Developmental dyscalculia is a familial learning disability

Whereas current evidence attests to a genetic component in the etiology of dyslexia and attention-deficit/hyperactivity disorder (ADHD), little is known about the role of genetics in developmental dyscalculia (DC). The objective of this study was to determine the familial aggregation of DC. Siblings and parents of children with DC were assessed for arithmetic, reading and attention disorders. The criteria for DC were an IQ higher than 85, poor performance in arithmetic, and a significant discrepancy between arithmetic achievement and IQ. The study group was composed of 39 children with DC, 21 mothers, 22 fathers, 90 siblings, and 16 second-degree relatives. We found that 66% of mothers, 40% of fathers, 53% of siblings, and 44% of second-degree relatives had DC. The intraclass correlation between the sib pairs was .27. A 95% confidential interval (CI) for the prevalence of DC among siblings of DC probands (see Note 1) ranged from 40% to 64%, indicating a familial prevalence almost tenfold higher than expected for the general population. IQ and attention problems were not risk factors for DC. We conclude that DC, like other learning disabilities, has a significant familial aggregation, suggesting a role for genetics in the evolution of this disorder.     

Longitudinal Study of Reading Disability and Attention-Deficit/Hyperactivity Disorder: Implications for Education

ABSTRACT— The majority of children who receive special education services meet criteria for reading disability (RD) or attention-deficit/hyperactivity disorder (ADHD), but additional research is needed to understand the long-term academic outcome of children in these groups. Individuals with RD only ( N = 71), ADHD only ( N = 66), both RD and ADHD ( N = 51), or neither disorder ( N = 118) were identified through the ongoing Colorado Learning Disabilities Research Center twin study and retested 5 years later. Results of the follow-up testing indicated that, in addition to ongoing reading difficulties, individuals with RD exhibited higher rates of academic difficulties, depression, and adolescent-onset conduct disorder. Initial ADHD status was associated with academic and social difficulties and elevated rates of nearly all comorbid disorders 5 years later. The group with comorbid RD and ADHD had more stable reading deficits than the group with RD without ADHD and exhibited greater impairment than groups with either disorder alone on outcome measures of academic functioning and social difficulties. These results suggest that individuals with both RD and ADHD are at increased risk for negative outcomes as adolescents and young adults and that when RD and ADHD co-occur, interventions should be provided for both disorders.     

Peer Status in Boys With and Without Attention-Deficit Hyperactivity Disorder: Predictions from Overt and Covert Antisocial Behavior, Social Isolation, and Authoritative Parenting Beliefs

Because of the centrality of peer relationship difficulties for children with attentiondeficit hyperactivity disorder (ADHD), we investigated behavioral (overt and covert antisocial activity), internalizing (self-reports and observed social isolation), and familial (authoritative, authoritarian, and permissive parenting beliefs) predictors of peer sociometric nominations among previously unfamiliar, ethnically diverse ADHD ( N=73 ) and comparison ( N=60 ) boys, aged 6–12 years. Authoritative maternal parenting beliefs and negatively weighted social isolation explained significant variance in positive peer regard; aggression, covert behavior, and authoritative parenting beliefs were the independent predictors of both negative peer status and peer social preference. We extended such predictions with statistical control of (1) child cognitive variables, (2) maternal psychopathology, and (3) ADHD boys, but authoritative parenting beliefs were stronger predictors in ADHD than in comparison youth. We discuss family-peer linkages regarding peer competence.     

Naming speed in dyslexia and dyscalculia

In four carefully selected samples of 8- to 10-year old children with dyslexia (but age adequate arithmetic skills), dyscalculia (but age adequate reading skills), dyslexia/dyscalculia and controls a domain-general deficit in rapid automatized naming (RAN) was found for both dyslexia groups. Dyscalculic children exhibited a domain-specific deficit in rapid naming of quantities. This finding is in line with recent assumptions that dyscalculia is associated with a neurobiological deficit in the processing of numerosities. In the dyslexia/dyscalculia group, RAN deficits were additive, that is, the dyslexia/dyscalculia group exhibited the sum of the deficits found in the dyslexia only and dyscalculia only groups. This finding suggests that the cognitive bases of dyslexia and dyscalculia are independent from each other. Within the naming speed paradigm no differential impact of special demands on the executive functions inhibition and shifting was found for any of the four groups.     

