Working memory deficits in children with specific learning disorders

The roles of cognitive and language abilities in predicting decoding and reading comprehension: comparisons of dyslexia and specific language impairment

This study aimed to (a) explore the roles of cognitive and language variables in predicting reading abilities of two groups of individuals with reading disabilities (i.e., dyslexia and specific language impairment) and (b) examine which variable(s) is the most predictive in differentiating two groups. Inclusion/exclusion criteria applied to categorize the two groups yielded a total of 63 participants (n = 44 for the dyslexia; n = 19 for the specific language impairment). A stepwise multiple regression approach was conducted to examine which cognitive and/or language variables made the largest contribution to reading abilities (i.e., Phonetic Decoding Efficiency, Word Attack, Sight Word Efficiency, and Passage Comprehension). Results revealed that there were significant differences in which measures of cognitive and language ability predicted individuals with dyslexia and speech and language impairments reading ability, showing that the cognitive and language variables underlying their difficulty with reading abilities were not the same across the two groups. A discriminant function analysis showed that a measure of Verbal Comprehension, Phonological Awareness, and Phonetic Decoding Efficiency can be used to differentiate the two groups. These findings support the tenet that dyslexia and specific language impairment are two subgroups of reading disabilities and that thorough diagnostic evaluations are needed to differentiate between these two subgroups. Distinctions of this nature are central to determining the type and intensity of language-based interventions.

Training of Visual-Spatial Working Memory in Preschool Children

Working memory, the ability to store and manipulate information is of great importance for scholastic achievement in children. In this study, we report four studies in which preschoolers were trained on a visual-spatial working memory span task, namely the Corsi Block Task. Across all four studies, we found significant training effects for the intervention groups compared to active control groups. Confirming recent research, no transfer effects to other working memory tasks were found. Most importantly, our training effects were mainly brought about by children performing below the median in the pretest and those showing median performance, thereby closing the gap to children performing above the median (compensation effect). We consider this finding of great interest to ensure comparable starting conditions when entering school with a relatively short intervention.

The importance of working memory for school achievement in primary school children with intellectual or learning disabilities

BACKGROUND

Given the well-known relation between intelligence and school achievement we expect children with normal intelligence to perform well at school and those with intelligence deficits to meet learning problems. But, contrary to these expectations, some children do not perform according to these predictions: children with normal intelligence but sub-average school achievement and children with lower intelligence but average success at school. Yet, it is an open question how the unexpected failure or success can be explained.

AIMS

This study examined the role of working memory sensu Baddeley (1986) for school achievement, especially for unexpected failure or success.

METHOD AND PROCEDURES

An extensive working memory battery with a total of 14 tasks for the phonological loop, the visual-spatial sketchpad and central executive skills was presented in individual sessions to four groups of children differing in IQ (normal vs. low) and school success (good vs. poor).

OUTCOMES AND RESULTS

Results reveal that children with sub-average school achievement showed deficits in working memory functioning, irrespective of intelligence. By contrast, children with regular school achievement did not show deficits in working memory, again irrespective of intelligence.

CONCLUSIONS AND IMPLICATIONS

Therefore working memory should be considered an important predictor of academic success that can lead both to unexpected overachievement and failure at school. Individual working memory competencies should be taken into account with regard to diagnosis and intervention for children with learning problems.

Polyunsaturated fatty acids (PUFAs) for children with specific learning disorders

BACKGROUND

About 5% of school children have a specific learning disorder, defined as unexpected failure to acquire adequate abilities in reading, writing or mathematics that is not a result of reduced intellectual ability, inadequate teaching or social deprivation. Of these events, 80% are reading disorders. Polyunsaturated fatty acids (PUFAs), in particular, omega-3 and omega-6 fatty acids, which normally are abundant in the brain and in the retina, are important for learning. Some children with specific learning disorders have been found to be deficient in these PUFAs, and it is argued that supplementation of PUFAs may help these children improve their learning abilities.

OBJECTIVES

1. To assess effects on learning outcomes of supplementation of polyunsaturated fatty acids (PUFAs) for children with specific learning disorders.2. To determine whether adverse effects of supplementation of PUFAs are reported in these children.

SEARCH METHODS

In November 2015, we searched CENTRAL, Ovid MEDLINE, Embase, PsycINFO, 10 other databases and two trials registers. We also searched the reference lists of relevant articles.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing PUFAs with placebo or no treatment in children younger than 18 years with specific learning disabilities, as diagnosed in accordance with the fifth (or earlier) edition of theDiagnostic and Statistical Manual of Mental Disorders (DSM-5), or the 10th (or earlier) revision of the International Classification of Diseases (ICD-10) or equivalent criteria. We included children with coexisting developmental disorders such as attention deficit hyperactivity disorder (ADHD) or autism.

DATA COLLECTION AND ANALYSIS

Two review authors (MLT and KHT) independently screened the titles and abstracts of articles identified by the search and eliminated all studies that did not meet the inclusion criteria. We contacted study authors to ask for missing information and clarification, when needed. We used the GRADE approach to assess the quality of evidence.

