Phonological storage and executive function deficits in children with mathematics difficulties

Children with mathematics difficulties suffer from working memory deficits. This study investigated the deficit profile of phonological storage and executive functions in working memory among children with mathematics difficulties. Based on multiple instruments and two assessment points, 68 children were screened out of 805 fifth graders. Of these 68 children, 18 were classified as children with only mathematics difficulties (MD), 20 were classified as children with mathematics and reading difficulties (MDRD), and 30 were typically developing (TD) peers matched on age and general ability. Measures for phonological storage, dual-task performance, inhibition, and updating of verbal and numerical materials were administered individually. Results showed that compared with the TD group, children with MD exhibited storage and inhibition deficits specific to numerical information and dual-task deficits of both verbal and numerical information, whereas children with MDRD showed extensive deficits on phonological storage and executive functions on both verbal and numerical tasks. Moreover, executive function deficits were not confined to phonological storage deficits. Implications of the findings for the working memory deficit profile and working memory training among children with mathematics difficulties were discussed.     

A comparison of working memory profiles in children with ADHD and DCD

The main objective of present study was to investigate whether the patterns of working memory performance differ as a function of attention and motor difficulties, and whether children with ADHD and DCD could be reliably discriminated on the basis of their memory deficits. A related aim was to investigate the link between their working memory profiles and academic attainment. Fifty children with ADHD-Combined, 55 children with DCD, and an age-matched group of 50 typically developing children with average working memory were assessed on standardized measures of working memory, IQ, and academic attainment (reading, spelling, comprehension, and math). The normal controls performed significantly better than both clinical groups on all working memory tests. Specific patterns emerged in the memory profile of the clinical groups: The children with DCD had a depressed performance in all working memory tests, with particularly low scores in visuospatial memory tasks; children with ADHD performed within age-expected levels in short-term memory but had a pervasive working memory deficit that impacted both verbal and visuospatial domains. The clinical groups could reliably be discriminated on the basis of their short-term memory scores. Their learning profiles were similar. It is possible that the working memory profiles of the children with ADHD and DCD are influenced by distinct underlying cognitive mechanisms, rather than a general neurodevelopmental delay. Despite these distinctive patterns of memory performance, both clinical groups performed similarly on academic attainments, suggesting that memory may underlie learning difficulties, independent of related clinical disorders.     

Working Memory and Cognitive Skills in Individuals with Down Syndrome

This work is aimed at analyzing working memory (WM) components and their relationships with other cognitive processes in individuals with Down syndrome (DS). Particular attention is given to examine whether a verbal WM deficit is due to difficulties in verbal abilities often showed by individuals with DS, or whether it is a deficit per se. A group of 20 individuals with DS was compared to a group of 20 typically developing (TD) children matched on vocabulary comprehension and to a group of 20 TD children matched on general verbal intelligence. The groups received a battery of 3 verbal and 3 visuospatial WM tasks requiring different degrees of control, and tests assessing verbal abilities (WPPSI verbal scale, PPVT), nonverbal skills (WPPSI performance scale), and logical thinking (LO). The results revealed that individuals with DS have deficits in both central executive (control) and verbal components of the WM system, and the latter one is independent of the general verbal abilities deficit. The data suggest that the development of central executive proceeds at a slower rate in individuals with DS and differently from TD children with comparable verbal abilities. The performance of individuals with DS on high-control WM tasks requires additional general resources that are strictly linked to intelligence.     

Numerical magnitude processing impairments in genetic syndromes: a cross‐syndrome comparison of Turner and 22q11.2 deletion syndromes

Cross‐syndrome comparisons offer an important window onto understanding heterogeneity in mathematical learning disabilities or dyscalculia. The present study therefore investigated symbolic numerical magnitude processing in two genetic syndromes that are both characterized by mathematical learning disabilities: Turner syndrome and 22q11.2 deletion syndrome (22q11DS). We further verified whether the phenotypic outcomes of these syndromes emerged from the same or different cognitive processes and therefore examined whether numerical impairments were related to working memory deficits, often observed in these syndromes. Participants were 24 girls with Turner syndrome, 25 children with 22q11DS and 48 well‐matched typically developing control children. All children completed a symbolic numerical magnitude comparison task and four additional working memory tasks. Both groups of children with genetic syndromes showed similar impairments in symbolic numerical magnitude processing compared to typically developing controls. Importantly, in Turner syndrome, group differences in symbolic numerical magnitude processing disappeared when their difficulties in visual‐spatial working memory were taken into account. In contrast, the difficulties in 22q11DS were not explained by poor visual‐spatial working memory. These data suggest that different factors underlie the symbolic numerical magnitude processing impairments in both patient groups with mathematical learning disabilities and highlight the value of cross‐syndrome comparisons for understanding different pathways to mathematical learning disabilities or dyscalculia.     

