The Cognitive Profile of Math Difficulties: A Meta-Analysis Based on Clinical Criteria

Math difficulties (MD) manifest across various domain-specific and domain-general abilities. However, the existing cognitive profile of MD is incomplete and thus not applicable in typical settings such as schools or clinics. So far, no review has applied inclusion criteria according to DSM or ICD, summarized domain-specific abilities or examined the validity of response time scores for MD identification. Based upon stringent clinical criteria, the current meta-analysis included 34 studies which compared cognitive performances of a group with MD (n = 680) and a group without MD (n = 1565). Criteria according to DSM and ICD were applied to identify MD (percentile rank <= 16, age range 8-12 years, no comorbidities/low IQ). Effect sizes for 22 abilities were estimated and separated by their level and type of scoring (AC = accuracy, RT = response time). A cognitive profile of MD was identified, characterized by distinct weaknesses in: (a) computation (calculation [AC], fact retrieval [AC]), (b) number sense (quantity processing [AC], quantity-number linking [RT], numerical relations [AC]), and (c) visual-spatial short-term storage [AC]. No particular strength was found. Severity of MD, group differences in reading performance and IQ did not significantly moderate the results. Further analyses revealed that (a) effects are larger when dealing with numbers or number words than with quantities, (b) MD is not accompanied by any weakness in abilities typically assigned to reading, and (c) weaknesses in visual-spatial short-term storage emphasize the notion that number and space are interlinked. The need for high-quality studies investigating domain-general abilities is discussed

Reproducibility of Brain Responses: High for Speech Perception, Low for Reading Difficulties

Neuroscience findings have recently received critique on the lack of replications. To examine the reproducibility of brain indices of speech sound discrimination and their role in dyslexia, a specific reading difficulty, brain event-related potentials using EEG were measured using the same cross-linguistic passive oddball paradigm in about 200 dyslexics and 200 typically reading 8-12-year-old children from four countries with different native languages. Brain responses indexing speech and non-speech sound discrimination were extremely reproducible, supporting the validity and reliability of cognitive neuroscience methods. Significant differences between typical and dyslexic readers were found when examined separately in different country and language samples. However, reading group differences occurred at different time windows and for different stimulus types between the four countries. This finding draws attention to the limited generalizability of atypical brain response findings in children with dyslexia across language environments and raises questions about a common neurobiological factor for dyslexia. Our results thus show the robustness of neuroscience methods in general while highlighting the need for multi-sample studies in the brain research of language disorders

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

Qualitative evaluation of a preventive intervention for the offspring of parents with a history of depression

Background: Meta-analyses of randomised controlled trials suggest that psychological interventions to reduce children’s risk of depression are effective. Nevertheless, these effects are modest and diminish over time. The Medical Research Council recommends a mixed-methods approach to the evaluation of complex interventions. By gaining a more thorough understanding of participants’ perspectives, qualitative evaluations of preventive interventions could improve their efficacy, longevity and transfer into clinical practice. Methods: 18 parents and 22 children who had received a 12-session family- and group-based cognitivebehavioural intervention to prevent youth depression as part of a randomised controlled trial took part in semistructured interviews or a focus group about aspects which had been perceived as helpful, elements they were still using after the intervention had ended, and suggestions they had for improving the intervention. Results: The chance to openly share and discuss their experiences of depression within and between families was considered helpful by both children and parents. Children benefitted the most from learning coping strategies for dealing with stress and many still used them in everyday life. Parents profited mostly from increasing positive family time, but noted that maintaining new routines after the end of the intervention proved difficult. Participants were generally content with the intervention but commented on how tiring and time consuming it was. Conclusions: Managing parents’ expectations of family-based interventions in terms of their own mental health needs (versus those of their children) and leaving more room for open discussions may result in interventions which are more appealing to participating families. Increasing intervals between sessions may be one means of improving the longevity of interventions. Trial registration: The original RCT this evaluation is a part of was registered under NCT02115880

Does sensitivity to orthographic regularities influence reading and spelling acquisition? A 1-year prospective study

Recent studies focused on the influence of orthographic processing on reading and spelling performance. It was found that orthographic processing is an independent predictor of reading and spelling performance in different languages and children of different ages. This study investigated sensitivity to orthographic regularities in German-speaking children (N = 31) prior and during formal reading and spelling instruction. In addition, the relationship between sensitivity to orthographic regularities and reading and spelling performance was explored. Two aspects of children's sensitivity to orthographic regularities (sensitivity to frequent double consonants and sensitivity to legal positions of double consonants) were measured with a nonword forced choice task. The results show that sensitivity to orthographic regularities improved significantly from kindergarten to first grade. Moreover, children's sensitivity to orthographic regularities at the end of first grade accounted for a significant amount of unique variance in their reading and spelling performance. These results suggest that orthographic sensitivity on a sublexical level is important for the development of reading and spelling skills

