Coordination of executive functions in monolingual and bilingual children

Two groups of 8-year-old children who were monolingual or bilingual completed a complex classification task in which they made semantic judgments on stimuli that were presented either visually or auditorily. The task requires coordinating a variety of executive control components, specifically working memory, inhibition, and shifting. When each of the visual and auditory tasks was presented alone, performance was comparable for children in the two groups. Combining the two modalities into a dual-task paradigm made the task more difficult, and on this combined task bilingual children maintained better accuracy than monolingual children, especially on the visual task. The results are interpreted in terms of the enhanced ability of bilingual children to coordinate the executive control components required in performing this complex task.     

Training and transfer effects of executive functions in preschool children

Executive functions, including working memory and inhibition, are of central importance to much of human behavior. Interventions intended to improve executive functions might therefore serve an important purpose. Previous studies show that working memory can be improved by training, but it is unknown if this also holds for inhibition, and whether it is possible to train executive functions in preschoolers. In the present study, preschool children received computerized training of either visuo‐spatial working memory or inhibition for 5 weeks. An active control group played commercially available computer games, and a passive control group took part in only pre‐ and posttesting. Children trained on working memory improved significantly on trained tasks; they showed training effects on non‐trained tests of spatial and verbal working memory, as well as transfer effects to attention. Children trained on inhibition showed a significant improvement over time on two out of three trained task paradigms, but no significant improvements relative to the control groups on tasks measuring working memory or attention. In neither of the two interventions were there effects on non‐trained inhibitory tasks. The results suggest that working memory training can have significant effects also among preschool children. The finding that inhibition could not be improved by either one of the two training programs might be due to the particular training program used in the present study or possibly indicate that executive functions differ in how easily they can be improved by training, which in turn might relate to differences in their underlying psychological and neural processes.     

Examining the development of attention and executive functions in children with a novel paradigm.

The development of attention and executive functions in normal children (7-12 years) was investigated using a novel selective reaching task, which involved reaching as rapidly as possible towards a target, while at times having to ignore a distractor. The information processing paradigm allowed the measurement of various distinct dimensions of behaviour within a single task. The largest improvements in vigilance, set-shifting, response inhibition, selective attention, and impulsive responding were observed to occur between the ages of 8 and 10, with a plateau in performance between 10 and 12 years of age. These findings, consistent with a step-wise model of development, coincide with the observed developmental spurt in frontal brain functions between 7 and 10 years of age, and indicate that attention and executive functions develop in parallel. This task appears to be a useful research tool in the assessment of attention and executive functions, within a single task. Thus it may have a role in determining which cognitive functions are most affected in different childhood disorders.     

Multivariate base rates for the assessment of executive functioning among children and adolescents

This study provides observed base rates of low executive functioning test scores among healthy children and adolescents, stratifies those base rates by narrow intellectual functioning and age groupings, and provides normative classification ranges to aid the interpretation of performances on the Delis-Kaplan Executive Function System (D-KEFS) in clinical practice and research. Participants included 875 children and adolescents between 8 and 19 years old from the D-KEFS normative sample (48% male; 52% female). Among these participants, 838 had complete data and were included in the current study. The racial/ethnic composition of the sample was: White (73.7%), African American (12.4%), Hispanic (11.1%), and other racial/ethnic backgrounds (2.7%). The Overall Test Battery Mean (OTBM) and the prevalence of low scores at various clinical cut-offs were calculated for the 13 primary scores from the D-KEFS Trail Making Test, Verbal Fluency Test, and Color-Word Interference Test. The OTBM and base rates were also calculated separately for those scores reflecting executive functioning (n = 7) and processing speed (n = 6). Healthy children and adolescents commonly obtained low scores on the D-KEFS tests considered here. Younger age, lower estimated full-scale intelligence quotient, and more test scores interpreted were associated with a greater frequency of low scores. Clinicians and researchers are encouraged to consider these multivariate base rates when assessing and attempting to identify executive functioning impairment among children and adolescents with the D-KEFS.     

