Kathleen Nielsen

Writing problems in developmental dyslexia ; Under-recognized and under-treated

The International Dyslexia Association defines dyslexia as unexpected problems of neurobiological origin in accuracy and rate of oral reading of single real words, single pseudowords, or text or of written spelling. However, prior research has focused more on the reading than the spelling problems of students with dyslexia. A test battery was administered to 122 children who met inclusion criteria for dyslexia and qualified their families for participation in a family genetics study that has been ongoing for over a decade. Their parents completed the same test battery. Although a past structural equation modeling study of typically developing children identified a significant path from handwriting to composition quality, the current structural equation modeling study identified a significant path from spelling to composition for children and their parents with dyslexia. Grapho-motor planning did not contribute uniquely to their composition, showing that writing is not just a motor skill. Students with dyslexia do have a problem in automatic letter writing and naming, which was related to impaired inhibition and verbal fluency, and may explain their spelling problems. Results are discussed in reference to the importance of providing explicit instruction in the phonological, orthographic, and morphological processes of spelling and in composition to students with dyslexia and not only offering accommodation for their writing problems.

Gender Differences in Severity of Writing and Reading Disabilities.

Gender differences in mean level of reading and writing skills were examined in 122 children (80 boys and 42 girls) and 200 adults (115 fathers and 85 mothers) who showed behavioral markers of dyslexia in a family genetics study. Gender differences were found in writing and replicated prior results for typically developing children: Boys and men were more impaired in handwriting and composing than were girls and women, but men, who were more impaired in those writing skills, were also more impaired in spelling than women. Men were more impaired than women in accuracy and rate of reading passages orally, but boys were not more impaired than girls on any of the reading measures. Males were consistently more impaired than females in orthographic skills, which may be the source of gender differences in writing, but not motor skills. Population-based studies that report gender differences in reading in children with dyslexia may be confounding reading and writing disorders--the latter being the true source of gender differences in both children and adults with dyslexia.

Evaluation of candidate genes for DYX1 and DYX2 in families with dyslexia.

Dyslexia is a common heterogeneous disorder with a significant genetic component. Multiple studies have replicated the evidence for linkage between variously defined phenotypes of dyslexia and chromosomal regions on 15q21 (DYX1) and 6p22.2 (DYX2). Based on association studies and the possibility for functional significance of several polymorphisms, candidate genes responsible for the observed linkage signal have been proposed—DYX1C1 for 15q21, and KIAA0319 and DCDC2 for 6p22.2. We investigated the evidence for contribution of these candidate genes to dyslexia in our sample of multigenerational families. Our previous quantitative linkage analyses in this dataset provided supportive evidence for linkage of dyslexia to the locus on chromosome 15, but not to the locus on chromosome 6. In the current study, we used probands from 191 families for a case control analysis, and proband‐parent trios for family‐based TDT analyses. The observation of weak evidence for transmission disequilibrium for one of the two studied polymorphisms in DYX1C1 suggests involvement of this gene in dyslexia in our dataset. We did not find evidence for the association of KIAA0319 or DCDC2 alleles to dyslexia in our sample. We observed a slight tendency for an intronic deletion in DCDC2 to be associated with worse performance on some quantitative measures of dyslexia in the probands in our sample, but not in their parents.

Genomewide scan for real-word reading subphenotypes of dyslexia: Novel chromosome 13 locus and genetic complexity

Dyslexia is a common learning disability exhibited as a delay in acquiring reading skills despite adequate intelligence and instruction. Reading single real words (real‐word reading, RWR) is especially impaired in many dyslexics. We performed a genome scan, using variance components (VC) linkage analysis and Bayesian Markov chain Monte Carlo (MCMC) joint segregation and linkage analysis, for three quantitative measures of RWR in 108 multigenerational families, with follow up of the strongest signals with parametric LOD score analyses. We used single‐word reading efficiency (SWE) to assess speed and accuracy of RWR, and word identification (WID) to assess accuracy alone. Adjusting SWE for WID provided a third measure of RWR efficiency. All three methods of analysis identified a strong linkage signal for SWE on chromosome 13q. Based on multipoint analysis with 13 markers we obtained a MCMC intensity ratio (IR) of 53.2 (chromosome‐wide P < 0.004), a VC LOD score of 2.29, and a parametric LOD score of 2.94, based on a quantitative‐trait model from MCMC segregation analysis (SA). A weaker signal for SWE on chromosome 2q occurred in the same location as a significant linkage peak seen previously in a scan for phonological decoding. MCMC oligogenic SA identified three models of transmission for WID, which could be assigned to two distinct linkage peaks on chromosomes 12 and 15. Taken together, these results indicate a locus for efficiency and accuracy of RWR on chromosome 13, and a complex model for inheritance of RWR accuracy with loci on chromosomes 12 and 15.

