Aspects Of Executive Function Research Articles

Causal Evidence from Humans for the Role of Mediodorsal Nucleus of the Thalamus in Working Memory.

The mediodorsal nucleus of the thalamus (MD), with its extensive connections to the lateral pFC, has been implicated in human working memory and executive functions. However, this understanding is based solely on indirect evidence from human lesion and imaging studies and animal studies. Direct, causal evidence from humans is missing. To obtain direct evidence for MD's role in humans, we studied patients treated with deep brain stimulation (DBS) for refractory epilepsy. This treatment is thought to prevent the generalization of a seizure by disrupting the functioning of the patient's anterior nuclei of the thalamus (ANT) with high-frequency electric stimulation. This structure is located superior and anterior to MD, and when the DBS lead is implanted in ANT, tip contacts of the lead typically penetrate through ANT into the adjoining MD. To study the role of MD in human executive functions and working memory, we periodically disrupted and recovered MD's function with high-frequency electric stimulation using DBS contacts reaching MD while participants performed a cognitive task engaging several aspects of executive functions. We hypothesized that the efficacy of executive functions, specifically working memory, is impaired when the functioning of MD is perturbed by high-frequency stimulation. Eight participants treated with ANT-DBS for refractory epilepsy performed a computer-based test of executive functions while DBS was repeatedly switched ON and OFF at MD and at the control location (ANT). In comparison to stimulation of the control location, when MD was stimulated, participants committed 2.26 times more errors in general (total errors; OR = 2.26, 95% CI [1.69, 3.01]) and 2.86 times more working memory-related errors specifically (incorrect button presses; OR = 2.88, CI [1.95, 4.24]). Similarly, participants committed 1.81 more errors in general ( OR = 1.81, CI [1.45, 2.24]) and 2.08 times more working memory-related errors ( OR = 2.08, CI [1.57, 2.75]) in comparison to no stimulation condition. "Total errors" is a composite score consisting of basic error types and was mostly driven by working memory-related errors. The facts that MD and a control location, ANT, are only few millimeters away from each other and that their stimulation produces very different results highlight the location-specific effect of DBS rather than regionally unspecific general effect. In conclusion, disrupting and recovering MD's function with high-frequency electric stimulation modulated participants' online working memory performance providing causal, in vivo evidence from humans for the role of MD in human working memory.

The divergent impact of catechol-O-methyltransferase (COMT) Val158Met genetic polymorphisms on executive function in adolescents with discrete patterns of childhood adversity

PurposeCatechol-O-methyltransferase (COMT) Val158Met functional polymorphisms play a crucial role in the development of executive function (EF), but their effect may be moderated by environmental factors such as childhood adversity. The present study aimed at testing the divergent impact of the COMT Val158Met genotype on EF in non-clinical adolescents with discrete patterns of childhood adversity. MethodsA total of 341 participants completed the Childhood Trauma Questionnaire, the self-reported version of the Behavior Rating Inventory of Executive Function, and self-administered questionnaires on familial function. The participants' COMT Val158Met genotype was determined. Associations among the variables were explored using latent class analysis and general linear models. ResultsWe found that Val/Val homozygotes showed significantly worse performance on behavioral shift, relative to Met allele carriers (F=5.921, p=0.015, Partial η2=0.018). Moreover, three typical patterns of childhood adversity, namely, low childhood adversity (23.5%), childhood neglect (59.8%), and high childhood adversity (16.7%), were found. Both childhood neglect and high childhood adversity had a negative impact on each aspect of EF and on global EF performance. Importantly, these results provided evidence for significant interaction effects, as adolescents with the Val/Val genotype showed inferior behavioral shift performance than Met carriers (F=6.647, p=0.010, Partial η2=0.020) in the presence of high childhood adversity. Furthermore, there were no differences between the genotypes for childhood neglect and low childhood adversity. ConclusionsOverall, this is the first study to show that an interaction between the COMT genotype and childhood adversity affects EF in non-clinical adolescents. These results suggest that the COMT genotype may operate as a susceptibility gene vulnerable to an adverse environment.

