Low Working Memory rather than ADHD Symptoms Predicts Poor Academic Achievement in School-Aged Children

Executive functions in patients with bilateral and unilateral peripheral vestibular dysfunction

Previous research suggests that patients with peripheral vestibular dysfunction (PVD) suffer from nonspatial cognitive problems, including executive impairments. However, previous studies that assessed executive functions are conflicting, limited to single executive components, and assessments are confounded by other cognitive functions. We compared performance in a comprehensive executive test battery in a large sample of 83 patients with several conditions of PVD (34 bilateral, 29 chronic unilateral, 20 acute unilateral) to healthy controls who were pairwise matched to patients regarding age, sex, and education. We assessed basic and complex executive functions with validated neuropsychological tests. Patients with bilateral PVD performed worse than controls in verbal initiation and working memory span, while other executive functions were preserved. Patients with chronic unilateral PVD had equal executive performance as controls. Patients with acute unilateral PVD performed worse than controls in the exact same tests as patients with bilateral PVD (verbal initiation, working memory span); however, this effect in patients with acute PVD diminished after correcting for multiple comparisons. Hearing loss and affective disorders did not influence our results. Vestibular related variables (disease duration, symptoms, dizziness handicap, deafferentation degree, and compensation) did not predict verbal initiation or working memory span in patients with bilateral PVD. The results suggest that bilateral PVD not only manifests in difficulties when solving spatial tasks but leads to more general neurocognitive deficits. This understanding is important for multidisciplinary workgroups (e.g., neurotologists, neurologists, audiologists) that are involved in diagnosing and treating patients with PVD. We recommend screening patients with PVD for executive impairments and if indicated providing them with cognitive training or psychoeducational support.

Neuropsychological Assessment of the Relationship of Working Memory with K-BIT Matrices and Vocabulary in Normal Development and ADHD Children and Adolescents

BACKGROUND

The present report tries to understand the possible relationship between working memory (WM) and intelligence measurements, using the direct scores of the Working Memory Test Battery for Children (WMTBC) and Kaufman's Brief Intelligence Test (K-BIT), in normal development (ND) and diagnosed attention deficit hyperactivity disorder (ADHD) children and adolescents.

RESULTS

Partial correlations, discounting the effect of age, showed a significant correlation in ND subjects between the central executive (CE) component of WM and the WM visuospatial sketchpad (VSS) component and the WM phonological loop (PL); also, significant correlations were obtained for the WM VSS with the K-BIT Matrices scores, the WM PL with the K-BIT Vocabulary, and the K-BIT Matrices scores with the K-BIT Vocabulary. For ADHD subjects, there were significant correlations between WM VSS and WM CE, and WM VSS and K-BIT Matrices. We tested the robustness of these correlations by selecting a small number of subjects through permutations; a robust correlation between WM CE and WM PL in ND, and between WM VSS and WM CE and WM VSS and K-BIT Matrices scores was obtained. These results were also supported by mediation analysis.

CONCLUSIONS

There is a relationship during development between WM as measured with WMTBC and general intelligence as measured with K-BIT in ND and ADHD subjects. The dysexecutive character of ADHD has been shown, given that by controlling for intelligence, the differences in WM performance between ND and ADHD disappear, except for WM CE. The results suggest that in ADHD subjects, the WM VSS component presents a more pivotal role during cognitive processing compared to ND subjects.

Listen up! ADHD slows spoken-word processing in adverse listening conditions: Evidence from eye movements

BACKGROUND

Cognitive skills such as sustained attention, inhibition and working memory are essential for speech processing, yet are often impaired in people with ADHD. Offline measures have indicated difficulties in speech recognition on multi-talker babble (MTB) background for young adults with ADHD (yaADHD). However, to-date no study has directly tested online speech processing in adverse conditions for yaADHD.

AIMS

Gauging the effects of ADHD on segregating the spoken target-word from its sound-sharing competitor, in MTB and working-memory (WM) load.

METHODS AND PROCEDURES

Twenty-four yaADHD and 22 matched controls that differ in sustained attention (SA) but not in WM were asked to follow spoken instructions presented on MTB to touch a named object, while retaining one (low-load) or four (high-load) digit/s for later recall. Their eye fixations were tracked.