Working memory deficit in children with mathematical difficulties: a general or specific deficit?

This study examined whether children with mathematical difficulties (MDs) or comorbid mathematical and reading difficulties have a working memory deficit and whether the hypothesized working memory deficit includes the whole working memory system or only specific components. In the study, 31 10-year-olds with MDs and 37 10-year-olds with both mathematical and reading difficulties were compared with 47 age-matched and 50 younger controls (9-year-olds) on a number of working memory tasks. Compared with the age-matched controls, both groups of children with MDs performed worse on tasks tapping the central executive (e.g., visual matrix span) and the phonological loop (e.g., word span). More important, the MD group performed worse than the younger controls on the counting span task, whereas the group with comorbid mathematical and reading difficulties performed worse on the counting span task and the visual matrix span task. These findings provide support for the assumption that children with MDs have a working memory deficit. More specifically, children with MDs have a central executive deficit connected to concurrent processing and storage of numerical and visual information.     

Age-related differences in learning disabled and skilled readers' working memory

This study determines whether age-related deficits in learning disabled (LD) readers' working memory performance reflect delays in retrieval efficiency and/or storage capacity. The study compared LD and skilled readers' working memory performance (N=226) across four age groups (7, 10, 13, and 20) for phonological, visual-spatial, and semantic information under initial (non-cued), gain (cues that bring performance to an asymptotic level), and maintenance conditions (asymptotic conditions without cues). The important results were that LD readers' working memory performance was inferior to skilled readers on verbal and visual-spatial working memory tasks across all age groups and these differences increased on gain and maintenance conditions when compared to initial conditions. These reading group differences remained when age, reading, and mathematics were partialed from the analysis. The results support a general capacity explanation of reading group differences that is not totally dependent on reading skill. These differences in capacity reflect demands placed on both the accessing of new information and the maintenance of old information that extend beyond the phonological system.     

Numerical and arithmetical cognition: patterns of functions and deficits in children at risk for a mathematical disability.

Based on performance on standard achievement tests, first-grade children (mean age = 82 months) with IQ scores in the low-average to high-average range were classified as at risk for a learning disability (LD) in mathematics, reading, or both. These at-risk children (n = 55) and a control group of academically normal peers (n = 35) were administered experimental tasks that assessed number comprehension and production skills, counting knowledge, arithmetic skills, working memory, and ease of retrieving information from long-term memory. Different patterns of intact cognitive functions and deficits were found for children in the different at-risk groups. As a set, performance on the experimental tasks accounted for roughly 50% and 10% of the group differences in mathematics and reading achievement, respectively, above and beyond the influence of IQ. Performance on the experimental tasks thus provides insights into the cognitive deficits underlying different forms of LD, as well as into the sources of individual differences in academic achievement.     

An exploratory study of gaze behaviour in young adults with developmental coordination disorder

Developmental Coordination Disorder (DCD) is characterized by substantial difficulties with motor coordination to the extent that it has a clear impact on the daily functioning of those who suffer from the disorder. Laboratory-based research indicated impaired oculomotor control in individuals with DCD. However, it is not clear how these oculomotor problems contribute to control and coordination in daily tasks. This study explored differences and similarities in gaze behaviour during reading and cup stacking between young adults with DCD and their matched typically developing counterparts (TD; aged 20–23 years). Gaze behaviour was recorded using eye-tracking, and hand movements were registered using a digital camera. Results of the reading tasks demonstrated similar behaviour between the groups, apart from a lower number of characters recorded per fixation in the DCD group. In cup stacking, the individuals with DCD were slower than their counterparts when three cups had to be displaced to a central target using the dominant hand. The gaze strategy of individuals with DCD involved systematic fixations on the cup or target prior to the hand movement to that cup or target, whereas these alternating saccades between cup and target were less obvious in the TD group. In the bimanual stacking task, where a pyramid of six cups had to be built on a central target using both hands, both groups mainly fixated the central target for the whole duration of the task, without distinct differences in gaze behaviour and duration of performance between individuals with and those without DCD. In conclusion, gaze behaviour of young adults with DCD shows differences from that of their typically developing counterparts that may be related to underlying oculomotor deficits in some but not all daily tasks.     

