儿童早期工作记忆与数学学习的关系

以往研究认为工作记忆对数学学习很重要,但是以往工作记忆和早期数学学习的关系研究结果并不一致。本研究运用元分析的方法回顾了33篇独立研究,含307项相关系数作为效应值,总被试量为42423名平均年龄3~8岁的儿童,旨在探讨工作记忆的3个主成分PL(语音回路)、VSSP(视觉空间画板)、CE(中央执行)与数学学习不同方面之间的关系,以及样本年龄对工作记忆和数学学习相关程度的调节作用。结果显示:工作记忆与数学学习确实存在强相关,工作记忆子成分中,CE与数学学习平均相关的程度最强。并且,CE与数学学习不同方面之间的相关程度不存在显著差异,PL、VSSP与数运算的相关程度比数概念更强,存在显著差异。样本年龄对CE、PL与数学学习之间相关关系存在显著调节作用,对VSSP与数学学习之间的相关关系不存在显著调节作用。文献梳理还发现,以往研究对数学学习的考察,大都聚焦数概念、数运算的内容,未来研究需要关注几何与空间、测量等方面内容。     

What Part of Working Memory is not Working in ADHD? Short-Term Memory, the Central Executive and Effects of Reinforcement

Deficits in Working Memory (WM) are related to symptoms of Attention-Deficit/Hyperactivity Disorder (ADHD). In children with ADHD visuospatial WM is most impaired. WM is composed of Short-Term Memory (STM) and a Central Executive (CE). Therefore, deficits in either or both STM and the CE may account for WM impairments in children with ADHD. WM-component studies investigating this find deficits in both STM and the CE. However, recent studies show that not only cognitive deficits, but also motivational deficits give rise to the aberrant WM performance of children with ADHD. To date, the influence of these motivational deficits on the components of WM has not been investigated. This study examined the effects of a standard (feedback-only) and a high level of reinforcement (feedback + 10 euros) on the visuospatial WM-, visuospatial STM-, and the CE performance of 86 children with ADHD and 62 typically-developing controls. With standard reinforcement the STM, CE, and WM performance of children with ADHD was worse than that of controls. High reinforcement improved STM and WM performance more in children with ADHD than in controls, but was unable to normalize their performance. High reinforcement did not appear to improve the CE-related performance of children with ADHD and controls. Motivational deficits have a detrimental effect on both the visuospatial WM performance and the STM performance of children with ADHD. Aside from motivational deficits, both the visuospatial STM and the CE of children with ADHD are impaired, and give rise to their deficits in visuospatial WM.     

A comparison of working memory profiles in school-aged children with Specific Language Impairment,Attention Deficit/Hyperactivity Disorder,Comorbid SLI and ADHD and their typically developing peers

The association between specific language impairment (SLI), attention deficit/hyperactivity disorder (ADHD), and working memory (WM) was examined. WM has been implicated in language acquisition and models of ADHD; however, evidence for WM deficits in SLI and ADHD has been inconsistent. The components of Baddeley's WM model were investigated in 18 children with SLI, 16 children with ADHD, 11 children with comorbid SLI+ADHD, and 24 typically developing (TD) children. The presence of SLI resulted in deficits in more components of WM than the presence of ADHD indicating that children with SLI are more vulnerable to WM deficits than those with ADHD.     

A comparison of working memory profiles in school-aged children with Specific Language Impairment, Attention Deficit/Hyperactivity Disorder, Comorbid SLI and ADHD and their typically developing peers

The association between specific language impairment (SLI), attention deficit/hyperactivity disorder (ADHD), and working memory (WM) was examined. WM has been implicated in language acquisition and models of ADHD; however, evidence for WM deficits in SLI and ADHD has been inconsistent. The components of Baddeley's WM model were investigated in 18 children with SLI, 16 children with ADHD, 11 children with comorbid SLI+ADHD, and 24 typically developing (TD) children. The presence of SLI resulted in deficits in more components of WM than the presence of ADHD indicating that children with SLI are more vulnerable to WM deficits than those with ADHD.     

