Working memory and inhibitory control deficits in children with ADHD: an experimental evaluation of competing model predictions.

Introduction: Children with ADHD demonstrate difficulties on many different neuropsychological tests. However, it remains unclear whether this pattern reflects a large number of distinct deficits or a small number of deficit(s) that broadly impact test performance. The current study is among the first experiments to systematically manipulate demands on both working memory and inhibition, with implications for competing conceptual models of ADHD pathogenesis. Method: A clinically evaluated, carefully phenotyped sample of 110 children with ADHD, anxiety disorders, or co-occurring ADHD+anxiety (Mage=10.35, 44 girls; 69% White Not Hispanic/Latino) completed a counterbalanced, double dissociation experiment, with two tasks each per inhibition (low vs. high) x working memory (low vs. high) condition. Results: Bayesian and frequentist models converged in indicating that both manipulations successfully increased demands on their target executive function (BF10>5.33x108, p<.001). Importantly, occupying children's limited capacity working memory system produced slower response times and reduced accuracy on inhibition tasks (BF10>317.42, p<.001, d=0.67-1.53). It also appeared to differentially reduce inhibition (and non-inhibition) accuracy for children with ADHD relative to children with anxiety (BF10=2.03, p=.02, d=0.50). In contrast, there was strong evidence against models that view working memory deficits as secondary outcomes of underlying inhibition deficits in ADHD (BF01=18.52, p=.85). Discussion: This pattern indicates that working memory broadly affects children's ability to inhibit prepotent tendencies and maintain fast/accurate performance, and may explain the errors that children with ADHD make on inhibition tests. These findings are broadly consistent with models describing working memory as a causal mechanism that gives rise to secondary impairments. In contrast, these findings provide evidence against models that view disinhibition as a cause of working memory difficulties or view working memory as a non-causal correlate or epiphenomenon in ADHD.

Working memory and math skills in children with and without ADHD.

OBJECTIVE: Children with attention-deficit/hyperactivity disorder (ADHD) frequently demonstrate deficits in working memory and in multiple domains of math skills, including underdeveloped problem-solving and computation skills. The Baddeley model of working memory posits a multicomponent system, including a domain-general central executive and two domain-specific subsystems-phonological short-term memory and visuospatial short-term memory. Extant literature indicates a strong link between neurocognitive deficits in working/short-term memory and math skills; however, the extent to which each component of working/short-term memory may account for this relation is unclear. METHOD: The present study was the first to use bifactor (S·I-1) modeling to examine relations between each working/short-term memory subcomponent (i.e., central executive, phonological short-term memory, and visuospatial short-term memory), ADHD symptoms, and math skills in a clinically evaluated sample of 186 children ages 8-13 (Myears = 10.40, SD = 1.49; 62 girls; 69% White/non-Hispanic). RESULTS: Structural equation modeling indicated that all three working/short-term memory components exert a significant and approximately equal effect on latent math skills (ß = .29-.50, all p < .05) and together explain 56% of the variance in children's math achievement (R² = .56). Exploratory analyses indicated that teacher-reported ADHD inattentive symptoms provided a small but significant contribution to predicting latent math skills (ΔR² = .07) and accounted for 24% of the central executive/math association. CONCLUSIONS: These findings suggest that math difficulties in children with ADHD and clinically evaluated children without ADHD are associated, in large part, with their neurocognitive vulnerabilities in working/short-term memory and, to a lesser extent, overt ADHD symptoms. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Does Anxiety Systematically Bias Estimates of Executive Functioning Deficits in Pediatric Attention-Deficit/Hyperactivity Disorder?

