Adaptive behavior in infants and toddlers with Down syndrome and fragile X syndrome.

Individuals with Down syndrome (DS) experience deficits across all domains of adaptive functioning, however little is known about the emergence and age-related changes of these impairments compared to other neurogenetic disorders with similar intellectual disability impairments, such as fragile X syndrome (FXS). Adaptive behavior is key for optimal functioning in these populations. Participants aged 5-45 months comprised three age-matched groups, DS (n = 64), FXS (n = 69), and typically developing controls (TD; n = 69). Adaptive behavior was measured on the Vineland Adaptive Behavior Scales-II. Regressions were used to examine adaptive behavior in a cross-sectional design across age. DS infants and toddlers evidenced deficits across all areas of adaptive behaviors compared to the age-matched TD group, with clear impairments present in the first year of life. Motor skills were the area of greatest weakness in children with DS with significant impairment evident at 12 months of age that remained low through 3 years. Compared to age-matched children with FXS, children with DS showed initially lower standard scores at 12 months of age, but slower declines in standard scores across age, resulting in less impaired functioning at 36 months. This is the first study to compare adaptive behavior in infants and toddlers with DS to FXS, and demonstrate the phenotypic specificity of adaptive profiles in this diagnostic group. These findings provide evidence that adaptive behavior should be a major target of intervention in children with FXS and DS, and that these differences are potentially driven by unique etiologies attributable to each disorder.

HPA axis function predicts development of working memory in boys with FXS.

The present study examines verbal working memory over time in boys with fragile X syndrome (FXS) compared to nonverbal mental-age (NVMA) matched, typically developing (TD) boys. Concomitantly, the relationship between cortisol-a physiological marker for stress-and verbal working memory performance over time is examined to understand the role of physiological mechanisms in cognitive development in FXS. Participants were assessed between one and three times over a 2-year time frame using two verbal working memory tests that differ in complexity: memory for words and auditory working memory with salivary cortisol collected at the beginning and end of each assessment. Multilevel modeling results indicate specific deficits over time on the memory for words task in boys with FXS compared to TD controls that is exacerbated by elevated baseline cortisol. Similar increasing rates of growth over time were observed for boys with FXS and TD controls on the more complex auditory working memory task, but only boys with FXS displayed an association of increased baseline cortisol and lower performance. This study highlights the benefit of investigations of how dynamic biological and cognitive factors interact and influence cognitive development over time.

Eye tracking as a measure of receptive vocabulary in children with autism spectrum disorders.

This study examined the utility of eye tracking research technology to measure speech comprehension in 14 young boys with autism spectrum disorders (ASD) and 15 developmentally matched boys with typical development. Using eye tracking research technology, children were tested on individualized sets of known and unknown words, identified based on their performance on the Peabody Picture Vocabulary Test. Children in both groups spent a significantly longer amount of time looking at the target picture when previous testing indicated the word was known (known condition). Children with ASD spent similar amounts of time looking at the target and non-target pictures when previous testing indicated the word was unknown (unknown condition). However, children with typical development looked longer at the target pictures in the unknown condition as well, potentially suggesting emergent vocabulary knowledge.

Opportunities, barriers, and recommendations in down syndrome research.

BACKGROUND: Recent advances in medical care have increased life expectancy and improved the quality of life for people with Down syndrome (DS). These advances are the result of both pre-clinical and clinical research but much about DS is still poorly understood. In 2020, the NIH announced their plan to update their DS research plan and requested input from the scientific and advocacy community. OBJECTIVE: The National Down Syndrome Society (NDSS) and the LuMind IDSC Foundation worked together with scientific and medical experts to develop recommendations for the NIH research plan. METHODS: NDSS and LuMind IDSC assembled over 50 experts across multiple disciplines and organized them in eleven working groups focused on specific issues for people with DS. RESULTS: This review article summarizes the research gaps and recommendations that have the potential to improve the health and quality of life for people with DS within the next decade. CONCLUSIONS: This review highlights many of the scientific gaps that exist in DS research. Based on these gaps, a multidisciplinary group of DS experts has made recommendations to advance DS research. This paper may also aid policymakers and the DS community to build a comprehensive national DS research strategy.