A systematic review of interventions for children presenting with dyscalculia in primary schools

The acquisition of numerical competency is regarded as imperative for quality of life and economic well-being. Many children have significant mathematical learning difficulties known as dyscalculia. The aim of this research was to systematically review the available literature for interventions with children presenting with dyscalculia in primary schools, in order to provide an evidence base of filtered information assessed for methodological rigour and coherence. The study evaluated literature from 2004 to 2014 that reported on interventions for primary school children presenting with dyscalculia. Specific databases were accessed to highlight literature for inclusion in the study. The studies were assessed at title, abstract and full text levels for quality based on the inclusion and exclusion criteria. The findings provide a base of effective interventions that can be used in the school setting for individual development with a holistic focus and present various methods of instruction for children presenting with dyscalculia.     

Linkages between child abuse and attention-deficit/hyperactivity disorder in girls: behavioral and social correlates

OBJECTIVE: The objectives of this study were to examine whether girls with attention-deficit/hyperactivity disorder (ADHD) are at increased risk of having histories of abuse and to assess whether the presence of an abuse history may constitute a distinct subgroup of youth with ADHD. METHOD: We examined rates and correlates of child abuse in an ethnically and socioeconomically diverse sample of girls with attention-deficit/hyperactivity disorder (ADHD; n=140) and a matched comparison sample of girls without ADHD (n=88), all aged 6-12 years. A thorough chart review reliably established documented rates of physical and sexual abuse in both samples. RESULTS: There were significantly higher rates of abuse for girls with ADHD (14.3%) than for the comparison sample (4.5%), with most of the abuse found in girls with the Combined as opposed to the Inattentive type. Higher rates of externalizing behaviors (including objective observations in a research summer camp) and peer rejection (indexed through peer sociometric nominations) characterized the subgroup of girls with ADHD with abuse histories compared to the subgroup without such histories, with moderate to large effect sizes. Subgroup differences regarding internalizing problems and cognitive deficits did not emerge. Findings regarding peer rejection were explained, in part, by higher rates of observed aggressive behavior in the abused subgroup. CONCLUSIONS: The findings raise important questions about the possible etiologic and/or exacerbating role of abusive trauma in a subgroup of children with ADHD.     

Working memory deficits in children with specific learning disorders

This article examines working memory functioning in children with specific developmental disorders of scholastic skills as defined by ICD-10. Ninety-seven second to fourth graders with a minimum IQ of 80 are compared using a 2 x 2 factorial (dyscalculia vs. no dyscalculia; dyslexia vs. no dyslexia) design. An extensive test battery assesses the three subcomponents of working memory described by Baddeley (1986): phonological loop, visual-spatial sketchpad, and central executive. Children with dyscalculia show deficits in visual-spatial memory; children with dyslexia show deficits in phonological and central executive functioning. When controlling for the influence of the phonological loop on the performance of the central executive, however, the effect is no longer significant. Although children with both reading and arithmetic disorders are consistently outperformed by all other groups, there is no significant interaction between the factors dyscalculia and dyslexia.     

Investigation of the Relationship of Attention Deficit Hyperactivity Disorder to the EKN1 Gene on Chromosome 15q21

