Gunilla Bohlin

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.

Executive Functions in Children Aged 6 to 13: A Dimensional and Developmental Study

A cross-sectional study using 92 children aged 6 to 13 years investigated the dimensionality and the development of executive functioning. The measures were drawn from developmentally relevant conceptualizations of executive functioning and included a go/no-go task, a verbal fluency task, a continuous performance task, a Stroop-like task, a hand movements task, and a digit span task. Analyses revealed 3 dimensions interpreted as Disinhibition, Speed/arousal, and Working memory/Fluency. Age and sex differences were analyzed for the delineated functions, which means that the results may be taken to represent age effects at the level of specific processes within the executive domain rather than on single tests. Age-dependent changes in childrens performance on all 3 dimensions were demonstrated, with 3 particularly active stages of maturation: early childhood (6-8 years of age), middle childhood (9-12 years of age), and during early adolescence. Sex differences were only found for the speed/arousal dimension. The results are discussed in terms of 2 developmental executive function frameworks (Barkley, 1997b; Roberts & Pennington, 1996), where inhibition and the interaction between inhibition and working memory, respectively, are seen as key in the development of executive functioning.

Emotionality, emotion regulation, and adaptation among 5- to 8-year-old children.

This study investigated relations between emotionality, emotion regulation, and childrens behavioral adaptation in a longitudinal design. Mothers rated emotionality and emotion regulation related to anger, fear, and positive emotions-exuberance for 151 children at age 5 and later at age 6 years 6 months. Emotionality and emotion regulation measures were modestly related. Preschool ratings at age 6 (n = 125), maternal ratings at age 6 years 6 months (n = 133), and elementary school ratings at age 8 (n = 135) of problems and competence were also collected. High anger emotionality and low regulation of positive emotions and exuberance predicted externalizing problem behavior and prosocial behavior. High fear emotionality and low fear regulation predicted internalizing problem behavior. There were few interactive effects of emotionality and regulation.

Attachment and social functioning: A longitudinal study from infancy to middle childhood

A longitudinal sample of 96 children was followed from 15 months of age to 8-9 years. Attachment relationships were studied in infancy with the Strange Situation and at school age with the separation anxiety Test. Social functioning was studied at school

Response inhibition, hyperactivity, and conduct problems among preschool children

Investigated the relation among response inhibition, hyperactivity, and conduct problems in a nonclinical sample of 115 preschool children, using 2 different types of go/no-go tasks as well as a Stroop-like task. In line with the assumption that hyperactivity is related to disinhibition, the results showed that it was the measures of response inhibition, and not other performance measures, that were related to teacher ratings of hyperactivity. There was also a significant relation between response inhibition and conduct problems. Interestingly, the correlation between response inhibition and conduct problems was not significant when partialling out the effect of hyperactivity, whereas the correlation between inhibition and hyperactivity did remain significant when controlling for conduct problems. Although the association between inhibition, hyperactivity, and conduct problems appeared to be partly different for boys and girls, these differences were not statistically significant.

Impact of executive functioning and symptoms of attention deficit hyperactivity disorder on children's peer relations and school performance.

This study examined the predictive relations from symptoms of Attention-deficit/hyperactivity disorder (ADHD) and executive functioning (EF) to social and school functioning in 112 (62 girls) school children. High levels of teacher and parent ratings of ADHD symptoms at the ages of 8–81/2 years, and poor EF measured at the age of 81/2, were associated with poor social functioning measured by peer nominations and poor teacher ratings of school functioning at the age of 91/2. ADHD symptoms independently predicted social and school functioning, whereas EF independently predicted only school functioning. Interaction effects between ADHD and EF and between EF and gender were found: At high levels of symptoms of inattention, the poorer the EF, the greater the need for special education. At high levels of symptoms of hyperactivity/impulsivity, the poorer the EF, the higher the levels of physical aggression. Girls with poor EF were less accepted by peers than equivalent boys.

