Language Phenotype for Reading and Writing Disability: A Family Approach

A theory-driven battery of 23 psychometric measures of reading, writing, and related language processes was administered to 102 probands (affected children in Grades 1 to 6 with documented reading problems, writing problems, or both) and both of their biological parents. Affected children and parents were compared on the structural relationships between related language processes (Verbal IQ [VIQ], orthographic, phonological, and rapid naming skills), component reading, (accuracy, rate, comprehension) and writing (handwriting, spelling, composition) skills. The orthographic factor had significant paths to all reading and writing skills, except reading comprehension, in both probands and adults. The phonological factor had significant paths to all reading and writing skills except reading rate and handwriting in probands, but in affected adults only if VIQ was removed. Rapid naming had significant paths only to reading rate in probands and adults. VIQ had significant paths to reading comprehension in probands and adults, and to reading accuracy, reading rate, spelling, and composition in affected adults, but not probands. These results are consistent with the claim of functional systems theory that the same language processes are orchestrated flexibly depending on task at hand. Results for across-age differences in the covariances among related language processes confirmed developmental predictions of connectionist theory. The number of language deficits (based on discrepancy from VIQ) uniquely predicted severity of reading and writing problems in children and spelling problems in adults.     

Learning disabilities and ADHD: overlapping spectrumn disorders

Clinical and psychoeducational data were analyzed for 119 children ages 8 to 16 years who were evaluated in a child diagnostic clinic. A learning disability (LD) was present in 70% of the children with attention-deficit/hyperactivity disorder (ADHD), with a learning disability in written expression two times more common (65%) than a learning disability in reading, math, or spelling. Children with LD and ADHD had more severe learning problems than children who had LD but no ADHD, and the former also had more severe attention problems than children who had ADHD but no LD. Further, children with ADHD but no LD had some degree of learning problem, and children with LD but no ADHD had some degree of attention problem. Results suggest that learning and attention problems are on a continuum, are interrelated, and usually coexist.     

Matthew effects in children with learning disabilities: Development of reading,IQ, and psychosocial problems from grade 2 to grade 8

Reading achievement, IQ, and behavior problems were assessed in second and eighth grade for a longitudinal sample of 57 children. Changes in these scores over time were compared for children with no learning disabilities versus children with math or reading disabilities (research-identified and/or school-identified). A widening of the group difference in IQ was seen between the math disabled and nondisabled groups, but otherwise the gaps between groups remained unchanged or narrowed over the six-year interval, indicating that hypothesized negative consequences of initial academic difficulties (“Matthew effects”) did not occur for most of the children with learning disabilities. Elevated rates of behavior problems were seen only for the group with math disabilities, suggesting that the type of learning disability needs to be taken into account in research on the association between academic and psychosocial problems.     

Longitudinal Stability of Reading-Related Skills and Their Prediction of Reading Development

Individual differences in word recognition, spelling, and reading comprehension for 324 children at a mean age of 16 were predicted from their reading-related skills (phoneme awareness, phonological decoding, rapid naming, and IQ) at a mean age of 10 years, after controlling the predictors for the autoregressive effects of the correlated reading skills. There were significant and longitudinally stable individual differences for all four reading-related skills that were independent from each of the reading and spelling skills. Yet the only significant longitudinal prediction of reading skills was from IQ at mean age 10 for reading comprehension at mean age 16. The extremely high longitudinal latent-trait stability correlations for individual differences in word recognition (.98) and spelling (.95) left little independent outcome variance that could be predicted by the reading-related skills. We discuss the practical and theoretical importance of these results and why they differ from studies of younger children.     