Recently a gene, termed EKN1, has been identified because of a chromosomal breakpoint that occurred in this gene. This chromosomal breakpoint was found in 4 family members that had specific reading disabilities (RDs), indicating that disruption of this gene may be contributing to the risk of developing RDs. This gene was further supported as contributing to RD by association studies. Because of the evidence from twin studies for shared genetic factors contributing to RD and attention deficit hyperactivity disorder (ADHD), particularly inattention symptoms, we investigated the relationship of DNA markers in this gene to ADHD and ADHD symptoms in a sample of 186 nuclear families (probands, their parents, and affected siblings) collected through a proband with ADHD. We used 6 polymorphic DNA markers located across the gene, including the 2 markers previously reported to be associated with RD in a Finnish sample and a marker associated with RD in a sample of families collected in Toronto. We found a trend for association for several markers to the ADHD phenotype analyzed as a categorical trait using the transmission disequilibrium test and significant evidence for biased transmission of the haplotypes containing these markers, χ²(3) = 9.312, p =. 025. Using quantitative analysis, we observed evidence for association of one of the haplotypes to the inattention and hyperactive/impulsive symptom dimensions as reported by parents and to the inattention symptoms as reported by teachers, as well as a trend for association with the reading phenotypes of word identification and decoding. The results provide preliminary support for the role of the EKN1 chromosomal region in ADHD, suggesting that this region may contribute to ADHD symptoms in addition to RD.     

Reading difficulties and attention‐deficit/hyperactivity behaviours: evidence of an early association in a nonclinical sample

Attention‐deficit/hyperactivity disorder (ADHD) often co‐occurs with reading disability. A cross‐sectional study in an Italian‐speaking, nonclinical sample was conducted in an attempt to document the existence of an early association between reading difficulties (RD) and ADHD behaviours. We recruited a sample of 369 children in their first year at primary school. Of the sample, 8.4% displayed RD; 7.0% had ADHD; 3.5% presented both RD and ADHD behaviours; 50% of the children with ADHD displayed RD; 41.9% of those with RD displayed ADHD behaviours. Low socioeconomic status was associated with a fourfold increased probability of displaying RD (odds ratio = 3.98), but not ADHD behaviours. In this nonclinical sample, we detected an early association between ADHD behaviours and RD. A key role in this association may be played by inattention symptoms, which occurred with significantly increased frequency also in the group presenting only RD.     

Time-of-day matters in text learning and recall: Evening lessons are advantageous for adults with ADHD though not for typical peers

Motor skill (“how-to” knowledge) consolidation is enhanced when individuals with ADHD practice at evening. We tested, in adults with and without ADHD, whether evening lessons are advantageous for recalling texts (declarative memory). Participants (N = 40) listened to and read narrative texts in morning and evening lessons (crossover study). Recall was tested immediately post-lesson and 24 h and 8–10 days later. Recall tended to decrease over time but independently of ADHD status or the time-of-day of the lesson. Nevertheless, typical participants showed a morning advantage immediately post-lesson and in later recall, correlated with stronger morning chronotype. In contrast, participants with ADHD benefited more from evening lessons; nearer their preferred time-of-day. In adults with ADHD long-term declarative memory was no less durable than in typical adults after both morning and evening lessons, but a mismatch with their preferred diurnal “on-peak” time can lead to less effective engagement in learning during morning lessons.     

Sensitivity of Four Subtests of the Test of Everyday Attention for Children (TEA‐Ch) to Stimulant Medication in Children with ADHD

Children with attention deficit hyperactivity disorder (ADHD) were examined on four subtests of the Test of Everyday Attention for Children (TEA‐Ch) when on and off stimulant medication. Performance was assessed relative to 18 individually age‐matched controls. Children with ADHD performed significantly worse on TEA‐Ch measures when off compared to when on stimulant medication. This was found in both predominantly inattentive (n = 6) and combined inattentive and hyperactive‐impulsive (n = 12) subtypes. The age‐matched controls significantly improved with repeated testing on most TEA‐Ch measures. Significant differences were found between the unmedicated children with ADHD and age‐matched controls on sustained attention (Score! and Walk Don’t Walk) and attention control measures (Same and Opposite Worlds). When the ADHD group was on stimulant medication, with the exception of the Walk Don’t Walk subtest, no significant differences were found between them and the age‐matched controls. Unlike the TEA‐Ch subtests, the significant differences between the two groups on the Test of Word Reading Efficiency (TOWRE) subtests remained when attentional status was altered in the children with ADHD. The study supports further investigations of the TEA‐Ch as a measure sensitive to changes in stimulant medication in children with ADHD.     