Interactions between working memory and language in young children with specific language impairment (SLI)

The underlying structure of working memory (WM) in young children with and without specific language impairment (SLI) was examined. The associations between the components of WM and the language abilities of young children with SLI were then analyzed. The Automated Working Memory Assessment and four linguistic tasks were administered to 58 children with SLI and 58 children without SLI, aged 4–5 years. The WM of the children was best represented by a model with four separate but interacting components of verbal storage, visuospatial storage, verbal central executive (CE), and visuospatial CE. The associations between the four components of WM did not differ significantly for the two groups of children. However, the individual components of WM showed varying associations with the language abilities of the children with SLI. The verbal CE component of WM was moderately to strongly associated with all the language abilities in children with SLI: receptive vocabulary, expressive vocabulary, verbal comprehension, and syntactic development. These results show verbal CE to be involved in a wide range of linguistic skills; the limited ability of young children with SLI to simultaneously store and process verbal information may constrain their acquisition of linguistic skills. Attention should thus be paid to the language problems of children with SLI, but also to the WM impairments that can contribute to their language problems.     

Recovery in Memory Function,and its Relationship to Academic Success,at 24 Months Following Pediatric TBI*

While a number of research papers have reported findings on memory deficits following traumatic brain injury (TBI), only limited studies have monitored the recovery of these skills over time. The present study examined memory ability and its effect on academic success in a group of children who had sustained a mild, moderate, or severe traumatic brain injury (TBI). Results showed that the severe TBI group exhibited greater deficits on memory tasks, irrespective of modality, in the acute, 6-, 12-, and 24-month postinjury stages, in comparison to mild and moderate TBI groups. Performance on academic measures was dependent on both injury severity and task demands. Preinjury academic ability and verbal memory indices best predicted academic success.     

Recovery in memory function, and its relationship to academic success, at 24 months following pediatric TBI.

While a number of research papers have reported findings on memory deficits following traumatic brain injury (TBI), only limited studies have monitored the recovery of these skills over time. The present study examined memory ability and its effect on academic success in a group of children who had sustained a mild, moderate, or severe traumatic brain injury (TBI). Results showed that the severe TBI group exhibited greater deficits on memory tasks, irrespective of modality, in the acute, 6-, 12-, and 24-month postinjury stages, in comparison to mild and moderate TBI groups. Performance on academic measures was dependent on both injury severity and task demands. Preinjury academic ability and verbal memory indices best predicted academic success.     

Working memory in very-low-birthweight children at the age of 11 years

The aim of this study is to investigate the working memory (WM) of very-low-birthweight (VLBW, ≤ 1500 g) children at the age of 11 years using Baddeley’s WM model. A regional cohort of 95 VLBW children was assessed for the domains of the WM model (central executive [CE], visuospatial sketchpad [VS], and phonological loop [PL]) using subtests from the Working Memory Test Battery for Children (WMTB-C) and the Wechsler Intelligence Scale for Children – Fourth Edition (WISC-IV). VLBW children were categorized into three groups according to their degree of brain pathology (normal, minor, or major) in neonatal brain magnetic resonance imaging at the term age, and the WM performance was compared between groups to test norms. The structure of the WM model was studied by analyzing correlations among domains. Even VLBW children with normal cognitive development (general ability index ≥ 85) performed worse compared to the test norms (M = 100, SD = 15) on CE (M = 87.64, SD = 20.54, p < .001) and VS (M = 91.65, SD = 11.03, p < .001), but their performance on PL was above the norm (M = 110.79, SD = 13.79, p < .001). VLBW children with major brain pathology performed significantly worse on VS and PL compared to the other groups. The correlations among the WM domains of the VLBW children differ from earlier findings in normative populations. To conclude, the WM of the VLBW children in the study differ—especially in the CE and VS subtest scores—from the normative population irrespective of the degree of brain pathology and level of cognitive development.     

Phonological loop and central executive contributions to oral comprehension skills of 5.5 to 9.5 years old children

Oral story comprehension in 5.5, 7.5 and 9.5 year old children is examined in relation to working memory (WM) contributions. The phonological loop (PL) of the Baddeley and Hitch WM model was assessed with word, non‐word and digit recall and a word list matching task. The central executive (CE) was assessed with listening, counting and backward digit recall tasks. A composite score was calculated for each WM component. Receptive vocabulary and oral comprehension were also assessed. Regression analyses demonstrated CE contributions to oral comprehension overall, and also to comprehension sub‐skills (above any vocabulary contributions). Effects were stronger in preschoolers and decreased with age. The PL did not play an important role in oral comprehension. Comprehension control was the comprehension skill best predicted. The study demonstrates the CE importance in off‐line comprehension processes during early childhood and the usefulness of assessing CE processes for identifying possible comprehension difficulties later at school. Copyright © 2010 John Wiley & Sons, Ltd.     

