The effect of parents' literacy skills and children's preliteracy skills on the risk of dyslexia

A Model of the Home Literacy Environment and Family Risk of Reading Difficulty in Relation to Children's Preschool Emergent Literacy

This study extends the research on the preschool home literacy environment (HLE) in the context of the family risk (FR) of reading disability (RD) by examining a multiple-deficit model of RD. A total of 1,171 six-year-old Norwegian children were assessed at school entry, the onset of formal reading instruction in Norway. Their parents completed a questionnaire regarding their own RD, education, and the HLE. The final sample after applying the inclusion criteria was 794 children and their parents. The findings suggest, first, that two HLE factors (access to print and reading-related activities) should be distinguished rather than treated as a single factor ("exposure to print") as the majority of previous studies have done. This finding suggests a three-factor HLE model that includes parents' reading interests and habits, reading-related activities, and access to print. Second, family risk of RD is related to some extent to the HLE, even after controlling for parents' education. Third, children's experiences in their home environments and their emergent literacy may not be independent of their family risk of RD. More importantly, this study highlights the potential protective role of the HLE, especially when there is a history of RD within the family. The reason is that the positive association between the HLE and children's code-related emergent literacy remains significant when controlling for family risk of RD (access to print → emergent literacy: 0.39 [0.01, 0.68], p < 0.01; reading-related activities → emergent literacy: 0.37 [0.02, 0.35], p < 0.01; parents' reading interests and habits → emergent literacy: 0.26 [0.001, 0.15], p < 0.01). This finding supports that children's emergent literacy can be improved via a modifiable, dynamic factor such as the HLE.

Predicting Reading Fluency Growth from Grade 2 to Age 23 with Parental and Child Factors

Purpose

Reading fluency establishes the basis for the strong literacy skills needed for academic success. We aim to trace how reading fluency develops from childhood to adulthood and identify factors that influence this development.

Method

In this study, 200 families were followed. All participating children (N = 200, 47% female) were ethnic Finns and spoke Finnish as their native language. The dataset included children's reading fluency assessments (in Grades 2, 3, and 8 and at age 23), their self-reports, and parental questionnaires. For data analysis, growth curve models that included cognitive, motivational, and parental predictors were constructed.

Results

Significant variations in both developmental rates and adult outcomes of reading fluency were found. The developmental rate was predicted by rapid automatized naming (RAN), letter knowledge, the formal home literacy environment (HLE) (measured in kindergarten) and reading motivation (measured in elementary school). Adult outcome (fluency at age 23) was predicted by RAN, letter knowledge, formal HLE, and parental dyslexia. Further, those who had parents with resolving reading difficulties were more likely to follow a resolving trajectory themselves compared with those whose parents had persistent reading difficulties.

Conclusion

Our findings offer novel insights into how reading fluency develops into adulthood and identify key areas for future research to better understand the mechanisms behind reading fluency development.

Children with developmental dyslexia have equivalent audiovisual speech perception performance but their perceptual weights differ

As reading is inherently a multisensory, audiovisual (AV) process where visual symbols (i.e., letters) are connected to speech sounds, the question has been raised whether individuals with reading difficulties, like children with developmental dyslexia (DD), have broader impairments in multisensory processing. This question has been posed before, yet it remains unanswered due to (a) the complexity and contentious etiology of DD along with (b) lack of consensus on developmentally appropriate AV processing tasks. We created an ecologically valid task for measuring multisensory AV processing by leveraging the natural phenomenon that speech perception improves when listeners are provided visual information from mouth movements (particularly when the auditory signal is degraded). We designed this AV processing task with low cognitive and linguistic demands such that children with and without DD would have equal unimodal (auditory and visual) performance. We then collected data in a group of 135 children (age 6.5-15) with an AV speech perception task to answer the following questions: (1) How do AV speech perception benefits manifest in children, with and without DD? (2) Do children all use the same perceptual weights to create AV speech perception benefits, and (3) what is the role of phonological processing in AV speech perception? We show that children with and without DD have equal AV speech perception benefits on this task, but that children with DD rely less on auditory processing in more difficult listening situations to create these benefits and weigh both incoming information streams differently. Lastly, any reported differences in speech perception in children with DD might be better explained by differences in phonological processing than differences in reading skills. RESEARCH HIGHLIGHTS: Children with versus without developmental dyslexia have equal audiovisual speech perception benefits, regardless of their phonological awareness or reading skills. Children with developmental dyslexia rely less on auditory performance to create audiovisual speech perception benefits. Individual differences in speech perception in children might be better explained by differences in phonological processing than differences in reading skills.

Home reading environment, sociometric and demographic factors associated with dyslexia in primary school students in China: A case-control study

Background

Developmental dyslexia (DD) has been generally recognized as a multifactorial psychological disorder in recent decades. However, studies on reading and learning environment, social and demographic factors affecting Chinese developmental dyslexia (DD) are still scarce in China. This study aims to explore multidimensional home influencing factors associated with DD before and after birth.

