Family patterns of developmental dyslexia. Part III: Spelling errors as behavioral phenotype

Spelling deficits in children with intellectual disabilities: Evidence from a regular orthography

Introduction

In individuals with intellectual disabilities (ID), efficient reading and writing skills promote social integration, self-autonomy, and independence. However, research has mainly focused on reading skills, while evidence on spelling skills is scarce and mostly on English-speaking subjects. In the present research project, we compared the spelling skills of children with intellectual disabilities (ID) learning in Italian, a regular orthography, to those of typically developing children matched for school level.

Methods

In the first study, the performance on a Passage Dictation Test of forty-four children with ID attending regular classrooms from 4th to 8th grades (mean age = 12.16 years; SD = 1.57) were compared with controls matched for sex and grade. In the second study, a Words and Nonwords Dictation Test was administered (with stimuli varying for lexicality, orthographic complexity, regularity of transcription, and the presence of different types of phonetic-phonological difficulties) to twenty-two children with ID attending regular classrooms from 4th to 8th grades (mean age = 12.2 years; SD = 1.37) and 22 controls matched for sex and grade. In both studies, an error analysis was performed to characterize types of misspellings. Separate ANOVAs were performed on z scores.

Results

Children with ID generally had a lower performance than controls. In the Passage Dictation Test, they showed a higher number of phonological (and phonetic-phonological) errors than phonologically plausible ones, indicating, as a group, predominant phonological difficulties as compared to lexical-orthographic ones. In the Words and Nonwords Dictation Test, they performed poorly on regular stimuli presenting specific types of phonetic-to-phonological difficulties (geminates, non-continuant consonants) and committed more minimal distance, context-sensitive and simple conversion misspellings. However, deficits in the orthographic-lexical procedure, as indicated by a low performance in words with unpredictable spelling, were present in a high percentage of children.

Discussion

It is concluded that children with ID have significant spelling difficulties not confined to the orthographic process but also in phoneme-to-grapheme mapping that, in a regular orthography like Italian, should be acquired early and easily.

Sleepiness, Neuropsychological Skills, and Scholastic Learning in Children

Excessive daytime sleepiness is a frequent condition among children and adolescents that may lead to several and significant daytime consequences, including impaired neurocognitive skills and scholastic performance. Here, we evaluated in one hundred and ninety-one unselected primary school children, the relationship between sleepiness and a wide range of cognitive and academic skills through a standardized neuropsychological test battery. In order to assess the statistical relationship, we performed a partial least squares path modelling, a non-parametrical approach which combined a model of paths between latent variables and the coefficients between indicators and dimensions. Results were validated through the bootstrap approach and suggest that sleepiness is not associated with all cognitive and scholastic abilities, but only with those relying on verbal abilities and complex cognitive functions (i.e., reading comprehension, oral/syntactic comprehension, spelling, and mathematic skills). Our data suggest the idea that sleepiness in children is associated mostly with “higher” (mainly verbal) cognitive function(s), while the visuospatial domain was not affected.

Spelling Impairments in Italian Dyslexic Children with and without a History of Early Language Delay. Are There Any Differences?

Language delay is considered a frequent antecedent of literacy problems and both may be linked to phonological impairment. However, while several studies have examined the relationship between language delay and reading impairment, relatively few have focused on spelling. In this study, spelling performance of 28 children with developmental dyslexia (DD), 14 children with a history of language delay (LD), and 14 children without (NoLD) and 28 control participants were examined. Spelling was investigated by a writing to dictation task that included orthographically regular stimuli (word and non-words), as well as words with unpredictable transcription. Results indicated that all dyslexic participants underperformed compared to controls on both regular and unpredictable transcription stimuli, but LD performance was generally the worst. Moreover, spelling impairment assumed different characteristics in LD and NoLD children. LD children were more sensitive to acoustic-to-phonological variables, showing relevant failure especially on stimuli containing geminate consonants but also on polysyllabic stimuli and those containing non-continuant consonants. Error analysis confirmed these results, with LD children producing a higher rate of phonological errors respect to NoLD children and controls. Results were coherent with the hypothesis that among dyslexic children, those with previous language delay have more severe spelling deficit, suffering from defective orthographic lexical acquisition together with long-lasting phonological difficulties.

