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Brain Sciences Dec 2021Dyslexia, a specific reading disability, is a common (up to 10% of children) and highly heritable (~70%) neurodevelopmental disorder. Behavioral and molecular genetic... (Review)
Review
Dyslexia, a specific reading disability, is a common (up to 10% of children) and highly heritable (~70%) neurodevelopmental disorder. Behavioral and molecular genetic approaches are aimed towards dissecting its significant genetic component. In the proposed review, we will summarize advances in twin and molecular genetic research from the past 20 years. First, we will briefly outline the clinical and educational presentation and epidemiology of dyslexia. Next, we will summarize results from twin studies, followed by molecular genetic research (e.g., genome-wide association studies (GWASs)). In particular, we will highlight converging key insights from genetic research. (1) Dyslexia is a highly polygenic neurodevelopmental disorder with a complex genetic architecture. (2) Dyslexia categories share a large proportion of genetics with continuously distributed measures of reading skills, with shared genetic risks also seen across development. (3) Dyslexia genetic risks are shared with those implicated in many other neurodevelopmental disorders (e.g., developmental language disorder and dyscalculia). Finally, we will discuss the implications and future directions. As the diversity of genetic studies continues to increase through international collaborate efforts, we will highlight the challenges in advances of genetics discoveries in this field.
PubMed: 35053771
DOI: 10.3390/brainsci12010027 -
Epilepsia Open Mar 2022The present study aimed to examine the prevalence of dyscalculia, dyslexia, and their comorbidity rates in a large population-based sample of children with idiopathic...
OBJECTIVE
The present study aimed to examine the prevalence of dyscalculia, dyslexia, and their comorbidity rates in a large population-based sample of children with idiopathic epilepsy (N = 2282) and a comparison sample of typically developing schoolchildren (N = 2371).
METHODS
Both groups of children were screened using an arithmetic fluency test for dyscalculia and a reading fluency test for dyslexia. Their comorbidity rates were assessed. The prevalence rates of dyscalculia, dyslexia, comorbidity, and isolated dyscalculia/dyslexia (ie, participants with comorbid dyslexia and dyscalculia were excluded) were analyzed.
RESULTS
In both -1.5 SD and -1 SD cutoff criterion, the prevalence rates were about two times higher in children with idiopathic epilepsy than in other schoolchildren; the prevalence rates of isolated dyslexia were higher in children with idiopathic epilepsy than in other schoolchildren (-1 SD: 10.9% vs 8.6%; -1.5 SD: 6.5% vs 4.7%). Meanwhile, comorbidity rates of dyscalculia and dyslexia were higher in children with idiopathic epilepsy than in other schoolchildren (32.7% vs 26.6%; 38.3% vs 23.5%, respectively). Overall, patterns of prevalence rates were different for children with idiopathic epilepsy and schoolchildren, in which children with idiopathic epilepsy had a higher prevalence rate of dyscalculia than dyslexia, while schoolchildren had a higher prevalence of dyslexia than dyscalculia, regardless of cutoff criteria. Interestingly, gender differences in the prevalence rates of all types of learning disabilities were found in schoolchildren, but there were only gender differences in the prevalence rates of dyslexia in children with idiopathic epilepsy.
SIGNIFICANCE
The results highlight the vulnerability of children with idiopathic epilepsy for learning disabilities and a differential pattern of gender differences in dyslexia. Moreover, different patterns of prevalence rates suggest that children with idiopathic epilepsy and schoolchildren are more prone to different types of learning disabilities. The findings suggest needs for special interventions of learning disabilities for children with idiopathic epilepsy.
Topics: Child; China; Comorbidity; Dyscalculia; Dyslexia; Epilepsy; Humans; Prevalence; Sex Factors
PubMed: 35007403
DOI: 10.1002/epi4.12577 -
Neuropsychologia Feb 2022Developmental dyscalculia (DD) is a specific learning disability affecting the development of numerical and arithmetical skills. The origin of DD is typically attributed...
Developmental dyscalculia (DD) is a specific learning disability affecting the development of numerical and arithmetical skills. The origin of DD is typically attributed to the suboptimal functioning of key regions within the dorsal visual stream (parietal cortex) which support numerical cognition. While DD individuals are often impaired in visual numerosity perception, the extent to which they also show a wider range of visual dysfunctions is poorly documented. In the current study we measured sensitivity to global motion (translational and flow), 2D static form (Glass patterns) and 3D structure from motion in adults with DD and control subjects. While sensitivity to global motion was comparable across groups, thresholds for static form and structure from motion were higher in the DD compared to the control group, irrespective of associated reading impairments. Glass pattern sensitivity predicted numerical abilities, and this relation could not be explained by recently reported differences in visual crowding. Since global form sensitivity has often been considered an index of ventral stream function, our findings could indicate a cortical dysfunction extending beyond the dorsal visual stream. Alternatively, they would fit with a role of parietal cortex in form perception under challenging conditions requiring multiple element integration.