Methods

A total of 60 dyslexic and 252 normal elementary school students graded 2-5 were recruited in Shantou, China. The Least Absolute Shrinkage and Selection Operator (LASSO) regression model was used for the social and demographic variables screening. Odds ratios (ORs) with 95 % confidence intervals (CIs) for associations between DD and related factors were estimated by multivariate logistic regression models.

Results

Through LASSO regression, we ultimately identified 13 key variables, including maternal education level and family monthly income, among others. The logistic regression analyses showed that the risk of DD was higher in children with lower maternal education levels. Divergent parenting styles may be a risk factor for developing DD as opposed to consistent parenting styles (OR = 4.93, 95%CI: 1.11-21.91). Children whose mothers suffered from malnutrition during pregnancy were more likely to develop DD (OR = 10.31, 95%CI: 1.84-37.86), as well as exposure to second-hand smoking at home every day (OR = 5.33, 95%CI: 1.52-18.66). Interestingly, children's active reading (OR = 0.26, 95%CI: 0.08-0.84; OR = 0.17, 95%CI: 0.04-0.76 for "sometimes" and "often" compared to none, respectively), children having extracurricular reading fairy tale books (OR = 0.37, 95%CI: 0.15-0.90), and children having extracurricular reading composition books (OR = 0.25, 95%CI: 0.09-0.69) were significant protective factors for DD.

Conclusions

Home reading environment, several educational, sociometric and demographic factors may influence the development of dyslexia. We should pay attention to these factors on the development of dyslexia, so as to provide the well social and familial environment to ensure the healthy development of children.

Intergenerational longitudinal associations between parental reading/musical traits, infants' auditory processing, and later phonological awareness skills

The intergenerational transmission of language/reading skills has been demonstrated by evidence reporting that parental literacy abilities contribute to the prediction of their offspring's language and reading skills. According to the "Intergenerational Multiple Deficit Model," literacy abilities of both parents are viewed as indicators of offspring's liability for literacy difficulties, since parents provide offspring with genetic and environmental endowment. Recently, studies focusing on the heritability of musical traits reached similar conclusions. The "Musical Abilities, Pleiotropy, Language, and Environment (MAPLE)" framework proposed that language/reading and musical traits share a common genetic architecture, and such shared components have an influence on the heritable neural underpinnings of basic-level skills underlying musical and language traits. Here, we investigate the intergenerational transmission of parental musical and language-related (reading) abilities on their offspring's neural response to a basic auditory stimulation (neural intermediate phenotype) and later phonological awareness skills, including in this complex association pattern the mediating effect of home environment. One-hundred and seventy-six families were involved in this study. Through self-report questionnaires we assessed parental reading abilities and musicality, as well as home literacy and musical environment. Offspring were involved in a longitudinal study: auditory processing was measured at 6  months of age by means of a Rapid Auditory Processing electrophysiological paradigm, and phonological awareness was assessed behaviorally at 5  years of age. Results reveal significant correlations between parents' reading skills and musical traits. Intergenerational associations were investigated through mediation analyses using structural equation modeling. For reading traits, the results revealed that paternal reading was indirectly associated with children's phonological awareness skills via their electrophysiological MisMatch Response at 6  months, while maternal reading was directly associated with children's phonological awareness. For musical traits, we found again that paternal musicality, rather than maternal characteristics, was associated with children's phonological phenotypes: in this case, the association was mediated by musical environment. These results provide some insight about the intergenerational pathways linking parental reading and musical traits, neural underpinnings of infants' auditory processing and later phonological awareness skills. Besides shedding light on possible intergenerational transmission mechanisms, this study may open up new perspectives for early intervention based on environmental enrichment.

Bioenvironmental Predictors of Childhood Reading and Speech Difficulties

PURPOSE

Reading and speech difficulties are common in childhood, yet it is not fully understood how much of their etiology is shared. This partly derives from methodological issues related to overlooking the potential co-occurrence between the two sets of difficulties. This study investigated the effects of five bioenvironmental predictors in a sample assessed for such co-occurrence.

METHOD

A combination of exploratory and confirmatory analyses was performed on longitudinal data from the National Child Development Study. Exploratory latent class analysis was performed on children's reading, speech, and language outcomes at ages 7 and 11 years. Membership in the obtained classes was modeled using a regression with sex and four early-life predictors: gestation period, socioeconomic status, maternal education, and the home reading environment.

RESULTS

The model yielded four latent classes that broadly reflected (1) average reading and speech, (2) excellent reading, (3) reading difficulties, and (4) speech difficulties. Early-life factors significantly predicted class membership. Male sex and preterm birth emerged as risk factors for both reading and speech difficulties. Protective effects against reading difficulties were identified for maternal education, and lower (but not higher) levels of socioeconomic status and the home reading environment.

CONCLUSIONS

Co-occurrence of reading and speech difficulties in the sample was low, and differential patterns of effect of the social environment were supported. Reading outcomes were under stronger malleable influence than speech outcomes.