OUTCOMES AND RESULTS

In the high-load condition, speech processing was less accurate and slowed by 140ms for yaADHD. In the low-load condition, the processing advantage shifted from early perceptual to later cognitive stages. Fixation transitions (hesitations) were inflated for yaADHD.

CONCLUSIONS AND IMPLICATIONS

ADHD slows speech processing in adverse listening conditions and increases hesitation, as speech unfolds in time. These effects, detected only by online eyetracking, relate to attentional difficulties. We suggest online speech processing as a novel purview on ADHD. WHAT THIS PAPER ADDS?: We suggest speech processing in adverse listening conditions as a novel vantage point on ADHD. Successful speech recognition in noise is essential for performance across daily settings: academic, employment and social interactions. It involves several executive functions, such as inhibition and sustained attention. Impaired performance in these functions is characteristic of ADHD. However, to date there is only scant research on speech processing in ADHD. The current study is the first to investigate online speech processing as the word unfolds in time using eyetracking for young adults with ADHD (yaADHD). This method uncovered slower speech processing in multi-talker babble noise for yaADHD compared to matched controls. The performance of yaADHD indicated increased hesitation between the spoken word and sound-sharing alternatives (e.g., CANdle-CANdy). These delays and hesitations, on the single word level, could accumulate in continuous speech to significantly impair communication in ADHD, with severe implications on their quality of life and academic success. Interestingly, whereas yaADHD and controls were matched on WM standardized tests, WM load appears to affect speech processing for yaADHD more than for controls. This suggests that ADHD may lead to inefficient deployment of WM resources that may not be detected when WM is tested alone. Note that these intricate differences could not be detected using traditional offline accuracy measures, further supporting the use of eyetracking in speech tasks. Finally, communication is vital for active living and wellbeing. We suggest paying attention to speech processing in ADHD in treatment and when considering accessibility and inclusion.

Teacher perceptions of working memory and executive function improvements following school-day cognitive training

Considerable research has documented the impact of teacher perceptions on students’ academic-related outcomes (e.g., classroom performance). This body of literature clearly shows that teacher perceptions (resulting from direct interactions with students) can have both positive and negative effects with respect to student behaviors and experiences in the classroom. What remains unclear is whether teachers perceive changes that result from interventions administered outside of their classrooms. The purpose of this study was to examine changes in teacher perceptions of working memory and executive function concerns (two important predictors of academic success) among students who participated in a computerized cognitive training program designed to enhance working memory skills. The current results indicate that teachers perceived fewer concerns following students’ participation in the training; this outcome was supplemented with significant improvements in the students’ working memory capabilities following the training program. These findings have important implications given the literature highlighting the relation between teacher perceptions and student outcomes as a function of a school-based computerized cognitive training intervention.

The relationship between executive function, neurodevelopmental disorder traits, and academic achievement in university students

Difficulties with executive function have often been identified in individuals with various neurodevelopmental disorders such as Autism Spectrum Disorder (ASD), Attention-Deficit Hyperactivity Disorder (ADHD), and Developmental Co-ordination Disorder (DCD). Additionally, in childhood and adolescence, executive functioning is an important predictor of academic achievement. However, less research has explored these relationships in adult students, and those with a high level of neurodevelopmental disorder traits but no clinical diagnosis. Therefore, the current study aimed to assess whether ASD, ADHD, and DCD traits can predict academic achievement in university students, and whether traits of these neurodevelopmental conditions moderate the relationship between executive function and academic achievement. Both neurotypical students and those with a clinical diagnosis of a neurodevelopmental disorder were able to participate, with the majority being neurotypical. Participants completed four self-report questionnaires and provided a measure of academic achievement based on their university assignment results. Traits of ASD, ADHD, and DCD alone did not predict achievement, however, traits of ADHD and DCD significantly moderated the relationship between executive function and academic achievement. ASD traits did not significantly moderate this relationship. Implications and suggestions for future research are also discussed.

Central executive training for ADHD: Effects on academic achievement, productivity, and success in the classroom

OBJECTIVE

Central executive training (CET) is a "Level 2" evidence-based treatment for improving ADHD-related executive dysfunction and behavioral symptoms, but the extent to which these gains extend to the disorder's well-documented academic difficulties is unknown.