The effect of age-at-testing on verbal memory among children following severe traumatic brain injury

Memory deficits are a common sequelae following childhood traumatic brain injury (TBI), which often have serious implications on age-related academic skills. The current study examined verbal memory performance using the Rey Auditory Verbal Learning Test (RAVLT) in a pediatric TBI sample. Verbal memory abilities as well as the effect of age at-testing on performance were examined. A sample of 67 children following severe TBI (age average = 12.3 ± 2.74) and 67 matched controls were evaluated using the RAVLT. Age effect at assessment was examined using two age groups: above and below 12 years of age during evaluation. Differences between groups were examined via the 9 RAVLT learning trials and the 7 composite scores conducted out of them. Children following TBI recalled significantly less words than controls on all RAVLT trials and had significantly lower scores on all composite scores. However, all of these scores fell within the low average range. Further analysis revealed significantly lower than average performance among the older children (above 12 years), while scores of the younger children following TBI fell within average limits. To conclude, verbal memory deficits among children following severe TBI demonstrate an age-at-testing effect with more prominent problems occurring above 12 years at the time of evaluation. Yet, age-appropriate performance among children below 12 years of age may not accurately describe memory abilities at younger ages following TBI. It is therefore recommended that clinicians address child’s age at testing and avoid using a single test as an indicator of verbal memory functioning post TBI.     

Attentional Skills in the Acute Phase Following Pediatric Traumatic Brain Injury

Only a limited number of studies have investigated attention following pediatric head-injury. The present study examined sustained attention and processing speed in a group of children who had sustained a mild (n = 27), moderate (n = 33) or severe (n = 16) traumatic brain injury (TBI). No significant differences were evident between the TBI groups on reaction time measures. Results did show that the severe TBI group exhibited greater deficits in the area of sustained attention, in comparison to children with mild and moderate injuries, in the acute stage following traumatic brain injury. This difficulty may impact on the future development of skills dependent on intact attentional capacity.     

Attentional skills in the acute phase following pediatric traumatic brain injury.

Only a limited number of studies have investigated attention following pediatric head-injury. The present study examined sustained attention and processing speed in a group of children who had sustained a mild (n = 27), moderate (n = 33) or severe (n = 16) traumatic brain injury (TBI). No significant differences were evident between the TBI groups on reaction time measures. Results did show that the severe TBI group exhibited greater deficits in the area of sustained attention, in comparison to children with mild and moderate injuries, in the acute stage following traumatic brain injury. This difficulty may impact on the future development of skills dependent on intact attentional capacity.     

Objectively-Measured Impulsivity and Attention-Deficit/Hyperactivity Disorder (ADHD): Testing Competing Predictions from the Working Memory and Behavioral Inhibition Models of ADHD

Impulsivity is a hallmark of two of the three DSM-IV ADHD subtypes and is associated with myriad adverse outcomes. Limited research, however, is available concerning the mechanisms and processes that contribute to impulsive responding by children with ADHD. The current study tested predictions from two competing models of ADHD-working memory (WM) and behavioral inhibition (BI)-to examine the extent to which ADHD-related impulsive responding was attributable to model-specific mechanisms and processes. Children with ADHD (n?=?21) and typically developing children (n?=?20) completed laboratory tasks that provided WM (domain-general central executive [CE], phonological/visuospatial storage/rehearsal) and BI indices (stop-signal reaction time [SSRT], stop-signal delay, mean reaction time). These indices were examined as potential mediators of ADHD-related impulsive responding on two objective and diverse laboratory tasks used commonly to assess impulsive responding (CPT: continuous performance test; VMTS: visual match-to-sample). Bias-corrected, bootstrapped mediation analyses revealed that CE processes significantly attenuated between-group impulsivity differences, such that the initial large-magnitude impulsivity differences were no longer significant on either task after accounting for ADHD-related CE deficits. In contrast, SSRT partially mediated ADHD-related impulsive responding on the CPT but not VMTS. This partial attenuation was no longer significant after accounting for shared variance between CE and SSRT; CE continued to attenuate the ADHD-impulsivity relationship after accounting for SSRT. These findings add to the growing literature implicating CE deficits in core ADHD behavioral and functional impairments, and suggest that cognitive interventions targeting CE rather than storage/rehearsal or BI processes may hold greater promise for alleviating ADHD-related impairments.     