The effects of ADHD on cognitive performance

Background: Attention-deficit hyperactivity disorder (ADHD) is a common and impairing neurodevelopmental disorder. The Cambridge Neuropsychological Test Automated Battery (CANTAB) is a computerized test battery with standardized procedures and solid psychometric properties targeting multiple neuropsychological functions.Aims: The aim of this study was to look at the effects of ADHD on cognitive performance using CANTAB expressed as a statistical interaction term in regression modeling.Methods: We assessed 112 drug-naïve subjects (age: 7–18 years) with ADHD based on DSM IV criteria and compared them to 95 control subjects (age: 7–18 years). All participants were administered five CANTAB tasks designed to capture different aspects of executive functioning: Stockings of Cambridge (SOC), Intra/Extra dimensional shift (IED), Spatial Working Memory (SWM), Simple Reaction Time (SRT) and Stop Signal Task (SST).Results: T-tests showed a difference between ADHD and control subjects in all cognitive measures except SOC. The majority of measures showed a non-linear effect of age. SWM strategy and SST direction errors showed a linear effect of age. ADHD diagnosis had a statistically significant effect on performance. For all tests except SOC, ADHD produced the main effect without interaction with age.Discussion: For all CANTAB measures, ADHD diagnosis had a significant effect on performance and produced this effect without interaction with age in all tests except SOC, indicating that the developmental trajectories were parallel in both groups. The results indicate that cognitive performance is impaired in youth with ADHD and that CANTAB can be a valuable tool in the diagnostic assessment of ADHD.

Executive Functioning Predicts Reflective Functioning in Mothers.

Parental reflective functioning (PRF) describes a parent's capacity for considering both their own and their child's thoughts, feelings, and behaviors, which can help parents to guide interactions with children. Given the cognitive demands of keeping infants in mind whilst caregiving, we examined the association between aspects of executive function (i.e., working memory and set-shifting) and PRF (employing the Parental Reflective Functioning Questionnaire) in recent mothers. In Study 1 (N=50), we found that better working memory was associated with higher levels of maternal interest and curiosity in their child's feelings. In Study 2 (N=68), we found that visual working memory and set-shifting capacity were also associated with higher levels of maternal interest and curiosity in their child's thoughts and feelings. Our results provide preliminary support for the association between executive processes and maternal reflective functioning. The implications of these findings and important future directions are discussed, including advancing our understanding of executive processes and PRF to support the broader family system.

How does being bilingual influence children with autism in the aspect of executive functions and social and communication competence

How does being bilingual influence children with autism in the aspect of executive functions and social and communication competence

Executive Functions and Externalizing Symptoms: Common and Unique Associations.

In discussing the four papers in this special issue, we provide our perspective on the authors' contributions and suggest directions for future research. First, we highlight the usefulness of the bi-factor model for investigating relations among specific aspects of executive functions (EFs) and externalizing symptoms. Next, we examine the role of EFs as a protective factor that can moderate the relation between risk factors - specifically, callous-unemotional behaviors - on externalizing symptoms. And finally, we address the contributions of innovative measurement approaches to understanding the relations between EFs and externalizing symptoms, using the state-space grid methodology as an example.

Constitutive loss and acute pharmacological manipulation of ErbB4 signaling do not affect attention and inhibitory control in mice.

The receptor tyrosine kinase ErbB4 and its ligand trophic factors of the neuregulin (NRG) family have been associated with schizophrenia and other mental disorders in human genetic studies. In vivo studies in mice have shown how abnormal Nrg-ErbB4 signaling leads to deviant behaviors relevant to distinct aspects of schizophrenia, including hyperactivity, sensory gating deficits, working and spatial memory deficits and impaired social behavior. However, so far little is known on the role of ErbB4 in attention and inhibitory control, two aspects of executive functions that are impaired in schizophrenia. Here we investigated the effects of constitutive loss of ErbB4 in the central nervous system of mice on performance in a 5-choice serial reaction time task (5CSRTT) assessing attention and inhibitory control. In this task, ErbB4-/- mice did not show deficits in various parameters of attention, and premature responses as measure of inhibitory control. Nonetheless, ErbB4-/- mice recapitulated a specific set of behavioral phenotypes associated with schizophrenia, including a deficit in spatial learning and memory in the Barnes Maze and in contextual fear learning, and a trend for a deficit in sensorimotor gating. Furthermore, we investigated the effect of acute pharmacological inhibition of ErbB tyrosine kinase receptor using the pan-ErbB kinase inhibitor JNJ-28871063 (JNJ), in an automated version of the 5CSRTT. JNJ did not affect attention and inhibitory control. In conclusion, our data suggest no direct involvement of a classical Nrg-ErbB4 pathway in attention and inhibitory control in mice, while it confirms the involvement of this pathway in other domains relevant to schizophrenia.