METHOD

Across two clinical trials, 108 children with attention-deficit/hyperactivity disorder (ADHD) 8-13 years old (M = 10.29, SD = 1.50; 32 girls; 75% White/Non-Hispanic) were treated with CET (n = 52), inhibitory control training (ICT; n = 29), or gold-standard behavioral parent training (BPT; n = 27).

RESULTS

CET was superior to BPT and ICT (d = 0.62-0.88) for improving masked teacher perceptions of academic success, impulse control, and academic productivity at 1-2 months posttreatment. At 2-4-month follow-up, CET (d = 0.76) and ICT (d = 0.54) were superior to BPT for improving objectively-tested academic achievement overall (reading comprehension, math problem-solving, language comprehension), and CET was superior to ICT (d = 0.56) for improving math problem-solving. The significant benefits of CET on academic success, academic productivity, reading comprehension, and math problem-solving replicated across both trials and were clinically significant as evidenced by low number needed to treat estimates (Needed to Treat; NNT = 3-7) and significantly higher proportions of individual cases demonstrating reliable improvements in academic success/productivity (33%-36% vs. 0%-18%) and achievement (38%-72% vs. 18%-54%) across outcomes (all p ≤ .01).

CONCLUSIONS

Results across the two trials provide strong support for the efficacy of CET for ADHD, and are consistent with model-driven hypotheses that academic difficulties in ADHD are due, in part, to these children's underdeveloped executive functioning abilities. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Shared Predictors of Academic Achievement in Children with ADHD: A Multi-Sample Study

OBJECTIVE

To identify common and shared predictors of academic achievement across samples of children with ADHD.

METHOD

Two clinically referred samples from New Zealand (1 n = 88, 82% boys; 2 n = 121, 79% boys) and two community samples from the United States (3 n = 111, 65% boys; 4 n = 114, 69% boys), completed similar diagnostic, cognitive and academic assessments. Hierarchical multiple regression analyses identified significant predictors of word reading, spelling, and math computation performance in each sample.

RESULTS

Entered after IQ, semantic language, age at testing, and verbal working memory emerged as consistent predictors of achievement across academic subjects and samples. Visual-spatial working memory contributed to variance in math performance only. Symptom severity explained limited variance.

CONCLUSIONS

We recommend evaluations of children with ADHD incorporate assessments of working memory and language skills. Classroom/academic interventions should accommodate reduced working memory and address any identified language weaknesses.

Utilizing Cognitive Training to Improve Working Memory, Attention, and Impulsivity in School-Aged Children with ADHD and SLD

Students’ use of working memory (WM) is a key to academic success, as many subject areas and various tasks school-aged children encounter require the ability to attend to, work with, and recall information. Children with poor WM ability typically struggle with academic work compared to similar-aged peers without WM deficits. Further, WM has been shown to be significantly correlated with inattention and disorganization in those with ADHD, and WM deficits have also been identified as a potential underpinning of specific learning disorder (SLD). As an intervention technique, the use of computerized cognitive training has demonstrated improved attention and working memory skills in children with WM deficits, and children that have completed cognitive training protocols have demonstrated performance improvements in reading and math. The current study aimed to examine the effectiveness of cognitive training (conducted in a clinical setting) for students diagnosed with ADHD and SLD. Using paired-samples t-tests and a psychometric network modeling technique, results from data obtained from a sample of 43 school-aged children showed (1) that attention and working memory improved following cognitive training and (2) that cognitive training might be related to cognitive structural changes found pre- to post-training among the variables being measured. Implications for clinical practice and school-based interventions are discussed.

Which 'Working' Components of Working Memory aren't Working in Youth with ADHD?