The Relationship of Spelling Recognition, RAN, and Phonological Awareness to Reading Skills in Older Poor Readers and Younger Reading-Matched Controls

The role of spelling recognition was examined in word reading skills and reading comprehension for dyslexic and nondyslexic children. Dyslexic and nondyslexic children were matched on their raw word reading proficiency. Relationships between spelling recognition and the following were examined for both groups of children: verbal ability, working memory, phonological measures, rapid naming, word reading, and reading comprehension. Children’s performance in spelling recognition was significantly associated with their skills in word reading and reading comprehension regardless of their reading disability status. Furthermore, spelling recognition contributed significant variance to reading comprehension for both dyslexic and nondyslexic children after the effects of phonological awareness, rapid naming, and word reading proficiency had been accounted for. The results support the role of spelling recognition in reading development for both groups of children and they are discussed using a componential reading fluency framework.     

Reading disability defined as a discrepancy between listening and reading comprehension: a longitudinal study of stability, gender differences, and prevalence

The purpose of this study was to determine whether defining reading disability by a discrepancy between group-administered tests of listening and reading comprehension would produce result similar in terms of stability, gender ratio, and prevalence to IQ-achievement test discrepancy definitions. The total population of a small school district (N = 1,008) was followed from prekindergarten through Grade 7-8 for 13 years. As is often seen in epidemiological studies using IQ and individually administered reading tests to define reading disability, stability in the classification of reading disability was low. Among the participants with a consistent reading disability, the male-to-female ratio was 3.2:1, compared with 1.3:1 for the 5.1% of the sample who were nondiscrepant poor readers in both lower and upper grades. A mean 2.7% of the population was classified as reading disabled over the eight-grade span, and only 1.7% demonstrated a consistent reading disability in both the lower and the upper grades. An increase in the ratio of nondiscrepant to discrepant poor readers after Grade 5 was due mainly to late-emerging poor readers. It was concluded that defining reading comprehension disability in terms of a discrepancy between listening and reading comprehension provides a fairly accurate estimate of the stability, gender ratio, and prevalence of the disorder.     

The validity of discrepancy-based definitions of reading disabilities.

This study addressed the validity of distinguishing children with reading disabilities according to the presence or absence of discrepancies between intelligence test scores and academic achievement. Three definitions of reading disability were used to provide criteria for five groups of children who (a) met a discrepancy-based definition uncorrected for the correlation of IQ and achievement; (b) met a discrepancy-based definition correcting for the correlation of IQ and achievement; (c) met a low achievement definition with no IQ discrepancy; (d) met criteria a and b; and (e) met none of the criteria and had no reading disability. Comparison of these five groups on a set of 10 neuropsychological tests corrected for correlations with IQ showed that group differences were small and accounted for little of the variability among groups. These results question the validity of segregating children with reading deficiencies according to discrepancies with IQ scores.     

Sound links in reading and spelling with discrepancy-defined dyslexics and children with moderate learning difficulties

This study reports the effects of a highly structuredindividually administered remedial teaching programmefor children with reading difficulties. Thephonological awareness, reading accuracy and spellingattainments of 28 children diagnosed as having low IQ(Mean IQ = 66, SD = 5.3) were compared with those of29 children diagnosed as having discrepancy defineddyslexia (Mean IQ = 95, SD = 8.4). The responsivenessto intervention of each group was also compared withteacher-referred reading-delayed children matched forinitial literacy skills. For reading accuracy andphonological awareness the dyslexic group respondedmore successfully than the low IQ group. The twogroups did not differ significantly on spelling. It isargued that the reading accuracy and phonologicalawareness results are in keeping with thephonological-core variable-difference (Stanovich &Siegel 1994) model of reading disability and that thegains of all groups on all measures were such thatthere is no obvious benefit in using IQ to selectchildren for a programme of individual teaching whichcombines reading with phonological awarenesstraining.     

Associations between academic and motor performance in a heterogeneous sample of children with learning disabilities

A heterogeneous sample of 137 school-aged children with learning disabilities (IQ > 80) attending special needs schools was examined on the Movement Assessment Battery for Children (MABC). The results show that compared to the available norm scores, 52.6% of the children tested performed below the 15th percentile on manual dexterity, 40.9% on ball skills, and 33.7% on balance skills. Furthermore, after controlling for IQ, significant small to moderate partial correlations were found between spelling and mathematics and the MABC total score, as well as small to moderate correlations between mathematics and balance, between reading and ball skills, and between spelling and manual dexterity. The present findings are compared with previously reported results obtained in more homogenous groups, and based on the resultant relationships between academic performance and motor development, recommendations for future motor intervention studies are made.     