MAIN RESULTS

Two small studies involving 116 children, mainly boys between 10 and 18 years of age, met the inclusion criteria. One study was conducted in a school setting, the other at a specialised clinic. Both studies used three months of a combination of omega-3 and omega-6 supplements as the intervention compared with placebo. Although both studies had generally low risk of bias, we judged the risk of reporting bias as unclear in one study, and as high in the other study. In addition, one of the studies was funded by industry and reported active company involvement in the study.None of the studies reported data on the primary outcomes of reading, writing, spelling and mathematics scores, as assessed by standardised tests.Evidence of low quality indicates that supplementation of PUFAs did not increase the risk of gastrointestinal disturbances (risk ratio 1.43, 95% confidence interval 0.25 to 8.15; two studies, 116 children). Investigators reported no other adverse effects.Both studies reported attention deficit hyperactivity disorder (ADHD)-related behaviour outcomes. We were unable to combine the results in a meta-analysis because one study reported findings as a continuous outcome, and the other as a dichotomous outcome. No other secondary outcomes were reported.We excluded one study because it used a cointervention (carnosine), and five other studies because they did not provide a robust diagnosis of a specific learning disorder. We identified one ongoing study and found three studies awaiting classification.

AUTHORS' CONCLUSIONS

Evidence is insufficient to permit any conclusions about the effect of PUFAs on the learning abilities of children with specific learning disorders. Well-designed RCTs with clearly defined populations of children with specific learning disorders who have been diagnosed by standardised diagnostic criteria are needed.

Shared and Unique Risk Factors Underlying Mathematical Disability and Reading and Spelling Disability

High comorbidity rates have been reported between mathematical learning disabilities (MD) and reading and spelling disabilities (RSD). Research has identified skills related to math, such as number sense (NS) and visuospatial working memory (visuospatial WM), as well as to literacy, such as phonological awareness (PA), rapid automatized naming (RAN) and verbal short-term memory (Verbal STM). In order to explain the high comorbidity rates between MD and RSD, 7–11-year-old children were assessed on a range of cognitive abilities related to literacy (PA, RAN, Verbal STM) and mathematical ability (visuospatial WM, NS). The group of children consisted of typically developing (TD) children (n = 32), children with MD (n = 26), children with RSD (n = 29), and combined MD and RSD (n = 43). It was hypothesized that, in line with the multiple deficit view on learning disorders, at least one unique predictor for both MD and RSD and a possible shared cognitive risk factor would be found to account for the comorbidity between the symptom dimensions literacy and math. Secondly, our hypotheses were that (a) a probabilistic multi-factorial risk factor model would provide a better fit to the data than a deterministic single risk factor model and (b) that a shared risk factor model would provide a better fit than the specific multi-factorial model. All our hypotheses were confirmed. NS and visuospatial WM were identified as unique cognitive predictors for MD, whereas PA and RAN were both associated with RSD. Also, a shared risk factor model with PA as a cognitive predictor for both RSD and MD fitted the data best, indicating that MD and RSD might co-occur due to a shared underlying deficit in phonological processing. Possible explanations are discussed in the context of sample selection and composition. This study shows that different cognitive factors play a role in mathematics and literacy, and that a phonological processing deficit might play a role in the occurrence of MD and RSD.

Subtypes and comorbidity in mathematical learning disabilities: Multidimensional study of verbal and visual memory processes is key to understanding

A large body of research suggests that mathematical learning disability (MLD) is related to working memory impairment. Here, I organize part of this literature through a meta-analysis of 36 studies with 665 MLD and 1049 control participants. I demonstrate that one subtype of MLD is associated with reading problems and weak verbal short-term and working memory. Another subtype of MLD does not have associated reading problems and is linked to weak visuospatial short-term and working memory. In order to better understand MLD we need to precisely define potentially modality-specific memory subprocesses and supporting executive functions, relevant for mathematical learning. This can be achieved by taking a multidimensional parametric approach systematically probing an extended network of cognitive functions. Rather than creating arbitrary subgroups and/or focus on a single factor, highly powered studies need to position individuals in a multidimensional parametric space. This will allow us to understand the multidimensional structure of cognitive functions and their relationship to mathematical performance.

Executive functions in adults with developmental dyslexia

BACKGROUND

Executive functioning (EF) deficits are well recognized in developmental dyslexia, yet the majority of studies have concerned children rather than adults, ignored the subjective experience of the individual with dyslexia (with regard to their own EFs), and have not followed current theoretical perspectives on EFs.

AIMS AND METHODS

The current study addressed these shortfalls by administering a self-report measure of EF (BRIEF-A; Roth, Isquith, & Gioia, 2005) and experimental tasks to IQ-matched groups of adults with and without dyslexia. The laboratory-based tasks tested the three factors constituting the framework of EF proposed by Miyake et al. (2000).

RESULTS

In comparison to the group without dyslexia, the participants with dyslexia self-reported more frequent EF problems in day-to-day life, with these difficulties centering on metacognitive processes (working memory, planning, task monitoring, and organization) rather than on the regulation of emotion and behaviour. The participants with dyslexia showed significant deficits in EF (inhibition, set shifting, and working memory).

CONCLUSIONS AND IMPLICATIONS

The findings indicated that dyslexia-related problems have an impact on the daily experience of adults with the condition. Further, EF difficulties are present in adulthood across a range of laboratory-based measures, and, given the nature of the experimental tasks presented, extend beyond difficulties related solely to phonological processing.