Topics: Adult; Dyscalculia; Form Perception; Humans; Mathematics; Motion Perception; Parietal Lobe; Visual Perception
PubMed: 34990696
DOI: 10.1016/j.neuropsychologia.2021.108140 -
Frontiers in Human Neuroscience 2021
PubMed: 34955796
DOI: 10.3389/fnhum.2021.811101 -
Psychological Science Jan 2022Mapping number to space is natural and spontaneous but often nonveridical, showing a clear compressive nonlinearity that is thought to reflect intrinsic logarithmic...
Mapping number to space is natural and spontaneous but often nonveridical, showing a clear compressive nonlinearity that is thought to reflect intrinsic logarithmic encoding of numerical values. We asked 78 adult participants to map dot arrays onto a number line across nine trials. Combining participant data, we confirmed that on the first trial, mapping was heavily compressed along the number line, but it became more linear across trials. Responses were well described by logarithmic compression but also by a parameter-free Bayesian model of central tendency, which quantitatively predicted the relationship between nonlinearity and number acuity. To experimentally test the Bayesian hypothesis, we asked 90 new participants to complete a color-line task in which they mapped noise-perturbed color patches to a "color line." When there was more noise at the high end of the color line, the mapping was logarithmic, but it became exponential with noise at the low end. We conclude that the nonlinearity of both number and color mapping reflects contextual Bayesian inference processes rather than intrinsic logarithmic encoding.
Topics: Adult; Bayes Theorem; Humans; Language; Noise; Uncertainty
PubMed: 34936846
DOI: 10.1177/09567976211034501 -
Journal of Neuroscience Research Feb 2022Developmental dyscalculia (DD) is a developmental learning disability associated with deficits in processing numerical and mathematical information. Several studies...
Developmental dyscalculia (DD) is a developmental learning disability associated with deficits in processing numerical and mathematical information. Several studies demonstrated functional network alterations in DD. Yet, there are no studies, which examined the structural network integrity in DD. We compared whole-brain maps of volume based structural covariance between 19 (4 males) children with DD and 18 (4 males) typically developing children. We found elevated structural covariance in the DD group between the anterior intraparietal sulcus to the middle temporal and frontal gyrus (p < 0.05, corrected). A hippocampus subfield analysis showed higher structural covariance in the DD group for area CA3 to the parahippocampal and calcarine sulcus, angular gyrus and anterior part of the intraparietal sulcus as well as to the lingual gyrus. Lower structural covariance in this group was seen for the subiculum to orbitofrontal gyrus, anterior insula and middle frontal gyrus. In contrast, the primary motor cortex (control region) revealed no difference in structural covariance between groups. Our results extend functional magnetic resonance studies by revealing abnormal gray matter integrity in children with DD. These findings thus indicate that the pathophysiology of DD is mediated by both structural and functional abnormalities in a network involved in number processing and memory function.
Topics: Brain; Child; Dyscalculia; Humans; Learning Disabilities; Magnetic Resonance Imaging; Male; Mathematics
PubMed: 34933406
DOI: 10.1002/jnr.24998 -
Frontiers in Human Neuroscience 2021Humans can quickly approximate how many objects are in a visual image, but no clear consensus has been achieved on the cognitive resources underlying this ability....
Humans can quickly approximate how many objects are in a visual image, but no clear consensus has been achieved on the cognitive resources underlying this ability. Previous work has lent support to the notion that mechanisms which explicitly represent the locations of multiple objects in the visual scene within a mental map are critical for both visuo-spatial working memory and enumeration (at least for relatively small numbers of items). Regarding the cognitive underpinnings of large numerosity perception, an issue currently subject to much controversy is why numerosity estimates are often non-veridical (i.e., susceptible to biases from non-numerical quantities). Such biases have been found to be particularly pronounced in individuals with developmental dyscalculia (DD), a learning disability affecting the acquisition of arithmetic skills. Motivated by findings showing that DD individuals are also often impaired in visuo-spatial working memory, we hypothesized that resources supporting this type of working memory, which allow for the simultaneous identification of multiple objects, might also be critical for precise and unbiased perception of larger numerosities. We therefore tested whether loading working memory of healthy adult participants during discrimination of large numerosities would lead to increased interference from non-numerical quantities. Participants performed a numerosity discrimination task on multi-item arrays in which numerical and non-numerical stimulus dimensions varied congruently or incongruently relative to each other, either in isolation or in the context of a concurrent visuo-spatial or verbal working memory task. During performance of the visuo-spatial, but not verbal, working memory task, precision in numerosity discrimination decreased, participants' choices became strongly biased by item size, and the strength of this bias correlated with measures of arithmetical skills. Moreover, the interference between numerosity and working memory tasks was bidirectional, with number discrimination impacting visuo-spatial (but not verbal) performance. Overall, these results suggest that representing visual numerosity in a way that is unbiased by non-numerical quantities relies on processes which explicitly segregate/identify the locations of multiple objects that are shared with visuo-spatial (but not verbal) working memory. This shared resource may potentially be impaired in DD, explaining the observed co-occurrence of working memory and numerosity discrimination deficits in this clinical population.
