Developmental and Acquired Dyslexias

Characterizing different types of developmental dyslexias in French: The Malabi screener

Reading is a complex process involving multiple stages. An impairment in any of these stages may cause distinct types of reading deficits- distinct types of dyslexia. We describe the Malabi, a screener to identify deficits in various orthographic, lexical, and sublexical components of the reading process in French. The Malabi utilizes stimuli that are sensitive to different forms of dyslexia, including "attentional dyslexia", as it is traditionally refered to, characterized by letter-to-word binding impairments leading to letter migrations between words (e.g., "bar cat" misread as "bat car"), and "letter-position dyslexia", resulting in letter transpositions within words (e.g., "destiny" misread as "density"). After collecting reading error norms from 138 French middle-school students, we analyzed error types of 16 students with developmental dyslexia. We identified three selective cases of attentional dyslexia and one case of letter-position dyslexia. Further tests confirmed our diagnosis and demonstrate, for the first time, how these dyslexias are manifested in French. These results underscore the significance of recognizing and discussing the existence of multiple dyslexias, both in research contexts when selecting participants for dyslexia studies, and in practical settings where educators and practitioners work with students to develop personalized support. The test and supporting materials are available on Open Science Framework (https://osf.io/3pgzb/).

Measuring the Emergence of Specific Abilities in Young Children with Autism Spectrum Disorders: The Example of Early Hyperlexic Traits

The presence of a restricted interest in written materials, including an early ability to name and recognize letters and numbers, is regularly reported in preschoolers with autism spectrum disorders (ASDs). There is, however, scarce information on this early ability akin to emerging hyperlexic traits in preschoolers with ASD younger than 3 years old. Here, we defined a measure of early naming and recognition of letters and numbers in 155 preschoolers with ASD using a sliding window approach combined with a 90th percentile threshold criterion, and subsequently compared the profiles of children with ASD with and without early hyperlexic traits. Using this measure, we found that 9% of children with ASD showed early hyperlexic traits. The early ability to name and recognize letters and numbers was associated with a higher level of restricted and repetitive behaviors yet more social-oriented behaviors at baseline and with better expressive and written communication at baseline and one year later. This study contributes to a better definition of the profile of children with ASD with an early ability in letters and numbers akin to emerging hyperlexic traits, a skill that is associated with promising social strengths and language abilities in this subgroup of children.

Functional basic reading skills in Williams syndrome

This study investigated whether individuals with Williams syndrome (WS) can attain a functional level of basic reading skills. The Study also investigated broader cognitive factors associated with reading ability in individuals with WS. Thirty individuals with WS participated in this study (mean chronological age 21 years and mean mental age 7 years 7 months). The results supported our hypotheses that: firstly, reading abilities would be heterogeneous in WS; secondly, at least some WS individuals are capable of achieving a functional basic reading level; and thirdly, on average, WS individuals would find reading of nonwords more difficult than reading of regular and irregular words. Moreover, higher reading ability was found to be associated with increased outcomes in adaptive functioning, in particular, Written and Expressive Communication skills and Community Living skills, highlighting the potential benefits of developing reading abilities in WS. Although Intelligence Quotient (IQ) was related to overall basic reading ability generally, it was not found to be a determining factor in reading subtypes. Several cognitive skills known to be related to reading ability in typically developing individuals were found to be associated with reading performance and reading subtypes. Implications for appropriate reading instruction are discussed.

Developmental graphemic buffer dysgraphia in English: A single case study

A single case study is reported of a 10-year-old, English-speaking boy, L.S., who presented with spelling errors similar to those described in acquired graphemic buffer dysgraphia (GBD). We used this case to evaluate the appropriateness of applying adult cognitive models to the investigation of developmental cognitive disorders. The dual-route model of spelling guided this investigation. L.S. primarily made "letter errors" (deletions, additions, substitutions, transpositions, or a combination of these errors) on words and nonwords and in all input (aural and visual) and output modalities (writing, typing, oral spelling); there was also some evidence of a length effect and U-shaped serial position curve. An effect of lexical variables on spelling performance was also found. We conclude that the most parsimonious account is an impairment at the level of the graphemic buffer and without systematic cognitive neuropsychological investigation, the nature of L.S.'s spelling difficulty would likely have been missed.

Teaching Psychopathology in a Galaxy Far, Far Away: The Light Side of the Force

Star Wars films are among the top box office hits of all time. The films have been popular internationally for almost 40 years. As such, both trainees and attending psychiatrists are likely to be aware of them. This article highlights a vast array of psychopathology in Star Wars films which can be useful in teaching, even when the characters are considered the "good guys". Included are as follows: histrionic, obsessive-compulsive, and dependent personality traits, perinatal psychiatric disorders, prodromal schizophrenia, pseudo-dementia, frontal lobe lesions, pathological gambling, and even malingering. As such, Star Wars has tremendous potential to teach psychiatric trainees about mental health issues.