Do the effects of computer-assisted practice differ for children with reading disabilities with and without IQ-achievement discrepancy?

This study was designed to assess whether the effects of computer-assisted practice on visual word recognition differed for children with reading disabilities (RD) with or without aptitude-achievement discrepancy. A sample of 73 Spanish children with low reading performance was selected using the discrepancy method, based on a standard score comparison (i.e., the difference between IQ and achievement standard scores). The sample was classified into three groups: (1) a group of 14 children with dyslexia (age M = 103.85 months; SD = 8.45) who received computer-based reading practice; (2) a group of 31 "garden-variety" (GV) poor readers (age M = 107.06 months; SD = 6.75) who received the same type of instruction; and (3) a group of 28 children with low reading performance (age M = 103.33 months; SD = 9.04) who did not receive computer-assisted practice. Children were pre- and posttested in word recognition, reading comprehension, phonological awareness, and visual and phonological tasks. The results indicated that both computer-assisted intervention groups showed improved word recognition compared to the control group. Nevertheless, children with dyslexia had more difficulties than GV poor readers during computer-based word reading under conditions that required extensive phonological computation, because their performance was more affected by low-frequency words and long words. In conclusion, we did not find empirical evidence in favor of the IQ-achievement discrepancy definition of reading disability, because IQ did not differentially predict treatment outcomes.     

Does IQ matter in adolescents' reading disability?

We studied the connection of IQ, reading disability (RD) and their interaction with reading, spelling and other cognitive skills in adolescents with average IQ and RD (n = 22), average IQ, non-RD (n = 71), below average IQ and RD (n = 29), and below average IQ non-RD (n = 33). IQ was not connected to reading and spelling in subjects without RD, but a connection to non-word spelling in subjects with RD existed. IQ and RD showed a connection to other cognitive skills (IQ to working memory, verbal memory and syntactic skills, RD to poor performance in text reading and rapid naming and both of them to reading comprehension, phonological and arithmetic skills), but no interaction existed. Our results are consistent with those of earlier studies showing that IQ does not play a significant role in the presentation of RD. However, adolescents with below average IQ and RD seemed to have much broader deficits in academically important skills such as arithmetic and reading comprehension than the other groups.     

Can reading disabilities be diagnosed without using intelligence tests?

Unlike conventional procedures, which use IQ in making diagnostic and eligibility decisions regarding learning disabilities, this demonstration study used listening comprehension and other reading-related tasks to make a differential diagnosis of reading disabilities. Tests of listening and reading comprehension were administered to 180 children from Grades 3 through 8. A regression equation was then derived to predict reading comprehension from listening comprehension. The regression equation was applied to the listening comprehension scores of seven children from Grades 3 to 8 who had reading difficulties, and their reading comprehension was predicted. Based on the discrepancy between their actual reading comprehension and the predicted reading comprehension, their reading difficulty was attributed to one of the following three factors: (a) poor decoding, (b) poor comprehension, or (c) a combination of poor decoding and poor comprehension. The validity of these diagnostic decisions was assessed by testing independently these children's word-decoding skill and reading speed. The results suggest that this diagnostic procedure has potential utility.     