Evaluation of executive functions in children and adolescents with familial Mediterranean fever

The aim of the present study was to investigate neuropsychological test performance in children and adolescents with familial Mediterranean fever (FMF). A total of 88 children and adolescents aged 8 to 17 years were included, 52 with FMF and 36 healthy controls. After the participants were administered the Children Depression Inventory (CDI) and the Screen for Child Anxiety Related Emotional Disorders (SCARED), they completed the battery tests of the Central Nervous System Vital Signs (CNSVS), a neurocognitive test battery, via computer. The battery calculates seven domain scores (Memory, Psychomotor Speed, Processing Speed, Reaction Time, Complex Attention, Executive Function, and Cognitive Flexibility) and a summary score (Neurocognition Index [NCI]). A statistically significant difference between the FMF and control groups was found in six out of seven domains, where the scores of the participants with FMF were found to be significantly lower than those of the control participants (p < .05). Although the mean Reaction Time score of the participants with FMF was found to be lower than that of the control participants, the finding was not statistically significant (p > .05). The mean CDI and SCARED scores of the participants with FMF were found to be significantly higher than those of the control participants (p < .05). Low scores in the Processing Speed and Psychomotor Speed domains of the CNSVS were significantly correlated with higher SCARED scores (r = ?.37, p = .01). Impaired cognitive functions should be taken into consideration in children and adolescents with FMF when assessing and managing this population.     

Self-regulation and inhibition in comorbid ADHD children: an evaluation of executive functions

The relationship between executive function and comorbid diagnoses in ADHD children is examined. One hundred six children between 7 and 15 years of age are assessed using the Tower of London (TOL), a test of executive function, and the Kiddie Schedule of Affective Disorders and Schizophrenia, Present and Lifetime Version, a diagnostic interview. All children met the diagnostic criteria for ADHD. A majority of the children had comorbid anxiety disorders, mood disorders, or oppositional defiant disorder. Measures on the TOL are total move score, total initiation time, and total rule violations. Age is predictive in all three measures of executive function as assessed by the TOL. Gender is predictive of total initiation time and total rule violations. Comorbid disorders are found to not have significance on executive function as measured by the TOL. This study concludes that comorbid disorders may not affect executive function.     

The development of analogy making in children: Cognitive load and executive functions

The aim of the current study was to investigate the performance of 6-, 8-, and 14-year-olds on an analogy-making task involving analogies in which there are competing perceptual and relational matches. We hypothesized that the selection of the common relational structure requires the inhibition of other salient features, in particular, perceptual matches. Using an A:B::C:D paradigm, we showed that children’s performance in analogy-making tasks depends crucially on the nature of the distractors. Children chose more perceptual distractors having a common feature with C compared with A or B (Experiment 1). In addition, they were also influenced by unstructured random textures. When measuring reaction times instead of accurate responses, only the 8-year-olds’ reaction times were significantly influenced by perceptual distractors. The 6-year-olds seemed to select the first match they noticed, and the 14-year-olds were not influenced (or much less influenced) by featural distractors. These results are compatible with an analogy-making account based on varying limitations in executive functioning at different ages.     

Attention problems and executive functions in children with spina bifida and hydrocephalus.

This study addressed the incidence of Attention-Deficit/Hyperactivity Disorder (ADHD) subtypes in children with spina bifida meningomyelocele and shunted hydrocephalus (SBH) as well as differences in executive functions among these subtypes. Parent rating scales revealed that 31% of the group with SBH could be identified with AD/HD, mostly the Inattentive type (23%). The group with SBH differed from normal controls on cognitive measures of executive functions, but subtype differences were not significant. Multivariate tests showed that children with SBH were rated with greater difficulties on the Behavior Rating Inventory of Executive Function (BRIEF) compared to controls; those with SBH and any subtype of ADHD differed from those with SBH and no ADHD; and those with ADHD (Combined Type) differed significantly from those with ADHD (Predominantly Inattentive Type). Subtype differences on univariate tests in the latter comparison were significant on the BRIEF Inhibit scale, showing more disinhibition in those with SBH and ADHD (Combined Type), but no significant differences were apparent on the BRIEF Sustain, Shift, and Initiate scales. The results show that the incidence of ADHD in children with SBH exceeds the population rate, is represented by problems with inattention rather than with impulsivity and hyperactivity; and that as with non-brain injured individuals, subtype differences in cognitive function remain to more clearly delineated.     

Clinical and statistical approaches to the assessment of brain damage in children

In an attempt at innovation in the clinical versus statistical prediction controversy, the present research examined three methods of assessing organic brain damage in a sample of sixty-eight 9- to 14-year-old children. Methods compared were clinical judgment (CP); existing actuarial norms (EAN); and derived statistical prediction (DSP), based on three psychological tests. The results were as follows: (a) None of the methods classified subjects significantly better than chance (p<.05); (b) there was no significant difference (p<.05) among the methods in terms of their rates of accurate classification; (c) CP based on combined tests did not result in higher predictive accuracy than those based on an individual test; (d) CP made after receiving feedback on accuracy showed an increase in number of correct classifications over prior CP; and (e) CP based on knowledge of the statistical prediction in addition to test data showed a higher rate of correct classification than DSP alone.     

