Genetic influences on language, reading, and mathematics skills in a national sample: an analysis using the National Longitudinal Survey of Youth

The Moderating Role of the DYX1C1 Gene in the Effect of Home Supervision on Chinese Children's Reading Achievements: Evidence from the Diathesis-Stress Model

The current study aimed to explore whether susceptible children (with differences in DYX1C1 (dyslexia susceptibility 1 candidate gene 1) gene) are more likely to be influenced by either supportive or adverse home supervision in their reading achievements. Home supervision, reading achievements, and genotype data were collected from a total of 745 fourth and fifth grade children and their parents in Chongqing, China. The results showed that there was a significant interaction between the rs11629841 polymorphism of the DYX1C1 gene and home supervision on children's reading achievements. A further analysis based on the re-parameterized regression model showed that the interaction best fit a weak diathesis-stress model, which indicated that the home supervision had a stronger predictive effect on children's reading achievements among children with the susceptible genotype than children with a non-susceptible genotype in a more adverse environment rather than in a supportive environment. These results suggested that children carrying different genotypes may need targeted interventions and that their parents should emphasize home supervision to develop their children's reading skills.

Genetic and Environmental Influences on Achievement Outcomes Based on Family History of Learning Disabilities Status

A risk to develop a learning disability has been shown to run in families. Having a positive family history of learning disability seems to account for mean differences in achievement outcomes (reading, math) in that children with a positive family history score significantly lower compared to their peers with no such family history. However, the role of family history status in explaining etiological (genetic and environmental) differences among these subgroups of children has yet to be established. The present study of 872 twins (M_age = 13.30, SD_age = 1.40) from the Florida Twin Project on Reading, Behavior, and Environment utilized a multigroup approach to examine etiological differences on reading, spelling, and math among two subgroups defined by family history status. Results showed significant mean differences on all achievement outcomes, aside from math; however, no significant etiological differences on any achievement outcome were found among the two subgroups. Results support previous literature that the risk for developing a learning disability is transmitted through a family, but this is seemingly not manifested by differential etiology.

Examining the Etiology of Reading Disability as Conceptualized by the Hybrid Model

A fairly recent definition of reading disability (RD) is that in the form of a hybrid model. The model views RD as a latent construct that is manifested through various observable unexpected impairments in reading related skills and through inadequate response to intervention. The current report evaluated this new conceptualization of RD from an etiological perspective. The sample consisted of 2737 twin pairs in first through fourth grade (M_age = 8.52) from the Florida Twin Project on Reading. Using twin analyses, results showed that a substantial proportion of genetic variance, a small proportion of shared environmental, and a small proportion of non-shared environmental variance was attributed to the RD factor. Findings suggest that the etiological architecture of RD closely mirrors the structure of the hybrid model of RD.

Test anxiety and a high-stakes standardized reading comprehension test: A behavioral genetics perspective

Past research suggests that reading comprehension test performance does not rely solely on targeted cognitive processes such as word reading, but also on other non-target aspects such as test anxiety. Using a genetically sensitive design, we sought to understand the genetic and environmental etiology of the association between test anxiety and reading comprehension as measured by a high-stakes test. Mirroring the behavioral literature of test anxiety, three different dimensions of test anxiety were examined in relation to reading comprehension, namely intrusive thoughts, autonomic reactions, and off-task behaviors. Participants included 426 sets of twins from the Florida Twin Project on Reading. The results indicated test anxiety was negatively associated with reading comprehension test performance, specifically through common shared environmental influences. The significant contribution of test anxiety to reading comprehension on a high-stakes test supports the notion that non-targeted factors may be interfering with accurately assessing students' reading abilities.

Stability of core language skill across the first decade of life in children at biological and social risk

BACKGROUND

Command of language is a fundamental skill, a cornerstone of multiple cognitive and socioemotional aspects of development, and a necessary ingredient of successful adjustment and functioning in society. Little is known about the developmental stability of language in at-risk youth or which biological and social risk factors moderate stability.

METHODS

This four-wave 10-year prospective longitudinal study evaluated stability of core language skill in 1,780 children in varying categories of biological and social risk in a multiage, multidomain, multimeasure, and multireporter framework.

RESULTS

Structural equation modeling supported loadings of diverse age-appropriate measures of child language on single latent variables of core language skill at 15 and 25 months and 5 and 11 years, respectively. Core language skill was stable over the first decade of life; significant and comparable stability coefficients were obtained for children with diverse biological and social risks, including poor health, welfare status, teen motherhood, ethnicity, gender, birth order, and families that changed in income and maternal education over the study period; stability in language was strong even accounting for child nonverbal intelligence and social competence, maternal education and language, and the family home environment.

