Focus on words: a twin study of reading and inattention

Socioeconomic status impacts genetic influences on the longitudinal dynamic relationship between temperament and general cognitive ability in childhood: The Louisville Twin Study

The current analysis investigates genetic and environmental influences on the bidirectional relationships between temperament and general cognitive ability (GCA). Measures of GCA and three temperament factors (persistence, approach, and reactivity) were collected from 486 children ages 4-9 years (80% white, 50% female) from the Louisville Twin Study from 1976 to 1998. The results indicated a bidirectional dynamic model of temperament influencing subsequent GCA and GCA influencing subsequent temperament. The dynamic relationship between temperament and GCA arose primarily from shared genetic variance, particularly in families with higher socioeconomic status, where input from temperament contributed on average 20% to genetic variance in GCA versus 0% in lower SES families.

Identifying Factors Influencing Attention in Adolescents with a Co-Created Questionnaire: A Citizen Science Approach with Secondary Students in Barcelona, Spain

Studies on factors that can influence attention in healthy adolescents are recent and focus on recurrent topics. Students' contribution to public health research often revolves around collecting data but rarely around creating data collection instruments. The ATENC!Ó project reunited secondary students and scientists to create a questionnaire including factors that students thought could affect their attention. We conducted a cross-sectional study to assess whether the factors included in this questionnaire had an effect on attention in adolescents. A total of 1667 students (13-16 years old) from 28 schools in Barcelona performed a validated attention test and answered the questionnaire. The response speed consistency (attentiveness), expressed as hit reaction time standard error (HRT-SE, in ms), was used as the primary outcome. Analyses were conducted using conditional linear regression with school as strata, adjusted for sociodemographic characteristics and further stratified by gender and maternal social class. Some factors showed a negative influence on attention, including taking medication and not reading regularly. We found a significant 14.3% (95% confidence interval: 3.4%, 25.3%) higher median of HRT-SE (increase inattentiveness) among students who reported not having a good relationship with classmates. Students' input into research is relevant for advancing the knowledge production in public health.

Reading Comprehension Impairment in Children With Neurofibromatosis Type 1 (NF1): The Need of Multimodal Assessment of Attention

Attention span, which has been shown to have an impact on reading quality in many other conditions, is one of the main cognitive disorders of neurofibromatosis type 1 (NF1). The aim of this work is to observe the impact of attention on reading comprehension, in NF1 and non-NF1 children. A multicenter, cross-sectional study was conducted on 150 children (8-12 years old) with or without NF1 (75 NF1 vs 75 non-NF1; 72 female, 78 male), matched for age, sex, handedness, and reading level, thus forming a continuum from good to poor readers in both NF1 and non-NF1 groups. Children with intellectual deficiency or neurologic or psychiatric disorder were excluded. Attentional skills were assessed by combining a parent questionnaire (Child Behavior CheckList) and a performance-based assessment (Conner's Continuous Performance Test-Second Edition). Reading comprehension was assessed through a standardized reading comprehension test (ORLEC Lobrot). The performance-based attention scores were associated with text and sentence comprehension ability (P = .0235 and P = .0164, respectively), while indirect questionnaire attention scores were only associated with sentence comprehension (P = .0263). For both groups, the correlations between questionnaire and performance-based measures were low. We have shown that reading comprehension is greatly influenced by attention in NF1 and non-NF1, even if predictors of good reading comprehension also include IQ score and reading accuracy. Indirect observer-rated questionnaires and direct performance-based measures of attention do not assess the same variables, are linked to different components of reading skills, and are not interchangeable assessments of attention difficulties. Both assessments are complementary and must be used simultaneously, leading to recommendations that support multimodal assessment of attention.

The heritability of reading and reading-related neurocognitive components: A multi-level meta-analysis

Reading ability is a complex task requiring the integration of multiple cognitive and perceptual systems supporting language, visual and orthographic processes, working memory, attention, motor movements, and higher-level comprehension and cognition. Estimates of genetic and environmental influences for some of these reading-related neurocognitive components vary across reports. By using a multi-level meta-analysis approach, we synthesized the results of behavioral genetic research on reading-related neurocognitive components (i.e. general reading, letter-word knowledge, phonological decoding, reading comprehension, spelling, phonological awareness, rapid automatized naming, and language) of 49 twin studies spanning 4.1-18.5 years of age, with a total sample size of more than 38,000 individuals. Except for language for which shared environment seems to play a more important role, the causal architecture across most of the reading-related neurocognitive components can be represented by the following equation a² > e² > c². Moderators analysis revealed that sex and spoken language did not affect the heritability of any reading-related skills; school grade levels moderated the heritability of general reading, reading comprehension and phonological awareness.

Poor stimulus discriminability as a common neuropsychological deficit between ADHD and reading ability in young children: a moderated mediation model

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is frequently associated with poorer reading ability; however, the specific neuropsychological domains linking this co-occurrence remain unclear. This study evaluates information-processing characteristics as possible neuropsychological links between ADHD symptoms and RA in a community-based sample of children and early adolescents with normal IQ (⩾70).