Autism Spectrum Disorder-Associated Behaviour in Infants with Down Syndrome.

BACKGROUND: Individuals with Down syndrome (DS) are at high risk for autism spectrum disorder (ASD) with ~20% of individuals meeting diagnostic criteria for ASD. Despite the high risk, there is no research documenting early signs of ASD in infants with DS or potential prodromal ASD-associated behaviors. AIM: This preliminary case-control study described ASD-associated behaviors in infants with DS contrasted to typically developing (TD) infants. PATIENTS AND METHODS: The Autism Observation Scale for Infants (AOSI) was used to describe ASD-related behaviors in 18 infants with DS (7-18 months) and 18 TD infants (9-14 months). RESULTS: Thirty nine percent (7 out of 18) of infants with DS in our sample were designated "at risk" for ASD on the AOSI with 100% of infants with DS demonstrating at least one feature of ASD. In contrast, only 11% (2 out of 18) of TD infants were designated "at risk" for ASD on the AOSI. Social and communication impairments appear to represent early signs of elevated ASD-associated behavior in infants with DS. CONCLUSIONS: Early signs of ASD-associated behavior appear present and detectable in infants with DS. These early signs mirror findings of other populations at risk for ASD with social communication as the primary behavioral impairment to signal elevated risk for the emergence of ASD. This study contributes to the refinement of the DS behavioral phenotype and identifies important next steps to help improve the identification, diagnosis, and treatment of ASD in DS.

Communicative Use of Triadic Eye Gaze in Children With Down Syndrome, Autism Spectrum Disorder, and Other Intellectual and Developmental Disabilities.

Purpose This study examines differences in the communicative use of triadic eye gaze (TEG) during a communicative interaction in 2 neurodevelopmental disorders: Down syndrome (DS) and autism spectrum disorders (ASD), and a 3rd group of varying disabilities associated with intellectual and developmental disabilities (IDDs). Also, the relationship between TEG use and language abilities was explored. Method Participants were 45 children, 15 in each group. The frequency of TEG was coded during a scripted communication assessment when children were between 3 and 6 years of age (37-73 months). Receptive and expressive language was measured using raw scores from the Mullen Scales of Early Learning concurrently between 3 and 6 years and again 2 years later when children were between 5 and 8 years (59-92 months). Results Descriptively, children with DS had a higher frequency of TEG than children with ASD and IDD, but significant differences were only observed between children with DS and ASD. More TEG at Time 1 in children with DS was associated with higher receptive language at Time 1 and higher expressive language at Time 2. For children with ASD, a trend for a positive association between TEG at Time 1 and language abilities at Time 2 was observed. No significant associations were observed for children with IDD. Conclusion Children with DS used TEG significantly more than children with ASD in this sample. Identifying strengths and weaknesses in TEG use is important because providing caregiver training to facilitate TEG can result in increased opportunities to respond with language models and promote language development.

Characteristics Associated with Autism Spectrum Disorder Risk in Individuals with Down Syndrome.

We examined autism spectrum disorder (ASD) risk in a large national sample of 203 individuals with Down syndrome, 6-25 years old, to determine the association of ASD risk with age, sex, IQ, adaptive behaviors, and maladaptive behaviors. We used a two-pronged approach by (1) considering ASD symptomatology continuously across the sample of individuals with DS and examining associations with each characteristic, and (2) dichotomizing our sample into high and low ASD risk groups and comparing groups on each characteristic. The pattern of results was largely similar across both types of analyses. ASD symptomatology/risk was negatively associated with IQ and adaptive behaviors and positively associated with certain types of maladaptive behaviors. Clinical implications for screening and therapeutic purposes are discussed.

Joint attention in Down syndrome: A meta-analysis.