Similarity interference in learning and retrieving arithmetic facts

Storing the solution of simple calculations in long-term memory is an important learning in primary school that is subsequently essential in adult daily living. While most children succeed in storing arithmetic facts to which they have been trained at school, huge individual differences are reported, particularly in children with developmental dyscalculia, who show a severe and persistent deficit in arithmetic facts learning. This chapter reports important advances in the understanding of the development of an arithmetic facts network and focuses on the detrimental effect of similarity interference. First, at the retrieval stage, connectionist models highlighted that the similarity of the neighbor problems in the arithmetic facts network creates interference. More recently, the similarity interference during the learning stage was pointed out in arithmetic facts learning. The interference parameter, that captures the proactive interference that a problem receives from previously learned problems, was shown as a substantial determinant of the performance across multiplication problems. This proactive interference was found both in children and adults and showed that when a problem is highly similar to previously learned ones, it is more difficult to remember it. Furthermore, the sensitivity to this similarity interference determined individual differences in the learning and retrieving of arithmetic facts, giving new insights for interindividual differences. Regarding the atypical development, hypersensitivity-to-interference in memory was related to arithmetic facts deficit in a single case of developmental dyscalculia and in a group of fourth-grade children with low arithmetic facts knowledge. In sum, the impact of similarity interference is shown in the learning stage of arithmetic facts and concerns the typical and atypical development.

Math anxiety and developmental dyscalculia: A study on working memory processes

INTRODUCTION

Although many children encounter difficulties in arithmetic, the underlying cognitive and emotive factors are still not fully understood. This study examined verbal and visuospatial short-term memory (STM) and working memory (WM) performance in children with developmental dyscalculia (DD) and high mathematics anxiety (MA) compared with typically developing (TD) children.

METHOD

Groups were matched on reading comprehension performance and IQ as well as on general anxiety. We aimed to test whether children with DD and MA were differently impaired in verbal and visuospatial STM and WM. Children were individually tested with four computerized tasks: two STM tasks (forward verbal and visuospatial recall) and two WM tasks (backward verbal and visuospatial recall).

RESULTS

Relative to children with TD, those with DD did not show impairments on the forward or backward verbal tasks, but showed specific impairments in the visuospatial WM task. In contrast, children with MA were particularly impaired in the verbal WM task.

CONCLUSIONS

Knowing the underlying cognitive processes that differentiate why children with DD and MA fail in math could have both educational and clinical implications.

WISC-IV Intellectual Profiles in Italian Children With Specific Learning Disorder and Related Impairments in Reading, Written Expression, and Mathematics

The fifth edition of theDiagnostic and Statistical Manual of Mental Disordersgrouped specific learning disabilities in the single diagnostic category of specific learning disorder (SLD), with specifiers for impairments in reading, written expression, and mathematics. This study aimed at investigating the intellectual profile, assessed with the fourth edition of theWechsler Intelligence Scale for Children(WISC-IV), of 172 children with a diagnosis of SLD, compared to 74 clinical referral controls. WISC-IV intellectual functioning in children with SLD was characterized by a significant discrepancy between general ability and cognitive proficiency (General Ability Index [GAI] > Cognitive Proficiency Index [CPI]), and worse performances on the Similarities, Digit Span, Letter-Number Sequencing, and Coding subtests, supporting models of multiple cognitive deficits at the basis of neurodevelopmental disorders as SLD. GAI was the best and more conservative measure provided by the WISC-IV to identify intellectual functioning in children with SLD, and the intellectual discrepancy between GAI and CPI could be considered a "cognitive sign" for the presence of SLD in a single diagnostic category. Cognitive deficits differed in subtypes of impairment (reading, written expression, and mathematics), supporting their distinction for empirical, educational, and rehabilitative purposes. These findings need further replication in larger samples and in comparison to typically developing children.

Cognitive Risk Factors for Specific Learning Disorder: Processing Speed, Temporal Processing, and Working Memory

High comorbidity rates between reading disorder (RD) and mathematics disorder (MD) indicate that, although the cognitive core deficits underlying these disorders are distinct, additional domain-general risk factors might be shared between the disorders. Three domain-general cognitive abilities were investigated in children with RD and MD: processing speed, temporal processing, and working memory. Since attention problems frequently co-occur with learning disorders, the study examined whether these three factors, which are known to be associated with attention problems, account for the comorbidity between these disorders. The sample comprised 99 primary school children in four groups: children with RD, children with MD, children with both disorders (RD+MD), and typically developing children (TD controls). Measures of processing speed, temporal processing, and memory were analyzed in a series of ANCOVAs including attention ratings as covariate. All three risk factors were associated with poor attention. After controlling for attention, associations with RD and MD differed: Although deficits in verbal memory were associated with both RD and MD, reduced processing speed was related to RD, but not MD; and the association with RD was restricted to processing speed for familiar nameable symbols. In contrast, impairments in temporal processing and visuospatial memory were associated with MD, but not RD.

A Meta-Analysis of Working Memory Deficits in Children With Learning Difficulties: Is There a Difference Between Verbal Domain and Numerical Domain?