CONCLUSIONS

Core language skill varies in stability with age but is robustly stable in children regardless of multiple biological and social risk factors.

Cross-Study Differences in the Etiology of Reading Comprehension: a Meta-Analytical Review of Twin Studies

Numerous twin studies have examined the genetic and environmental etiology of reading comprehension, though it is likely that etiological estimates are influenced by unidentified sample conditions (e.g. Tucker-Drob and Bates, Psychol Sci:0956797615612727, 2015). The purpose of this meta-analysis was to average the etiological influences of reading comprehension and to explore the potential moderators influencing these estimates. Results revealed an average heritability estimate of h² = 0.59, with significant variation in estimates across studies, suggesting potential moderation. Moderation results indicated publication year, grade level, project, zygosity methods, and response type moderated heritability estimates. The average shared environmental estimate was c² = 0.16, with publication year, grade and zygosity methods acting as significant moderators. These findings support the role of genetics on reading comprehension, and a small significant role of shared environmental influences. The results suggest that our interpretation of how genes and environments influence reading comprehension should reflect aspects of study and sample.

Examining Associations Among ADHD, Homework Behavior, and Reading Comprehension: A Twin Study

Previous literature has indicated an important association between reading comprehension and both attention-deficit/hyperactivity disorder (ADHD) and homework habits. This investigation sought to extend previous knowledge by providing information about how ADHD and homework behavior (i.e., completing homework regularly) may jointly influence reading comprehension. Using a genetically sensitive design, this study examined the genetic and environmental influences on and between ADHD, homework behavior and reading comprehension. Participants for this study included 691 twin pairs (351 monozygotic, 340 same-sex dizygotic) from the Florida Twin Project on Behavior and Environment (FTP-BE) and 2647 twin pairs (865 monozygotic, 1782 dizygotic) from the larger Florida Twin Project on Reading (FTP-R) in Grades 3 through 7. Three separate models, each representing a different definition of ADHD (full ADHD, inattention only, and hyperactivity/impulsivity only), showed similar patterns of results; therefore, results of the full ADHD model are discussed. Overlapping genetic influences were found between ADHD, homework behavior, and reading comprehension, but no shared environmental influences among all three. However, shared environmental influences overlapped between homework behavior and reading comprehension. Although the sources of this environmental overlap are unknown, these results have implications for improving homework practices and their subsequent influence on literacy skills through homework environments.

The NLSY Kinship Links: Using the NLSY79 and NLSY-Children Data to Conduct Genetically-Informed and Family-Oriented Research

The National Longitudinal Survey of Youth datasets (NLSY79; NLSY-Children/Young Adults; NLSY97) have extensive family pedigree information contained within them. These data sources are based on probability sampling, a longitudinal design, and a cross-generational and within-family data structure, with hundreds of phenotypes relevant to behavior genetic (BG) researchers, as well as to other developmental and family researchers. These datasets provide a unique and powerful source of information for BG researchers. But much of the information required for biometrical modeling has been hidden, and has required substantial programming effort to uncover-until recently. Our research team has spent over 20 years developing kinship links to genetically inform biometrical modeling. In the most recent release of kinship links from two of the NLSY datasets, the direct kinship indicators included in the 2006 surveys allowed successful and unambiguous linking of over 94 % of the potential pairs. In this paper, we provide details for research teams interested in using the NLSY data portfolio to conduct BG (and other family-oriented) research.

Heritability of head motion during resting state functional MRI in 462 healthy twins

Head motion (HM) is a critical confounding factor in functional MRI. Here we investigate whether HM during resting state functional MRI (RS-fMRI) is influenced by genetic factors in a sample of 462 twins (65% female; 101 MZ (monozygotic) and 130 DZ (dizygotic) twin pairs; mean age: 21 (SD = 3.16), range 16-29). Heritability estimates for three HM components-mean translation (MT), maximum translation (MAXT) and mean rotation (MR)-ranged from 37 to 51%. We detected a significant common genetic influence on HM variability, with about two-thirds (genetic correlations range 0.76-1.00) of the variance shared between MR, MT and MAXT. A composite metric (HM-PC1), which aggregated these three, was also moderately heritable (h(2) = 42%). Using a sub-sample (N = 35) of the twins we confirmed that mean and maximum translational and rotational motions were consistent "traits" over repeated scans (r = 0.53-0.59); reliability was even higher for the composite metric (r = 0.66). In addition, phenotypic and cross-trait cross-twin correlations between HM and resting state functional connectivities (RS-FCs) with Brodmann areas (BA) 44 and 45, in which RS-FCs were found to be moderately heritable (BA44: h(2) = 0.23 (sd = 0.041), BA45: h(2) = 0.26 (sd = 0.061)), indicated that HM might not represent a major bias in genetic studies using FCs. Even so, the HM effect on FC was not completely eliminated after regression. HM may be a valuable endophenotype whose relationship with brain disorders remains to be elucidated.