BACKGROUND: Some studies have indicated that joint attention may be a relative strength in Down syndrome (DS), but other studies have not. AIM: To conduct a meta-analysis of joint attention in DS to more conclusively determine if this is a relative strength or weakness when compared to children with typical development (TD), developmental disabilities (DD), and autism spectrum disorder (ASD). METHODS AND PROCEDURES: Journal articles published before September 13, 2016, were identified by using the search terms "Down syndrome" and "joint attention" or "coordinating attention". Identified studies were reviewed and coded for inclusion criteria, descriptive information, and outcome variables. OUTCOMES AND RESULTS: Eleven studies (553 participants) met inclusion criteria. Children with DS showed similar joint attention as TD children and higher joint attention than children with DD and ASD. Meta-regression revealed a significant association between age and joint attention effect sizes in the DS vs. TD contrast. CONCLUSIONS AND IMPLICATIONS: Joint attention appears to not be a weakness for children with DS, but may be commensurate with developmental level. Joint attention may be a relative strength in comparison to other skills associated with the DS behavioral phenotype. Early interventions for children with DS may benefit from leveraging joint attention skills.

The Longitudinal Effects of Parenting on Adaptive Behavior in Children with Fragile X Syndrome.

Several studies have reported declines in adaptive behavior amongst children with fragile X syndrome (FXS) starting in middle childhood. We examined the effects of maternal responsivity on adaptive behavior in 55 children with FXS visited 5-6 times in their homes from early through middle childhood. Our analyses indicated that sustained maternal responsivity had a significant positive impact on the trajectories of communication and to a lesser extent other adaptive behavior domains through middle childhood with many effects remaining significant after controlling for autism symptoms and developmental level. For children who showed declines in adaptive behavior during middle childhood, sustained high levels of maternal responsivity minimized the amount of decline observed in the communication, socialization, and daily living domains.

Early social communication in infants with fragile X syndrome and infant siblings of children with autism spectrum disorder.

BACKGROUND: Little research in fragile X syndrome (FXS) has prospectively examined early social communication. AIMS: To compare early social communication in infants with FXS, infant siblings of children with autism spectrum disorder (ASIBs), and typically developing (TD) infants. METHODS AND PROCEDURES: Participants were 18 infants with FXS, 21 ASIBs, and 22 TD infants between 7.5-14.5 months. Social communication was coded using the Communication Complexity Scale during the administration of Autism Observation Scale for Infants. OUTCOMES AND RESULTS: Descriptively different patterns were seen across the three groups. Overall infants with FXS had lower social communication than ASIBs or TD infants when controlling for nonverbal cognitive abilities. However, infants with FXS had similar levels of social communication as ASIBs or TD infants during peek-a-boo. No differences were observed between ASIBs and TD infants. For all infants, higher social communication was related to lower ASD risk. CONCLUSIONS AND IMPLICATIONS: Findings provide insight into the developmental course of social communication in FXS. The dynamic nature of social games may help to stimulate communication in infants with FXS. Language interventions with a strong social component may be particularly effective for promoting language development in FXS.

Joint Attention and Early Social Developmental Cascades in Neurogenetic Disorders.

This review examines what is known about joint attention and early social development in three neurogenetic syndromes: Down syndrome, Williams syndrome, and fragile X syndrome. In addition, the potential cascading effects of joint attention on subsequent social development, especially social interaction and social cognition are proposed. The potential issues and complexities associated with conducting prospective, longitudinal studies of infant social development in neurogenetic disorders are discussed.

Joint Engagement and Early Language in Young Children With Fragile X Syndrome.

Purpose: In this study, we examine joint engagement (JE) in young children with fragile X syndrome (FXS) and its relationship to language abilities and autism spectrum disorder symptomatology at 24 to 36 months (toddler period) and 59 to 68 months (child period). Method: Participants were 28 children with FXS (24 boys, four girls) and their mothers. Videotaped home observations were conducted during the toddler period and coded for JE. Language abilities were measured at both ages from a developmental assessment, a functional measure, and from a language sample. The Childhood Autism Rating Scale (Schopler, Reichler, & Renner, 1988) was completed at both ages. Results: Children with FXS spent more time in supported JE than in coordinated JE. Using a weighted JE variable, we found that children with FXS who had higher weighted JE scores also had more advanced expressive language skills at both the toddler and child periods. Weighted JE was negatively related to autism symptomatology in the toddler period. Conclusion: This study provides evidence that children with FXS who use more JE also have more advanced expressive language skills in early development. Therefore, existing early interventions that target JE behaviors may be effective for promoting language, social communication, and social interaction in this population.