Executive function and weight status in children: A one-year longitudinal perspective

There is considerable evidence for an association between obesity and impaired executive function (EF) in adolescents and adults. However, little research has examined EF in overweight or obese children. Furthermore, data on EF in underweight individuals is lacking. In addition, there is no consensus on the directionality of the relationship between Body Mass Index (BMI) and EF, and longitudinal studies are rare. Thus, the present study examined whether children differ in their performance on a battery of EF tasks depending on their weight status (underweight, normal-weight, overweight), and investigated the longitudinal cross-lagged associations between EF and BMI. Hot EF (delay of gratification, affective decision-making), cool EF (attention shifting, inhibition, working memory [WM] updating), and BMI were assessed in 1,657 German elementary-school children at two time points, approximately one year apart. Overweight children exhibited slightly poorer attention shifting, WM updating, and affective decision-making abilities as compared to normal-weight children. Unexpectedly, they did not show any deficits in inhibition or delay of gratification. EF levels of underweight children did not differ significantly from those of normal-weight children. Furthermore, poor attention shifting and enhanced affective decision-making predicted a slightly higher BMI one year later, and a higher BMI also predicted poorer attention shifting and WM updating one year later. The latter association between BMI and subsequent EF scores, however, diminished when controlling for socioeconomic status. Results indicate that hot and cool EF plays a role in the weight development of children, and might be a promising factor to address in preventive interventions.     

Improving Working Memory in Children with Attention-Deficit/Hyperactivity Disorder: The Separate and Combined Effects of Incentives and Stimulant Medication

Working memory (WM) is considered a core deficit in Attention-Deficit/ Hyperactivity Disorder (ADHD), with numerous studies demonstrating impaired WM among children with ADHD. We tested the degree to which WM in children with ADHD was improved by performance-based incentives, an analog of behavioral intervention. In two studies, WM performance was assessed using a visuo-spatial n-back task. Study 1 compared children (ages 9-12?years) with ADHD-Combined type (n?=?24) to a group of typically developing (TD) children (n?=?32). Study 1 replicated WM deficits among children with ADHD. Incentives improved WM, particularly among children with ADHD. The provision of incentives reduced the ADHD-control group difference by approximately half but did not normalize WM. Study 2 examined the separate and combined effects of incentives and stimulant medication among 17 children with ADHD-Combined type. Both incentives and a moderate dose of long-acting methylphenidate (MPH; ~0.3?mg/kg t.i.d. equivalent) robustly improved WM relative to the no-incentive, placebo condition. The combination of incentives and medication improved WM significantly more than either incentives or MPH alone. These studies indicate that contingencies markedly improve WM among children with ADHD-Combined type, with effect sizes comparable to a moderate dose of stimulant medication. More broadly, this work calls attention to the role of motivation in studying cognitive deficits in ADHD and in testing multifactorial models of ADHD.     

Working memory deficits in developmental dyscalculia: The importance of serial order

Although a number of studies suggests a link between working memory (WM) storage capacity of short-term memory and calculation abilities, the nature of verbal WM deficits in children with developmental dyscalculia (DD) remains poorly understood. We explored verbal WM capacity in DD by focusing on the distinction between memory for item information (the items to be retained) and memory for order information (the order of the items within a list). We hypothesized that WM for order could be specifically related to impaired numerical abilities given that recent studies suggest close interactions between the representation of order information in WM and ordinal numerical processing. We investigated item and order WM abilities as well as basic numerical processing abilities in 16 children with DD (age: 8–11 years) and 16 typically developing children matched on age, IQ, and reading abilities. The DD group performed significantly poorer than controls in the order WM condition but not in the item WM condition. In addition, the DD group performed significantly slower than the control group on a numerical order judgment task. The present results show significantly reduced serial order WM abilities in DD coupled with less efficient numerical ordinal processing abilities, reflecting more general difficulties in explicit processing of ordinal information.     