Relationships between cognitive and behavioral measures of executive function in children with brain disease.

This study addressed the clinical and construct validity of the Behavior Rating Inventory of Executive Function. (BRIEF: Gioia, Isquith, Guy, & Kenworthy, 2000), a questionnaire designed to tap behavioral aspects of executive functions in children. BRIEF profiles in early treated phenylketonuria (PKU; n=44), early treated hydrocephalus (n=45), frontal focal lesions (n=20) and controls (n=80) were examined. Clinical validity was supported through significant between-group comparisons, especially between the frontal focal lesion group and other groups. To examine construct validity, raw scores on cognitive executive function measures including the Contingency Naming Test (CNT), Rey Complex Figure (RCF), Tower of London (TOL), and Controlled Oral Word Association Test (COWAT), were correlated with BRIEF scale scores. Few significant correlations were found, indicating cognitive and behavioral measures appear to tap different constructs within the executive function domain. A dissociation was found between behavioral and cognitive impairments in the frontal as opposed to PKU and hydrocephalus groups. This is discussed in relation to underlying pathology, the cognitive measures used, and possible limitations in the BRIEF's usefulness for measuring behavioral executive dysfunction in groups only mildly affected by neurological compromise.     

Developmental trajectories in toddlers' self-restraint predict individual differences in executive functions 14 years later: a behavioral genetic analysis

We examined whether self-restraint in early childhood predicted individual differences in 3 executive functions (EFs; inhibiting prepotent responses, updating working memory, and shifting task sets) in late adolescence in a sample of approximately 950 twins. At ages 14, 20, 24, and 36 months, the children were shown an attractive toy and told not to touch it for 30 s. Latency to touch the toy increased with age, and latent class growth modeling distinguished 2 groups of children that differed in their latencies to touch the toy at all 4 time points. Using confirmatory factor analysis, we decomposed the 3 EFs (measured with latent variables at age 17 years) into a Common EF factor (isomorphic to response inhibition ability) and 2 factors specific to updating and shifting. Less-restrained children had significantly lower scores on the Common EF factor, equivalent scores on the Updating-Specific factor, and higher scores on the Shifting-Specific factor than did the more-restrained children. The less-restrained group also had lower IQ scores, but this effect was entirely mediated by the EF components. Twin models indicated that the associations were primarily genetic in origin for the Common EF variable but split between genetics and nonshared environment for the Shifting-Specific variable. These results suggest a biological relation between individual differences in self-restraint and EFs, one that begins early in life and persists into late adolescence.     

Divergent thinking and the core executive functions: a state-of-the-art review

Cognitive Processing - The study of the relationships between divergent thinking and the core executive functions is long standing. However, the literature on this topic is not conclusive. The...     

On the evolutionary origins of executive functions

In this paper it is proposed that the prefrontal lobe participates in two closely related but different executive function abilities: (1) "metacognitive executive functions": problem solving, planning, concept formation, strategy development and implementation, controlling attention, working memory, and the like; that is, executive functions as they are usually understood in contemporary neuroscience; and (2) "emotional/motivational executive functions": coordinating cognition and emotion/motivation (that is, fulfilling biological needs according to some existing conditions). The first one depends on the dorsolateral prefrontal areas, whereas the second one is associated with orbitofrontal and medial frontal areas. Current tests of executive functions basically tap the first ability (metacognitive). Solving everyday problems (functional application of executive functions), however, mostly requires the second ability (emotional/motivational); therefore, these tests have limited ecological validity. Contrary to the traditional points of view, recent evidence suggests that the human prefrontal lobe is similar to other primates and hominids. Other primates and hominids may possess the second (emotional executive functions) prefrontal ability, -but not the first (metacognitive executive functions) one. It is argued that metacognitive executive functions are significantly dependent on culture and cultural instruments. They probably are the result of the development and evolution of some "conceptualization instruments"; language (and written language as an extension of oral language) may represent the most important one. The second executive function ability (emotional/motivational) probably is the result of a biological evolution shared by other primates.     

A model for the behavioral assessment of behavior disorders in children: Measurement considerations and practical application

School psychologists have traditionally experienced difficulty in assessing children referred to them for behavior disorders. Given this reported difficulty, a behavioral assessment model is proposed which specifies three types of assessment information: direct observations, rating scale data, and interview data. Characteristics of these three types of assessment information are discussed, along with recommendations for their use. Two psychological models are suggested to guide school psychologists through the assessment process. Bergan's behavioral consultation model is recommended for securing valid and reliable interview and observational data, and Campbell and Fiske's multitrait-multimethod model is proposed as a means of logically integrating behavioral assessment information. The notion of convergence or agreement between dissimilar assessment methods is discussed.     