Do Children With Fragile X Syndrome Show Declines or Plateaus in Adaptive Behavior?

This study explores if children with fragile X syndrome (FXS) show advances, declines, or plateaus in adaptive behavior over time and the relationship of nonverbal cognitive abilities and autistic behavior on these trajectories. Parents of 55 children with FXS completed the Vineland Adaptive Behavior Scales ( Sparrow, Balla, & Cicchetti, 1984 ; Sparrow, Cicchetti, & Balla, 2005 ) between 3 and 6 times from 2 to 10 years of age. Using raw scores, results indicate that about half of the sample showed advances in adaptive behavior, whereas the other half showed declines, indicating a regression in skills. Children who were more cognitively advanced and had less autistic behaviors had higher trajectories. Understanding the developmental course of adaptive behavior in FXS has implications for educational planning and intervention, especially for those children showing declines.

Adaptive behavior and problem behavior in young children with Williams syndrome.

The present study compares the adaptive behavior profile of 18 young children with Williams syndrome (WS) and a developmentally matched group of 19 children with developmental disabilities and examines the relationship between adaptive behavior and problem behaviors in WS. Parents completed the Vineland Adaptive Behavioral Scales-Interview edition and the Developmental Behavior Checklist-Primary Caregiver version (WS only). Children with WS had higher adaptive communication scores than children with other developmental disabilities. Children with WS demonstrated relative strengths in adaptive communication and socialization, coupled with relative weaknesses in daily living. Adaptive communication and socialization were negatively associated with problem behaviors in social relating in WS.

Role of maternal gesture use in speech use by children with fragile X syndrome.

PURPOSE: The purpose of this study was to investigate how maternal gesture relates to speech production by children with fragile X syndrome (FXS). METHOD: Participants were 27 young children with FXS (23 boys, 4 girls) and their mothers. Videotaped home observations were conducted between the ages of 25 and 37 months (toddler period) and again between the ages of 60 and 71 months (child period). The videos were later coded for types of maternal utterances and maternal gestures that preceded child speech productions. Children were also assessed with the Mullen Scales of Early Learning at both ages. RESULTS: Maternal gesture use in the toddler period was positively related to expressive language scores at both age periods and was related to receptive language scores in the child period. Maternal proximal pointing, in comparison to other gestures, evoked more speech responses from children during the mother-child interactions, particularly when combined with wh-questions. CONCLUSION: This study adds to the growing body of research on the importance of contextual variables, such as maternal gestures, in child language development. Parental gesture use may be an easily added ingredient to parent-focused early language intervention programs.

Early intersubjective skills and the understanding of intentionality in young children with Down syndrome.

This study examined the relationship between early intersubjective skills (joint attention and affect sharing) and the development of the understanding of intentionality in 16 young children with Down syndrome (DS) and 16 developmentally matched children with other developmental disabilities (DD). The study of intentionality focuses on how children come to understand the goal-directed actions of others and is an important precursor to the development of more complex social cognitive skills, such as theory of mind. Joint attention and affect sharing were examined using the Early Social Communication Scales (Mundy, Sigman, & Kasari, 1990; Seibert, Hogan, & Mundy, 1982). Meltzoff's (1995) behavioral reenactment paradigm was used to examine the understanding of intentionality. For children with DS, higher rates of affect sharing were associated with poorer intention reading abilities. This pattern was not observed in children with other DD. These results suggest that the intersubjective strengths associated with DS may not support the development of intentionality-interpretation skills. Future research is needed to explore if children with DS have the joint attention behaviors needed to be intentional.