Recent studies suggest that neurobiological anomalies are already detectable in pre-school children with a family history of developmental dyslexia (DD). However, there is a lack of longitudinal ...studies showing a direct link between those differences at a preliterate age and the subsequent literacy difficulties seen in school. It is also not clear whether the prediction of DD in pre-school children can be significantly improved when considering neurobiological predictors, compared to models based on behavioral literacy precursors only.
We recruited 53 pre-reading children either with (N=25) or without a family risk of DD (N=28). Quantitative T1 MNI data and literacy precursor abilities were assessed at kindergarten age. A subsample of 35 children was tested for literacy skills either one or two years later, that is, either in first or second grade.
The group comparison of quantitative T1 measures revealed significantly higher T1 intensities in the left anterior arcuate fascicle (AF), suggesting reduced myelin concentration in preliterate children at risk of DD. A logistic regression showed that DD can be predicted significantly better (p=.024) when neuroanatomical differences between groups are used as predictors (80%) compared to a model based on behavioral predictors only (63%). The Wald statistic confirmed that the T1 intensity of the left AF is a statistically significant predictor of DD (p<.05).
Our longitudinal results provide evidence for the hypothesis that neuroanatomical anomalies in children with a family risk of DD are related to subsequent problems in acquiring literacy. Particularly, solid white matter organization in the left anterior arcuate fascicle seems to play a pivotal role.
In this article, we critically review the evidence for overlap among three developmental disorders, namely speech sound disorder (SSD), language impairment (LI), and reading disability (RD), at three ...levels of analysis: diagnostic, cognitive, and etiological. We find that while overlap exists at all three levels, it varies by comorbidity subtype, and the relations among these three disorders are complex and not fully understood. We evaluate which comorbidity models can be rejected or supported as explanations for why and how these three disorders overlap and what new data are needed to better define their relations.
Sex‐related differences in reading achievement Granocchio, Elisa; De Salvatore, Marinella; Bonanomi, Elisa ...
Journal of neuroscience research,
20/May , Volume:
101, Issue:
5
Journal Article
Peer reviewed
Over the last 40 years, ever‐growing interest in sex‐related differences in the human brain has led to a vast amount of literature on the subject, a small part of which relates to studies of ...differences in the ability to read. The data concerning typically developing children mainly come from school‐based screening projects (Programme for International Student Assessment, INVALSI) and partially from the standardization of reading tests. These have revealed the existence of a gap in favor of females that primarily appears during adolescence and in situations of sociocultural disadvantage, usually explained on the basis of environmental factors such as socioeconomic status and gender‐based education. Dyslexia is a neurodevelopmental disorder that is significantly more prevalent among males, a difference that neuroimaging and genetic studies have attributed to the presence of hormone‐related protective factors in females, although it has been hypothesized that a different neurocognitive substrate may also be involved. However, the literature on the subject is still limited, and further studies of the interactions between genetic risk, environmental factors, and brain phenotypes are needed to clarify why females are better at performing reading tasks and less susceptible to dyslexia, regardless of their language or the educational system in the country in which they live. The aim of this mini‐review was to describe the studies that have investigated sex‐related differences in reading ability in both typically and atypically developing subjects.
Fluent reading depends on a complex set of cognitive processes that must work together in perfect concert. Rapid automatized naming (RAN) tasks provide insight into this system, acting as a microcosm ...of the processes involved in reading. In this review, we examine both RAN and reading fluency and how each has shaped our understanding of reading disabilities. We explore the research that led to our current understanding of the relationships between RAN and reading and what makes RAN unique as a cognitive measure. We explore how the automaticity that supports RAN affects reading across development, reading abilities, and languages, and the biological bases of these processes. Finally, we bring these converging areas of knowledge together by examining what the collective studies of RAN and reading fluency contribute to our goals of creating optimal assessments and interventions that help every child become a fluent, comprehending reader.
We followed children at family risk of dyslexia and children with preschool language difficulties from age 3½, comparing them with controls (N = 234). At age 8, children were classified as having ...dyslexia or Developmental Language Disorder (DLD) and compared at earlier time points with controls. Children with dyslexia have specific difficulties with phonology and emergent reading skills in the preschool period, whereas children with DLD, with or without dyslexia, show a wider range of impairments including significant problems with executive and motor tasks. For children with both dyslexia and DLD, difficulties with phonology are generally more severe than those observed in children with dyslexia or DLD alone. Findings confirm that poor phonology is the major cognitive risk factor for dyslexia.
Although dyslexia is the most common learning disorder in children, it has not received adequate attention in Saudi Arabia.
This study aimed at determining the prevalence of dyslexia among Saudi ...students in Grades 3–6, exploring associations between severity of dyslexia, its behavioral indicators, gender and grade, and the moderating role of grade in the relationship between severity and behavioral indicators.
The sample consisted of 2848 female students and 2647 male students in Zulfi governorate, Saudi Arabia. A survey-based mixed-methods design was chosen including a structured interview with teachers and three assessments using the Diagnostic Assessment Scale for Dyslexia, the Arabic Reading Test, and the Dyslexia Behavioral Indicators Scale.