Substance use, substance abuse, and LD among adolescents with a childhood history of ADHD

A clinic-referred sample of 109 children with attention-deficit/hyperactivity disorder (ADHD) was followed into adolescence for the ascertainment of alcohol and other drug use and abuse. Learning disability (reading or math) in childhood was examined as a predictor of adolescent substance use and substance use disorder for alcohol and marijuana. No statistically significant group differences for children with LD versus those without LD emerged even after using different methods to compute LD. IQ/achievement discrepancy scores were similarly not predictive of later use or abuse. However, children with ADHD who had higher IQs and higher levels of academic achievement in childhood were more likely to try cigarettes, to smoke daily, and to have their first drink of alcohol or first cigarette at an early age. Children with ADHD who had higher reading achievement scores were less likely to have later alcohol use disorder. Although these findings are necessarily preliminary, due to the small number of children interviewed, the pattern of results suggests that level of cognitive functioning--rather than discrepancy between IQ and achievement--is important for the prediction of later substance use and abuse, at least in this clinic-referred sample of children with ADHD. Further, different mechanisms of risk related to cognitive functioning may be operating for experimentation with legal drugs such as alcohol and tobacco, regular cigarette smoking, and problematic alcohol use.     

The role of IQ in a component model of reading

The purpose of this study was to test the role of visual processing speed and IQ in a model of reading. This study investigated whether the processes involved in reading differ between a group of children with and a group without reading disability. These two groups of children completed tests of reading comprehension, listening comprehension, decoding, processing speed, and intelligence. The results indicated that processing speed explains a significant amount of variance in reading comprehension over that accounted for by the simple view of reading. Also, IQ accounts for a significant amount of variance in reading over that accounted for by the simple view of reading and processing speed. Path analyses indicated that the effect of IQ on reading is partially mediated by decoding in the children with reading disability. The results point to the importance of the role of IQ in predicting reading comprehension.     

What We Know,What We Still Need to Know: Teaching Adolescents to Write

The purpose of this study was to uncover any differences in the early reading and spelling processes of children learning to read in a first language (L1) and children learning to read in a second language (L2). The reading and spelling development of native Dutch-speaking children and minority children in the first two grades of elementary school were compared. The children were given a number of tasks to test their vocabulary knowledge and the efficiency of their word decoding (including grapheme knowledge and word blending), word spelling (including cipher knowledge and phonemic segmentation), and reading comprehension processes. Analyses of variance were used to test for differences between the L1 and L2 learners. LISREL analyses were used to explore the components underlying the reading and spelling processes in the 2 groups of children. The results showed that the minority children kept up with the native Dutch-speaking children on word blending and word decoding tasks. On word spelling and reading comprehension, however, the minority children were found to be less efficient than their monolingual Dutch peers. The structural models for word decoding and word spelling were highly comparable for the 2 groups. For reading comprehension, vocabulary knowledge was found to have more of an impact on the L2 learners than on the L1 learners. This finding suggests that children learning to read in an L2 should be helped to build their lexical knowledge and that reading instruction should be matched to this knowledge.     

Academic underachievement among children with epilepsy: proportion exceeding psychometric criteria for learning disability and associated risk factors

This study assessed rates of learning disabilities (LD) by several psychometric definitions in children with epilepsy and identified risk factors. Participants (N = 173, ages 8-15 years) completed IQ screening, academic achievement testing, and structured interviews. Children with significant head injury, chronic physical conditions, or mental retardation were excluded. Using an IQ-achievement discrepancy definition, 48% exceeded the cutoff for LD in at least one academic area; using low-achievement definitions, 41% to 62% exceeded cutoffs in at least one academic area. Younger children with generalized nonabsence seizures were at increased risk for math LD using the IQ-achievement discrepancy definition; age of seizure onset and attention-deficit/hyperactivity disorder (ADHD) were risk factors for reading and math LD using low-achievement definitions. Writing was the most common domain affected, but neither ADHD nor seizure variables reliably identified children at risk for writing LD. Although children with earlier seizure onset, generalized nonabsence seizures, and comorbid ADHD appear to be at increased risk for some types of LD by some definitions, these findings largely suggest that all children with epilepsy should be considered vulnerable to LD. A diagnosis of epilepsy (even with controlled seizures and less severe seizure types) should provide sufficient cause to screen school-age children for LD and comorbid ADHD.     