Children with learning difficulties suffer from working memory (WM) deficits. Yet the specificity of deficits associated with different types of learning difficulties remains unclear. Further research can contribute to our understanding of the nature of WM and the relationship between it and learning difficulties. The current meta-analysis synthesized research on verbal WM and numerical WM among children with reading difficulties (RD), children with mathematics difficulties (MD), and children with reading and mathematics difficulties (RDMD). A total of 29 studies subsuming 110 comparisons were included. Results showed that compared to typically developing children, all learning difficulty groups demonstrated deficits in verbal WM and numerical WM, with RDMD children showing the most severe WM deficits. MD children and RD children showed comparable verbal WM deficits, but MD children showed more severe numerical WM deficits than RD children. Neither severity of learning difficulties nor type of academic screening emerged as a moderator of WM deficit profiles. Although the findings indicate the domain-general nature of WM deficits in RD, MD, and RDMD children, the numerical WM deficits of children with MD and RDMD may reflect the domain-specific nature of WM deficits.

Working Memory in Children With Learning Disabilities in Reading Versus Spelling: Searching for Overlapping and Specific Cognitive Factors

In transparent orthographies like German, isolated learning disabilities in either reading or spelling are common and occur as often as a combined reading and spelling disability. However, most issues surrounding the cognitive causes of these isolated or combined literacy difficulties are yet unresolved. Recently, working memory dysfunctions have been demonstrated to be promising in explaining the emergence of literacy difficulties. Thus, we applied a 2 (reading disability: yes vs. no) × 2 (spelling disability: yes vs. no) factorial design to examine distinct and overlapping working memory profiles associated with learning disabilities in reading versus spelling. Working memory was assessed in 204 third graders, and multivariate analyses of variance were conducted for each working memory component. Children with spelling disability suffered from more pronounced phonological loop impairments than those with reading disability. In contrast, domain-general central-executive dysfunctions were solely associated with reading disability, but not with spelling disability. Concerning the visuospatial sketchpad, no impairments were found. In sum, children with reading disability and those with spelling disability seem to be characterized by different working memory profiles. Thus, it is important to take both reading and spelling into account when investigating cognitive factors of literacy difficulties in transparent orthographies.

Improving working memory abilities in individuals with Down syndrome: a treatment case study

Working memory (WM) skills of individuals with Down's syndrome (DS) tend to be very poor compared to typically developing children of similar mental age. In particular, research has found that in individuals with DS visuo-spatial WM is better preserved than verbal WM. This study investigated whether it is possible to train short-term memory (STM) and WM abilities in individuals with DS. The cases of two teenage children are reported: EH, 17 years and 3 months, and AS, 15 years and 11 months. A school-based treatment targeting visuo-spatial WM was given to EH and AS for six weeks. Both prior to and after the treatment, they completed a set of assessments to measure WM abilities and their performance was compared with younger typically developing non-verbal mental age controls. The results showed that the trained participants improved their performance in some of the trained and non-trained WM tasks proposed, especially with regard to the tasks assessing visuo-spatial WM abilities. These findings are discussed on the basis of their theoretical, educational, and clinical implications.

Lernschwierigkeiten. Wie man einen pädagogisch-psychologischen Dauerbrenner immer wieder aufs Neue befeuern kann

Zusammenfassung. Ausgehend von definitorischen Überlegungen werden Häufigkeiten und Ursachen von Lernschwierigkeiten thematisiert sowie Erkenntnisse über evidenzbasierte Interventionen. Neben bereichsspezifischen Dysfunktionen gelten für Minderleistungen beim Lesen und in der Rechtschreibung sowie im Rechnen Defizite in bereichsübergreifenden kognitiven Grundfunktionen als ursächlich. Metaanalysen weisen auf eine Überlegenheit symptomspezifischer Interventionsmaßnahmen im Vergleich zu symptomunspezifischen Funktionstrainings hin. Mit dem Konzept der Instruktionsresponsivität (RTI) und einer Hinwendung zu formativer (Lernverlaufs-)Diagnostik existiert eine Alternative zur herkömmlichen Kategorisierungsdiagnostik.

[Formula: see text]Working memory outcomes following traumatic brain injury in children: A systematic review with meta-analysis

The aim of this review is to systematically examine the literature concerning multicomponent working memory (WM)-comprising a central executive (CE), two storage components (phonological loop, PL and visuo-spatial sketchpad, VSSP), and episodic buffer (EB)-in pediatric traumatic brain injury (TBI). Electronic searches were conducted of MEDLINE, PsychINFO and EMBASE up to October 2014 with the inclusion criteria of children and adolescents with TBI, and quantitative methods to assess at least one component of WM. Meta-analytic procedures calculated pooled effect sizes for WM outcomes. Of the studies examined, 27 met the inclusion criteria. Children with TBI exhibited deficits in the CE and PL, but not in the VSSP, and no study could be found which examined the EB. Qualitative analysis found that greater TBI severity was associated with poorer CE functioning in five out of nine studies. Differences in patterns of brain activation were evident in four out of five fMRI studies that examined WM in TBI children and controls. Deficits in CE were associated with poorer mathematical skills in the only study that examined relations between WM and academic deficits. Notwithstanding the heterogeneity of the studies reviewed, TBI places children at risk of WM deficits. Moreover, this meta-analysis suggests that various components of WM have differential vulnerability to pediatric TBI, with significant deficits found in the CE and PL, but not in the VSSP (although the VSSP has rarely been examined to date). Future studies should be theoretically driven, employ tasks assessing all components of the WM model and examine the functional ramifications (including academic outcomes) of WM deficits in this population.