Growing evidence suggests that childhood ADHD is associated with larger impairments in working memory relative to inhibition. However, most studies have not considered the role of co-occurring anxiety on these estimates - a potentially significant confound given prior evidence that anxiety may increase working memory difficulties but decrease inhibition difficulties for these children. The current study extends prior work to examine the extent to which co-occurring anxiety may be systematically affecting recent estimates of the magnitude of working memory/inhibitory control deficits in ADHD. The carefully-phenotyped sample included 197 children with ADHD and 142 children without ADHD between the ages of 8 and 13 years (N = 339; Mage = 10.31, SD = 1.39; 144 female participants). Results demonstrated that ADHD diagnosis predicted small impairments in inhibitory control (d = 0.31) and large impairments in working memory (d = 0.99). However, child trait anxiety assessed dimensionally across multiple informants (child, parent, teacher) did not uniquely predict either executive function, nor did it moderate estimates of ADHD-related working memory/inhibition deficits. When evaluating anxiety categorically and controlling for ADHD, anxiety diagnosis predicted slightly better working memory (d = 0.19) but not inhibitory control for clinically evaluated children generally. Findings from the current study indicate that trait anxiety, measured dimensionally or categorically, does not differentially affect estimates of executive dysfunction in pediatric ADHD. Further, results suggest that trait anxiety is generally not associated with executive dysfunction above and beyond the impact of co-occurring ADHD. Future research is needed to further assess the role of anxiety in ADHD behavioral symptomatology, neurocognitive functioning, and mechanisms underlying these relations.

Evaluating the Simple View of Reading for Children With Attention-Deficit/Hyperactivity Disorder.

The 'simple view of reading' is an influential model of reading comprehension which asserts that children's reading comprehension performance can be explained entirely by their decoding and language comprehension skills. Children with ADHD often exhibit difficulty across all three of these reading domains on standardized achievement tests, yet it is unclear whether the simple view of reading is sufficient to explain reading comprehension performance for these children. The current study was the first to use multiple indicators and latent estimates to examine the veracity of key predictions from the simple view of reading in a clinically-evaluated sample of 250 children with and without ADHD (ages 8-13, Mage=10.29, SD=1.47; 93 girls; 70% White/Non-Hispanic). Results of the full-sample structural equation model revealed that decoding and language comprehension explained all (R2=.99) of the variance in reading comprehension for children with and without ADHD. Further, multigroup modeling (ADHD, Non-ADHD) indicated that there was no difference in the quantity of variance explained for children with ADHD versus clinically-evaluated children without ADHD, and that the quantity of explained variance did not differ from 100% for either group. Sensitivity analyses indicated that these effects were generally robust to control for monomethod bias, time sampling error, and IQ. These findings are consistent with 'simple view' predictions that decoding and language comprehension are both necessary and together sufficient for explaining children's reading comprehension skills. The findings extend prior work by indicating that the 'simple view' holds for both children with ADHD and clinically-evaluated children without ADHD.

Central executive training for ADHD: Impact on organizational skills at home and school. A randomized controlled trial.

OBJECTIVE: The current randomized controlled trial (RCT) was the first to examine the benefits of central executive training (CET, which trains the working components of working memory [WM]) for reducing organizational skills difficulties relative to a carefully matched neurocognitive training intervention (inhibitory control training [ICT]). METHOD: A carefully phenotyped sample of 73 children with attention-deficit/hyperactivity-impulsivity disorder (ADHD; ages 8-13, M = 10.15, SD = 1.43; 20 girls; 73% White/Non-Hispanic) participated in a preregistered RCT of CET versus ICT (both 10-week treatments). Parent-rated task planning, organized actions, and memory/materials management data were collected at pretreatment, posttreatment, and 2-4 month follow-up; teacher ratings were obtained at pretreatment and 1-2 month follow-up. RESULTS: CET was superior to ICT for improving organizational skills based on teacher report (Treatment × Time interaction: d = 0.61, p = .01, BF10 = 31.61). The CET group also improved significantly based on parent report, but this improvement was equivalent in both groups (main effect of time: d = 0.48, p < .001, BF10 = 3.13 × 107; Treatment × Time interaction: d = 0.29, p = .25, BF01 = 3.73). Post hocs/preregistered planned contrasts indicated that CET produced significant and clinically meaningful (number needed to treat = 3-8) pre/post gains on all three parent (d = 0.50 -0.62) and all three teacher (d = 0.46 -0.95) subscales, with gains that were maintained at 1-2 month (teacher report) and 2-4 month follow-up (parent report) for five of six outcomes. CONCLUSIONS: Results provide strong initial evidence that CET produces robust and lasting downstream improvements in school-based organizational skills for children with ADHD based on teacher report. These findings are generally consistent with model-driven predictions that ADHD-related organizational problems are secondary outcomes caused, at least in part, by underdeveloped working memory abilities. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Are Reading Interventions Effective for At-Risk Readers with ADHD? A Meta-Analysis.