The role of verbal and nonverbal memory in the Family Pictures Subtest: Data from children with specific language impairment

This study examined the contribution of verbal and visual memory to performance on the Family Pictures subtest of the Children’s Memory Scale. This subtest purports to assess declarative memory functioning in the visual/nonverbal domain. A total of 115 nine-year-old children participated in this study. Fifty-eight had specific language impairment (SLI), whilst the remaining 57 were typically developing (TD), with no history of language difficulties. Results showed that the children with SLI, who had intact declarative memory for visual but not verbal information, obtained significantly lower scores on the Family Pictures subtest when compared to the TD group. Regression analyses revealed that across the entire sample, individual differences on the Family Pictures subtest was best predicted by a measure of verbal working memory. These results question whether the Family Pictures subtest can be considered a measure of visual memory in pediatric populations. These results have implications for the interpretation of scores on this subtest regarding the nature of the types of neurocognitive difficulties children may exhibit.     

Basic number processing in children with specific learning disorders: Comorbidity of reading and mathematics disorders

As well as being the hallmark of mathematics disorders, deficits in number processing have also been reported for individuals with reading disorders. The aim of the present study was to investigate separately the components of numerical processing affected in reading and mathematical disorders within the framework of the Triple Code Model. Children with reading disorders (RD), mathematics disorders (MD), comorbid deficits (RD + MD), and typically developing children (TD) were tested on verbal, visual-verbal, and nonverbal number tasks. As expected, children with MD were impaired across a broad range of numerical tasks. In contrast, children with RD were impaired in (visual-)verbal number tasks but showed age-appropriate performance in nonverbal number skills, suggesting their impairments were domain specific and related to their reading difficulties. The comorbid group showed an additive profile of the impairments of the two single-deficit groups. Performance in speeded verbal number tasks was related to rapid automatized naming, a measure of visual-verbal access in the RD but not in the MD group. The results indicate that deficits in number skills are due to different underlying cognitive deficits in children with RD compared to children with MD: a phonological deficit in RD and a deficit in processing numerosities in MD.     

The influence of strategies on relationships between working memory and cognitive skills

The aim of this study was to test the effect of administration method on relationships between working memory span tasks and cognitive skills. Participants completed both participant-administered and experimenter-administered working memory measures in both verbal and visuospatial domains. Although the tasks were equally reliable, the additional time taken to implement strategies in the participant-administered tasks in the verbal domain reduced the correlations between working memory and reading comprehension and arithmetic. These findings did not extend to a visuospatial working memory measure, for which there was no significant difference between the participant-administered and experimenter-administered tasks in terms of their relationships with comprehension and arithmetic. However, performance on experimenter-administered working memory tasks in both verbal and visuospatial domains predicted unique variance in comprehension and arithmetic while controlling for scores on the participant-administered tasks. The results are discussed in terms of theoretical and practical implications for working memory research.     

Attention switching and working memory spans

Barrouillet and Camos () concluded from their developmental study on working memory that when performing complex span tasks, individuals maintain memory items by switching rapidly their attention from processing to storage while performing the concurrent task. Thus, a processing component that would require a continuous attentional focusing should have a highly detrimental effect on span. The present study verifies two predictions issuing from this hypothesis by comparing the classical self‐paced reading and operation span tasks with new computer‐paced tasks in adults. First, any increase in the pace at which the processing component of a working memory span task has to be performed impedes switching and then leads to lower spans. Second, when presented at a fast pace, even simple activities such as reading letters or adding and subtracting 1 to small numbers have an effect on spans as detrimental as complex activities like reading and understanding sentences or solving complex equations.     