Despite replicated evidence for working memory deficits in youth with ADHD, no study has comprehensively assessed all three primary 'working' subcomponents of the working memory system in these children. Children ages 8-13 with (n = 45) and without (n = 41) ADHD (40% female; M_age = 10.5; 65% Caucasian/Non-Hispanic) completed a counterbalanced battery of nine tasks (three per construct) assessing working memory reordering (maintaining and rearranging information in mind), updating (active monitoring of incoming information and replacing outdated with relevant information), and dual-processing (maintaining information in mind while performing a secondary task). Detailed analytic plans were preregistered. Bayesian t-tests indicated that, at the group level, children with ADHD exhibited significant impairments in working memory reordering (BF₁₀ = 4.64 × 10⁵; d = 1.34) and updating (BF₁₀ = 9.49; d = 0.64), but not dual-processing (BF₀₁ = 1.33; d = 0.37). Overall, 67%-71% of youth with ADHD exhibited impairment in at least one central executive working memory domain. Reordering showed the most ADHD-related impairment, with 75% classified as below average or impaired, and none demonstrating strengths. The majority of children with ADHD (52%-57%) demonstrated average or better abilities in the remaining two domains, with a notable minority demonstrating strengths in updating (8%) and dual-processing (20%). Notably, impairments in domain-general central executive working memory, rather than individual subcomponents, predicted ADHD severity, suggesting that common rather than specific working memory mechanisms may be central to understanding ADHD symptoms. These impairment estimates extend prior work by providing initial evidence that children with ADHD not only exhibit heterogeneous profiles across cognitive domains but also exhibit significant heterogeneity within subcomponents of key cognitive processes.

Number of words at age 2.5 years is associated with intellectual functioning at age 7 years in the SELMA study

AIM

We examined the association between the number of words used at age 2.5 years and deficits in intellectual functioning at age 7 years, in 549 children, and whether such association is confirmed by parental concern about the child's development.

METHODS

Parental reports of how many words their children used at age 2.5 years were analysed for the association to intellectual functioning (assessed with Wechsler Intelligence Scale for Children - Fourth Edition,WISC-IV) at age 7 years using linear regression, adjusting for sex, maternal education level, parental IQ and smoking during pregnancy. Parental concern at age 7 years was examined with the Early Symptomatic Syndromes Eliciting Neurodevelopmental Clinical Examinations-Questionnaire (ESSENCE-Q).

RESULTS

Adjusted linear regression showed that use of 50 words or fewer at age 2.5 years, relative to use of more than 50 words, was associated with lower scores of Full-scale IQ (B = 7.27, p = 0.001), verbal comprehension (B = 8.53, p < 0.001), working memory (B = 9.04, p < 0.001) and perceptual reasoning (B = 4.21, p = 0.045), in the WISC-IV, at age 7 years. Parental concern was more common in the group that used 50 words or fewer (Mann-Whitney U test, p = 0.011).

CONCLUSION

This easily accessible measure of number of words seems to be a valuable marker for intellectual functioning later in life.

Activities of daily living and working memory in pediatric attention-deficit/hyperactivity disorder (ADHD)

Most children with ADHD have impaired working memory abilities. These working memory deficits predict impairments in activities of daily living (ADLs) for adults with ADHD. However, our understanding of the relation between pediatric ADHD and ADLs is limited. Thus, this study aimed to examine (1) the extent to which pediatric ADHD is associated with ADL difficulties; and if so (2) the extent to which these difficulties are related to their well-documented working memory difficulties and/or core ADHD inattentive and hyperactive/impulsive symptom domains. A well-characterized, clinically evaluated sample of 141 children ages 8-13 years (M = 10.36, SD = 1.46; 51 girls; 70% White/non-Hispanic) were administered a battery of well-validated working memory tests and assessed for ADHD symptoms (teacher-ratings) and ADL difficulties (parent-ratings); cross-informant reports were used to control for mono-informant bias. Children with ADHD exhibited medium magnitude difficulties with ADLs (d = 0.61, p < .005, 38% impaired). Results of the bias-corrected, bootstrapped conditional effects model indicated that lower working memory predicted reduced performance of age-expected ADLs (β =0.28) and greater ADHD inattentive (β = -0.40) and hyperactive/impulsive symptoms (β = -0.16). Greater inattentive, but not hyperactive/impulsive, symptoms predicted greater ADL difficulties (β = -0.36) even after controlling for working memory. Interestingly, working memory exerted a significant indirect effect on ADLs via inattentive (indirect effect: β = 0.15, effect ratio = .54) but not hyperactive/impulsive symptoms. These findings implicate ADHD inattentive symptoms as a potential mechanism underlying ADL difficulties for children with ADHD, both independently and via working memory's role in regulating attention.

Neural basis of working memory in ADHD: Load versus complexity

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Working memory (WM).

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Load versus Complexity.

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ADHD.

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FMRI.

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Working Memory Striatum and Cerebellum.