The multiple-level framework of developmental dyslexia: the long trace from a neurodevelopmental deficit to an impaired cultural technique

Developmental dyslexia is a neurodevelopmental disorder characterized by an unexpected impairment in literacy acquisition leading to specific poor academic achievement and possible secondary symptoms. The multi-level framework of developmental dyslexia considers five levels of a causal pathway on which a given genotype is expressed and hierarchically transmitted from one level to the next under the increasing influence of individual learning-relevant traits and environmental factors moderated by cultural conditions. These levels are the neurobiological, the information processing and the skill level (prerequisites and acquisition of literacy skills), the academic achievement level and the level of secondary effects. Various risk factors are present at each level within the assumed causal pathway and can increase the likelihood of exhibiting developmental dyslexia. Transition from one level to the next is neither unidirectional nor inevitable. This fact has direct implications for prevention and intervention which can mitigate transitions from one level to the next. In this paper, various evidence-based theories and findings regarding deficits at different levels are placed in the proposed framework. In addition, the moderating effect of cultural impact at and between information processing and skill levels are further elaborated based on a review of findings regarding influences of different writing systems and orthographies. These differences impose culture-specific demands for literacy-specific cognitive procedures, influencing both literacy acquisition and the manifestation of developmental dyslexia.

Revisiting Multifactor Models of Dyslexia: Do They Fit Empirical Data and What Are Their Implications for Intervention?

Developmental dyslexia can be viewed as the result of the effects of single deficits or multiple deficits. This study presents a test of the applicability of a multifactor-interactive model (MFi-M) with a preliminary set of five variables corresponding to different neuropsychological functions involved in the reading process. The model has been tested on a sample of 55 school-age children with developmental dyslexia. The results show that the data fit a model in which each variable contributes to the reading ability in a non-additive but rather interactive way. These findings constitute a preliminary validation of the plausibility of the MFi-M, and encourage further research to add relevant factors and specify their relative weights. It is further discussed how subtype-based intervention approaches can be a suitable and advantageous framework for clinical intervention in a MFi-M perspective.

Development of an Abbreviated Adult Reading History Questionnaire (ARHQ-Brief) Using a Machine Learning Approach

Several crucial reasons exist to determine whether an adult has had a reading disorder (RD) and to predict a child's likelihood of developing RD. The Adult Reading History Questionnaire (ARHQ) is among the most commonly used self-reported questionnaires. High ARHQ scores indicate an increased likelihood that an adult had RD as a child and that their children may develop RD. This study focused on whether a subset of ARHQ items (ARHQ-Brief) could be equally effective in assessing adults' reading history as the full ARHQ. We used a machine learning approach, lasso (known as L1 regularization), and identified 6 of 23 items that resulted in the ARHQ-Brief. Data from 97 adults and 47 children were included. With the ARHQ-Brief, we report a threshold of 0.323 as suitable to identify past likelihood of RD in adults with a sensitivity of 72.4% and a specificity of 81.5%. Comparison of predictive performances between ARHQ-Brief and the full ARHQ showed that ARHQ-Brief explained an additional 10%-35.2% of the variance in adult and child reading. Furthermore, we validated ARHQ-Brief's superior ability to predict reading ability using an independent sample of 28 children. We close by discussing limitations and future directions.

Visual Implicit Learning Abilities in Infants at Familial Risk for Language and Learning Impairments

The ability of infants to track transitional probabilities (Statistical Learning—SL) and to extract and generalize high-order rules (Rule Learning—RL) from sequences of items have been proposed as being pivotal for the acquisition of language and reading skills. Although there is ample evidence of specific associations between SL and RL abilities and, respectively, vocabulary and grammar skills, research exploring SL and RL as early markers of language and learning (dis)abilities is still scarce. Here we investigated the efficiency of visual SL and RL skills in typically developing (TD) seven-month-old infants and in seven-month-old infants at high risk (HR) for language learning impairment. Infants were tested in two visual-habituation tasks aimed to measure their ability to extract transitional probabilities (SL task) or high-order, repetition-based rules (RL task) from sequences of visual shapes. Post-habituation looking time preferences revealed that both TD and HR infants succeeded in learning the statistical structure (SL task), while only TD infants, but not HR infants, were able to learn and generalize the high-order rule (RL task). These findings suggest that SL and RL may contribute differently to the emergence of language learning impairment and support the hypothesis that a mechanism linked to the extraction of grammar structures may contribute to the disorder.

Long-term effects of the home literacy environment on reading development: Familial risk for dyslexia as a moderator

This study aimed to gain better understanding of the associations between literacy activities at home and long-term language and literacy development. We extended the home literacy environment (HLE) model of Sénéchal and LeFevre (Child Development [2002], Vol. 73, pp. 445-460) by including repeated assessments of shared reading, oral language, and reading comprehension development, including examination of familial risk for dyslexia as a moderator, and following development over time from ages 2 to 15 years. Of the 198 Finnish participants, 106 have familial risk for dyslexia due to parental dyslexia. Our path models include development in vocabulary (2-5.5 years), emerging literacy (5.5 years), reading fluency (8 and 9 years), and reading comprehension (8, 9, and 15 years) as well as shared book reading with parents (2, 4, 5, 8, and 9 years), teaching literacy at home (4.5 years), and reading motivation (8-9 years). The results supported the HLE model in that teaching literacy at home predicted stronger emerging literacy skills, whereas shared book reading predicted vocabulary development and reading motivation. Both emerging literacy and vocabulary predicted reading development. Familial risk for dyslexia was a significant moderator regarding several paths; vocabulary, reading fluency, and shared reading were stronger predictors of reading comprehension among children with familial risk for dyslexia, whereas reading motivation was a stronger predictor of reading comprehension among adolescents with no familial risk. The findings underline the importance of shared reading and suggest a long-standing impact of shared reading on reading development both directly and through oral language development and reading motivation.