Genome Scan of a Nonword Repetition Phenotype in Families with Dyslexia: Evidence for Multiple Loci

To understand the genetic architecture of dyslexia and identify the locations of genes involved, we performed linkage analyses in multigenerational families using a phonological memory phenotype—Nonword Repetition (NWR). A genome scan was first performed on 438 people from 51 families (DS-1) and linkage was assessed using variance components (VC), Bayesian oligogenic (BO), and parametric analyses. For replication, the genome scan and analyses were repeated on 693 people from 93 families (DS-2). For the combined set (DS-C), analyses were performed with all three methods in the regions that were identified in both samples. In DS-1, regions on chromosomes 4p, 6q, 12p, 17q, and 22q exceeded our initial threshold for linkage, with 17q providing a parametric LOD score of 3.2. Analysis with DS-2 confirmed the locations on chromosomes 4p and 12p. The strongest VC and BO signals in both samples were on chromosome 4p in DS-C, with a parametric multipoint LODmax of 2.36 for the 4p locus. Our linkage analyses of NWR in dyslexia provide suggestive and reproducible evidence for linkage to 4p12 and 12p in both samples, and significant evidence for linkage to 17q in one of the samples. These results warrant further studies of phonological memory and chromosomal regions identified here in other datasets.

Relationships between language input and letter output modes in writing notes and summaries for students in grades 4 to 9 with persisting writing disabilities.

Abstract This study in programmatic research on technology-supported instruction first identified, through pretesting using evidence-based criteria, students with persisting specific learning disabilities (SLDs) in written language during middle childhood (grades 4–6) and early adolescence (grades 7–9). Participants then completed computerized writing instruction and posttesting. The 12 computer lessons varied output modes (letter production by stylus alternating with hunt and peck keyboarding versus by pencil with grooves alternating with touch typing on keyboard), input (read or heard source material), and task (notes or summaries). Posttesting and coded notes and summaries showed the effectiveness of computerized writing instruction on both writing tasks for multiple modes of language input and letter production output for improving letter production and related writing skills.

Emotional and Behavioral Correlates of Persisting Specific Learning Disabilities in Written Language During Middle Childhood and Early Adolescence

Parents completed the Behavior Assessment System for Children, Second Edition: Parent Rating Scale (BASC2 PRS) while their children (94 boys, 61 girls; M = 11 years 11 months) were given tests. Evidence-based profiles of multiple test scores and history (emergence and persistence) were used to assign to groups without specific learning disabilities in written language (SLDs-WL; n = 42 control) or with SLDs-WL (n = 29 dysgraphia, n = 65 dyslexia, or n = 19 oral and written language learning disability [OWL LD]). Parent ratings fell in the clinical or at-risk ranges for some individuals in all groups, but mean BASC2 PRS ratings showed nine significant main effects for group (n = 4): Behavioral Symptoms Index, Internalizing Problems Composite, Adaptive Skills Composite, two Clinical Scales (Atypicality and Attention Problems), and four Adaptive Scales (Adaptability, Activities of Daily Living, Leadership, and Functional Communication). Each SLDs-WL group differed significantly from the control group on these nine ratings, except dysgraphia on Atypicality and dyslexia on Adaptive Composite, Adaptability, and Leadership; and each correlated with one or more hallmark impairments associated with a specific SLD-WL. In a functional magnetic resonance imaging (fMRI) study (without OWL LD), the dysgraphia and dyslexia groups, but not control group, showed connectivity with amygdala; BASC2 PRS Internalizing Problems Composite (internal stress) correlated with amygdala connectivity from two cortical regions involved in written word processing and production for total sample (N = 40). Applications to assessing emotional and behavioral correlates of SLDs-WL for educational services and future research are discussed.

Evidence-Based Reading and Writing Assessment for Dyslexia in Adolescents and Young Adults.