Heterogeneity in ADHD: neuropsychological pathways, comorbidity and symptom domains.

The aim of the present study was to investigate different neuropsychological impairments and comorbid behavioral problems in relation to symptoms of Attention-Deficit/Hyperactivity Disorder (ADHD), studying the independent effects of different functions as well as specific relations to symptoms of hyperactivity/impulsivity and inattention. A community-based sample of school children (n = 182; the higher end of the ADHD symptom range was oversampled) completed neuropsychological tasks designed to measure executive function (EF), state regulation and delay aversion. Behavioral symptoms were measured through parental and teacher ratings of the DSM-IV criteria for ADHD and Oppositional Defiant Disorder (ODD). Both categorical and dimensional analyses were used to acquire a deeper understanding of ADHD. The results supported the notion that EF and state regulation constitute independent pathways to ADHD, primarily to symptoms of inattention. In addition, the present study points to the importance of viewing ADHD as a heterogeneous condition also with regard to the differential impact of neuropsychological functioning and comorbidity on different ADHD symptom groups and the two ADHD symptom domains.

Early feeding problems in a normal population

The prevalence of parentally experienced infant feeding problems was explored in two samples (N = 841 and N = 567) of infants, aged between 30 and 71 weeks. Correlates to specific problem types were sought. One-fourth of the parents had experienced feeding problems during the infants first 6 months and more than 10% reported ongoing problems. Colic was the most commonly reported early appearing problem, while refusal of solids, poor appetite, and general refusal to eat were the most common problems after the first 6 months. Maternal health factors, severe and longlasting breastfeeding problems, and problematic mealtime behaviors were associated with colic, while vomiting was only related to breastfeeding problems. The refusal-to-eat group presented the largest number of correlates including family feeding problems, problematic meal behaviors, and health problems. The only aspects distinguishing all problem groups from controls were parental anxiety about infant health and sibling feeding problems.

How well do measures of inhibition and other executive functions discriminate between children with ADHD and controls

The aim of the present study was to evaluate the usefulness of Barkley’s (1997a) model of inhibition and executive functioning in describing the deficits associated with Attention Deficit Hyperactivity Disorder (ADHD). Besides group differences, the present study addressed the question of independent effects of inhibition and the other executive functions in discriminating between children with ADHD and controls and how well, in terms of sensitivity and specificity, these measures can classify the children into the correct group. The results showed that children with ADHD differed significantly from controls with regard to measures of inhibition as well as all other executive function measures, except repetition of hand movements. In logistic regression models, three different measures tapping inhibition, working memory and emotion regulation were shown to be significant independent predictors of group membership. The sensitivity for these three variables as a set was 76.2, the specificity was 90.5, with a total of 86% of the sample correctly classified. When excluding the parental rating of emotion regulation, the overall classification rate decreased some, but was still relatively high in comparison with previous studies within this area of research.

Relations Between Inhibition, Executive Functioning, and ADHD Symptoms: A Longitudinal Study from Age 5 to 8½ Years

The present study examined whether inhibition measured as early as preschool can predict more general executive functioning and ADHD symptoms at school age. In contrast to previous studies, the present study focused specifically on ADHD symptoms rather than general disruptive behavior problems, and boys and girls were studied separately. The main result was that inhibition was strongly related to ADHD symptoms both in school and at home for boys, but only in the school context for girls. Early inhibition was also significantly related to later executive functioning, and concurrent relations were found between executive functioning and ADHD symptoms, although in both cases only for boys. Besides this, inhibition added significantly to the variance, beyond that of executive functioning, which meant that for boys, inhibition and the other executive functioning explained about half the variance in inattention problems. The stronger relation between inhibition, executive functioning and ADHD symptoms for boys compared to girls could suggests that either the predictors of ADHD are different for the two sexes, or girls are more often equipped with some factor that protects them from developing ADHD symptoms, despite poor executive functioning. However, it is also possible that relations are just harder to demonstrate for girls due to their lower incidence of disruptive problem behaviors.