Shared storybook reading with children at family risk of dyslexia

Background

Shared storybook reading is an important context for language learning and often constitutes young children's first encounter with the printed word. The quality of early shared reading interactions is a known predictor of language and reading development, but few studies have examined these interactions in children at family risk of dyslexia.

Methods

This exploratory study describes the quality of shared storybook reading between mothers and their 3- to 4-year-old children at family risk of dyslexia (FR; n = 18) in comparison with dyads with no known risk (no-FR; n = 13). Mother-child interactions while sharing a familiar and an unfamiliar storybook were coded for type of extra-textual talk (meaning-related talk at the concrete and abstract levels; print-related talk) and affective quality. Maternal and child language and literacy skills were considered as potential correlates of shared reading quality.

Results

The linguistic and affective quality of shared reading was broadly comparable across FR and no-FR dyads, particularly when sharing a book they knew well, with large within-group variation. Mothers contributed more concrete meaning-related talk when introducing an unfamiliar book to their children; children contributed more extra-textual talk overall when sharing a familiar book. Maternal language, but not reading, skills were related to the linguistic quality of shared reading. The affective quality of reading interactions was rated more highly in dyads where mothers and children had stronger language skills.

Conclusions

These results suggest that the quality of shared reading does not vary systematically as a function of children's risk of dyslexia but is related to maternal language skills. This finding needs to be replicated in a larger sample in order to better understand the risk and protective factors associated with dyslexia.

Highlights

What is already known about this topic The quality of extra-textual talk during shared reading between parents and preschoolers predicts later language and literacy outcomes in typically developing children.The affective quality of early shared reading predicts children's motivation to read independently in later childhood.Children at family risk of dyslexia are more likely than their peers with no family risk to have difficulty learning to read and may show weaknesses in oral language skills. What this paper adds The linguistic and affective quality of shared reading between mothers and preschool children is broadly similar when children are at family risk of dyslexia compared with no family risk.The type and quantity of extra-textual talk contributed by mothers and children appears to differ according to the familiarity of the storybook, but replication of the findings in a larger sample is required.The linguistic and affective quality of shared reading is related to maternal language skills. Implications for theory, policy or practice Shared storybook reading offers rich language learning opportunities for children at family risk of dyslexia.Maternal language skills may be an important determinant of the interactional quality of shared reading.The linguistic and affective quality of shared reading is not clearly associated with maternal reading difficulties.

Animal models of developmental dyslexia: Where we are and what we are missing

Developmental dyslexia (DD) is a complex neurodevelopmental disorder and the most common learning disability among both school-aged children and across languages. Recently, sensory and cognitive mechanisms have been reported to be potential endophenotypes (EPs) for DD, and nine DD-candidate genes have been identified. Animal models have been used to investigate the etiopathological pathways that underlie the development of complex traits, as they enable the effects of genetic and/or environmental manipulations to be evaluated. Animal research designs have also been linked to cutting-edge clinical research questions by capitalizing on the use of EPs. For the present scoping review, we reviewed previous studies of murine models investigating the effects of DD-candidate genes. Moreover, we highlighted the use of animal models as an innovative way to unravel new insights behind the pathophysiology of reading (dis)ability and to assess cutting-edge preclinical models.

The effects of book exposure and reading interest on oral language skills of children with and without a familial risk of dyslexia

The potential role of home literacy environment (HLE) in children's language development has been widely studied. However, data on the HLE of children with familial risk (FR) of dyslexia are limited. In this longitudinal study, we examined (a) whether amount of book exposure and reading interest at age 4 were different in samples of Norwegian FR and no FR-children, respectively, (b) whether these home literacy-related factors exerted different effects depending on family-risk status on vocabulary and grammar skills at school entry age (6 years) and (c) whether they contributed independently to language outcomes at age 6, after controlling for the 4;6-year language skills. Results showed no significant between-group differences in book exposure and reading interest. Furthermore, while interest in reading did not affect vocabulary and grammar in either group, book exposure contributed to vocabulary skills only in the FR-group by school entry. However, this longitudinal association was mediated by lexical skills at age 4;6, implying that the HLE has a positive indirect effect on later language development through its effect on early language. Thus, these findings can be taken to suggest that early intervention including exposure to various book-reading activities for pre-school FR-children with poor expressive vocabulary is worth considering.

Language difficulties are a shared risk factor for both reading disorder and mathematics disorder

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Disorders of language (DLD), reading (RD) and mathematics (MD) are highly comorbid.

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RD and MD is associated with familial dyslexia and preschool language difficulties.