Can Motivation Normalize Working Memory and Task Persistence in Children with Attention-Deficit/Hyperactivity Disorder? The Effects of Money and Computer-Gaming

Visual-spatial Working Memory (WM) is the most impaired executive function in children with Attention-Deficit/Hyperactivity Disorder (ADHD). Some suggest that deficits in executive functioning are caused by motivational deficits. However, there are no studies that investigate the effects of motivation on the visual-spatial WM of children with- and without ADHD. Studies examining this in executive functions other than WM, show inconsistent results. These inconsistencies may be related to differences in the reinforcement used. The effects of different reinforcers on WM performance were investigated in 30 children with ADHD and 31 non-ADHD controls. A visual-spatial WM task was administered in four reinforcement conditions: Feedback-only, 1 euro, 10 euros, and a computer-game version of the task. In the Feedback-only condition, children with ADHD performed worse on the WM measure than controls. Although incentives significantly improved the WM performance of children with ADHD, even the strongest incentives (10 euros and Gaming) were unable to normalize their performance. Feedback-only provided sufficient reinforcement for controls to reach optimal performance, while children with ADHD required extra reinforcement. Only children with ADHD showed a decrease in performance over time. Importantly, the strongest incentives (10 euros and Gaming) normalized persistence of performance in these children, whereas 1 euro had no such effect. Both executive and motivational deficits give rise to visual-spatial WM deficits in ADHD. Problems with task-persistence in ADHD result from motivational deficits. In ADHD-reinforcement studies and clinical practice (e.g., assessment), reinforcement intensity can be a confounding factor and should be taken into account. Gaming can be a cost-effective way to maximize performance in ADHD.     

Working memory and behavioral inhibition in boys with ADHD: An experimental examination of competing models

Working memory (WM) and behavioral inhibition impairments have garnered significant attention as candidate core features, endophenotypes, and/or associated neurocognitive deficits of attention-deficit/hyperactivity disorder (ADHD). The relationship between ADHD-related WM and inhibition deficits remains relatively unclear, however, with inferences about the constructs’ directional relationship stemming predominantly from correlational research. The current study utilized a dual-task paradigm to experimentally examine the relationship between ADHD-related WM and behavioral inhibition deficits. A total of 31 boys (15 ADHD and 16 typically developing [TD]) aged 8–12 years completed WM (1-back and 2-back), behavioral inhibition (stop-signal task [SST]), and dual-condition (1-back/SST and 2-back/SST) experimental tasks. Children with ADHD exhibited significant, large-magnitude WM deficits for the 1-back condition but were not significantly different from children in the TD group for the 2-back, 1-back/SST, and 2-back/SST conditions. Children with ADHD also exhibited significant inhibition deficits for the SST, 1-back/SST, and 2-back/SST conditions, but the within-group effect was not significant. The findings suggest that ADHD-related stop-signal demands are upstream, or compete for, resources involved in controlled-focused attention and/or other central executive (CE), WM processes.     

Social problem-solving skills in children with traumatic brain injury: long-term outcomes and prediction of social competence.

The effects of childhood traumatic brain injury (TBI) on social problem-solving were examined in 35 children with severe TBI, 40 children with moderate TBI, and 46 children with orthopedic injuries (OI). The children were recruited prospectively following injuries that occurred between 6 and 12 years of age. They were followed longitudinally, and ranged from 9 to 18 years of age at the time of the current study, which occurred on average 4 years post injury. They were administered a semi-structured interview used in previous research on social problem-solving to assess the developmental level of their responses to hypothetical dilemmas involving social conflict. Children in the severe TBI group defined the social dilemmas and generated alternative strategies to solve those dilemmas at the same developmental level as did children in the OI group. However, they articulated lower-level strategies as the best way to solve the dilemmas and used lower-level reasoning to evaluate the effectiveness of the strategies. After controlling for group membership, race, socioeconomic status, IQ, and age, children's social problem-solving, and particularly the developmental level of their preferred strategies for resolving conflicts, predicted parents ratings of children's social skills, peer relationships, aggressive behavior, and academic performance. The findings indicate that children with severe TBI demonstrate selective, long-term deficits in their social problem-solving skills that may help to account for their poor social and academic outcomes.     

Impairments of Attention Following Childhood Traumatic Brain Injury

Attentional deficits are commonly reported following traumatic brain injury (TBI) in adults, although the occurrence of such problems is less well documented in young children. This study aimed to investigate residual attentional abilities associated with TBI during childhood, by examining a number of aspects of attention including sustained, focussed, and divided attention, attentional shift, and response inhibition. Eighteen children with a history of TBI, aged between 8 and 14 years and 18 non-injured matched controls participated in the study. Results show that attentional skills may be differentially impaired after TBI, with children who have sustained moderate-to-severe TBI exhibiting significant deficits on the following attentional domains: sustain, focus, and response inhibition. These findings support the view that attentional impairments following pediatric TBI, while not global, may be more generalized than those reported for adult samples, perhaps reflecting the relative immaturity of attentional skills at the time of injury.