DYSLEXIA – AN OVERVIEW OF ASSESSMENT AND TREATMENT METHODS

This article will give an overview of the different methods of assessment and treatment currently used in the field of dyslexia with a special focus on genetic research. Based on the modification and extension of the multilevel model of Valtin (1989, modified by Witruk, 1993b), assessment and treatment methods will be discussed due to their primary objectives. These methods will be described regarding primary causes (biological risk factors), secondary causes (partial performance deficits), primary symptoms (reading and writing problems) and secondary symptoms (emotional and behavioural disorders). Keywords: Multilevel model of dyslexia, genetics, magnocellular deficit, partial performanc

Human and cervid osseous materials used for barbed point manufacture in Mesolithic Doggerland

Barbed bone points originally deposited in Doggerland are regularly collected from the shores of the Netherlands. Their typology and direct 14C dating suggest they are of Mesolithic age. However, the species of which the barbed points were made cannot be identified based on morphological criteria. The bones used to produce the barbed points have been intensively modified during manufacture, use, and post-depositional processes. Here, we taxonomically assess ten barbed points found on the Dutch shore using mass spectrometry and collagen peptide mass fingerprinting alongside newly acquired 14C ages and δ13C and δ15N measurements. Our results demonstrate a sufficient preservation of unmodified collagen for mass spectrometry-based taxonomic identifications of bone and antler artefacts which have been preserved in marine environments since the beginning of the Holocene. We show that Homo sapiens bones as well as Cervus elaphus bones and antlers were transformed into barbed points. The 14C dating of nine barbed points yielded uncalibrated ages between 9.5 and 7.3 ka 14C BP. The δ13C and δ15N values of the seven cervid bone points fall within the range of herbivores, recovered from the North Sea, whereas the two human bone points indicate a freshwater and/or terrestrial fauna diet. The wide-scale application of ZooMS is a critical next step towards revealing the selection of species for osseous-tool manufacture in the context of Mesolithic Doggerland, but also further afield. The selection of Cervus elaphus and human bone for manufacturing barbed points in Mesolithic Doggerland is unlikely to have been opportunistic and instead seems to be strategic in nature. Further, the occurrence of Homo sapiens and Cervus elaphus bones in our random and limited dataset suggests that the selection of these species for barbed point production was non-random and subject to specific criteria. By highlighting the transformation of human bones into barbed points – possibly used as weapons – our study provides additional evidence for the complex manipulation of human remains during the Mesolithic, now also evidenced in Doggerland

Humans as a resource:ZooMS analysis on points from Mesolithic Doggerland

Several bone and antler points from Mesolithic Doggerland have been dated and analysed to determine the animal species from which they were made. The points were found on beaches of South-Holland, but their primary depositional site lies in front of the coast in the North Sea. 14C-dates have given an estimated age of 11.000 to 8.000 years old. The decisions made for the production of the points can inform us about the human makers. ZooMS (Zooarchaeology by Mass Spectrometry) was used on ten points in order to identify the taxon from which they were made. We’ve obtained fascinating and unexpected results. There seems to be a preference for the use of red deer, but two examples for the usage of human bone were found as well. This is a surprising discovery as human remains are not commonly used to make tools. Moreover, human bones are not the most suitable material to produce a point. Therefore, the use of human bone to manufacture bone points seems to be more related to symbolism and culture. Future research will provide more clarity in the coming years

Early cortical surface plasticity relates to basic mathematical learning

Children lay the foundation for later academic achievement by acquiring core mathematical abilities in the first school years. Neural reorganization processes associated with individual differences in early mathematical learning, however, are still poorly understood. To fill this research gap, we followed a sample of 5-6-year-old children longitudinally to the end of second grade in school (age 7–8 years) combining magnetic resonance imaging (MRI) with comprehensive behavioral assessments. We report significant links between the rate of neuroplastic change of cortical surface anatomy, and children's early mathematical skills. In particular, most of the behavioral variance (about 73%) of children's visuospatial abilities was explained by the change in cortical thickness in the right superior parietal cortex. Moreover, half of the behavioral variance (about 55%) of children's arithmetic abilities was explained by the change in cortical folding in the right intraparietal sulcus. Additional associations for arithmetic abilities were found for cortical thickness change of the right temporal lobe, and the left middle occipital gyrus. Visuospatial abilities were related to right precentral and supramarginal thickness, as well as right medial frontal gyrus folding plasticity. These effects were independent of other individual differences in IQ, literacy and maternal education. Our findings highlight the critical role of cortical plasticity during the acquisition of fundamental mathematical abilities

