Attention across modalities as a longitudinal predictor of early outcomes: the case of fragile X syndrome.
ABSTRACT Fragile X syndrome (FXS) is an early diagnosed monogenic disorder, associated with a striking pattern of cognitive/attentional difficulties and a high risk of poor behavioural outcomes. FXS therefore represents an ideal model disorder to study prospectively the impact of early attention deficits on behaviour.
Thirty-seven boys with FXS aged 4-10 years and 74 typically developing (TD) boys took part. Study 1 was designed to assess visual and auditory attention at two time-points, 1 year apart. Study 2 investigated attention to multimodal information. Both tested attention markers as longitudinal predictors of risk for poor behaviour in FXS.
Children with FXS attended less well than mental-age matched TD boys and experienced greater difficulties with auditory compared to visual stimuli. In addition, unlike TD children, they did not benefit from multimodal information. Attention markers were significant predictors of later behavioural difficulties in boys with FXS.
Findings demonstrate, for the first time, greater difficulties with auditory attention and atypical processing of multimodal information, in addition to pervasive global attentional difficulties in boys with FXS. Attention predicted outcomes longitudinally, underscoring the need to dissect what drives differing developmental trajectories for individual children within a seemingly homogeneous group.
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Article: The fragile X prevalence paradox.[show abstract] [hide abstract]
ABSTRACT: Although fragile X syndrome (FXS; OMIM #300624) is generally regarded as the most common inherited form of cognitive impairment 1-3, there is little consensus as to its prevalence in the general population or to sex-specific differences in prevalence. Estimates of FXS prevalence (~1/4,000 - 1/8,000) that are based on population projections from cohorts of children with special education needs (SEN) generally underestimate the extent of clinical involvement (comprehensive summary: 4), since many individuals affected by the behavioral, emotional, and/or learning disabilities of FXS have IQs in the normal or borderline range. 5, 6 The latter individuals may not be included in cohorts that use cognitive impairment as an inclusion criterion, a problem that is particularly marked for girls, with the majority having IQs within the normal range.7.Journal of Medical Genetics 05/2008; 45(8):498-9. · 5.70 Impact Factor
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ABSTRACT: The performance of 54 boys with fragile X syndrome (FXS), ages 7 to 13 years, was compared to that of a group of typically developing boys who were matched on mental age (MA) and ethnicity across multiple measures of executive function (EF). Boys with FXS varied in their ability to complete EF measures, with only 25.9% being able to complete a set-shifting task and 94.4% being able to complete a memory for word span task. When compared to the control group, and controlling for MA and maternal education, boys with FXS showed significant deficits in inhibition, working memory, cognitive flexibility/set-shifting, and planning. No group differences were observed in processing speed. Mental age significantly impacted performance on working memory, set-shifting, planning, and processing speed tasks for both groups. In boys with FXS, MA significantly predicted performance on working memory and set-shifting tasks. Our findings suggest that deficits in EF in boys with FXS are not solely attributable to developmental delays but, rather, present as a true array of neurocognitive deficits.Neuropsychology 02/2008; 22(1):36-47. · 3.58 Impact Factor
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ABSTRACT: To determine recent trends in the diagnosis of children with fragile X syndrome (FXS) and identify factors associated with the timing of diagnosis. More than 1000 families of children with FXS participated in a national survey. Of these, 249 had their first child (213 boys, 36 girls) diagnosed between 2001 and 2007 and did not know about FXS in their family before diagnosis. These parents answered questions about the average age of first concerns, developmental delays, early intervention, and the FXS diagnosis. They also provided other information about their child and family, reported who made the diagnosis, and described ramifications for other children and extended family members. The average age of FXS diagnosis of boys remained relatively stable across the 7-year period at approximately 35 to 37 months. The 36 girls with full mutation were given the diagnosis at an average age of 41.6 months. A trend was noted in earlier diagnosis of developmental delay for boys in more recent years. Approximately 25% of the families of male children had a second child with the full mutation before the diagnosis was given to the first child; 14 (39%) of the 36 families of female children had a second child with the full mutation before the diagnosis. Despite patient advocacy, professional recommendations regarding prompt referral for genetic testing, and increased exposure to information about FXS in the pediatric literature, no changes were detected in the age of diagnosis of FXS during the time period studied. Earlier identification in the absence of systematic screening will likely continue to be a challenge.PEDIATRICS 09/2009; 124(2):527-33. · 4.47 Impact Factor