The influence of strategies on relationships between working memory and cognitive skills

The aim of this study was to test the effect of administration method on relationships between working memory span tasks and cognitive skills. Participants completed both participant-administered and experimenter-administered working memory measures in both verbal and visuospatial domains. Although the tasks were equally reliable, the additional time taken to implement strategies in the participant-administered tasks in the verbal domain reduced the correlations between working memory and reading comprehension and arithmetic. These findings did not extend to a visuospatial working memory measure, for which there was no significant difference between the participant-administered and experimenter-administered tasks in terms of their relationships with comprehension and arithmetic. However, performance on experimenter-administered working memory tasks in both verbal and visuospatial domains predicted unique variance in comprehension and arithmetic while controlling for scores on the participant-administered tasks. The results are discussed in terms of theoretical and practical implications for working memory research.     

The academic outcomes of working memory and metacognitive strategy training in children: A double‐blind randomized controlled trial

Working memory training has been shown to improve performance on untrained working memory tasks in typically developing children, at least when compared to non‐adaptive training; however, there is little evidence that it improves academic outcomes. The lack of transfer to academic outcomes may be because children are only learning skills and strategies in a very narrow context, which they are unable to apply to other tasks. Metacognitive strategy interventions, which promote metacognitive awareness and teach children general strategies that can be used on a variety of tasks, may be a crucial missing link in this regard. In this double‐blind randomized controlled trial, 95 typically developing children aged 9–14 years were allocated to three cognitive training programmes that were conducted daily after‐school. One group received Cogmed working memory training, another group received concurrent Cogmed and metacognitive strategy training, and the control group received adaptive visual search training, which better controls for expectancy and motivation than non‐adaptive training. Children were assessed on four working memory tasks, reading comprehension, and mathematical reasoning before, immediately after, and 3 months after training. Working memory training improved working memory and mathematical reasoning relative to the control group. The improvements in working memory were maintained 3 months later, and these were significantly greater for the group that received metacognitive strategy training, compared to working memory training alone. Working memory training is a potentially effective educational intervention when provided in addition to school; however, future research will need to investigate ways to maintain academic improvements long term and to optimize metacognitive strategy training to promote far‐transfer. A video abstract of this article can be viewed at https://youtu.be/-7MML48ZFgw     

On the interpretation of working memory span in adults

Experimental research into children's working memory span has shown that retention duration contributes substantially to span performance, while processing efficiency need not be related to concurrent memory load (Towse, Hitch, & Hutton, 1998). These findings have been used to argue for a model of working memory span that emphasizes time-based forgetting rather than the popular resource-sharing or tradeoff framework. The present paper considers whether adults perform working memory span tasks in a qualitatively different way. Data from reading span and operation span tasks show that adults' performance can be distinguished from that of children, but also that a task-switching model of working memory span can explain some important aspects of performance.     

Peer Relationships and Emotional Well-Being of Children with Sickle Cell Disease: A Controlled Replication

This study investigated the effects of stimulus presentation modality on working memory performance in elementary school-age children ages 7–13. The experimental paradigm implemented a multitrial learning task incorporating three presentation modalities: Auditory, Visual, and simultaneous Auditory plus Visual. The first experiment compared the learning and memory performance of older and younger elementary school children. The second experiment compared verbal learning and memory performance in elementary school children with major depressive disorder (MDD) to the performance of nondepressed children. All participants benefited from the pictorial presentation of information during learning and recall of information as compared to the auditory presentation alone. Both age and socioeconomic status affected working memory performance in typically developing children. Children with depression demonstrated a more passive learning style during the auditory list acquisition. The present study supports the pictorial superiority hypothesis in verbal learning tasks and the theory that working memory matures during elementary school years. Furthermore, current results indicate that complex working memory measures are not entirely independent of previous experience.     

