Mathematical learning disabilities in children with 22q11.2 deletion syndrome: A review

Centre for Parenting, Child Welfare and Disabilities, Katholieke Universiteit Leuven, Leuven, Belgium.
Developmental Disabilities Research Reviews (Impact Factor: 2.75). 01/2009; 15(1):4-10. DOI: 10.1002/ddrr.44
Source: PubMed


Mathematical learning disabilities (MLD) occur frequently in children with specific genetic disorders, like Turner syndrome, fragile X syndrome and neurofibromatosis. This review focuses on MLD in children with chromosome 22q11.2 deletion syndrome (22q11DS). This syndrome is the most common known microdeletion syndrome with a prevalence of at least 1:4000 to 1:6000 live births. Although the clinical presentation of 22q11DS is quite variable, its major characteristics include velopharyngeal abnormalities, congenital cardiac anomalies, mild facial dysmorphism and learning difficulties. Children with 22q11DS show considerable difficulties in mathematics, despite relatively normal reading performance. While fact retrieval seems to be preserved, impairments in procedural calculation and word problem solving are particularly prominent. Children with 22q11DS also have substantial difficulties in understanding and representing numerical quantities, possibly related to poor visuospatial attention, which all might stem from their underlying abnormalities in the inferior parietal cortex. This review ends with a discussion on how research on genetic disorders might aid our understanding of MLD in general.

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Available from: Bert De Smedt, Oct 05, 2015
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    • "[20] with mean full-scale intelligence quotient (FSIQ) typically ranging from 70 to 85 [21] with a general strength in verbal relative to nonverbal domains [22] in most individuals. The specificity of these impairments is indicated by group differences on nonverbal tasks of: spatial attention [23,24], executive function [25,26], visuomotor skills [27], visuospatial skills [28], and numerical [23], and arithmetical thinking [29]. "
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    ABSTRACT: Chromosome 22q11.2 deletion syndrome (22q11.2DS), fragile X syndrome (FXS), and Turner syndrome (TS) are complex and variable developmental syndromes caused by different genetic abnormalities; yet, they share similar cognitive impairments in the domains of numbers, space, and time. The atypical development of foundational neural networks that underpin the attentional system is thought to result in further impairments in higher-order cognitive functions. The current study investigates whether children with similar higher-order cognitive impairments but different genetic disorders also show similar impairments in alerting, orienting and executive control of attention. Girls with 22q11.2DS, FXS, or TS and typically developing (TD) girls, aged 7 to 15 years, completed an attention network test, a flanker task with alerting and orienting cues. Exploration of reaction times and accuracy allowed us to test for potential commonalities in attentional functioning in alerting, orienting and executive control. Linear regression models were used to test whether the predictors of group and chronological age were able to predict differences in attention indices. Girls with 22q11.2DS, FXS, or TS demonstrated unimpaired function of the alerting system and impaired function of the executive control system. Diagnosis-specific impairments were found such that girls with FXS made more errors and had a reduced orienting index, while girls with 22q11.2DS showed specific age-related deficits in the executive control system. These results suggest that the control but not the implementation of attention is selectively impaired in girls with 22q11.2DS, TS or FXS. Additionally, the age effect on executive control in girls with 22q11.2DS implies a possible altered developmental trajectory.
    Journal of Neurodevelopmental Disorders 03/2014; 6(1):5. DOI:10.1186/1866-1955-6-5 · 3.27 Impact Factor
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    • "A closer examination of specific cognitive abilities reveals deficits in a number of domains, many of which are independent of IQ, including visualspatial processing, executive functioning, attention, verbal learning and working memory (Sobin et al. 2005; Lewandowski et al. 2007a). Decrements in cognitive ability can lead to poor academic performance in these children, and indeed, research has found notable deficits in arithmetic among children with 22q11DS, whereas reading and spelling skills are relatively stronger (Moss et al. 1999; Simon 2008; De Smedt et al. 2009). "
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    ABSTRACT: Background: Children with 22q11.2 deletion syndrome (22q11DS) are at risk for social-behavioural and neurocognitive sequelae throughout development. The current study examined the impact of family environmental characteristics on social-behavioural and cognitive outcomes in this paediatric population. Method: Guardians of children with 22q11DS were recruited through two medical genetics clinics. Consenting guardians were asked to complete several questionnaires regarding their child's social, emotional and behavioural functioning, as well as family social environment and parenting styles. Children with 22q11DS were asked to undergo a cognitive assessment, including IQ and achievement testing, and measures of attention, executive function and memory. Results: Modest associations were found between aspects of the family social environment and parenting styles with social-behavioural and cognitive/academic outcomes. Regression models indicated that physical punishment, socioeconomic status, parental control and family organisation significantly predicted social-behavioural and cognitive outcomes in children with 22q11DS. Conclusion: Characteristics of the family social environment and parenting approaches appear to be associated with functional outcomes of children with 22q11DS. Understanding the impact of environmental variables on developmental outcomes can be useful in determining more effective targets for intervention. This will be important in order to improve the quality of life of individuals affected by 22q11DS.
    Journal of Intellectual Disability Research 06/2013; 58(1). DOI:10.1111/jir.12054 · 2.41 Impact Factor
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    • "includes non-verbal impairments that stand in contrast to relative strengths in the verbal domain [7]. These non-verbal impairments include, but are not limited to, impairments in attention, spatial cognition, quantitative cognition, and arithmetical processing [8-10]. "
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    ABSTRACT: Chromosome 22q11.2 deletion syndrome (22q11.2DS) results from a 1.5- to 3-megabase deletion on the long arm of chromosome 22 and occurs in approximately 1 in 4000 live births. Previous studies indicate that children with 22q11.2DS are impaired on tasks involving spatial attention. However, the degree to which these impairments are due to volitionally generated (endogenous) or reflexive (exogenous) orienting of attention is unclear. Additionally, the efficacy of these component attention processes throughout child development in 22q11.2DS has yet to be examined. Here we compared the performance of a wide age range (7 to 14 years) of children with 22q11.2DS to typically developing (TD) children on a comprehensive visual cueing paradigm to dissociate the contributions of endogenous and exogenous attentional impairments. Paired and two-sample t-tests were used to compare outcome measures within a group or between groups. Additionally, repeated measures regression models were fit to the data in order to examine effects of age on performance. We found that children with 22q11.2DS were impaired on a cueing task with an endogenous cue, but not on the same task with an exogenous cue. Additionally, it was younger children exclusively who were impaired on endogenous cueing when compared to age-matched TD children. Older children with 22q11.2DS performed comparably to age-matched TD peers on the endogenous cueing task. These results suggest that endogenous but not exogenous orienting of attention is selectively impaired in children with 22q11.2DS. Additionally, the age effect on cueing in children with 22q11.2DS suggests a possible altered developmental trajectory of endogenous cueing.
    Journal of Neurodevelopmental Disorders 02/2012; 4(1):5. DOI:10.1186/1866-1955-4-5 · 3.27 Impact Factor
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