Neuropsychological Profile of Specific Executive Dysfunctions in Patients with Deficit and Non-deficit Schizophrenia.

Objectives: Although it has been shown that there are more profound deficits present in deficit schizophrenia (DS) patients than in non-deficit schizophrenia (NDS) patients, there still remain some matters requiring further investigation. In this context, we formulated three research aims: (1) to compare executive functions between the investigated groups, (2) to determine the relationship between particular aspects of executive functions within the groups, and (3) to draw up a neuropsychological profile for executive functions.Methods: The study involved 148 schizophrenia patients divided into two groups on the basis of the Schedule for the Deficit Syndrome: DS (n = 70) and NDS (n = 78). Patients were matched for sex, age, years of education, and overall cognitive functioning. For assessing executive functions we used the Wisconsin Card Sorting Test (WCST), the Trail Making Test (TMT), the Phonemic Verbal Fluency Test (VFT P), the Stroop Color and Word Test (SCWT), and the Go/No Go task (GNG).Results: Deficit schizophrenia patients scored lower on the WCST and TMT (relative flexibility) than did the NDS patients. There were no inter-group differences in the VFT P, SCWT (relative inhibition), or GNG. There were significant correlations between WCST and TMT scores in both groups. The general neuropsychological profiles were similar in both groups.Conclusion: Deficit schizophrenia patients exhibited slightly greater interference with concept formation and non-verbal cognitive flexibility. Therefore, such problems may be specific to this particular type of schizophrenia. These results may be useful for the development of neuropsychological diagnostic methods for patients with schizophrenia.

Cross-Disorder Cognitive Impairments in Youth Referred for Neuropsychiatric Evaluation.

Studies suggest that impairments in some of the same domains of cognition occur in different neuropsychiatric conditions, including those known to share genetic liability. Yet, direct, multi-disorder cognitive comparisons are limited, and it remains unclear whether overlapping deficits are due to comorbidity. We aimed to extend the literature by examining cognition across different neuropsychiatric conditions and addressing comorbidity. Subjects were 486 youth consecutively referred for neuropsychiatric evaluation and enrolled in the Longitudinal Study of Genetic Influences on Cognition. First, we assessed general ability, reaction time variability (RTV), and aspects of executive functions (EFs) in youth with non-comorbid forms of attention-deficit/hyperactivity disorder (ADHD), mood disorders and autism spectrum disorder (ASD), as well as in youth with psychosis. Second, we determined the impact of comorbid ADHD on cognition in youth with ASD and mood disorders. For EFs (working memory, inhibition, and shifting/ flexibility), we observed weaknesses in all diagnostic groups when participants' own ability was the referent. Decrements were subtle in relation to published normative data. For RTV, weaknesses emerged in youth with ADHD and mood disorders, but trend-level results could not rule out decrements in other conditions. Comorbidity with ADHD did not impact the pattern of weaknesses for youth with ASD or mood disorders but increased the magnitude of the decrement in those with mood disorders. Youth with ADHD, mood disorders, ASD, and psychosis show EF weaknesses that are not due to comorbidity. Whether such cognitive difficulties reflect genetic liability shared among these conditions requires further study. (JINS, 2018, 24, 91-103).