Comparisons of numerical magnitudes in children with different levels of mathematical achievement. An ERP study

The ability to map between non-symbolic and symbolic magnitude representations is crucial in the development of mathematics and this map is disturbed in children with math difficulties. In addition, positive parietal ERPs have been found to be sensitive to the number distance effect and skills solving arithmetic problems. Therefore we aimed to contrast the behavioral and ERP responses in children with different levels of mathematical achievement: low (LA), average (AA) and high (HA), while comparing symbolic and non-symbolic magnitudes. The results showed that LA children repeatedly failed when comparing magnitudes, particularly the symbolic ones. In addition, a positive correlation between correct responses while analyzing symbolic quantities and WRAT-4 scores emerged. The amplitude of N200 was significantly larger during non-symbolic comparisons. In addition, P2P amplitude was consistently smaller in LA children while comparing both symbolic and non-symbolic quantities, and correlated positively with the WRAT-4 scores. The latency of P3 seemed to be sensitive to the type of numerical comparison. The results suggest that math difficulties might be related to a more general magnitude representation problem, and that ERP are useful to study its timecourse in children with different mathematical skills.

Working Memory and Number Sense as Predictors of Mathematical (Dis-)Ability

Recent research has pointed to two possible causes of mathematical (dis-)ability: working memory and number sense, although only few studies have compared the relations between working memory and mathematics and between number sense and mathematics. In this study, both constructs were studied in relation to mathematics in general, and to mathematical learning disabilities (MLD) in particular. The sample consisted of 154 children aged between 6 and 10 years, including 26 children with MLD. Children performing low on either number sense or visual-spatial working memory scored lower on math tests than children without such a weakness. Children with a double weakness scored the lowest. These results confirm the important role of both visual-spatial working memory and number sense in mathematical development.

Developmental Dyscalculia

Developmental dyscalculia (DD) is a specific learning disorder that affects the acquisition of arithmetic skills and number processing in children. A high comorbidity between DD and other neurodevelopmental disorders (e.g., dyslexia, attention-deficit/hyperactivity disorder [ADHD]) as well as substantial heterogeneity in cognitive profiles have been reported. Current studies indicate that DD is persistent, has a genetic component, and is related to functional and structural alterations of brain areas involved in magnitude representation. Recent neuronal and behavioral evidence is presented, showing that DD entails (a) impairments in two preverbal core systems of number, an approximate system for estimating larger magnitudes and an exact system for representing small magnitudes, (b) deficits in symbolic number processing, (c) aberrant and nonadaptive neuronal activation in basic magnitude processing and calculation, (d) dysfunctional arithmetic fact retrieval and persistent use of counting strategies in calculation, and (e) deficits in visuospatial working memory and the central executive. Finally, open research questions, including the role of domain-general cognitive resources in DD, causes and developmental consequences of comorbidity, as well as design and evaluation of interventions for DD, are briefly discussed.

Working Memory Functioning in Children With Poor Mathematical Skills

Previous research on working memory (WM) in children with poor mathematical skills has yielded heterogeneous results, possibly due to inconsistent consideration of the IQ–achievement discrepancy and additional reading and spelling difficulties. To examine the impact of both, the WM of 68 average-achieving and 68 low-achieving third-graders in mathematics was assessed. Preliminary analyses showed that poor mathematical skills were associated with poor WM. Afterwards, children with isolated mathematical difficulties were separated from those with additional reading and spelling difficulties. Half of each group fulfilled the IQ–achievement discrepancy, resulting in a 2 (additional reading and spelling difficulties: yes/no) by 2 (IQ–achievement discrepancy: yes/no) factorial design. Analyses revealed that not fulfilling the IQ–achievement discrepancy was associated with poor visual WM, whereas additional reading and spelling difficulties were associated with poor central executive functioning in children fulfilling the IQ–achievement discrepancy. Therefore, WM in children with poor mathematical skills differs according to the IQ–achievement discrepancy and additional reading and/or spelling difficulties.

A synthesis of mathematical and cognitive performances of students with mathematics learning disabilities

The purpose of this study was to synthesize the findings from 23 articles that compared the mathematical and cognitive performances of students with mathematics learning disabilities (LD) to (a) students with LD in mathematics and reading, (b) age- or grade-matched students with no LD, and (c) mathematical-ability-matched younger students with no LD. Overall results revealed that students with mathematics LD exhibited higher word problem-solving abilities and no significant group differences on working memory, long-term memory, and metacognition measures compared to students with LD in mathematics and reading. Findings also revealed students with mathematics LD demonstrated significantly lower performance compared to age- or grade-matched students with no LD on both mathematical and cognitive measures. Comparison between students with mathematics LD and younger students with no LD revealed mixed outcomes on mathematical measures and generally no significant group differences on cognitive measures.

Cognitive components of a mathematical processing network in 9-year-old children

We determined how various cognitive abilities, including several measures of a proposed domain-specific number sense, relate to mathematical competence in nearly 100 9-year-old children with normal reading skill. Results are consistent with an extended number processing network and suggest that important processing nodes of this network are phonological processing, verbal knowledge, visuo-spatial short-term and working memory, spatial ability and general executive functioning. The model was highly specific to predicting arithmetic performance. There were no strong relations between mathematical achievement and verbal short-term and working memory, sustained attention, response inhibition, finger knowledge and symbolic number comparison performance. Non-verbal intelligence measures were also non-significant predictors when added to our model. Number sense variables were non-significant predictors in the model and they were also non-significant predictors when entered into regression analysis with only a single visuo-spatial WM measure. Number sense variables were predicted by sustained attention. Results support a network theory of mathematical competence in primary school children and falsify the importance of a proposed modular 'number sense'. We suggest an 'executive memory function centric' model of mathematical processing. Mapping a complex processing network requires that studies consider the complex predictor space of mathematics rather than just focusing on a single or a few explanatory factors.