OBJECTIVE: Utilizing a multi-level meta-analytic approach, this review is the first to systematically quantify the efficacy of reading interventions for school-aged children with ADHD and identify potential factors that may increase the success of reading-related interventions for these children. METHOD: 18 studies (15 peer-reviewed articles, 3 dissertations) published from 1986 to 2020 (N = 564) were meta-analyzed. RESULTS: Findings revealed reading interventions are highly effective for improving reading skills based on both study-developed/curriculum-based measures (g = 1.91) and standardized/norm-referenced achievement tests (g = 1.11) in high-quality studies of children with rigorously-diagnosed ADHD. Reading interventions that include at least 30 hours of intervention targeting decoding/phonemic awareness meet all benchmarks to be considered a Level 1 (Well-Established) Evidence-Based Practice with Strong Research Support for children with ADHD based on clinical and special education criteria. CONCLUSIONS: Our findings collectively indicate that reading interventions should be the first-line treatment for reading difficulties among at-risk readers with ADHD.

Does central executive training and/or inhibitory control training improve emotion regulation for children with attention-deficit/hyperactivity disorder? A randomized controlled trial.

Introduction: Approximately 48-54% of children with attention-deficit/hyperactivity disorder (ADHD) have impairing difficulties with emotion regulation, and these difficulties are not ameliorated by first-line ADHD treatments. Working memory and inhibitory control represent promising intervention targets given their functional, if not causal, links with ADHD-related emotion dysregulation. Methods: This preregistered randomized controlled trial tested whether two digital therapeutic training protocols that have been previously shown to improve working memory (Central Executive Training [CET]) and inhibitory control (Inhibitory Control Training [ICT]) can improve emotion regulation in a sample of 94 children with ADHD aged 8-13 years (M = 10.22, SD = 1.43; 76% White/non-Hispanic; 29 girls). Results: Results of Bayesian mixed model ANOVAs indicated both treatment groups demonstrated significant decreases in emotion dysregulation relative to pre-treatment at immediate post-treatment (parent report; d = 1.25, BF10 = 8.04 × 1013, p < 0.001), at 1-2 months after completing treatment (teacher report; d = 0.99, BF10 = 1.22 × 106, p < 0.001), and at 2-4-months follow-up (parent report; d = 1.22, BF10 = 1.15 × 1014, p < 0.001). Contrary to our hypotheses, the CET and ICT groups demonstrated equivalent reductions in emotion dysregulation and maintenance of effects. Exploratory analyses revealed that results were robust to control for informant expectancies, ADHD medication status/changes, in-person vs. at-home treatment, child age, and time from treatment completion to post-treatment ratings. Discussion: To determine whether working memory and inhibitory control are causally linked with ADHD-related emotion dysregulation, future studies should include active control conditions that do not train executive functions prior to making decisions about the clinical utility of CET/ICT for the treatment of emotion dysregulation in ADHD. Clinical trial registration: [https://clinicaltrials.gov/], identifier [NCT03324464].

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).

Cancer ecosystem assessment in West Africa: health systems gaps to prevent and control cancers in three countries: Ghana, Nigeria and Senegal.