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The comorbidity between RD and MD arises because of shared risk factors.

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Children with RD should be assessed for MD and vice versa.

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Interventions for MD should take account of likely language problems.

Disorders of reading and mathematics co-occur at greater than chance rates, but they are often studied separately. This article reports the reading and arithmetic outcomes at 9 years of age from a longitudinal study of 224 children at high risk for dyslexia. Using a cutoff at the 10th centile, groups of children with reading disorder (RD), mathematics disorder (MD), and comorbid reading disorder and math disorder (RD&MD) were identified. The risk of these disorders was elevated in children selected in preschool with language difficulties or at family risk for dyslexia. There was a high degree of comorbidity between RD and MD, and many cases—particularly in the comorbid group—also reached the diagnostic threshold for developmental language disorder (DLD). On measures of language, phoneme awareness, rapid automatized naming (RAN) digits, and rated inattention, there was a stepwise pattern: RD > MD > RD&MD. Poor language was associated with each disorder and appears to be a cognitive risk factor for RD, MD, and RD&MD. These findings suggest that there are shared genetic risk factors operating for both RD and MD.

Longitudinal Effects of the Home Learning Environment and Parental Difficulties on Reading and Math Development Across Grades 1-9

This study focuses on parental reading and mathematical difficulties, the home literacy environment, and the home numeracy environment as well as their predictive role in Finnish children’s reading and mathematical development through Grades 1–9. We examined if parental reading and mathematical difficulties directly predict children’s academic performance and/or if they are mediated by the home learning environment. Mothers (n = 1590) and fathers (n = 1507) reported on their reading and mathematical difficulties as well as on the home environment (shared reading, teaching literacy, and numeracy) when their children were in kindergarten. Tests for reading fluency, reading comprehension, and arithmetic fluency were administered to children in Grades 1, 2, 3, 4, 7, and 9. Parental reading difficulties predicted children’s reading fluency, whereas parental mathematical difficulties predicted their reading comprehension and arithmetic fluency. Familial risk was associated with neither formal nor informal home environment factors, whereas maternal education had a significant relationship with both, with higher levels of education among mothers predicting less time spent on teaching activities and more time spent on shared reading. In addition, shared reading was significantly associated with the development of reading comprehension up to Grades 3 and 4, whereas other components of the home learning environment were not associated with any assessed skills. Our study highlights that taken together, familial risk, parental education, and the home learning environment form a complex pattern of associations with children’s mathematical and reading skills.

Pre-literacy heterogeneity in Dutch-speaking kindergartners: latent profile analysis

Research demonstrated that a dyslexia diagnosis is mainly given after the most effective time for intervention has passed, referred to as the dyslexia paradox. Although some pre-reading cognitive measures have been found to be strong predictors of early literacy acquisition, i.e., phonological awareness (PA), letter knowledge (LK), and rapid automatized naming (RAN), more insight in the variability of pre-reading profiles might be of great importance for early identification of children who have an elevated risk for developing dyslexia and to provide tailor-made interventions. To address this issue, this study used a latent profile analysis (LPA) to disentangle different pre-reading profiles in a sample of 1091 Dutch-speaking kindergartners. Four profiles emerged: high performers (16.50%), average performers (40.24%), below-average performers with average IQ (25.57%), and below-average performers with below-average IQ (17.69%). These results suggested two at-risk profiles diverging in IQ, which are presumably more likely to develop dyslexia later on. Although below-average profiles differed significantly in rapid naming and IQ, no clear evidence for the double-deficit theory was found in Dutch-speaking kindergartners. Educational level and reading history of the parents appeared to be predictive for children's classification membership. Our results point towards the heterogeneity that is already present in kindergartners and the possibility to identify at-risk profiles prior to reading instruction, which may be the foundation for earlier targeted interventions. However, more extended research is needed to determine the stability of these profiles across time and across different languages.

Unraveling the Relation Between Reading Comprehension and Print Exposure

The purpose of this study was to test the directionality of influence between reading comprehension (RC) and print exposure (PE), thereby estimating genetic and environmental effects of this relation. The sample consisted of 910 twins in fourth through ninth grades (M_age  = 12.33 years, SD = 1.41) from the Florida Twin Project on Reading, Behavior, and Environment. Using direction-of-causation model in a twin design, results supported a direction of influence running from RC to PE. This relation was underpinned by genetic and environmental factors of RC as well as PE. Implications for reading education are discussed.

The interplay of socio-economic status represented by paternal educational level, white matter structure and reading

A child’s school achievement is influenced by environmental factors. The environmental factors, when represented by socio-economic status (SES) of the family, have been demonstrated to be related to the reading skills of a child. The neural correlates of the relation between SES and reading have been less thoroughly investigated. The present study expands current research by exploring the relation between SES, quantified by paternal educational level, reading of the offspring and the structure of white matter pathways in the left hemisphere as derived from DTI-based tractography analyses. Therefore, three dorsal white matter pathways, i.e. the long, anterior and posterior segments of the arcuate fasciculus (AF), and three ventral white matter pathways, i.e. the inferior fronto-occipital fasciculus (IFOF), the inferior longitudinal fasciculus (ILF) and the uncinate fasciculus (UF), were manually dissected in the left hemisphere of 34 adolescents with a wide range of reading skills. The results demonstrated a relation between word reading, SES quantified by paternal educational level, and fractional anisotropy (FA) within the left dorsal AF segment and the left ventral UF. Thus, the present study proposes a relationship between paternal educational level and a specific white matter pathway that is important for reading, aiming to guide future research that can determine processes underlying this relationship.