Modeling individual differences in text reading fluency: a different pattern of predictors for typically developing and dyslexic readers

This study was aimed at predicting individual differences in text reading fluency. The basic proposal included two factors, i.e., the ability to decode letter strings (measured by discrete pseudo-word reading) and integration of the various sub-components involved in reading (measured by Rapid Automatized Naming, RAN). Subsequently, a third factor was added to the model, i.e., naming of discrete digits. In order to use homogeneous measures, all contributing variables considered the entire processing of the item, including pronunciation time. The model, which was based on commonality analysis, was applied to data from a group of 43 typically developing readers (11- to 13-year-olds) and a group of 25 chronologically matched dyslexic children. In typically developing readers, both orthographic decoding and integration of reading sub-components contributed significantly to the overall prediction of text reading fluency. The model prediction was higher (from ca. 37 to 52% of the explained variance) when we included the naming of discrete digits variable, which had a suppressive effect on pseudo-word reading. In the dyslexic readers, the variance explained by the two-factor model was high (69%) and did not change when the third factor was added. The lack of a suppression effect was likely due to the prominent individual differences in poor orthographic decoding of the dyslexic children. Analyses on data from both groups of children were replicated by using patches of colors as stimuli (both in the RAN task and in the discrete naming task) obtaining similar results. We conclude that it is possible to predict much of the variance in text-reading fluency using basic processes, such as orthographic decoding and integration of reading sub-components, even without taking into consideration higher-order linguistic factors such as lexical, semantic and contextual abilities. The approach validity of using proximal vs. distal causes to predict reading fluency is discussed.

Predicting reading comprehension academic achievement in late adolescents with velo-cardio-facial (22q11.2 deletion) syndrome (VCFS): a longitudinal study

BACKGROUND

The primary objective of the current study was to examine the childhood predictors of adolescent reading comprehension in velo-cardio-facial syndrome (VCFS). Although much research has focused on mathematics skills among individuals with VCFS, no studies have examined predictors of reading comprehension.

METHODS

69 late adolescents with VCFS, 23 siblings of youth with VCFS and 30 community controls participated in a longitudinal research project and had repeat neuropsychological test batteries and psychiatric evaluations every 3 years. The Wechsler Individual Achievement Test-2nd edition (WIAT-II) Reading Comprehension subtest served as our primary outcome variable.

RESULTS

Consistent with previous research, children and adolescents with VCFS had mean reading comprehension scores on the WIAT-II, that were approximately two standard deviations below the mean and word reading scores approximately one standard deviation below the mean. A more novel finding is that relative to both control groups, individuals with VCFS demonstrated a longitudinal decline in reading comprehension abilities yet a slight increase in word reading abilities. In the combined control sample, WISC-III FSIQ, WIAT-II Word Reading, WISC-III Vocabulary and CVLT-C List A Trial 1 accounted for 75% of the variance in Time 3 WIAT-II Reading Comprehension scores. In the VCFS sample, WISC-III FSIQ, BASC-Teacher Aggression, CVLT-C Intrusions, Tower of London, Visual Span Backwards, WCST Non-perseverative Errors, WIAT-II Word Reading and WISC-III Freedom from Distractibility index accounted for 85% of the variance in Time 3 WIAT-II Reading Comprehension scores. A principal component analysis with promax rotation computed on the statistically significant Time 1 predictor variables in the VCFS sample resulted in three factors: Word reading decoding/Interference control, Self-Control/Self-Monitoring and Working Memory.

CONCLUSIONS

Childhood predictors of late adolescent reading comprehension in VCFS differ in some meaningful ways from predictors in the non-VCFS population. These results offer some guidance for how best to consider intervention efforts to improve reading comprehension in the VCFS population.

The role of the efferent auditory system in developmental dyslexia

OBJECTIVE

To assess the role of the efferent auditory system by inhibition of contralateral otoacoustic emission in dyslexic children with auditory processing disorders.

METHODS

The study sample was 34 children: 17 with dyslexia and 17 age-matched controls. Sensitive speech tests (low-pass filtered, time-compressed, distorted and dichotic) were performed to assess coexisting auditory processing disorder. Distortion-product otoacoustic emission (DPOAE) values were measured in basal condition and with contralateral broadband noise signal delivered via an earphone transducer at 60 dB SPL.

RESULTS

The lower scores at sensitive speech testing confirmed the association of an auditory processing disorder in the dyslexic children. DPOAE values were significantly attenuated by contralateral inhibition only in the control group (p=0.001; dyslexics, p=0.19); attenuation was not significant at any frequency in the dyslexic group.

CONCLUSIONS

The differences in DPOAE attenuation between the groups, although not statistically significant, suggest alterations in the auditory efferent system in the dyslexic population. These alterations may affect language perception. If confirmed in further studies with larger samples, these results could provide insight into a possible pathophysiological background of dyslexia.