INTRODUCTION: Sub-Saharan Africa is experiencing a rapid epidemiological transition with the increasing incidence of Non-Communicable Diseases (NCD). Among these, cancer is one of the main causes of death in adults. This is a public health problem whose burden is unknown due to lack of statistical data. In addition, the already overburdened health systems are experiencing enormous constraints to address the problem with the double challenge of communicable and NCDs. METHODS: The purpose of this evaluation was to assess the capacity and needs of health systems to prevent and control cancer. A cross-sectional study, using both quantitative and qualitative methods, was conducted between April 2017 and February 2018 in target countries, through in-depth interviews with key actors, direct observations and documents review. The WHO framework for health system strengthening with the 6 pillars was used for the gaps analysis. RESULTS: Little priority is given to the fight against cancer because of low political commitment. Programs´ resources are very limited and there is a poor coordination of the actions. Human resources are insufficient, and most of them are concentrated in the capital city. This limits access to care with a late consultation of patients. Diagnosis and treatment services are expensive and generally paid by households. Finally, the unavailability of reliable data at national level hinders the decision-based evidence. CONCLUSION: There is an urgent need to create strong partnerships at national and regional levels to (i) Advocate for a strong political commitment; (ii) Strengthen the coordination of actions and create more synergy among stakeholders; (iii) Improve the quality and quantity of human resources; (iv) Extend universal health coverage to cancer and improve program funding; and (v) Set up cancer registries at national level.

Anterior cingulate cortex is necessary for adaptation of action plans.

Previous research has focused on the anterior cingulate cortex (ACC) as a key brain region in the mitigation of the competition that arises from two simultaneously active signals. However, to date, no study has demonstrated that ACC is necessary for this form of behavioral flexibility, nor have any studies shown that ACC acts by modulating downstream brain regions such as the dorsal medial striatum (DMS) that encode action plans necessary for task completion. Here, we performed unilateral excitotoxic lesions of ACC while recording downstream from the ipsilateral hemisphere of DMS in rats, performing a variant of the STOP-signal task. We show that on STOP trials lesioned rats perform worse, in part due to the failure of timely directional action plans to emerge in the DMS, as well as the overrepresentation of the to-be-inhibited behavior. Collectively, our findings suggest that ACC is necessary for the mitigation of competing inputs and validates many of the existing theoretical predictions for the role of ACC in cognitive control.

[Characteristics of work-related injuries and the fate of the victims: about 133 cases reported to the Social Security Fund in Dakar, Senegal]. / Caractéristiques des accidents du travail et devenir des victimes: à propos de 133 cas déclarés auprès de la Caisse de Sécurité Sociale de Dakar (Sénégal).

INTRODUCTION: Work-related injuries have an impact on social security system of the country, on the victims as well as on their relatives. The objective is the aim of our study was to describe the different characteristics of work-related injuries reported to the Social Security Fund (CSS) in Dakar as well as the socioprofessional course of the victims. METHODS: We conducted a retrospective cross-sectional study over a period of 5 years, from 2002 to 2006. Data were collected from 133 cases out of 9 308 reported to the CSS. Various parameters were studied: the socioprofessional characteristics of victims and the lesional features of the injuries. The victims were interviewed to gather informations about their socioprofessional history and their professional situation. RESULTS: The average age of patients was 37,55 years, with a male predominance (99,22 %). BPW (22.6%) and fishing (15%) sectors were most affected. Almost two thirds of injuries happened in the workplace (77.4%). These injuries resulted in fractures in 51.7% of cases and affected the hand in 30.1% of cases. Nearly two thirds of injured subjects (60.9%) had resumed their profession. Thirty one subjects were fired and 12 were redeployed. The average period of temporary total incapacity was 236.7 days. The median annual pension was 1 640 329 CFA Francs (2 504,31 Euros). CONCLUSION: In Senegal, work-related injuries don't have specific characteristics, as described elsewhere. The low resources allocated to the victims and the lack of supporting social-policy measures explain the different types of suffering of the victims and their families.