Beyond genes: A systematic review of environmental risk factors in specific reading disorder

BACKGROUND

While an understanding of the genetic contributions to specific reading disorder (RD) is emerging, there is no agreement about which putative hazard factors are clearly involved in the aetiology of this disorder.

AIMS

A literature review looking at the impact of environmental risk variables implicated in RD either per se or when interacting with the genes.

METHODS AND PROCEDURES

We performed a systematic literature review using the following keywords: dyslexia OR reading disability AND environmental risk factors OR environmental hazard factors, in the following electronic databases: PubMed, Scopus and PsycINFO, without any time restrictions.

OUTCOMES AND RESULTS

Gestational weeks and birth weight are among the pre- and peri-natal risk factors shown to reliably predict reading readiness and the odds of having RD. Inconclusive findings have been reported for maternal cigarette smoking, family history of psychiatric and medical diseases, and risk of miscarriage. A broad definition of familial socio-economic status and home literacy environment have been identified as good life-long risk predictors of reading skills.

CONCLUSIONS AND IMPLICATIONS

We highlighted the need to consider environmental hazards, their interactions and interactions with RD-candidate genes in the study of the aetiology of RD in order to provide much-needed insight into how these variables influence 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.

Pathways Into Literacy: The Role of Early Oral Language Abilities and Family Risk for Dyslexia

The present study investigated the role of early oral language and family risk for dyslexia in the two developmental pathways toward reading comprehension, through word reading and through oral language abilities. The sample contained 237 children (164 at family risk for dyslexia) from the Dutch Dyslexia Program. Longitudinal data were obtained on seven occasions when children were between 4 and 12 years old. The relationship between early oral language ability and reading comprehension at the age of 12 years was mediated by preliteracy skills and word-decoding ability for the first pathway and by later language abilities for the second pathway. Family risk influenced literacy development through its subsequent relations with preliteracy skills, word decoding, and reading comprehension. Although performance on language measures was often lower for the family-risk group than for the no-family-risk group, family risk did not have a specific relation with either early or later oral language abilities.

Familial history of reading difficulty is associated with diffused bilateral brain activation during reading and greater association with visual attention abilities

Reading difficulty (RD; or dyslexia) is a heritable condition characterized by slow, inaccurate reading accompanied by executive dysfunction, specifically with respect to visual attention. The current study was designed to examine the effect of familial history of RD on the relationship between reading and visual attention abilities in children with RD using a functional MRI reading task. Seventy-one children with RD participated in the study. Based on parental reports of the existence of RD in one or both of each child's parents, children with RD were divided into two groups: (1) those with a familial history of RD and (2) those without a familial history of RD. Reading and visual attention measures were collected from all participants. Functional MRI data during word reading was acquired in 30 participants of the entire cohort. Children with or without a familial history of RD demonstrated below-average reading and visual attention scores, with greater interaction between these measures in the group with a familial history of RD. Greater bilateral and diffused activation during word reading also were found in this group. We suggest that a familial history of RD is related to greater association between lower reading abilities and visual attention abilities. Parental history of RD therefore may be an important preschool screener (before reading age) to prompt early intervention focused on executive functions and reading-related skills.

White matter pathways mediate parental effects on children's reading precursors

Previous studies have shown that the link between parental and offspring's reading is mediated by the cognitive system of the offspring, yet information about the mediating role of the neurobiological system is missing. This family study includes cognitive and diffusion MRI (dMRI) data collected in 71 pre-readers as well as parental reading and environmental data. Using sequential path analyses, which take into account the interrelationships between the different components, we observed mediating effects of the neurobiological system. More specifically, fathers' reading skills predicted reading of the child by operating through a child's left ventral white matter pathway. For mothers no clear mediating role of the neural system was observed. Given that our study involves children who have not yet learned to read and that environmental measures were taken into account, the paternal effect on a child's white matter pathway is unlikely to be only driven by environmental factors. Future intergenerational studies focusing on the genetic, neurobiological and cognitive level of parents and offspring will provide more insight in the relative contribution of parental environment and genes.

Genetic transmission of reading ability

Reading is the processing of written language. Family resemblance for reading (dis)ability might be due to transmission of a genetic liability or due to family environment, including cultural transmission from parents to offspring. Familial-risk studies exploring neurobehavioral precursors for dyslexia and twin studies can only speak to some of these issues, but a combined twin-family study can resolve the nature of the transmitted risk. Word-reading fluency scores of 1100 participants from 431 families (with twins, siblings and their parents) were analyzed to estimate genetic and environmental sources of variance, and to test the presence of assortative mating and cultural transmission. Results show that variation in reading ability is mainly caused by additive and non-additive genetic factors (64%). The substantial assortative mating (r_{father-mother}=0.38) has scientific and clinical implications. We conclude that parents and offspring tend to resemble each other for genetic reasons, and not due to cultural transmission.

