Trajectories and Predictors of the Development of Very Young Boys with Fragile X Syndrome

Department of Psychology, University of South Carolina, Barnwell College, Columbia, SC 29208, USA.
Journal of Pediatric Psychology (Impact Factor: 2.91). 09/2009; 34(8):827-36. DOI: 10.1093/jpepsy/jsn129
Source: PubMed


To describe the development of young boys with fragile X syndrome (FXS).
Fifty-five boys (aged 8-48 months at study entry) with the full mutation FXS received multiple developmental assessments.
As expected, the boys' rate of development was significantly lower than chronological age expectations. No evidence of slowing in the rate of development was found. Autistic behavior was negatively associated with development, but maternal IQ was not. Developmental delays were evident in some domains as early as 9 months; however, initial detection of delays is complicated by measures and criteria used. Developmental age scores at 31 months of age were related to scores obtained at 61 months of age only in the global composite and visual reception domain.
Developmental delays are evident in some infants with FXS as young as 9 months of age. Pediatric psychologists need to be informed about the developmental profiles in young children with FXS to accurately diagnose, treat, and support these children and their families.

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    • "Lastly, the trend of increased baseline cortisol over a 2-year timespan in boys with FXS aged 8– 12 years of age is the first longitudinal report of cortisol in this population. This extends existing evidence showing a relationship between cortisol and social behavior in boys with FXS at a single time point (Hall, Lightbody, Huffman,Lazzeroni, & Reiss, 2009;Hessl et al., 2006;Roberts, Clarke, et al., 2009;Roberts, Mankowski, et al., 2009), and is consistent with the literature on TD populations showing increased levels of baseline cortisol reflecting chronic stress and negatively influence learning and working memory performance (Oei et al., 2006;Taverniers et al., 2010;Wolf, 2009). While no research has investigated the relationships between working memory performance and salivary cortisol in FXS or other populations with intellectual or developmental disabilities , our results suggest that this group, and potentially other neurodevelopmental disorders, is sensitive to the effects of stress on working memory performance that are, perhaps, additive to the impact of cognitive impairment. "
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    ABSTRACT: 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.
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    • "It is paradoxical that, given the tremendous richness of data that accrues from using longitudinal methodology, relatively few studies have chosen this pathway. From these few studies, there is already emerging evidence to indicate a dynamic cognitive profile in children with FXS for social cognition (Hernandez et al., 2009), adaptive functioning (Roberts et al., 2009) and general intelligence (Hall et al., 2008). Our data extends this research by suggesting that in FXS attentional control and WM clearly do not index developmental freeze: if followed longitudinally, even across two time points, children with the condition show improvements in performance that were not either captured by cross-sectional comparisons or by teacher-reported behavioral scores. "
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    ABSTRACT: 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.
    Full-text · Article · May 2013 · Development and Psychopathology
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    • "Typically, the developmental trajectory in children with FXS is approximately 50% of the normal rate and expressive language is even lower [50]. A recent study reports that developmental delays in receptive and expressive language domains were evident by 9 month of age in children with FXS [51]. Language is an important domain because it most strongly correlates with intellectual ability. "
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    ABSTRACT: Young children with fragile X syndrome (FXS) often experience anxiety, irritability, and hyperactivity related to sensory hyperarousal. However, there are no medication recommendations with documented efficacy for children under 5 years old of age with FXS. We examined data through a chart review for 45 children with FXS, 12-50 months old, using the Mullen Scales of Early Learning (MSEL) for baseline and longitudinal assessments. All children had clinical level of anxiety, language delays based on MSEL scores, and similar early learning composite (ELC) scores at their first visit to our clinic. Incidence of autism spectrum disorder (ASD) was similar in both groups. There were 11 children who were treated with sertraline, and these patients were retrospectively compared to 34 children who were not treated with sertraline by chart review. The baseline assessments were done at ages ranging from 18 to 44 months (mean 26.9, SD 7.99) and from 12 to 50 months (mean 29.94, SD 8.64) for treated and not treated groups, respectively. Mean rate of improvement in both expressive and receptive language development was significantly higher in the group who was treated with sertraline (P < 0.0001 and P = 0.0071, resp.). This data supports the need for a controlled trial of sertraline treatment in young children with FXS.
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