Association between attention deficit-hyperactivity disorder and learning disorders

This article discusses the relationship between attention deficit-hyperactivity disorder (ADHD) and learning disability (LD). The relevant literature is outlined, and empirical data are presented from a prospective follow-up study of 600 speech/language-impaired children. The data show an increased prevalence of both LD and ADHD among children with early speech/language impairments. Furthermore, LD was strongly associated with ADHD in both the initial and follow-up samples. Also, the children with LD had increased rates of other psychiatric disorders (e.g., behavior disorders, mood disorders, anxiety disorders). The implications of these data are discussed with regard to the possible etiology of the ADHD-LD association, treatment for children with LD and ADHD, and promising hypotheses for future research.     

Cognitive Endophenotypes of Dyslexia

The study investigated cognitive deficits associated with dyslexia and familial risk of dyslexia (endophenotypes) by comparing children from families with and without a history of dyslexia. Eighty-eight school-aged children were assessed on measures of phonology, language and rapid automatized naming. A series of regression analyses with family risk and dyslexia status as predictors indicated that word recall, morphology, and rapid automatized naming were associated with the deficit, whereas the two phonological measures (phoneme awareness and nonword repetition) were associated with both literacy deficits and family risk, suggesting that the phonological deficit is an endophenotype of dyslexia. Whereas the association with familial risk was similar for the two phonological measures, they differed in their relation to dyslexia status: Phoneme awareness showed a stronger association with dyslexia than risk status, whereas nonword repetition was more strongly related to the risk. The data are interpreted within the framework of multiple deficit models of dyslexia.     

Predictors of primary school teachers’ knowledge about developmental dyscalculia

Developmental dyscalculia is a specific learning disability that is described as a heterogeneous and persistent cognitive disorder. Given the need to detect and intervene as early as possible to minimise its effects, teachers’ knowledge about symptoms, characteristics and effective intervention strategies in dyscalculia is essential. Given the lack of research about this topic and measures to evaluate teachers’ knowledge, this study aims to present a literature-based measure to evaluate knowledge about developmental dyscalculia and to investigate the predictors of this type of knowledge. Data were collected from a sample of 175 primary school teachers. The measure presented adequate psychometric properties. Teachers’ personal characteristics such as age and gender did not predict their knowledge about dyscalculia. Being a Special Education teacher predicted a higher knowledge of intervention strategies in dyscalculia and having heard about dyscalculia predicted higher knowledge about not only intervention strategies but also dyscalculia characteristics. The data are discussed, and suggestions for further studies are presented.     

Dyscalculia: A unifying concept in understanding mathematics learning disabilities

Abstract

Individuals display a mathematics disability when their performance on standardized calculation tests or on numerical reasoning tasks is comparatively low, given their age, education and intellectual reasoning ability. Low performance due to cerebral trauma Is called acquired dyscalculia. Mathematical learning difficulties with similar features but without evidence of cerebral trauma are referred to as developmental dyscalculia. This review identifies types of developmental dyscalculia, the neuropsychological processes that are linked with them and procedures for Identifying dyscalculia.     

An intervention approach for children with teacher- and parent-identified attentional difficulties

Using a multimodal and multi-informant method for diagnosis, we selected 33 children by teacher and parent nomination for attention and work completion problems that met DSM-IV criteria for attention-deficit/hyperactivity disorder (ADHD). Of the 33 children in this group, 21 participated in the initial intervention, and 12 were placed in an ADHD control group and received the intervention after pre- and posttesting. A similarly selected group of 21 children without difficulties in attention and work completion served as a control group. Each child was assessed on pre- and posttest measures of visual and auditory attention. After an 18-week intervention period that included attention and problem-solving training, all children in the intervention and control groups were retested on visual and auditory tasks. Children in both ADHD groups showed significantly poorer initial performance on the visual attention task. Whereas the ADHD intervention group showed commensurate performance to the nondisabled control group after training, the ADHD control group did not show significant improvement over the same period. Auditory attention was poorer compared to the control group for both ADHD groups initially and improved only for the ADHD intervention group. These findings are discussed as a possible intervention for children with difficulties in strategy selection in a classroom setting.     