The Association of Poor Academic Performance with Tic Disorders: A Longitudinal, Mainstream School-Based Population Study

BACKGROUND

Little is known about the academic performance of students with tic disorders (TD). Our aim was to investigate the association of TD and poor academic performance over time.

METHODS

Longitudinal, observational study of mainstream schoolchildren comparing grade retention (GR) and learning disorders (LD) in students with vs. without TD between 2010 and 2014. Students with vs. without TD based on DSM-IV-TR criteria, or with vs. without GR and LD were compared in terms of comorbidities, school, and environmental characteristics. The association of TD with GR was analyzed using hazard ratios (HRs) with 95% CIs, and with LD using logistic regression analysis [Odds ratio (OR)].

RESULTS

Two hundred fifty-eight students were included (mean age 14.0 ± 1.71 years, 143 [55.4%] males). The incident rate for TD and GR was 2.6 and 3.3 per 100 persons-year, respectively. LD found in 21 (9.9%) students was associated with TD (OR 11.62, 95% CI 2.21-60.90, p = 0.004), and attention deficit hyperactivity disorder (ADHD; OR 6.63, 95% CI 1.55-28.37, p = 0.01). Low psychological support (HRs 12.79, 95% CI 3.39-48.17) and low sport participation (HRs 6.41, 95% CI 1.54-26.78) were risk factors for GR.

CONCLUSIONS

TD was associated with academic difficulties, namely, LD in conjunction with ADHD but not GR. The diagnosis of TD and comorbidities, and the initiation of proper treatment could have a favorable impact on school performance, and consequently on social development.

Word Decoding Development during Phonics Instruction in Children at Risk for Dyslexia

In the present study, we examined the early word decoding development of 73 children at genetic risk of dyslexia and 73 matched controls. We conducted monthly curriculum-embedded word decoding measures during the first 5 months of phonics-based reading instruction followed by standardized word decoding measures halfway and by the end of first grade. In kindergarten, vocabulary, phonological awareness, lexical retrieval, and verbal and visual short-term memory were assessed. The results showed that the children at risk were less skilled in phonemic awareness in kindergarten. During the first 5 months of reading instruction, children at risk were less efficient in word decoding and the discrepancy increased over the months. In subsequent months, the discrepancy prevailed for simple words but increased for more complex words. Phonemic awareness and lexical retrieval predicted the reading development in children at risk and controls to the same extent. It is concluded that children at risk are behind their typical peers in word decoding development starting from the very beginning. Furthermore, it is concluded that the disadvantage increased during phonics instruction and that the same predictors underlie the development of word decoding in the two groups of children. Copyright © 2017 John Wiley & Sons, Ltd.

Child and environmental risk factors predicting readiness for learning in children at high risk of dyslexia

We investigate the role of distal, proximal, and child risk factors as predictors of reading readiness and attention and behavior in children at risk of dyslexia. The parents of a longitudinal sample of 251 preschool children, including children at family risk of dyslexia and children with preschool language difficulties, provided measures of socioeconomic status, home literacy environment, family stresses, and child health via interviews and questionnaires. Assessments of children's reading-related skills, behavior, and attention were used to define their readiness for learning at school entry. Children at family risk of dyslexia and children with preschool language difficulties experienced more environmental adversities and health risks than controls. The risks associated with family risk of dyslexia and with language status were additive. Both home literacy environment and child health predicted reading readiness while home literacy environment and family stresses predicted attention and behavior. Family risk of dyslexia did not predict readiness to learn once other risks were controlled and so seems likely to be best conceptualized as representing gene-environment correlations. Pooling across risks defined a cumulative risk index, which was a significant predictor of reading readiness and, together with nonverbal ability, accounted for 31% of the variance between children.

The Role of Categorical Speech Perception and Phonological Processing in Familial Risk Children With and Without Dyslexia

PURPOSE

This study assessed whether a categorical speech perception (CP) deficit is associated with dyslexia or familial risk for dyslexia, by exploring a possible cascading relation from speech perception to phonology to reading and by identifying whether speech perception distinguishes familial risk (FR) children with dyslexia (FRD) from those without dyslexia (FRND).

METHOD

Data were collected from 9-year-old FRD (n = 37) and FRND (n = 41) children and age-matched controls (n = 49) on CP identification and discrimination and on the phonological processing measures rapid automatized naming, phoneme awareness, and nonword repetition.

RESULTS

The FRD group performed more poorly on CP than the FRND and control groups. Findings on phonological processing align with the literature in that (a) phonological processing related to reading and (b) the FRD group showed the lowest phonological processing outcomes. Furthermore, CP correlated weakly with reading, but this relationship was fully mediated by rapid automatized naming.

CONCLUSION

Although CP phonological skills are related to dyslexia, there was no strong evidence for a cascade from CP to phonology to reading. Deficits in CP at the behavioral level are not directly associated with dyslexia.