METHOD

The participants (n = 1857, aged 6-15 years, 47% female) were evaluated for reading ability (reading single words aloud) and information processing [stimulus discriminability in the two-choice reaction-time task estimated using diffusion models]. ADHD symptoms were ascertained through informant (parent) report using the Development and Well-Being Assessment (DAWBA). Verbal working memory (VWM; digit span backwards), visuospatial working memory (VSWM, Corsi Blocks backwards), sex, socioeconomic status, and IQ were included as covariates.

RESULTS

In a moderated mediation model, stimulus discriminability mediated the effect of ADHD on reading ability. This indirect effect was moderated by age such that a larger effect was seen among younger children.

CONCLUSION

The findings support the hypothesis that ADHD and reading ability are linked among young children via a neuropsychological deficit related to stimulus discriminability. Early interventions targeting stimulus discriminability might improve symptoms of inattention/hyperactivity and reading ability.

Phenotype refinement for comorbid attention deficit hyperactivity disorder and reading disability

Comorbidity between Attention Deficit Hyperactivity Disorder (ADHD) and reading disability (RD) is common; however, the heritability of this comorbidity is not well understood. This may be due to the complexity and heterogeneity of ADHD and RD phenotypes. Using alternative ADHD-RD sub-phenotypes instead of those arising from the DSM-IV may lead to greater success in the search for comorbid ADHD-RD susceptibility genes. Therefore, this study aims to refine ADHD-RD phenotypes into homogenous informative sub-phenotypes using latent class analysis (LCA). LCA was performed on 2,610 Australian twin families (6,535 individuals) in order to generate probabilistic genetically distinct classes that define ADHD-RD subtypes, including comorbidity, based on related symptom clusters. The LCA separated the phenotypes for ADHD and RD into nine classes. One class was unaffected; three classes demonstrated the three DSM-IV subtypes of ADHD, three subtypes showed different severities of RD, and two classes expressed a combination of RD and ADHD subtypes. LCA proved effective in refining the phenotypes of ADHD alone, RD alone, and ADHD-RD comorbidity, and its ability to classify them into homogenous groups based on clusters of symptoms, suggesting that the latent classes may be robust enough to use in molecular genetic studies.

Inattention, hyperactivity, and emergent literacy: different facets of inattention relate uniquely to preschoolers' reading-related skills

Although extant studies indicate that there is a strong association between attention deficit/hyperactivity disorder and reading ability in elementary school children, knowledge regarding the relation between inattentive and hyperactive/impulsive behaviors and emergent literacy in preschool children is less established. This study examined the unique and overlapping relations between measures that assess inattention and hyperactivity/impulsivity and emergent literacy skills in preschool children. Participants included 204 preschool children (M age = 56 months, 50.9% female, 79.8% European American). Behavioral rating scales were completed by teachers, and the Continuous Performance Test (CPT) and the Test of Preschool Early Literacy were completed by the preschoolers. Across measures, inattention was a unique correlate of emergent literacy skills, whereas hyperactivity/impulsivity was not. Both rating scales and the CPT indices of inattention were uniquely associated with emergent literacy skills. These results suggest that these measures are assessing different manifestations of inattention that are both unique correlates of early reading skills.

A Twin and Adoption Study of Reading Achievement: Exploration of Shared-Environmental and Gene-Environment-Interaction Effects

Existing behavior-genetic research implicates substantial influence of heredity and modest influence of shared environment on reading achievement and reading disability. Applying DeFries-Fulker analysis to a combined sample of twins and adoptees (N = 4,886, including 266 reading-disabled probands), the present study replicates prior findings of considerable heritability for both reading achievement and reading disability. A simple biometric model adequately described parent and offspring data (combined N = 9,430 parents and offspring) across differing types of families present in the sample Analyses yielded a high heritability estimate (around 0.70) and a negligible shared-environmentality estimate for both reading achievement and reading disability. No evidence of gene × environment interaction was found for parental reading ability and parental educational attainment, the two moderators analyzed.

The genetic association between ADHD symptoms and reading difficulties: the role of inattentiveness and IQ

Previous studies have documented the primarily genetic aetiology for the stronger phenotypic covariance between reading disability and ADHD inattention symptoms, compared to hyperactivity-impulsivity symptoms. In this study, we examined to what extent this covariation could be attributed to “generalist genes” shared with general cognitive ability or to “specialist” genes which may specifically underlie processes linking inattention symptoms and reading difficulties. We used multivariate structural equation modeling on IQ, parent and teacher ADHD ratings and parent ratings on reading difficulties from a general population sample of 1312 twins aged 7.9–10.9 years. The covariance between reading difficulties and ADHD inattention symptoms was largely driven by genetic (45%) and child-specific environment (21%) factors not shared with IQ and hyperactivity-impulsivity; only 11% of the covariance was due to genetic effects common with IQ. Aetiological influences shared among all phenotypes explained 47% of the variance in reading difficulties. The current study, using a general population sample, extends previous findings by showing, first, that the shared genetic variability between reading difficulties and ADHD inattention symptoms is largely independent from genes contributing to general cognitive ability and, second, that child-specific environment factors, independent from IQ, also contribute to the covariation between reading difficulties and inattention symptoms.