Executive control training from middle childhood to adolescence

Executive functions (EFs) include a number of higher-level cognitive control abilities, such as cognitive flexibility, inhibition, and working memory, which are instrumental in supporting action control and the flexible adaptation changing environments. These control functions are supported by the prefrontal cortex and therefore develop rapidly across childhood and mature well into late adolescence. Given that executive control is a strong predictor for various life outcomes, such as academic achievement, socioeconomic status, and physical health, numerous training interventions have been designed to improve executive functioning across the lifespan, many of them targeting children and adolescents. Despite the increasing popularity of these trainings, their results are neither robust nor consistent, and the transferability of training-induced performance improvements to untrained tasks seems to be limited. In this review, we provide a selective overview of the developmental literature on process-based cognitive interventions by discussing (1) the concept and the development of EFs and their neural underpinnings, (2) the effects of different types of executive control training in normally developing children and adolescents, (3) individual differences in training-related performance gains as well as (4) the potential of cognitive training interventions for the application in clinical and educational contexts. Based on recent findings, we consider how transfer of process-based executive control trainings may be supported and how interventions may be tailored to the needs of specific age groups or populations.

Working memory and executive functions: effects of training on academic achievement

The aim of this review is to illustrate the role of working memory and executive functions for scholastic achievement as an introduction to the question of whether and how working memory and executive control training may improve academic abilities. The review of current research showed limited but converging evidence for positive effects of process-based complex working-memory training on academic abilities, particularly in the domain of reading. These benefits occurred in children suffering from cognitive and academic deficits as well as in healthy students. Transfer of training to mathematical abilities seemed to be very limited and to depend on the training regime and the characteristics of the study sample. A core issue in training research is whether high- or low-achieving children benefit more from cognitive training. Individual differences in terms of training-related benefits suggested that process-based working memory and executive control training often induced compensation effects with larger benefits in low performing individuals. Finally, we discuss the effects of process-based training in relation to other types of interventions aimed at improving academic achievement.

Einfluss kognitiver Merkmale und häuslicher Umgebung auf die Entwicklung numerischer Kompetenzen im Vorschulalter

Das Ziel der längsschnittlich angelegten Studie besteht darin, frühe Einflussfaktoren auf die numerische Entwicklung im Alter von sechs Jahren ausfindig zu machen. Hierzu werden kognitive Faktoren (Intelligenz, Arbeitsgedächtnis, Abruf von Informationen aus dem Langzeitgedächtnis, phonologische Bewusstheit) sowie Merkmale der sozialen Umgebung (sozioökonomischer Status, Migrationshintergrund, Home Numeracy Environment, Home Literacy Environment, mütterliche Selbsteinschätzung in Bezug auf Mathematik) als Prädiktoren für die numerischen Kompetenzen an einer Stichprobe von 132 Fünfjährigen analysiert. Die Ergebnisse legen ein multiples Bedingungsgefüge nahe. Während die Intelligenz und die phonologische Bewusstheit keinen bedeutsamen Beitrag zur Varianzaufklärung leisteten, stellten das visuell-räumliche Arbeitsgedächtnis sowie die Abrufgeschwindigkeit aus dem Langzeitgedächtnis wichtige Einflussfaktoren der frühen numerischen Leistungen dar. Von den Merkmalen der sozialen Umwelt konnten darüber hinaus der sozioökonomische Status und die häusliche numerische Umgebung zusätzlich bis zu 12 % Varianz aufklären. Die Bedeutung der Befunde für die Diagnostik und Intervention bei Risikokindern wird diskutiert.

Developmental dyscalculia is related to visuo-spatial memory and inhibition impairment

Developmental dyscalculia is thought to be a specific impairment of mathematics ability. Currently dominant cognitive neuroscience theories of developmental dyscalculia suggest that it originates from the impairment of the magnitude representation of the human brain, residing in the intraparietal sulcus, or from impaired connections between number symbols and the magnitude representation. However, behavioral research offers several alternative theories for developmental dyscalculia and neuro-imaging also suggests that impairments in developmental dyscalculia may be linked to disruptions of other functions of the intraparietal sulcus than the magnitude representation. Strikingly, the magnitude representation theory has never been explicitly contrasted with a range of alternatives in a systematic fashion. Here we have filled this gap by directly contrasting five alternative theories (magnitude representation, working memory, inhibition, attention and spatial processing) of developmental dyscalculia in 9-10-year-old primary school children. Participants were selected from a pool of 1004 children and took part in 16 tests and nine experiments. The dominant features of developmental dyscalculia are visuo-spatial working memory, visuo-spatial short-term memory and inhibitory function (interference suppression) impairment. We hypothesize that inhibition impairment is related to the disruption of central executive memory function. Potential problems of visuo-spatial processing and attentional function in developmental dyscalculia probably depend on short-term memory/working memory and inhibition impairments. The magnitude representation theory of developmental dyscalculia was not supported.

