventions. The study helps to isolate a phenotypic basis for future empirical work on the female protective effect using neuroimaging, EEG, and genomic methodologies.

Using weighted communication scoring procedures in naturalistic play samples: Preliminary validation in preschool-aged boys with autism or fragile X syndrome

In the present study, we provide a preliminary evaluation of the validity and reliability of using weighting procedures to measure communication in play samples for preschool-aged boys with autism or fragile X syndrome (FXS). Because weighting procedure communication scores (WPCSs) reflect growth in both communicative frequency and complexity, establishing the psychometrics of the component scores, in addition to the overall metric, affords investigators the opportunity to describe growth within and across skills. Results, for both groups, provide support regarding the psychometric appropriateness (i.e., convergent validity, divergent validity, and internal consistency) for all WPCSs. That said, a trend was observed for reliability scores to be slightly lower or more variable in boys with autism than in boys with FXS. Finally, although significant associations were observed in the associations between WPCSs across play contexts, contexts effects were observed for all three WPCSs. Together, results from this study provide promising preliminary data indicating the utility of using WPCSs in children with neurodevelopmental disabilities. Lay Summary: Language supports long-term positive outcomes; it is important to identify accurate and flexible ways of measuring language in children over time. We considered the effectiveness of using a procedure that considers changes in the number of communication acts and the types of acts produced during a play session by preschool-aged boys with autism or fragile X syndrome. These procedures were found to be valid and reliable.

Joint attention performance in preschool-aged boys with autism or fragile X syndrome

Early development marks a period of rapid learning facilitated by children's natural curiosity about the people around them. In children with typical development, these early social attentional preferences set the foundation for learning about and from the surrounding world of people. Much of this learning happens using joint attention, the ability to coordinate attention between people and objects of mutual interest. It is well documented that decreased gaze use is commonly observed in individuals with autism and individuals with fragile X syndrome (FXS). Despite the growing body of research comparing phenotypic similarities between individuals with autism and individuals with FXS, no studies have directly compared joint attention performance between these groups. In the present study, we considered the similarities and differences in joint attention between preschool-aged boys with autism or FXS, and the relation between joint attention, language, and other phenotypic characteristics known to differ between boys with autism and boys with FXS. Although joint attention appeared similar, between-group differences emerged when controlling for the influence of age, non-verbal IQ, and autism symptom severity. Differences were also observed when considering how joint attention performance related to other aspects of the phenotype. For example, strong positive associations were observed between joint attention and language performance in boys with autism but not boys with FXS, even after controlling for non-verbal IQ. In contrast, the negative association between joint attention and anxiety symptom severity was significant and stronger in boys with FXS than in autism. These data offer preliminary insights into the similarities and differences between the autism and FXS phenotypes.