Evaluation of a numeracy intervention program focusing on basic numerical knowledge and conceptual knowledge: a pilot study

The preliminary results of this study suggested that children with developmental dyscalculia benefit from a numeracy intervention program that focuses on basic numerical knowledge and conceptual knowledge. All children in the experimental group showed considerable and partly significant performance increases on all calculation components. Six children with developmental dyscalculia were trained individually and in small-group settings for a relatively short duration (one school semester). We argue that the positive intervention effects to a large extent are attributable to the explicit teaching of numerical domains that often have been found to be neglected in school mathematics.     

Childhood maltreatment and conduct disorder: Independent predictors of criminal outcomes in ADHD youth

ObjectiveChildren with attention-deficit/hyperactivity disorder (ADHD) are at heightened risk for maltreatment in childhood and criminality as they enter into adolescence and early adulthood. Here, we investigated the effect of moderate to severe childhood maltreatment on later criminality among adolescents/young adults diagnosed with ADHD in childhood while accounting for the contributions of other known risk factors such as early conduct disorder (CD).MethodsEighty-eight participants from a longitudinal study of children diagnosed with ADHD and screened for comorbid disorders at age 7–11 years were assessed for maltreatment histories at the time of the 10-year adolescent follow-up. Detailed juvenile and adult criminal records were obtained from the New York State Division of Criminal Justice Services approximately 3-years after commencement of the follow-up study. We used regression analyses to determine predictors of adolescent/young adult criminal behavior.ResultsModerate to severe childhood maltreatment increased the risk of adolescent/young adult arrest over and above the risk associated with childhood CD, while both childhood maltreatment and childhood CD significantly increased the risk of recidivism. ADHD youth classified as maltreated were three and a half times more likely to be arrested when compared to ADHD youth without a maltreatment classification.ConclusionWe established maltreatment as a risk factor for criminality in ADHD youth and demonstrated that this relationship was independent of the contributions of CD, and established risk factor for antisocial behavior in this population. The findings highlight the need for maltreatment screening in children with ADHD in order to identify those at heightened risk for criminal activity, and target treatment to improve outcome in this high-risk group of children.     

Supporting children with genetic syndromes in the classroom: the example of 22q deletion syndrome

An increasing number of children are likely to have a known genetic cause for their special educational needs. One such genetic condition is 22q11.2 deletion syndrome (22qDS), a genetic syndrome associated with early speech and language difficulties, global and specific cognitive impairments, difficulties with attention and difficulties with social‐emotional functioning. In this article the learning and behavioural strengths and needs of this genetic syndrome are described along with recommendations for classroom‐based interventions. Suggested recommendations in the learning and emotional‐behavioural domains for the syndrome draw on a number of approaches that have been found to be useful for children with a range of conditions including ADHD, ASD and dyscalculia. While teachers cannot be expected to know about all potential genetic causes for special educational needs, knowing that a genetic condition is likely to be associated with a pattern of relative cognitive and behavioural strengths and needs is important.     

Familial resemblance for measures of reading performance in families of reading-disabled and control twins

In order to assess familial resemblance for measures of reading performance, data from 314 pairs of twins in which at least one member of each pair is reading-disabled [142 monozygotic (MZ) and 172 dizygotic (DZ) twin pairs], 273 matched control pairs (131 MZ and 142 DZ pairs), and their parents were subjected to both correlation and regression analyses. Results indicate that parent-offspring resemblance in families of reading-disabled probands does not differ substantially from that in families of controls. In general, the correlations and regressions for MZ twin pairs are greater than those for DZ twins; thus, individual differences in reading performance are due at least in part to heritable influences. As expected, regression coefficients are consistently larger than correlation coefficients for both parent-offspring and proband-cotwin comparisons in the reading-disabled sample, illustrating that regression analyses are more appropriate than correlations for assessing familial resemblance in selected samples.