Teacher Judgments of Student Reading and Math Skills: Associations With Child- and Classroom-Related Factors

The purpose of the study was to examine whether students’ linguistic skills and task-avoidant behavior (i.e., the child-related factors) and the mean level of academic skills (reading comprehension and math) of classmates (i.e., the class-related factor) are associated with teacher judgments of children’s reading comprehension and math skills. The participants were third-grade Estonian-speaking students (n?=?656; age 9?11 years) and their classroom teachers (n?=?51). The results of the structural equation modeling path analyses indicated that teachers tend to judge students showing higher academic and linguistic skills and lower avoidance behavior as higher on the reading comprehension and math skills. In contrast, the classmates’ higher academic skill level was related to lower judgments of individual children’s reading comprehension and math skills by teachers.     

Identifying sex differences in reading disability

The issue of sex differences in reading disability has been of recent interest in relation to sex ratios in families with reading disabled children and to possible sex biases in referred populations. Data from a study of 570 twins are used to develop alternative definitions of reading disability that vary in the manner to which sex effects are taken into account. These definitions include discrepancies between reading quotients and IQ, the use of the regression of reading onto IQ and chronological age/reading age differences. In each case the reading and spelling disability was defined either separately for the sexes or based upon the data for the sexes combined and with and without an IQ>90 exclusion criterion. The consequences of using the alternative definitions for prevalence, sex ratio and heritability are examined. The results demonstrate that the characteristics of reading disabled children vary with the way disability is defined. The excess of males seems to be a robust finding. Definitions that take into account differences in mean score for males and females reduce but do not eradicate the sex ratio. From the genetic analysis, there is no support for the suggestion that the genetic effect on reading is greater for females than males. It is concluded that the use of regression based procedures for identifying reading disability is desirable but that at present there is insufficient evidence to justify the adoption of separate regression procedures for the two sexes.     

Early reading success and its relationship to reading achievement and reading volume: replication of ‘10 years later’

Cunningham and Stanovich reported a longitudinal investigation over 10 years that examined the unique influence of exposure to print in explaining individual differences on various measures of reading achievement and declarative (general) knowledge. The present study replicated their investigation with a larger number of participants and additional measures of literacy and language skills. Fifty-four 1st graders were administered reading, spelling, vocabulary, IQ, and listening comprehension measures and then followed to the end of 10th grade. At the end of 10th grade, they were administered an IQ test and measures of reading comprehension, language ability, general knowledge, and exposure to print. Results showed that 1st grade reading skills were a strong predictor of 10th grade outcomes. Second and third-grade reading skills were predictive of individual differences in print exposure even after 10th grade reading comprehension and language ability had been partialed. Individual differences in print exposure also predicted differences in the growth of reading ability, word decoding, spelling, vocabulary, and listening comprehension throughout the elementary grades. Findings confirm the powerful, long-term benefits of providing children with a fast start in reading and support the reciprocal nature of strong reading skills and engagement in reading and reading-related activities.     

Pathsways to school achievement in very preterm and full term children

Individual differences in academic success were investigated in a geographically defined whole-population sample of very preterm children with a gestational age of less than 32 weeks or a birth weight of less than 1500 gm. The sample consisted of 264 very preterm children (75.6% of German-speaking survivors) and 264 controls matched for gender, socioeconomic status, marital status and age of mother, who were studied from birth. The present analyses focused on the impact of cognitive skills assessed at ages 6 and 8 on academic success at the age 13. IQ scores, prereading skills, reading, spelling, and math performance assessed during the last kindergarten year and again at the end of Grade 2 were used as predictors of academic success in early adolescence. Differences between very pretern children and controls in cognitive abilities already observed in earlier assessments remained stable over time, with controls on average performing more than half a standard deviation above the level of preterm children. Preterm children also performed poorer on the literacy measures and indicators of math performance. Multivariate and causal modeling revealed different prediction patterns for the two groups. Whereas IQ was particularly important for the prediction of academic success in the pre-term sample, general IQ was less relevant for the prediction of academic success in the control group. When subgroups of at-risk children were formed according to birth weight categories, we found that school problems were most pronounced for children with extremely low birth weight (1000 gm and less).