Developmental dyslexia in a regular orthography: can the reading profile be reduced to strategic control?

In languages with regular orthographies, the identification of different forms of reading impairment (such as surface or phonological dyslexia) has proved elusive. Alternatively, it has been proposed that different patterns of errors depend upon strategic choices on the part of the reader. The present study aimed to test this strategic interpretation by evaluating the effectiveness of instructions to read quickly (or accurately) in modifying the reading rate and types of errors of dyslexic children. Further, drawing on an error classification based on the contrast between sounding-out behaviour and word substitution, we examined the types of reading error that best characterize the deficit in a language with regular orthography (Italian). Thirty children with dyslexia and 30 chronologically age-matched controls read aloud passages and word lists with instructions to emphasize either rate or accuracy. When asked to read quickly, children with dyslexia increased their reading rate (although less than skilled children). However, the type of instructions had little influence on reading errors. Therefore, the results did not support the view that strategic control has an important role in modulating the types of reading errors made by children with dyslexia. For word lists, sounding-out behaviour, errors in stress assignment, and form-related nonwords were useful to correctly identifying children with dyslexia. For text passages, sounding-out behaviour and form-related errors were the best predictors of group membership. Thus, specific types of errors are a fundamental component of the reading deficit in children who speak a language with regular orthography over and above their reading slowness.

Memory profiles of Down, Williams, and fragile X syndromes: implications for reading development

The purpose of this review was to understand the types of memory impairments that are associated with intellectual disability (ID, formerly called mental retardation) and the implications of these impairments for reading development. Specifically, studies on working memory, delayed memory and learning, and semantic/conceptual memory in Down syndrome, Williams syndrome, and fragile X syndrome were examined. A distinct memory profile emerged for each of the 3 etiologies of ID. Memory profiles are discussed in relation to strengths and weaknesses in reading skills in these three etiologies. We suggest that reading instruction be designed to capitalize on relatively stronger memory skills while providing extra support for especially challenging aspects of reading.

A theoretical molecular network for dyslexia: integrating available genetic findings

Developmental dyslexia is a common specific childhood learning disorder with a strong heritable component. Previous studies using different genetic approaches have identified several genetic loci and candidate genes for dyslexia. In this article, we have integrated the current knowledge on 14 dyslexia candidate genes suggested by cytogenetic findings, linkage and association studies. We found that 10 of the 14 dyslexia candidate genes (ROBO1, KIAA0319, KIAA0319L, S100B, DOCK4, FMR1, DIP2A, GTF2I, DYX1C1 and DCDC2) fit into a theoretical molecular network involved in neuronal migration and neurite outgrowth. Based on this, we also propose three novel dyslexia candidate genes (SLIT2, HMGB1 and VAPA) from known linkage regions, and we discuss the possible involvement of genes emerging from the two reported genome-wide association studies for reading impairment-related phenotypes in the identified network.

Language and Literacy Development of Children with Williams Syndrome

Children with Williams syndrome, a rare neurodevelopmental disorder caused by deletion of ~25 genes on chromosome 7q11.23, evidence large individual differences in both broad language and reading abilities. Nevertheless, as a group, children with this syndrome show a consistent pattern characterized by relative strengths in concrete vocabulary and phonological processing (language skills strongly related to single-word reading) and relative weaknesses in relational concepts, receptive grammar, verbal working memory, comprehension monitoring, and discourse (language skills strongly related to reading comprehension). Children with Williams syndrome who have been taught reading using a systematic phonics approach both decode and comprehend significantly better than children who have been taught using a whole-word approach. Consideration of these patterns in the context of what is known about the reading development of children in the general population provides a strong foundation for facilitating the reading development of children with Williams syndrome.

Genomic sister-disorders of neurodevelopment: an evolutionary approach

Genomic sister-disorders are defined here as diseases mediated by duplications versus deletions of the same region. Such disorders can provide unique information concerning the genomic underpinnings of human neurodevelopment because effects of diametric variation in gene copy number on cognitive and behavioral phenotypes can be inferred. We describe evidence from the literature on deletions versus duplications for the regions underlying the best-known human neurogenetic sister-disorders, including Williams syndrome, Velocardiofacial syndrome, and Smith-Magenis syndrome, as well as the X-chromosomal conditions Klinefelter and Turner syndromes. These data suggest that diametric copy-number alterations can, like diametric alterations to imprinted genes, generate contrasting phenotypes associated with autistic-spectrum and psychotic-spectrum conditions. Genomically based perturbations to the development of the human social brain are thus apparently mediated to a notable degree by effects of variation in gene copy number. We also conducted the first analyses of positive selection for genes in the regions affected by these disorders. We found evidence consistent with adaptive evolution of protein-coding genes, or selective sweeps, for three of the four sets of sister-syndromes analyzed. These studies of selection facilitate identification of candidate genes for the phenotypes observed and lend a novel evolutionary dimension to the analysis of human cognitive architecture and neurogenetic disorders.