Cognitive impact in children with “benign” childhood focal epilepsy with centrotemporal spikes

Background Cognitive alterations are associated with benign childhood focal epilepsy with centrotemporal spikes (BCECTS) including aspects of executive functions. Objectives This study presents the performance profile on attention and executive function tests of fifty-eight children (BCECTS, n = 30 and controls, n = 28) aged 8-13 years. Methods The following tools were employed: Vocabulary and Block Design subtests from the Wechsler Intelligence Scale for Children III, Stroop Test, Modified Card Sorting Test, Controlled Oral Word Association – FAS and Tower of London. Results Children with BCECTS presented average IQ measure, although their performance was statistically worse when compared to the control group. Children with BCECTS showed significantly lower performance compared to the control group in the following variables: total number of recollected words on the oral fluency test, total number of categories, categorization effect and total number of errors in MCST; and execution time for the Stroop Test Card 1. After controlling for the IQ effect, the total number of errors in the MCST did not show any significant difference between the groups. Discussion Children with BCECTS showed lower performance in attention and executive functions when compared to healthy children. The results suggest that the concept of “benign” BCECTS should be reconsidered.

Neurocognitive outcomes in children with unilateral basal ganglia arterial ischemic stroke and secondary hemidystonia

ABSTRACTDystonia is a movement disorder that involves excessive, involuntary muscle contractions resulting in repetitive movements and/or abnormal posturing. One common cause of unilateral dystonia in childhood is ischemic stroke involving the basal ganglia and/or thalamus. Virtually nothing is known about neuropsychological outcomes in children who have dystonia following basal ganglia stroke. The present study explored whether or not children with secondary dystonia experience additional cognitive challenges when compared to children with similar patterns of brain injury, but no dystonia. We examined intellectual function, academics, and several aspects of executive function in children with unilateral basal ganglia stroke during childhood, comparing those with dystonia and those without. Although groups did not differ in terms of lesion size, we found significantly lower performance on measures of verbal and nonverbal reasoning, inhibitory control, and academic ability in children with secondary dystonia compared to those without. In contrast, there were no significant group differences on parent ratings of their child’s executive function in daily life. These findings suggest that maladaptive reorganization following basal ganglia stroke may contribute to the development of secondary dystonia and also to poor intellectual and academic outcomes in this group.

HIV-associated executive dysfunction in the era of modern antiretroviral therapy: A systematic review and meta-analysis

ABSTRACTObjective: While some reports suggest that HIV+ individuals continue to display executive function (EF) impairment in the era of cART, findings have been contradictory and appear to differ based on the aspect of EF being measured. To improve the understanding of how discrete executive abilities may be differentially affected or spared in the context of HIV infection, we conducted a systematic review and meta-analysis to (a) determine whether and to what extent HIV+ adults experience deficits in EFs, and (b) understand how demographic and clinical characteristics may modify the associations between HIV infection and executive abilities.Method: Studies comparing HIV+ and HIV-uninfected groups on measures of working memory, set-shifting, inhibition, decision-making, and apathy between 2000 and 2017 were identified from three databases. Effect sizes (Cohen’s d) were calculated using inverse variance weighted random effects models. Meta-regression was used to examine the moderating effect of demographic and clinical variables.Results: Thirty-seven studies (n = 3935 HIV+; n = 2483 HIV-uninfected) were included in the meta-analysis. Pooled effect sizes for deficits associated with HIV infection were small for domains of set-shifting (d = −0.34, 95% CI [−0.47, −0.20]) and inhibition (d = −0.31, 95% CI [−0.40, −0.21]), somewhat larger for measures of decision-making (d = −0.41, 95% CI [−0.53, −0.28]) and working memory (d = −0.42, 95% CI [−0.59, −0.29]), and largest for apathy (d = −0.87, 95% CI [−1.09, −0.66]). Meta-regression demonstrated that age, sex, education, current CD4 count, and substance dependence differentially moderated the effects of HIV infection on specific EFs. However, lower nadir CD4 count was the only variable associated with greater deficits in nearly all EF domains.Conclusions: Our results suggest that discrete domains of EF may be differentially affected by HIV infection and moderating demographic and clinical variables. These findings have implications for the development of targeted cognitive remediation strategies.