Neuropsychological Outcomes of Preterm Triplets Discordant for Birthweight: A Case Report

Multiple gestation is associated with a higher incidence of preterm birth and preterm birth often results in later neurocognitive and behavioral problems that persist into adulthood. The medical, neurobiological, familial, and socio-environmental factors determinant for an individual are unpredictable. We present neuropsychological data for fraternal triplets discordant for birthweight whose school-age outcome was inconsistent with the low birthweight literature and for whom neurobiological variables appeared especially pertinent. Preterm infants may achieve optimal outcomes, although etiological factors leading to such outcomes may depend heavily on care center variables that limit or avoid intracerebral and other medical complications of prematurity.

The Influence of Family History on Reading Remediation and Reading Skills in Children With Dyslexia

This study examined whether family history of reading disability influences the efficacy of reading remediation. A retrospective review of children’s performance in a reading remediation program was carried out along with parental interviews for 102 families. Significant improvements were found in the areas of nonword decoding, phonological awareness, and spelling following the reading remediation program. Younger children and children with lower IQs tended to receive less benefit from the remediation program. Having a paternal history of dyslexia was associated with smaller improvements in nonword decoding scores. Maternal history of dyslexia was not a significant predictor of changes in nonword decoding. These findings suggest that some reading skills may be most effectively integrated at later stages of development. They also point to the possibility of unique relationships that may exist between parents and children who have reading disabilities.

Neurodevelopmental dysfunction and specific learning disabilities in school-aged twins

The frequency of the developmental dysfunction and specific learning disabilities were assessed in the retrospective study in the group of 56 school-aged twins. The relationships between genetic, perinatal and social factors and learning disability were also determined. It was found that 12.5% of twins had learning disabilities. The most common neurodevelopmental dysfunction were language disorders, poor graphomotor fluency and poor fine motor dexterity. It was also found that educational difficulty were associated with prematurity, low Apgar scores, neonatal complications and familial predisposition.

Is preschool language impairment a risk factor for dyslexia in adolescence?

The literacy skills of 56 school leavers from the Bishop and Edmundson (1987) cohort of preschoolers with specific language impairment (SLI) were assessed at 15 years. The SLI group performed worse on tests of reading, spelling, and reading comprehension than age-matched controls and the literacy outcomes were particularly poor for those with Performance IQ less than 100. The rate of specific reading retardation in the SLI group had increased between the ages of 8 1/2 and 15 years and there had been a substantial drop in reading accuracy, relative to age. However, over 35% had reading skills within the normal range and those who had had isolated impairments of expressive phonology had a particularly good outcome. Our findings highlight the limitations of discrepancy definitions of dyslexia that do not take account of the changing demands of reading over time. We argue that children's phonological difficulties place them at risk of literacy failure at the outset of reading and that later, impairments of other language skills compromise development to adult levels of fluency.

A candidate phenotype for familial dyslexia

The probative analysis of genotype-phenotype relations in familial dyslexia requires operationally defined psychobiological outcome variables that are not confounded by cultural differences of orthography or other factors that may influence the clinical ascertainment and diagnosis of dyslexia. Timing precision, as expressed in coordinated motor action, was used as an objective behavioral measure that can be mapped on current knowledge of central nervous system functions as well as on the most salient non-reading deficits in developmental dyslexia. Dyslexia families with four distinct pedigrees and a normally reading reference group were the study subjects. The results indicated that impaired timing precision in bimanual coordination and in motor speech were transmitted vertically in affected members of about half of dyslexia families. Motor coordination deficits were associated with a disposition to make dysphonemic spelling errors. It is proposed that impaired timing precision identifies a behavioral phenotype in some familial dyslexia subtypes. The detailed analysis of coarticulation in speech production may be one pathway by which impaired timing precision in motor action impinges on reading and writing deficits in developmental dyslexia.