Double-Deficit Hypothesis in a Clinical Sample: Extension Beyond Reading

This study explored the double-deficit hypothesis (DDH) in a transparent orthography (Finnish) and extended the view from reading disabilities to comorbidity of learning-related problems in math and attention. Children referred for evaluation of learning disabilities in second through sixth grade (N = 205) were divided into four groups based on rapid automatized naming (RAN) and phonological awareness (PA) according to the DDH: the double-deficit group, the naming speed deficit-only group, the phonological deficit-only group, and the no-deficit group. The results supported the DDH in that the prevalence and severity of reading disability were greatest in the double-deficit group. Despite the greater prevalence of reading disabilities in single-deficit groups compared to the no-deficit group, the means of reading measures in the single-deficit groups were similar to those of the no-deficit group. The PA single-deficit group was poorer in spelling than the no-deficit group and single-naming-deficit group. Deficits in RAN or PA were primarily linked to reading disabilities but not with math or attention problems. The results supported the DDH partially and indicate that deficits in RAN and PA are specific to reading disabilities.

Cognitive and familial risk evidence converged: A data-driven identification of distinct and homogeneous subtypes within the heterogeneous sample of reading disabled children

The evident degree of heterogeneity observed in reading disabled children has puzzled reading researchers for decades. Recent advances in the genetic underpinnings of reading disability have indicated that the heritable, familial risk for dyslexia is a major risk factor. The present data-driven, classification attempt aims to revisit the possibility of identifying distinct cognitive deficit profiles in a large sample of second to fourth grade reading disabled children. In this sample, we investigated whether genetic and environmental risk factors are able to distinguish between poor reader subtypes. In this profile, we included reading-related measures of phonemic awareness, letter-speech sound processing and rapid naming, known as candidate vulnerability markers associated with dyslexia and familial risk for dyslexia, as well as general cognitive abilities (non-verbal IQ and vocabulary). Clustering was based on a 200 multi-start K-means approach. Results revealed four emerging subtypes of which the first subtype showed no cognitive deficits underlying their poor reading skills (Reading-only impaired poor readers). The other three subtypes shared a core phonological deficit (PA) with a variable and discriminative expression across the other underlying vulnerability markers. More specific, type 2 showed low to poor performance across all reading-related and general cognitive abilities (general poor readers), type 3 showed a specific letter-speech sound mapping deficit next to a PA deficit (PA-LS specific poor readers) and type 4 showed a specific rapid naming deficit complementing their phonological weakness (PA-RAN specific poor readers). The first three poor reader profiles were more characterized by variable environmental risk factor, while the fourth, PA-RAN poor reader subtype showed a significantly strong familial risk for dyslexia. Overall, when we zoom in on the heterogeneous phenomenon of reading disability, unique and distinct cognitive subtypes can be identified, distinguishing between those poor readers more influences by the role of genes and those more influenced by environmental risk factors. Taking into account this diversity of distinct cognitive subtypes, instead of looking at the reading disabled sample as a whole, will help tailor future diagnostic and intervention efforts more specifically to the needs of children with such a specific deficit and risk pattern, as well as providing a more promising way forward for genetic studies of dyslexia.

Psychosocial Functioning of Children with and without Dyslexia: A Follow-up Study from Ages Four to Nine

This longitudinal study compares developmental changes in psychosocial functioning during the transition into school of children with and without dyslexia. In addition, it examines the effects of gender and family risk for dyslexia in terms of the associations between dyslexia and psychosocial functioning. Children's psychosocial functioning (social skills, inattention and externalizing and internalizing problems) was evaluated by their parents at ages 4, 6 and 9, and diagnosis for dyslexia was made at age 8 (in grade 2). The findings indicated that children with dyslexia were already rated as having poorer social skills and being more inattentive than were typical readers before their entry into school. Significant interactions of gender and diagnosis of dyslexia emerged for social skills and inattention. The social skills of boys with dyslexia improved after school entry as compared to the level of girls without dyslexia, whereas the social skills of girls with dyslexia did not improve. Boys with dyslexia were rated as showing a high level of inattention both prior to and after school entry, whereas, for girls with dyslexia, inattention ratings increased after school entry, eventually matching the boys' levels.

The intergenerational multiple deficit model and the case of dyslexia

Which children go on to develop dyslexia? Since dyslexia has a multifactorial etiology, this question can be restated as: what are the factors that put children at high risk for developing dyslexia? It is argued that a useful theoretical framework to address this question is Pennington’s (2006) multiple deficit model (MDM). This model replaces models that attribute dyslexia to a single underlying cause. Subsequently, the generalist genes hypothesis for learning (dis)abilities (Plomin and Kovas, 2005) is described and integrated with the MDM. Next, findings are presented from a longitudinal study with children at family risk for dyslexia. Such studies can contribute to testing and specifying the MDM. In this study, risk factors at both the child and family level were investigated. This led to the proposed intergenerational MDM, in which both parents confer liability via intertwined genetic and environmental pathways. Future scientific directions are discussed to investigate parent-offspring resemblance and transmission patterns, which will shed new light on disorder etiology.