Working memory (WM) deficits are key in attention deficit hyperactivity disorder (ADHD). Nevertheless, WM is not universally impaired in ADHD. Additionally, the neural basis for WM deficits in ADHD has not been conclusively established, with regions including the prefrontal cortex, cerebellum, and caudate being implicated. These contradictions may be related to conceptualizations of WM capacity, such as load (amount of information) versus operational-complexity (maintenance-recall or manipulation). For instance, relative to neurotypical (NT) individuals, complex WM operations could be impaired in ADHD, while simpler operations are spared. Alternatively, all operations may be impaired at higher loads. Here, we compared the impact of these two components of WM capacity: load and operational-complexity, between ADHD and NT, behaviorally and neurally. We hypothesized that the impact of WM load would be greater in ADHD, and the neural activation would be altered. Participants (age-range 12–23 years; 50 ADHD (18 females); 82 NT (41 females)) recalled three or four objects (load) in forward or backward order (operational-complexity) during functional magnetic resonance imaging scanning. The effects of diagnosis and task were compared on performance and neural engagement. Behaviorally, we found significant interactions between diagnosis and load, and between diagnosis, load, and complexity. Neurally, we found an interaction between diagnosis and load in the right striatum, and between diagnosis and complexity in the right cerebellum and left occipital gyrus. The ADHD group displayed hypo-activation compared to NT group during higher load and greater complexity. This informs mechanisms of functional problems related to WM in adolescents and young adults with ADHD (e.g., academic performance) and remedial interventions (e.g., WM-training).

Effects of a five-day HD-tDCS application to the right IFG depend on current intensity: A study in children and adolescents with ADHD

Impaired executive functions in ADHD are associated with hypoactivity of the right inferior frontal gyrus (IFG). This region was targeted via repetitive applications of anodal, high-definition transcranial direct current simulation (HD-tDCS) on five consecutive days in 33 ADHD patients (10-17years) and in a healthy control group (n=13, only sham). Patients received either sham (n=13) or verum tDCS with 0.5mA (n=9) or 0.25mA (n=11) depending on individual cutaneous sensitivity. During stimulation, participants performed a combined working memory and response inhibition paradigm (n-back/nogo). At baseline, post, and a 4-month follow up, electroencephalography was recorded during this task. Moreover, interference control (flanker task) and spatial working memory (spanboard task) were assessed to explore possible transfer effects. Omission errors and reaction time variability in all tasks served as measures of attention. In the 0.25mA group increased nogo commission errors indicated a detrimental tDCS effect on response inhibition. After the 5-day stimulation, attentional improvements in the 0.5mA group were indicated by reduced omission errors and reaction time variability. Variability improvements were still evident at follow up. In all groups, nogo P3 amplitudes were reduced post-stimulation, but in the 0.5mA group this reduction was smaller than in the 0.25mA group. Results of the current study suggest distinct effects of tDCS with different current intensities demonstrating the importance of a deeper understanding on the impact of stimulation parameters and repeated tDCS applications to develop effective tDCS-based therapy approaches in ADHD.

Economical Assessment of Working Memory and Response Inhibition in ADHD Using a Combined n-back/Nogo Paradigm: An ERP Study

The development of cognitive interventions in attention-deficit/hyperactivity disorder (ADHD) often requires the assessment of multiple cognitive functions. However, experimental settings consisting of various tasks are particularly strenuous for patients and can thus result in poor data quality. For the economical assessment of working memory and response inhibition, this study aims to validate a combined n-back/nogo paradigm by comparing it to single task versions and to demonstrate its applicability for ADHD research. Twenty-five healthy individuals and 34 ADHD patients between 9 and 16 years participated in this event-related potential (ERP) study. Healthy controls underwent single task versions of a 2-back working memory task and a go/nogo response inhibition task as well as the introduced combined 2-back/nogo task. This combined task demonstrated a comparable ERP structure for working memory and response inhibition aspects as single task versions. Behaviorally, higher working memory performance during the combined paradigm indicated lower task difficulty, while high correlations between combined and single task versions still indicated valid working memory measures. For response inhibition performance, different task versions resulted in similar outcomes. The application of the combined n-back/nogo paradigm in ADHD patients revealed the expected working memory and response inhibition deficits, increased omission errors, reaction times, and standard deviation of reaction time, as well as diminished n-back P3 and nogo P3 amplitudes. We conclude that the combined n-back/nogo task is an effective paradigm for the economical assessment of working memory and response inhibition deficits in ADHD on a behavioral and neurophysiological level.