The same working memory and reading and writing achievement phenotypes (behavioral markers of genetic variants) validated in prior research with younger children and older adults in a multi-generational family genetics study of dyslexia were used to study 81 adolescent and young adults (ages 16 to 25) from that study. Dyslexia is impaired word reading and spelling skills below the population mean and ability to use oral language to express thinking. These working memory predictor measures were given and used to predict reading and writing achievement: Coding (storing and processing) heard and spoken words (phonological coding), read and written words (orthographic coding), base words and affixes (morphological coding), and accumulating words over time (syntax coding); Cross-Code Integration (phonological loop for linking phonological name and orthographic letter codes and orthographic loop for linking orthographic letter codes and finger sequencing codes), and Supervisory Attention (focused and switching attention and self-monitoring during written word finding). Multiple regressions showed that most predictors explained individual difference in at least one reading or writing outcome, but which predictors explained unique variance beyond shared variance depended on outcome. ANOVAs confirmed that research-supported criteria for dyslexia validated for younger children and their parents could be used to diagnose which adolescents and young adults did (n=31) or did not (n=50) meet research criteria for dyslexia. Findings are discussed in reference to the heterogeneity of phenotypes (behavioral markers of genetic variables) and their application to assessment for accommodations and ongoing instruction for adolescents and young adults with dyslexia.

Insights about the role of movement in literacy learning based on movement ABC-2 checklist parent ratings for students with and without persisting specific learning disabilities

Movement, which draws on motor skills and executive functions for managing them, plays an important role in literacy learning (e.g., movement of mouth during oral reading and movement of hand and fingers during writing); but relatively little research has focused on movement skills in students with specific learning disabilities as the current study did. Parents completed normed Movement Assessment Battery for Children Checklist, 2nd edition (ABC-2), ratings and their children in grades 4 to 9 (M = 11 years, 11 months; 94 boys, 61 girls) completed diagnostic assessment used to assign them to diagnostic groups: control typical language learning (N = 42), dysgraphia (impaired handwriting) (N = 29), dyslexia (impaired word decoding/reading and spelling) (N = 65), or oral and written language learning disability (OWL LD) (impaired syntax in oral and written language) (N = 19). The research aims were to (a) correlate the Movement ABC-2 parent ratings for Scale A Static/Predictable Environment (15 items) and Scale B Dynamic/Unpredictable Environment (15 items) with reading and writing achievement in total sample varying within and across different skills; and (b) compare each specific learning disability group with the control group on Movement ABC-2 parent ratings for Scale A, Scale B, and Scale C Movement-Related (Non-Motor Executive Functions, or Self-Efficacy, or Affect) (13 items). At least one Movement ABC-2 parent rating was correlated with each assessed literacy achievement skill. Each of three specific learning disability groups differed from the control group on two Scale A (static/predictable environment) items (fastens buttons and forms letters with pencil or pen) and on three Scale C items (distractibility, overactive, and underestimates own ability); but only OWL LD differed from control on Scale B (dynamic/unpredictable environment) items. Applications of findings to assessment and instruction for students ascertained for and diagnosed with persisting specific learning disabilities in literacy learning, and future research directions are discussed.

Behavioral and brain evidence for language by ear, mouth, eye, and hand and motor skills in literacy learning

ABSTRACT Two studies were conducted of students with and without persisting Specific Learning Disabilities (SLDs-WL) in Grades 4 to 9 (M = 11 years, 11 months) that supported the hypotheses that CELF 4 parent ratings for listening (language by ear), speaking (language by mouth), reading (language by eye), and writing (language by hand) were correlated with both (a) normed, standardized behavioral measures of listening, speaking, reading, and writing achievement (Study 1, 94 boys and 61 girls); and (b) fMRI connectivity or DTI white matter integrity involving brain regions for primary motor functions or motor planning and control, or motor timing in a subsample of right handers who did not wear metal (Study 2, 28 boys and 16 girls). Results of these assessment studies, which have implications for planning instruction for three SLDs-WL (dysgraphia, dyslexia, and oral and written language learning disability [OWL LD]), show that more than multisensory instruction is relevant. Language by ear, by mouth, by eye, and by hand, as well as motor planning, control, and output skills and motor timing should also be considered. Research is also reviewed that supports other processes beyond multisensory input alone that should also be considered for students with SLDs-WL.