Working memory deficits in boys with attention deficit/hyperactivity disorder (ADHD): An examination of orthographic coding and episodic buffer processes

The episodic buffer component of working memory was examined in children with attention deficit/hyperactivity disorder (ADHD) and typically developing peers (TD). Thirty-two children (ADHD = 16, TD = 16) completed three versions of a phonological working memory task that varied with regard to stimulus presentation modality (auditory, visual, or dual auditory and visual), as well as a visuospatial task. Children with ADHD experienced the largest magnitude working memory deficits when phonological stimuli were presented via a unimodal, auditory format. Their performance improved during visual and dual modality conditions but remained significantly below the performance of children in the TD group. In contrast, the TD group did not exhibit performance differences between the auditory- and visual-phonological conditions but recalled significantly more stimuli during the dual-phonological condition. Furthermore, relative to TD children, children with ADHD recalled disproportionately fewer phonological stimuli as set sizes increased, regardless of presentation modality. Finally, an examination of working memory components indicated that the largest magnitude between-group difference was associated with the central executive. Collectively, these findings suggest that ADHD-related working memory deficits reflect a combination of impaired central executive and phonological storage/rehearsal processes, as well as an impaired ability to benefit from bound multimodal information processed by the episodic buffer.     

Working memory, psychiatric symptoms, and academic performance at school

Previous studies of the relationship among working memory function, academic performance, and behavior in children have focused mainly on clinical populations. In the present study, the associations of the performance in audio- and visuospatial working memory tasks to teacher reported academic achievement and psychiatric symptoms were evaluated in a sample of fifty-five 6-13-year-old school children. Working memory function was measured by visual and auditory n-back tasks. Information on incorrect responses, reaction times, and multiple and missed responses were collected during the tasks. The children's academic performance and behavioral and emotional status were evaluated by the Teacher Report Form. The results showed that good spatial working memory performance was associated with academic success at school. Children with low working memory performance, especially audiospatial memory, were reported to have more academic and attentional/behavioral difficulties at school than children with good working memory performance. An increased number of multiple and missed responses in the auditory and visual tasks was associated with teacher reported attentional/behavioral problems and in visual tasks with teacher reported anxiety/depressive symptoms. The results suggest that working memory deficits may underlie some learning difficulties and behavioral problems related to impulsivity, difficulties in concentration, and hyperactivity. On the other hand, it is possible that anxiety/depressive symptoms affect working memory function, as well as the ability to concentrate, leading to a lower level of academic performance at school.     

Does working memory training lead to generalized improvements in children with low working memory? A randomized controlled trial

Children with low working memory typically make poor educational progress, and it has been speculated that difficulties in meeting the heavy working memory demands of the classroom may be a contributory factor. Intensive working memory training has been shown to boost performance on untrained memory tasks in a variety of populations. This first randomized controlled trial with low working memory children investigated whether the benefits of training extend beyond standard working memory tasks to other more complex activities typical of the classroom in which working memory plays a role, as well as to other cognitive skills and developing academic abilities. Children aged 7–9 years received either adaptive working memory training, non‐adaptive working memory training with low memory loads, or no training. Adaptive training was associated with selective improvements in multiple untrained tests of working memory, with no evidence of changes in classroom analogues of activities that tax working memory, or any other cognitive assessments. Gains in verbal working memory were sustained one year after training. Thus the benefits of working memory training delivered in this way may not extend beyond structured working memory tasks.     

The Measurement of Verbal Working Memory Capacity and Its Relation to Reading Comprehension

Ninety-four subjects were tested on the Daneman and Carpenter (1980) reading span task, four versions of a related sentence span task in which reaction times and accuracy on sentence processing were measured along with sentence-final word recall, two number generation tasks designed to test working memory, digit span, and two shape-generation tasks designed to measure visual-spatial working memory. Forty-four subjects were retested on a subset of these measures at a 3-month interval. All subjects were tested on standard vocabulary and reading tests. Correlational analyses showed better internal consistency and test-retest reliability of the sentence span tasks than of the Daneman-Carpenter reading span task. Factor analysis showed no factor that could be related to a central verbal working memory; rotated factors suggested groupings of tests into factors that correspond to digitrelated tasks, spatial tasks, sentence processing in sentence span tasks, and recall in sentence span tasks. Correlational analyses and regression analyses showed that the sentence processing component of the sentence span tasks was the best predictor of performance on the reading test, with a small independent contribution of the recall component. The results suggest that sentence span tasks are unreliable unless measurements are made of both their sentence processing and recall components, and that the predictive value of these tasks for reading comprehension abilities lies in the overlap of operations rather than in limitations in verbal working memory that apply to both.