Schizotypy-Independent and Schizotypy-Modulated Cognitive Impairments in Unaffected First-Degree Relatives of Schizophrenia-spectrum Patients.

The aim of the study was to compare the neurocognitive profile of unaffected first-degree relatives of schizophrenia patients with control individuals, controlling for different schizotypal traits. One hundred and fifteen adult unaffected first-degree relatives of schizophrenia-spectrum patients and 122 controls were tested for schizotypy with the Schizotypal Personality Questionnaire. They also underwent a thorough neurocognitive assessment with a range of tasks covering several aspects of executive functioning. Between-group differences in cognition were examined first with multivariate analysis of variance and then with a series of multivariate analyses of covariance, including the schizotypal dimensions as covariates. The relatives had higher scores on all schizotypal dimensions compared with controls and poorer planning, problem solving, strategy formation and working memory, irrespective of schizotypal traits. They also scored lower in executive working memory and verbal fluency. The difference in executive working memory was sensitive to the effects of paranoid and negative schizotypy (both dimensions abolished the between-group difference) whereas the difference in verbal fluency was sensitive only to the effects of paranoid schizotypy. Neither cognitive-perceptual nor disorganized schizotypy accounted for any differences in neurocognition between relatives and the controls. Impairments in planning, problem solving, strategy formation and working memory are "core" impairments in the schizophrenia-spectrum, possibly due to high heritability effects in these functions. Impairments in executive working memory and verbal fluency are associated with paranoid and negative schizotypy, possibly due to alterations in a common fronto-temporo-parietal neural network.

Does real time variability in inhibitory control drive snacking behavior? An intensive longitudinal study.

Laboratory eating studies and cross-sectional surveys indicate individuals with inefficient executive function (EF) consume more unhealthy snacks than others. However, the importance of EF in determining snacking behavior in the "real world" has not been established. Contemporary behavioral and self-control theories posit EF as a dynamic resource fluctuating over time. Consequently, a test of the relevance of EF to behavior within individuals is required. This study tested within- and between-person effects of real-time variability in objectively measured inhibitory control (a core facet of EF) on subsequent snacking behavior in daily life. A community sample of 64 adults recorded snacking behavior and completed a short Go/No-Go test (assessing inhibitory control) hourly over 7 consecutive days, yielding a total well-powered sample of 6,284 data-points. Generalized linear mixed models using lagged effects examined within-person and between-person effects of inhibitory control efficiency on snacking behavior. When Go/No-Go test responses were 100 ms slower than the person-mean (indicating periods of poorer inhibitory control), snack consumption in the following hour was 25.67% higher, Exp (γ) = 1.26, p = .002, 95% confidence interval (CI) [1.06, 1.49]. Between-individuals, person-mean reaction time (RT) did not predict snack consumption, Exp (γ) = 1.02, p = .965, 95% CI [0.71, 1.46]. RT variability in inhibitory control efficiency is highly relevant to snacking behavior within individuals. Inhibitory control is an important driver of snacking in everyday life and an important target for interventions. (PsycINFO Database Record

Systematic behavioural observation of executive performance after brain injury

ABSTRACTObjective: To develop an ecologically valid measure of executive functioning (i.e. Planning and Organization, Executive Memory, Initiation, Cognitive Shifting, Impulsivity, Sustained and Directed Attention, Error Detection, Error Correction and Time Management) during a functional chocolate brownie cooking task.Methods: In Study 1, the inter-rater reliability of a novel behavioural observation assessment method was assessed with 10 people with traumatic brain injury (TBI). In Study 2, 27 people with TBI and 16 healthy controls completed the functional task along with other measures of executive functioning to assess validity.Results: Intraclass correlation coefficients for six of the nine aspects of executive functioning ranged from .54 to 1.00. Percentage agreements for the remaining aspects ranged from 70% to 90%. Significant and non-significant, moderate, correlations were found between the functional cooking task and standard neuropsychological measures. The healthy control group performed better than the TBI group in six areas (d = 0.56 to 1.23).Conclusions: In this initial trial of a novel assessment method, adequate inter-rater reliability was found. The measure was associated with standard neuropsychological measures, and our healthy control group performed better than the TBI group. The measure appears to be an ecologically valid measure of executive functioning.