Prädiktoren der Lesekompetenz bei Kindern mit Deutsch als Zweitsprache

Die vorliegende Längsschnittstudie beschäftigt sich mit der Frage, ob sich Ergebnisse hinsichtlich vorschulischer Prädiktoren der Lesekompetenz einsprachig deutscher Kinder auf Kinder mit Deutsch als Zweitsprache (DaZ) übertragen lassen. Ein Pfadmodell zur Vorhersage der Lesekompetenz zum Ende der ersten bzw. zweiten Klassenstufe wurde dabei sowohl auf einsprachige (n = 111) als auch auf DaZ-Kinder (n = 282) angewendet. Zunächst wurde die Pfadstruktur der am Ende der Kindergartenzeit bzw. zu Beginn der Schulzeit erfassten Vorläuferfertigkeiten nonverbale Intelligenz, phonologisches Arbeitsgedächtnis, sprachliche Kompetenz, Schnelles Benennen, Buchstabenkenntnis und phonologische Bewusstheit untereinander betrachtet. Hier unterschieden sich die Effektmuster bei einsprachigen und DaZ-Kindern nicht signifikant. Ebenso zeigt sich in beiden Sprachgruppen ein vergleichbares Bild hinsichtlich der Einflussfaktoren des Leseverständnisses. Bedeutsame Unterschiede zwischen den Sprachgruppen ergaben sich jedoch bezüglich der Vorhersage der Lesegeschwindigkeit: In der Gruppe der einsprachigen Kinder war die phonologische Bewusstheit der bedeutsamste Prädiktor. Bei den DaZ-Kindern hingegen war der Einfluss der phonologischen Bewusstheit auf die Lesegeschwindigkeit nicht von Bedeutung, dafür erfolgte der größte Teil der Varianzaufklärung durch die nonverbale Intelligenz.

Mental additions and verbal-domain interference in children with developmental dyscalculia

This study examined the involvement of verbal and visuo-spatial domains in solving addition problems with carrying in a sample of children diagnosed with developmental dyscalculia (DD) divided into two groups: (i) those with DD alone and (ii) those with DD and dyslexia. Age and stage matched typically developing (TD) children were also studied. The addition problems were presented horizontally or vertically and associated with verbal or visuo-spatial information. Study results showed that DD children's performance on mental calculation tasks was more impaired when they tackled horizontally presented addition problems compared to vertically presented ones that are associated to verbal domain involvement. The performance pattern in the two DD groups was found to be similar. The theoretical, clinical and educational implications of these findings are discussed.

Die computergestützte Aufmerksamkeitstestbatterie für Kinder (KITAP): Zusammenhänge mit dem Arbeitsgedächtnis und der Verarbeitungsgeschwindigkeit

Die vorliegende Studie überprüft Zusammenhänge zwischen verschiedenen Aspekten der Aufmerksamkeit (Subtests der KITAP: Ablenkbarkeit, Alertness, Flexibilität, geteilte Aufmerksamkeit und Go/NoGo) mit kognitiven Leistungen (Subskalen im HAWIK-IV: Verarbeitungsgeschwindigkeit und Arbeitsgedächtnis). Dazu wurden N = 456 Kinder (52.2 % Jungen) im Alter von 7 bis 10 Jahren (M = 105 Monate, SD = 5.86) untersucht. Die Aspekte der Aufmerksamkeit ließen sich nicht überzeugend differenzieren, eine konfirmatorische Faktorenanalyse ergab zwei latente Variablen (Leistungsgeschwindigkeit und Leistungsgüte) mit gutem Modellfit. Die Leistungsgüte hängt signifikant mit dem Arbeitsgedächtnis und der Verarbeitungsgeschwindigkeit zusammen (r = -.31 bzw. r = -.24). Die Leistungsgeschwindigkeit zeigt bedeutsame, aber niedrigere Zusammenhänge mit den kognitiven Leistungen. Folgerungen für die differenzierte Interpretation der KITAP-Subtests werden diskutiert.

Rethinking ADHD and LD in DSM-5: proposed changes in diagnostic criteria

The Diagnostic and Statistical Manual of Mental Disorders (DSM) is currently undergoing revision that will lead to a fifth edition (DSM-5) in 2013. This article first provides a brief synopsis of the DSM-5 administrative structure, procedures, and guiding principles to enhance understanding of how changes are made in the DSM. The next two sections (on attention-deficit/hyperactivity disorder and learning disorders, respectively) highlight the major concerns and controversies surrounding the DSM-IV diagnostic criteria for these two disorders and provide a rationale for the proposed changes to the criteria, along with a commentary on the empirical evidence on which the proposed changes were based.

An Introduction to Optimal Design

In this article we give an elementary introduction to optimal design for some basic statistical models. Research questions coming from a project on dyscalculia are used as illustrative examples throughout this article. First, basic design issues are considered for the t-test and simple regression and then extended to the general linear model. Finally, we will outline optimal designs for nonlinear statistical models. As a simple example, logistic regression with a binary explanatory variable is used.