The Wisconsin Card Sorting Test and the cognitive assessment of prefrontal executive functions: A critical update

For over four decades the Wisconsin Card Sorting Test (WCST) has been one of the most distinctive tests of prefrontal function. Clinical research and recent brain imaging have brought into question the validity and specificity of this test as a marker of frontal dysfunction. Clinical studies with neurological patients have confirmed that, in its traditional form, the WCST fails to discriminate between frontal and non-frontal lesions. In addition, functional brain imaging studies show rapid and widespread activation across frontal and non-frontal brain regions during WCST performance. These studies suggest that the concept of an anatomically pure test of prefrontal function is not only empirically unattainable, but also theoretically inaccurate. The aim of the present review is to examine the causes of these criticisms and to resolve them by incorporating new methodological and conceptual advances in order to improve the construct validity of WCST scores and their relationship to prefrontal executive functions. We conclude that these objectives can be achieved by drawing on theory-guided experimental design, and on precise spatial and temporal sampling of brain activity, and then exemplify this using an integrative model of prefrontal function [i.e., Miller, E. K. (2000). The prefrontal cortex and cognitive control. Nature Reviews Neuroscience, 1, 59–65.] combined with the formal information theoretical approach to cognitive control [Koechlin, E., & Summerfield, C. (2007). An information theoretical approach to prefrontal executive function. Trends in Cognitive Sciences, 11, 229–235.].     

Working memory as a predictor of written arithmetical skills in children: The importance of central executive functions

Background . The study was conducted in an attempt to further our understanding of how working memory contributes to written arithmetical skills in children. Aim . The aim was to pinpoint the contribution of different central executive functions and to examine the contribution of the two subcomponents of children's written arithmetical skills. Sample and method . A total of 141 third‐ and fourth‐graders were administered arithmetical tasks and measures of working memory, fluid IQ and reading. Regression analysis was used to examine the relationship between working memory and written arithmetical skills. Results . Three central executive measures (counting span, trail making and verbal fluency) and one phonological loop measure (Digit Span) were significant and predictors of arithmetical performance when the influence of reading, age and IQ was controlled for in the analysis. Conclusions . The present findings demonstrate that working memory, in general, and the central executive, in particular, contribute to children's arithmetical skills. It was hypothesized that monitoring and coordinating multiple processes, and accessing arithmetical knowledge from long‐term memory, are important central executive functions during arithmetical performance. The contribution of the phonological loop and the central executive (concurrent processing and storage of numerical information) indicates that children aged 9–10 years primarily utilize verbal coding strategies during written arithmetical performance.     

Coding processes and executive functions in multiple sclerosis

Although episodic memory deficit in patients with multiple sclerosis (ME) is a well established fact, there is no agreement about the origin of this disorder in terms of cognitive processes. Whereas most of the studies attribute this deficit to defects in memory recovery processes, others contribute evidence in favor of the hypothesis that considers that it originates in difficulties in coding memory processes.However, the analysis of the relationship between coding processes and memory functioning in ME is a scantly studied topic. In the present article, we studied coding processes and their relationships with executive control processes in a group of patients with ME. We used a set of indexes of the Test of Verbal Learning from the TAVEC test for the evaluation of the coding processes. To assess the executive processes we used a semantic verbal fluency task, the WCST, and WAIS III scale of matrixes. We worked with 36 patients with ME diagnosis and 36 healthy control participants, paired by age and educational level. The results showed a deficit in the coding processes and the existence of a significant association between these processes and executive functioning.     

Assessment of executive functions in a Brazilian sample of bipolar subjects

Research has demonstrated impairments in executive functions in Bipolar Mood Disorder patients. Evidence shows that this impairment is present in both periods of active symptoms of the disorder, as well as euthymic stages, and is compounded by mood episodes, especially manic phases. The purpose of this study was to compare the executive performance of a sample of Brazilian bipolar patients in depressive episodes, (44 participants), euthymia (37 participants), and in controls (43 participants). The main instrument for evaluation was the Wisconsin Card Sorting Test. Significant differences were found in performance on the Wisconsin Card Sorting Test between Bipolar subjects (Type I) (both in depression and euthymia) and the controls. No significant correlations were found between the number of manic episodes and the performance on execute measurement variables. The findings suggest that the executive dysfunctions in Bipolar Disorder may be related to both transitory and permanent deficits.