Speech-language pathologists' knowledge of genetics: perceived confidence, attitudes, knowledge acquisition and practice-based variables

The purpose of this study was to determine (a) the general knowledge bases demonstrated by school-based speech-language pathologists (SLPs) in the area of genetics, (b) the confidence levels of SLPs in providing services to children and their families with genetic disorders/syndromes, (c) the attitudes of SLPs regarding genetics and communication disorders, (d) the primary sources used by SLPs to learn about genetic disorders/syndromes, and (e) the association between general knowledge, confidence, attitudes, the number of years of experience working as an SLP, and the number of children currently provided services with genetic disorders/syndromes on SLPs' caseloads. Survey data from a nationwide sample of 533 SLPs was analyzed. Results showed SLPs earned a median knowledge score about genetics of 66% correct responses. Their mean confidence and attitude ratings were in the "unsure" categories while they reported they learned about genetics from three main sources, (a) self-study via web and internet-based searches, (b) on-the-job training and (c) popular press magazines and newspapers. Analyses revealed that Confidence summary scores, Attitude Summary scores, the number of children with genetic disorders/syndromes on SLPs' caseloads are positively associated with the ratings of participants with the highest Knowledge scores.

LEARNING OUTCOMES

Readers will be able to (a) explain the important links between developmental and communication disabilities and genetics, (b) describe the associations between knowledge about genetics and confidence, attitudes, and the number of children with genetic disorders/syndromes on their caseloads, and (c) outline the clinical and theoretical implications of the results from this study.

A nationally representative study of the association between communication impairment at 4-5 years and children's life activities at 7-9 years

PURPOSE

To examine the longitudinal association between communication impairment (primary or secondary diagnosis) and children's Activities and Participation (International Classification of Functioning, Disability and Health--Children and Youth [ICF-CY]; World Health Organization [WHO], 2007).

METHOD

Participants were 4,329 children in the Longitudinal Study of Australian Children (LSAC; Australian Institute of Family Studies [AIFS], 2009): 1,041 (24.0%) of these children were identified with communication impairment at 4-5 years of age, and 3,288 (76.0%) of these children were not identified with a communication impairment. At age 7-9 years, Activities and Participation (WHO, 2007) outcomes across 5 ICF-CY domains were provided by (a) teachers (Academic Rating Scales [National Center for Education Statistics (NCES), 2002], Approach to Learning Scale [Gresham & Elliott, 1990], School Progress Scale (AIFS, 2009), Strengths and Difficulties Questionnaire [SDQ; Goodman, 1997], and Student-Teacher Relationship Scale [Pianta, 2001]); (b) parents (School-Age Inventory of Temperament [McClowry, 1995] and SDQ); (c) children (Marsh Self-Description Questionnaire-III [Marsh, 1992], School Liking [Ladd & Price, 1987], and Bullying [Kochenderfer & Ladd, 1997]); and (d) child assessment (Peabody Picture Vocabulary Test--III: Adapted; Rothman, 2003).

RESULTS

Children identified with communication impairment at age 4-5 years performed significantly poorer at age 7-9 years on all outcomes. Parents and teachers reported slower progression in reading, writing, and overall school achievement than peers. Children reported more bullying, poorer peer relationships, and less enjoyment of school than did their peers. Analyses of covariance tests confirmed significant associations between communication impairment and outcomes, over and above the effects of sex, age, Indigenous status, and socioeconomic status.

CONCLUSION

Consideration of the breadth and longevity of Activities and Participation outcomes reveals the potential extent and severity of communication impairment and directs future research and practice.

Using Language Sampling to Measure Language Growth

This article illustrates how speech-language pathologists (SLPs) can use language sampling and growth curve modeling (GCM) to examine the language growth rates of English Language Learners. GCM data on language samples provides SLPs with powerful, new tools to evaluate actual progress over time instead of relying on single, static measurement endpoints to determine typical development.

Data Recycling: Using Existing Databases to Increase Research Capacity in Speech-Language Development and Disorders

Purpose

This clinical forum was organized to provide a means for informing the research and clinical communities of one mechanism through which research capacity might be enhanced within the field of speech-language pathology. Specifically, forum authors describe the process of conducting secondary analyses of extant databases to answer questions of relevance to speech and language development and disorders.

Method

This prologue defines the concept of secondary analysis of databases and provides an overview of each of the articles that make up the forum.

Conclusion

Researchers invested in addressing basic and applied problems of relevance to speech and language services in schools can make use of a variety of extant databases to increase research capacity.