Comparison between conventional and HD-tDCS of the right inferior frontal gyrus in children and adolescents with ADHD

OBJECTIVE

To investigate whether the effects of HD-tDCS and conventional tDCS of the right IFG are superior to the effects of sham stimulation for the improvement of working memory performance in ADHD.

METHODS

15 ADHD patients between 10 and 16 years underwent three tDCS sessions in which conventional, HD and sham tDCS of the right IFG were applied. In all sessions a 2-back working memory task was solved and EEG was recorded. Baseline data were assessed from 15 age matched healthy controls.

RESULTS

In ADHD patients, increased positive values of P300 and N200 mean amplitudes were found after conventional and HD-tDCS. Thus, both components were more in resemblance to ERPs in healthy controls. Behavioral performance was not generally influenced by tDCS but effects of HD-tDCS depended on individual hyperactive/impulsive symptom load. The rate of responders for HD-tDCS was equivalent to the responder rate for conventional tDCS.

CONCLUSIONS

ERP data indicate that HD-tDCS is equally suitable as conventional tDCS for the recruitment of the right IFG in the context of working memory processing.

SIGNIFICANCE

HD-tDCS of the right IFG is a promising approach for neuromodulation in ADHD but further research is necessary to develop adaptations that produce reliable behavioral benefits.

Working Memory Training Is Associated with Changes in Resting State Functional Connectivity in Children Who Were Born Extremely Preterm: a Randomized Controlled Trial

Children born extremely preterm (EP; < 28 weeks of gestation) or extremely low birth weight (ELBW; < 1000 g) are at increased risk of working memory deficits compared with their term-born peers and may benefit from working memory training. This study aimed to determine whether Cogmed Working Memory Training®, compared with a placebo training program, was associated with changes in resting-state functional connectivity (rsfc) and whether these changes correlated with working memory performance in EP/ELBW children. Twenty-one 7-year-old EP/ELBW children were enrolled in a double-blinded randomized controlled trial and had magnetic resonance imaging (MRI) assessments (Cogmed, n = 12; placebo (a non-adaptive version of Cogmed), n = 9). Prior to training (baseline) and 2 weeks post-training, all children received a cognitive assessment, inclusive of immediate memory and working memory measures and an MRI. The Cogmed Improvement Index was used as a measure of improvement in trained activities in the Cogmed group. Resting-state functional MRI was used to measure training-related changes in intra- and inter-network rsfc. The networks assessed include the default mode network, the left and right central executive networks, the bilateral executive network, the dorsal attention network, and the salience network. rsfc data were compared between treatment groups and investigated in relation to changes in working memory performance. There was little evidence of differences in intra- or inter-network rsfc strength changes from baseline to post-training between treatment groups. In the Cogmed group, working memory performance was associated with increased rsfc from baseline to post-training within the precuneus network, but not in the placebo group. In the Cogmed group, results that did not survive multiple comparison correction further showed that improvement in trained activities was associated with increased rsfc between the left central and bilateral executive networks, and with decreased rsfc within the right central executive network and between the right central executive and salience networks. Changes in rsfc may facilitate working memory performance following Cogmed training. Further studies are needed to investigate how changes in rsfc are associated with behavioral changes to better support working memory in vulnerable groups.

The efficacy of a training that combines activities on working memory and metacognition: Transfer and maintenance effects in children with ADHD and typical development

Introduction: It has been demonstrated that children with attention deficit and hyperactivity disorder (ADHD) have impairments in working memory (WM), and particularly its visuospatial component, responsible for academic underachievement. Furthermore, children with ADHD have difficulty in metacognition, and consequently use inappropriate strategies to control attention and impulsive behavior. The aim of the present study was to devise a training that combined individual exercises on visuospatial WM and group metacognitive activities capable of helping children with ADHD to ameliorate their performance in executive functioning tasks, and to contain their inattentive and hyperactive/impulsive behavior. Method: A combined training that focused on visuospatial WM and metacognition was administered to 12 children with a diagnosis of ADHD and 15 typically-developing children. Tasks on executive functions and questionnaires for parents and teachers were administered before and at the end of the training, and one month after the post-test. Specific short- and long-term training gains and transfer effects were examined. Effects of the training on parents' and teachers' ratings were also considered. Results: Specific gains and transfer effects were found at the post-test and long-term assessments in both typically-developing children and those with ADHD. Parents' and teachers' ratings also indicated an improvement in the symptomatic behavior of children with ADHD. Conclusion: The results of this study have clinical and educational implications. A training that combines individual computerized visuospatial WM activities with metacognitive group reflection about useful strategies seems to produce promising results, helping children with ADHD to improve their executive functioning and behavioral problems.