A comparison of orthographic processing in children with and without reading and spelling disorder in a regular orthography

Orthographic processing is a construct that encompasses the skills of recognizing, storing, accessing, and applying the print conventions of a writing system. Few studies have investigated orthographic processing in dyslexic children and it is not yet clear whether lexical and sublexical orthographic processing are both impaired in these children. The present study examined orthographic processing in dyslexic children (N = 19, below-average word reading as well as below average spelling skills, T-values < 40) and typically developing children (N = 32) aged 8-10 years. Different aspects of orthographic processing were measured. Word-specific knowledge (lexical level) was assessed with an Orthographic Choice Task. General orthographic knowledge (sublexical level) was assessed with three pseudoword tasks. The Freq-Choice-Task is a choice task that measures children's knowledge of frequent double consonants (e.g., nilemm-nilebb). The Pos-Choice-Task measures children's knowledge about legal positions of double consonants (e.g., sinnum-ssinum). The Pos-Speed-Task measures children's ability to identify orthographic irregularities in words presented singly (e.g., mmotin). Results show that dyslexic children are able to discriminate illegal/infrequent letter pattern from legal/frequent letter pattern. Seeing either a word with legal or illegal letter patterns singly (Pos-Speed-Task), dyslexic children show deficits in identifying illegal letter pattern as wrong, whereas they have no problems to identify legal letter pattern as correct. Furthermore, dyslexic children show a reduced word specific orthographic knowledge. Additionally, the present study demonstrated that word representations as well as sensitivity to legal letter pattern influence reading and spelling performance

Economic evaluation of dyslexia intervention

In many countries, intervention costs are not covered by public health care. A critical basis for deciding whether an intervention is covered or not is to analyse the relation between benefits and costs of the intervention, and to quantify the consequential costs. In this study, a cost-utility analysis was computed to investigate the costs of individualized dyslexia intervention while quantifying the benefit in terms of health-related quality of life in a sample of 36 individuals with dyslexia. In addition, educational outcomes and costs of untreated dyslexia for the society were estimated using information for class repetition, school success, and unemployment rates from previous studies and official statistics. A significant increase in quality of life with medium effect sizes was found across all quality-of-life measures. Increases in quality of life were domain-specific, thus occurring specifically in those domains that are affected by learning disorders. The cost-utility ratio was 9,782 Euros per quality adjusted life years (QALYs), which is in line with similar therapy forms, such as speech therapy. The loss of productivity for untreated dyslexia in the German population was estimated for class repetition and reduced income due to lower school degrees. The cost-utility analysis and the calculation of consequential costs suggest that the dyslexia intervention is cost-effective

Predictors of reading and spelling skills in German: The role of morphological awareness

Background: The role of morphological awareness for literacy development is non-controversial, but it is likely to depend on the characteristics of a specific orthography. Previous studies analysing the role of morphological awareness are mainly based on English samples; thus, it is unclear how generalisable these results are. In the current study, we evaluated the predictive pattern of morphological awareness on reading and spelling in German, which is characterised by high consistency between morphology and orthography. While many words cannot be spelled correctly by relying on phoneme-grapheme mappings, morphological awareness can be reliably used to infer the correct spelling for many words. In contrast, morphological awareness seems less important for reading in German given the high consistency of grapheme-phoneme mappings. Therefore, we hypothesised that the predictive pattern of morphological awareness for spelling is higher than for reading due to the structure of German orthography. In addition, we examined whether the association between morphological awareness and spelling reflects specific awareness about morphemic units or rather general knowledge about frequent and permissible letter sequences in words. Method: We developed web-based tasks that allowed us to assess morphological awareness using pseudowords. Based on the data of 3,122 third and fourth graders, we analysed the predictive pattern of morphological awareness on reading and spelling after controlling for non-verbal cognitive abilities, age/grade, phoneme awareness and sublexical orthographic sensitivity. Results: We found that morphological awareness accounted for significant amounts of unique variance over and above sublexical orthographic sensitivity in both literacy measures but was a better predictor for spelling than for reading. Conclusions: The role of morphological awareness depends on the structure of a given orthography. In German, this is reflected by differences in the predictive pattern between reading and spelling skills. Furthermore, results support the specific role of morphological awareness for spelling in the German orthography