Dyslexia was assessed in 5.86 % of the total sample. It was twice as prevalent among male students as among female students (6.54 % and 3.83 %, respectively). The mean score for behavioral indicators of dyslexia was also significantly higher for male than for female students. The correlation between dyslexia severity and behavioral indicators score was high and significant, with grade level as a significant moderator.
We found that, for children with dyslexia in Saudi Arabia, dyslexia was twice as prevalent among male students as among female students. Early dyslexia diagnosis and intervention services are suggested to reduce the risk for reading problems.
•This research yields a better understanding of the role of grade progression on the relationship between severity of dyslexia and its behavioral indicators.•This research showed that in children with dyslexia in Saudi Arabia, the dyslexia was twice as prevalent among male students as among female students.•The behavioral indictors of dyslexia were higher in male students than in female students•Correlations between dyslexia severity and behavioral indicators were higher for female than male students•The results indicate that as the student grade level increased the negative relationship between dyslexia severity and behavioral indicators of dyslexia decreased.
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•Reading training is related to an increased reading ability in children.•Greater “gains” in reading were related with low GLX concentrations for children with dyslexia.•This study ...supports the extension of the neural noise hypothesis in dyslexia.
The “neural noise” hypothesis suggests that individuals with dyslexia have high glutamate concentrations associated with their reading challenges. Different reading intervention programs have showed low GLX (a combined measure for glutamine and glutamate obtained with in vivo magnetic resonance spectroscopy) in association with reading improvement. Several studies demonstrated improved reading and increased activation in the anterior cingulate cortex following an-executive-function (EF)-based reading intervention. The goals of the current study are two-fold: 1) to determine if the effect of the EF-based reading program extends also to the metabolite concentrations and in particular, on the GLX concentrations in the anterior cingulate cortex; 2) to expand the neural noise hypothesis in dyslexia also to neural networks supporting additional parts of the reading networks, i.e. in specific regions related to executive function skills.
Children with dyslexia and typical readers were trained on the EF-based reading program. Reading ability was assessed before and after training while spectroscopy data was obtained at the end of the program. The association between change in reading scores following intervention and GLX concentrations was examined.
Greater “gains” in word reading were associated with low GLX, Glu, Cr, and NAA concentrations for children with dyslexia compared to typical readers.
These results suggest that the improvement reported following the EF-based reading intervention program also involved a low GLX concentration, as well as additional metabolites previously associated with better reading ability (Glx, Cr, NAA) which may point at the decreased neural noise, especially in the anterior cingulate cortex, as a possible mechanism for the effect of this program.
Background
This study considers the role of early speech difficulties in literacy development, in the context of additional risk factors.
Method
Children were identified with speech sound disorder ...(SSD) at the age of 3½ years, on the basis of performance on the Diagnostic Evaluation of Articulation and Phonology. Their literacy skills were assessed at the start of formal reading instruction (age 5½), using measures of phoneme awareness, word‐level reading and spelling; and 3 years later (age 8), using measures of word‐level reading, spelling and reading comprehension.
Results
The presence of early SSD conferred a small but significant risk of poor phonemic skills and spelling at the age of 5½ and of poor word reading at the age of 8. Furthermore, within the group with SSD, the persistence of speech difficulties to the point of school entry was associated with poorer emergent literacy skills, and children with ‘disordered’ speech errors had poorer word reading skills than children whose speech errors indicated ‘delay’. In contrast, the initial severity of SSD was not a significant predictor of reading development. Beyond the domain of speech, the presence of a co‐occurring language impairment was strongly predictive of literacy skills and having a family risk of dyslexia predicted additional variance in literacy at both time‐points.
Conclusions
Early SSD alone has only modest effects on literacy development but when additional risk factors are present, these can have serious negative consequences, consistent with the view that multiple risks accumulate to predict reading disorders.
Developmental dyslexia (decoding-based reading disorder; RD) is a complex trait with multifactorial origins at the genetic, neural, and cognitive levels. There is evidence that low-level ...sensory-processing deficits precede and underlie phonological problems, which are one of the best-documented aspects of RD. RD is also associated with impairments in integrating visual symbols with their corresponding speech sounds. Although causal relationships between sensory processing, print–speech integration, and fluent reading, and their neural bases are debated, these processes all require precise timing mechanisms across distributed brain networks. Neural excitability and neural noise are fundamental to these timing mechanisms. Here, we propose that neural noise stemming from increased neural excitability in cortical networks implicated in reading is one key distal contributor to RD.
Some researchers suggest that deficits in attention and working memory influence the development of dyslexia, whereas others propose that these deficits are more likely due to reduced global ...processing speed. The current study aimed to investigate behavioral performance in children with dyslexia compared to typically developing controls on two tasks: a visual oddball task for attention and an n-back task for working memory. We measured P300 event-related potentials (ERP) amplitude and latency for both tasks. Our results demonstrated reduced behavioral accuracy and P300 amplitude for the children with dyslexia compared to their typically developing peers in both the n-back and visual oddball tasks. We also found no differences in response time or P300 latency between these groups on either task. These findings support the idea that children with dyslexia experience deficits in cognitive processes related to working memory and attention, but do not exhibit decreased global processing speed on these tasks.
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