Phonologische Verarbeitung bei Grundschulkindern mit schwacher Lesefähigkeit

Defizite in der phonologischen Informationsverarbeitung werden heute als Kernsymptom der Lese-Rechtschreibstörung betrachtet. In Trainingsstudien mit betroffenen Kindern erwiesen sich Phonemwahrnehmungsfähigkeiten als trainierbar, und Programme, in denen Aufgaben zur phonologischen Bewusstheit mit der systematischen Vermittlung von Phonem-Graphem-Zuordnungen kombiniert wurden, zeigten Transfereffekte auf Lese- und Rechtschreibleistungen. Ausgehend von diesen Erkenntnissen wurde ein computerbasiertes Trainingsprogramm zur Förderung der Phonemwahrnehmung, der phonologischen Bewusstheit und der Graphem-Phonem-Zuordnungen für deutschsprachige Grundschulkinder mit Lese-Rechtschreibstörung entwickelt. Aufgrund der besonderen Relevanz der Vokallänge für die deutsche Orthographie enthält das Programm neben Aufgaben, die auf Konsonanten fokussieren, auch Vokallängenaufgaben. Bei der Konzipierung des Programms wurden etablierte, ursprünglich für andere Sprachen entwickelte Aufgaben an die deutsche Phonologie angepasst und in ein computerbasiertes Format übersetzt. Im Rahmen der vorliegenden Studie sollte überprüft werden, ob die konstruierten Trainingsaufgaben die spezifischen Defizite von Kindern mit Lese-Rechtschreibstörung wie intendiert abbilden. Hierzu wurden leseschwache Dritt- und Viertklässler (n = 35) mit mindestens durchschnittlichen Lesern derselben Klassenstufen (n = 75; Kontrollgruppe) hinsichtlich ihrer Leistungen in den Aufgaben verglichen. Die leseschwachen Kinder zeigten in allen Aufgaben schlechtere Leistungen als die Kontrollgruppe. Die Effektstärken der Gruppenunterschiede (Cohen's d) lagen im mittleren bis hohen Bereich (0.50 – 2.19). Die Ergebnisse bestätigen, dass die Aufgaben des Trainingsprogramms die spezifischen Defizite leseschwacher Kinder abbilden. Ein Training mit diesen Aufgaben erscheint daher grundsätzlich sinnvoll. Die Wirkungen eines solchen Trainings auf die schriftsprachlichen Leistungen von Kindern mit Lese-Rechtschreibstörung werden in zukünftigen Studien überprüft.

Polyunsaturated fatty acids (PUFAs) for children with specific learning disorders

BACKGROUND

About 5% of schoolchildren have a specific learning disorder, defined as an unexpected failure to acquire adequate abilities in reading, writing or mathematic skills not as a result of reduced intellectual ability, inadequate teaching or social deprivation. Of these, 80% are reading disorders. Polyunsaturated fatty acids (PUFAs), in particular omega-3 and omega-6 fatty acids, which are found abundantly in the brain and retina are important for learning. Some children with specific learning disorders have been found to be deficient in these PUFAs, and it is argued that supplementation of PUFAs may help these children improve their learning abilities.

OBJECTIVES

To assess the effects of polyunsaturated fatty acids (PUFAs) supplementation for children with specific learning disorders, on learning outcomes.

SEARCH METHODS

We searched the following databases in April 2012: CENTRAL (2012, Issue 4), MEDLINE (1948 to April Week 2 2012), EMBASE (1980 to 2012 Week 16), PsycINFO (1806 to April 2012), ERIC (1966 to April 2012), Science Citation Index (1970 to 20 April 2012), Social Science Citation Index (1970 to 20 April 2012), Conference Proceedings Citation Index-Science (1970 to 20 April 2012), Conference Proceedings Citation Index-Social Sciences and Humanites (1970 to 20 April 2012), Cochrane Database of Systematic Reviews (2012, Issue 4), DARE (2012, Issue 2) , ZETOC (24 April 2012) and WorldCat (24 April 2012). We searched the WHO International Clinical Trials Registry Platform and ClinicalTrials.gov on 24 April 2012. We also searched the reference lists of relevant articles identified by the searches.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials comparing polyunsaturated fatty acids (PUFAs) with placebo or no treatment in children aged below 18 years with specific learning disabilities diagnosed using DSM-IV, ICD-10 or equivalent criteria. We intended to include participants with co-existing developmental disorders such as attention deficit hyperactivity disorder (ADHD) or autism.

DATA COLLECTION AND ANALYSIS

Two authors (ML and KH) independently screened the titles and abstracts of the search results and eliminated all studies that did not meet the inclusion criteria. Authors were contacted for missing information and clarifications when needed.

MAIN RESULTS

We did not find any studies suitable for inclusion in the review. One study is awaiting classification as we were unable to get any information from the study author.

AUTHORS' CONCLUSIONS

There is insufficient evidence to draw any conclusion about the use of PUFAs for children with specific learning disorders. There is a need for well designed randomised studies to support or refute the use of PUFAs in this group of children.

Revisiting Discrepancy Theory in Learning Disabilities: What Went Wrong and Why We Should Go Back

The rise in popularity of Response to Intervention (RTI) as a method of identifying Learning Disabilities (LD) is partially due to the psychometric and theoretical issues inherent to the use of IQ tests in the once popular discrepancy method of identification. However, both RTI and discrepancy theories have their shortcomings, and criticisms directed at either method are usually applicable to both. This conceptual article puts forward a justification for using tests of the cognitive processes that are implicated in LD as a better method of LD identification. Although the unsuitability of the discrepancy method to accurately identify LD students is well established, it does represent the construct of LD well. Therefore, the discrepancy method can be used as an effective baseline measure against which improved identification procedures based on cognitive processes can be measured. Once these cognitive processes are more clearly defined, tests of these processes offer promise for LD identification.