Abstract P015: A Novel Healthy Blood Pressure Phenotype is Associated With Better Cardiovascular Health Benefits and Neuropsychological Performance in the Long Life Family Study

Introduction: We assessed the hypothesis that a novel healthy blood pressure phenotype is familial and sought to identify factors associated with this phenotype in the Long Life Family Study (LLFS). Methods: The LLFS is a unique multi-center, international study that recruited families demonstrating clustering for longevity. Families were recruited from four centers; three in the U.S.: Boston, New York, and Pittsburgh and one in Denmark. The pedigrees included two generations: 1) probands and their siblings and 2) offspring of participants in the proband generation. Offspring (n=2211, ages 32-88, mean age=60.5; 43% male) were classified as having healthy blood pressure if their age- and sex-adjusted systolic blood pressure z-score was between -1.5 and -0.5 (i.e., a systolic blood pressure lower than expected for their age and sex, but not “too low”). Offspring on anti-hypertensive medications were classified as not having healthy blood pressure. Families (n=419) were defined as having healthy blood pressure if ≥2 and ≥50% of their offspring met the healthy blood pressure phenotype. Results: There were 476 (22%) offspring who met the healthy blood pressure phenotype. These offspring tended to have a better health profile than remaining offspring. When examining families, only 44 (11%) families met the criteria for healthy blood pressure. Both offspring and probands from families with healthy blood pressure performed better on neuropsychological tests that place demands on complex attention and executive function than offspring and probands from remaining families. Among families with healthy blood pressure, a higher proportion of offspring met the American Heart Association ideal cardiovascular health definition compared to remaining families (11% versus 4%, respectively, p<0.0001; not including the diet component). There was also a larger proportion of probands (n=1164, ages 71-110, mean age=90.5; 45% male) who met the American Heart Association ideal cardiovascular health definition when compared to the U.S. prevalence for ≥6 components among those ages ≥60 (1% versus 0.1%, respectively). Conclusion: In this cohort of familial longevity, few families had a novel healthy blood pressure phenotype in multiple members. Families and individuals with healthy blood pressure performed better on neuropsychological tests that represent aspects of executive function and had a higher proportion with ideal cardiovascular health than the U.S. population. In summary, a novel healthy blood pressure phenotype was rarely familial in this cohort; however, when it was, it was associated with cognitive and cardiovascular health benefits. Blood pressure may be a key pathway for family longevity.

Development of a scale of executive functioning for the RBANS

ABSTRACTThe Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) is a cognitive battery that contains scales of several cognitive abilities, but no scale in the instrument is exclusively dedicated to executive functioning. Although the subtests allow for observation of executive-type errors, each error is of fairly low base rate, and healthy and clinical normative data are lacking on the frequency of these types of errors, making their significance difficult to interpret in isolation. The aim of this project was to create an RBANS executive errors scale (RBANS EE) with items comprised of qualitatively dysexecutive errors committed throughout the test. Participants included Veterans referred for outpatient neuropsychological testing. Items were initially selected based on theoretical literature and were retained based on item-total correlations. The RBANS EE (a percentage calculated by dividing the number of dysexecutive errors by the total number of responses) was moderately related to each of seven established measures of executive functioning and was strongly predictive of dichotomous classification of executive impairment. Thus, the scale had solid concurrent validity, justifying its use as a supplementary scale. The RBANS EE requires no additional administration time and can provide a quantified measure of otherwise unmeasured aspects of executive functioning.