PubMed: 34867244
DOI: 10.3389/fnhum.2021.751098 -
PLoS Biology Sep 2021Mathematical learning deficits are defined as a neurodevelopmental disorder (dyscalculia) in the International Classification of Diseases. It is not known, however, how...
Mathematical learning deficits are defined as a neurodevelopmental disorder (dyscalculia) in the International Classification of Diseases. It is not known, however, how such deficits emerge in the course of early brain development. Here, we conducted functional and structural magnetic resonance imaging (MRI) experiments in 3- to 6-year-old children without formal mathematical learning experience. We followed this sample until the age of 7 to 9 years, identified individuals who developed deficits, and matched them to a typically developing control group using comprehensive behavioral assessments. Multivariate pattern classification distinguished future cases from controls with up to 87% accuracy based on the regional functional activity of the right posterior parietal cortex (PPC), the network-level functional activity of the right dorsolateral prefrontal cortex (DLPFC), and the effective functional and structural connectivity of these regions. Our results indicate that mathematical learning deficits originate from atypical development of a frontoparietal network that is already detectable in early childhood.
Topics: Brain; Brain Mapping; Child; Child Development; Child, Preschool; Dyscalculia; Female; Humans; Longitudinal Studies; Magnetic Resonance Imaging; Male; Neural Pathways; Parietal Lobe; Prefrontal Cortex
PubMed: 34591838
DOI: 10.1371/journal.pbio.3001407 -
Frontiers in Neuroscience 2021Impaired phonological processing is a leading symptom of multifactorial language and learning disorders suggesting a common biological basis. Here we evaluated studies...
Impaired phonological processing is a leading symptom of multifactorial language and learning disorders suggesting a common biological basis. Here we evaluated studies of dyslexia, dyscalculia, specific language impairment (SLI), and the logopenic variant of primary progressive aphasia (lvPPA) seeking for shared risk genes in Broca's and Wernicke's regions, being key for phonological processing within the complex language network. The identified "phonology-related genes" from literature were functionally characterized using Atlas-based expression mapping (JuGEx) and gene set enrichment. Out of 643 publications from the last decade until now, we extracted 21 candidate genes of which 13 overlapped with dyslexia and SLI, six with dyslexia and dyscalculia, and two with dyslexia, dyscalculia, and SLI. No overlap was observed between the childhood disorders and the late-onset lvPPA often showing symptoms of learning disorders earlier in life. Multiple genes were enriched in Gene Ontology terms of the topics learning () and neuronal development (, , , , ). Twelve genes showed above-average expression across both regions indicating moderate-to-high gene activity in the investigated cortical part of the language network. Of these, three genes were differentially expressed suggesting potential regional specializations: was upregulated in Broca's region, while and were upregulated in Wernicke's region. encodes a magnesium-dependent calcium transporter which fits with reports about disturbed calcium and magnesium levels for dyslexia and other communication disorders. (formerly known as ) is involved in neuronal migration supporting the hypothesis of disturbed migration in dyslexia. is a transcription factor that regulates a number of genes involved in development of speech and language. Overall, our interdisciplinary and multi-tiered approach provided evidence that genetic and transcriptional variation of , , and may play a role in physiological and pathological aspects of phonological processing.
PubMed: 34539327
DOI: 10.3389/fnins.2021.680762 -
BMC Neurology Sep 2021Autoimmune encephalitis (AE) is a rare inflammatory disorder characterized by important psychiatric and neurologic symptoms. The literature documents high rates of...
BACKGROUND
Autoimmune encephalitis (AE) is a rare inflammatory disorder characterized by important psychiatric and neurologic symptoms. The literature documents high rates of neuropsychological dysfunction in N-methyl D-aspartate-receptor (NMDAr) encephalitis but papers don't consider specifically calculation disturbances between the long-term deficits, although deficits in executive control and episodic memory were less likely to resolve.
CASE REPORT
Here we present a severe case of NMDAr encephalitis in a young patient without a relevant past medical history. Upon first examination he presented psycho-motor slowdown, speech disorders, severe cognitive deficits in all areas: concentration, attention, memory, language, dual task functions, increased latency in responses, severe dyscalculia. Upon first evaluation, the young patient underwent a battery of neuropsychological tests and he showed a dysexecutive syndrome with performances significantly low for age and education. Our patient hence underwent 1 month of intensive cognitive rehabilitation. After the rehabilitation treatment, he presented an amelioration in all domains except calculations.
CONCLUSIONS
In our patient the calculation disorder has proved to be the most relevant problem and the most difficult to treat. Clinicians should consider a careful approach to determine the prognosis of this syndrome because of the wide range of deficits, the need of prolonged treatment and the rate of long-term sequelae.
Topics: Anti-N-Methyl-D-Aspartate Receptor Encephalitis; Encephalitis; Executive Function; Hashimoto Disease; Humans; Male; Neuropsychological Tests
PubMed: 34507555
DOI: 10.1186/s12883-021-02370-x