Genome-wide association scan identifies new variants associated with a cognitive predictor of dyslexia

Developmental dyslexia (DD) is one of the most prevalent learning disorders, with high impact on school and psychosocial development and high comorbidity with conditions like attention-deficit hyperactivity disorder (ADHD), depression, and anxiety. DD is characterized by deficits in different cognitive skills, including word reading, spelling, rapid naming, and phonology. To investigate the genetic basis of DD, we conducted a genome-wide association study (GWAS) of these skills within one of the largest studies available, including nine cohorts of reading-impaired and typically developing children of European ancestry (N = 2562-3468). We observed a genome-wide significant effect (p <1 x 10(-8)) on rapid automatized naming of letters (RANlet) for variants on 18q12.2, within MIR924HG (micro-RNA 924 host gene; rs17663182 p = 4.73 x 10(-9)), and a suggestive association on 8q12.3 within NKAIN3 (encoding a cation transporter; rs16928927, p = 2.25 x 10(-8)). rs17663182 (18q12.2) also showed genome-wide significant multivariate associations with RAN measures (p = 1.15 x 10(-8)) and with all the cognitive traits tested (p = 3.07 x 10(-8)), suggesting (relational) pleiotropic effects of this variant. A polygenic risk score (PRS) analysis revealed significant genetic overlaps of some of the DD-related traits with educational attainment (EDUyears) and ADHD. Reading and spelling abilities were positively associated with EDUyears (p similar to [10(-5)-10(-7)]) and negatively associated with ADHD PRS (p similar to [10(-8)-10(-17)]). This corroborates a long-standing hypothesis on the partly shared genetic etiology of DD and ADHD, at the genome-wide level. Our findings suggest new candidate DD susceptibility genes and provide new insights into the genetics of dyslexia and its comorbities.Peer reviewe

Genome-wide association study reveals new insights into the heritability and genetic correlates of developmental dyslexia

Developmental dyslexia (DD) is a learning disorder affecting the ability to read, with a heritability of 40-60%. A notable part of this heritability remains unexplained, and large genetic studies are warranted to identify new susceptibility genes and clarify the genetic bases of dyslexia. We carried out a genome-wide association study (GWAS) on 2274 dyslexia cases and 6272 controls, testing associations at the single variant, gene, and pathway level, and estimating heritability using single-nucleotide polymorphism (SNP) data. We also calculated polygenic scores (PGSs) based on large-scale GWAS data for different neuropsychiatric disorders and cortical brain measures, educational attainment, and fluid intelligence, testing them for association with dyslexia status in our sample. We observed statistically significant (p <2.8 x 10(-6)) enrichment of associations at the gene level, forLOC388780(20p13; uncharacterized gene), and forVEPH1(3q25), a gene implicated in brain development. We estimated an SNP-based heritability of 20-25% for DD, and observed significant associations of dyslexia risk with PGSs for attention deficit hyperactivity disorder (atp(T) = 0.05 in the training GWAS: OR = 1.23[1.16; 1.30] per standard deviation increase;p = 8 x 10(-13)), bipolar disorder (1.53[1.44; 1.63];p = 1 x 10(-43)), schizophrenia (1.36[1.28; 1.45];p = 4 x 10(-22)), psychiatric cross-disorder susceptibility (1.23[1.16; 1.30];p = 3 x 10(-12)), cortical thickness of the transverse temporal gyrus (0.90[0.86; 0.96];p = 5 x 10(-4)), educational attainment (0.86[0.82; 0.91];p = 2 x 10(-7)), and intelligence (0.72[0.68; 0.76];p = 9 x 10(-29)). This study suggests an important contribution of common genetic variants to dyslexia risk, and novel genomic overlaps with psychiatric conditions like bipolar disorder, schizophrenia, and cross-disorder susceptibility. Moreover, it revealed the presence of shared genetic foundations with a neural correlate previously implicated in dyslexia by neuroimaging evidence.Peer reviewe