P102 Multiple-electrode tDCS montage modulates shifting and risk taking behaviors

Introduction Risk taking and set-shifting are two domain aspects of executive functions which play a fundamental part in our everyday life. Although the involvement of the pre-frontal cortex in executive functions is well established, there is a debate regarding the lateralization of the prefrontal cognitive control network (Goel and Vartanian, 2005; Witt and Stevens, 2013). Different stimulation studies demonstrated inconsistent results regarding to which montage resulted in enhanced set- shifting and decreased risk taking behaviors (Fecteau et al., 2007; Leite et al., 2013). The inconsistencies might partially result from bilateral involvement of the dorsal lateral prefrontal cortex (DLPFC), because previous stimulation studies could activate by anodal stimulation only the left or right DLPFC, but not both. Objectives Here we aimed to explore this debate by applying a novel three-electrodes transcranial direct current stimulation (tDCS) montage over the left and right dorsal lateral prefrontal cortex (DLPFC) to modulate cognitive control tasks. Materials & method In a between subjects design, 34 healthy participants were randomly assigned to either active tDCS or sham group. After the stimulation, the participants performed cognitive control tasks (Wisconsin Card Sorting Test (WCST) and the Balloon Analogue Risk Task (BART). Results A one-way MANCOVA revealed a significant multivariate main effect for stimulation group F(2, 27) = 4.53, p Download : Download high-res image (287KB) Download : Download full-size image Conclusions We demonstrated enhancement of both shifting and risk taking via reduction of the observed reaction time. The current study points out to new possibilities for tDCS montage, which enable anodal stimulation of two different brain regions simultaneously and thus contributes to a better understanding of the neural networks and hemispheric connectivity.

Executive Function Variation in Children With Conduct Problems: Influences of Coexisting Reading Difficulties

It is unknown whether children with conduct problems (CP) and poor reading (PR) skills exhibit more profound executive function impairments than children with CP only and whether such impairments are explained by coexisting PR. Executive functions were compared in four groups of 7- to 8-year-old children: 26 CP only, 35 PR only, 27 CP-PR, and 31 comparison (COM) children with neither CP nor PR. The Conners’ Teacher Rating Scale–28 and a sentence completion reading test were used to assess CP and PR skills. The Wechsler Intelligence Scale for Children–Third Edition Backward Digit Span, the Conners’ Continuous Performance Test, and the Tower of London were used to assess three aspects of executive function: verbal working memory, response inhibition, and planning, respectively. The CP-PR group had lower verbal working memory than the CP-only and COM groups, but the difference was not significant after intellectual ability, inattention, and hyperactivity were controlled. The CP-PR group made more errors in the planning task (rule violations) than the COM and CP-only groups, but the difference was not significant after intellectual ability was controlled. No significant group differences were found in response inhibition. A specific PR group effect was found for verbal working memory. Children with CP-PR have more prominent executive function impairments that cannot be attributed to coexisting PR.

Exhaustive Exercise Alters Thinking Times in a Tower of London Task in a Time-Dependent Manner.

Purpose: In contrast to other aspects of executive functions, acute exercise-induced alterations in planning are poorly investigated. While only few studies report improved planning performances after exercise, even less is known about their time course after exhaustive exercise.Methods: One hundred and nineteen healthy adults performed the Tower of London (ToL) task at baseline, followed by a graded exercise test (GXT). Participants were subsequently randomized into one of four groups (immediately, 30, 60, and 90 min after the GXT) to repeat the ToL. Main outcomes of the ToL were planning (number of tasks completed in the minimum number of moves), solutions (correct responses independent of the given number of moves) as well as thinking times (time between presentation of each problem and first action) for tasks with varying difficulty (four-, five,- and six-move problems). Blood lactate levels were analyzed as a potential mediator.Results: No effect of exercise on planning could be detected. In contrast to complex problem conditions, median thinking times deteriorated significantly in the immediately after GXT tested group in less challenging problem conditions (four-move problems: p = 0.001, F = 5.933, df = 3; five-move problems: p = 0.005, F = 4.548, df = 3). Decreased lactate elimination rates were associated with impaired median thinking times across all groups ΔMTT4-6 (p = 0.001, r = −0.309), ΔMTT4 (p < 0.001, r = −0.367), and ΔMTT5 (p = 0.001, r = −0.290).Conclusion: These results suggest that planning does not improve within 90 min after exhaustive exercise. In line with previous research, revealing a negative impact of exhaustive exercise on memory and attention, our study extends this knowledge of exercise-induced alterations in cognitive functioning as thinking times as subcomponents of planning are negatively affected immediately after exercise. This is further associated with peripheral lactate levels.