Influence of weight status at 2 years on memory performance at 4-5 years of age

Background: Memory performance is a cognitive function that is affected by environmental, genetic and socioeconomic factors, as well as by weight status.Aim: To evaluate the association of weight status at 2 years of age with the memory performance of children at 4-5 years of age.Subjects and methods: A cross-sectional study that used baseline data (2012) and data from two follow-up periods (2014 and 2016) of the PREDI Cohort Study. Participants were mother-child pairs 4-5 years after delivery who were seen between July 2016 and August 2017. The children's memory performance was evaluated individually using a validated Brazilian instrument.Results: Of the 203 children included in the study, 117 (57.6%), 52 (25.6%) and 34 (16.8%) had low, moderate and high memory performance, respectively. After adjusting for potential confounders, children with a BMI > 85th percentile had 3.33-times higher odds of exhibiting lower memory performance at 4-5 years of age than those with a BMI ≤ 85th percentile. In addition to the children's BMI at 2 years of age, mother's education was another independent determinant of children's memory performance. There was a progressive increase in the odds of children having lower memory performance at 4-5 years of age as the mother's education decreased.Conclusion: Primary prevention of overweight and management of cognitive functions may be important strategies to improve the cognitive development of children in the future.

A Review of Heterogeneity in Attention Deficit/Hyperactivity Disorder (ADHD)

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder that affects approximately 8%–12% of children worldwide. Throughout an individual’s lifetime, ADHD can significantly increase risk for other psychiatric disorders, educational and occupational failure, accidents, criminality, social disability and addictions. No single risk factor is necessary or sufficient to cause ADHD. The multifactorial causation of ADHD is reflected in the heterogeneity of this disorder, as indicated by its diversity of psychiatric comorbidities, varied clinical profiles, patterns of neurocognitive impairment and developmental trajectories, and the wide range of structural and functional brain anomalies. Although evidence-based treatments can reduce ADHD symptoms in a substantial portion of affected individuals, there is yet no curative treatment for ADHD. A number of theoretical models of the emergence and developmental trajectories of ADHD have been proposed, aimed at providing systematic guides for clinical research and practice. We conducted a comprehensive review of the current status of research in understanding the heterogeneity of ADHD in terms of etiology, clinical profiles and trajectories, and neurobiological mechanisms. We suggest that further research focus on investigating the impact of the etiological risk factors and their interactions with developmental neural mechanisms and clinical profiles in ADHD. Such research would have heuristic value for identifying biologically homogeneous subgroups and could facilitate the development of novel and more tailored interventions that target underlying neural anomalies characteristic of more homogeneous subgroups.

Effectiveness of a working memory intervention program in children with language disorders

The aim of this study was twofold: first, to obtain a neuropsychological characterization of children with language disorders, and second, to evaluate the effectiveness of an intervention program on working memory. We used a pretest-instruction-posttest design, carefully identifying a sample of 32 children with language disorders whom we then evaluated for short-term verbal and visuospatial memory, verbal and visuospatial working memory, attention, processing speed, and lexical-semantic skills. We then implemented an intervention program on working memory consisting of 72 sessions of 15 minutes each, after which we repeated the neuropsychological assessment of these functions. Children with language disorders performed worse than children in the control group in all memory tasks evaluated and in the lexical-semantic processing task. After the intervention, children with language disorders showed a significant increase over their own previous performance in all variables. Children with language disorders show significant cognitive deficits and not just linguistic impairment. We offer conclusive findings on the effectiveness of the intervention program used. Finally, we obtained partial support for the existence of a causal link between improved performance on memory tasks and performance in a lexical-semantic task.