Interference suppression vs. response inhibition: An explanation for the absence of a bilingual advantage in preschoolers’ Stroop task performance

The well-documented advantage that bilingual speakers demonstrate across the lifespan on measures of controlled attention is not observed in preschoolers’ performance on Stroop task variations. We examined the role of task demands in explaining this discrepancy. Whereas the Color/Word Stroop used with adult participants requires interference suppression, the Stroop task typically used with preschoolers requires only response inhibition. We developed an age-appropriate conflict task that measures interference suppression. Fifty-one preschool children (26 bilinguals) completed this new Bivalent Shape Task and the Day/Night task used in previous research. Bilingual in comparison to monolingual children performed better on incongruent trials of the Bivalent Shape Task, but did not differ on other measures. The results indicate that the discrepancy between preschoolers and older individuals in performance on Stroop task adaptations results from characteristics of the task rather than developmental differences. Further, the findings provide additional support for the importance of interference suppression as a mechanism underlying the bilingual advantage.     

A group comparison of those with hypertension and other chronic illness: A factor and item level analysis of anger and hostility

Abstract

A considerable body of research has suggested that essential hypertension is related to both expressed anger and suppressed hostility. This study suggests and provides some evidence that these reported results may simply have arisen as the result of a lack of proper statistical control and differential item functioning across the items on which the measures were based. Three groups of respondents were selected (a) those diagnosed as having hypertension (b) a group who admitted to having a chronic medical condition unrelated to hypertension and (c) individuals who did not have a chronic medical condition. A confirmatory factor model was used to test the structure of a measure of expressed anger and suppressed hostility. Differences were then examined across the three conditions at both the factor and item levels within a MIMIC structure and controlling for age and gender. Differential effects were found between females and males on two observed measures of expressed anger. Age had a direct effect on both the measure of expressed anger and suppressed hostility. After the effects of age and gender were controlled, no statistically significant group differences were found. Previous results indicating a difference on expressed anger and suppressed hostility may, as in the present analysis, be put down to a combination of lack of appropriate statistical control, and to ignoring the differential pattern of responding across the observed measures.     

The effects of stressor predictability on lymphocyte proliferation in humans

Abstract

To demonstrate the effects of predictable and unpredictable stressors on immune function, 36 male subjects were randomly assigned to complete ten trials of either a predictable or unpredictable cold pressor task or a non-stressful warm pressor control task. The predictable and no-stressor groups were given information about the duration of each pressor trial and a countdown of seconds passed from beginning to end of each trial. The unpredictable stressor group received no information. Self-report, cardiovascular, and biochemical measures were taken throughout the tasks in order to ascertain the effectiveness of the predictability and stressor manipulations. Lymphocyte proliferation to concanavalin A (Con A) and pokeweed mitogen (PWM) were measured before, during and after the tasks. Lymphocyte proliferation to Con A (10/μg/ml) was significantly reduced only in response to the unpredictable stressor suggesting that predictability buffered the effect of the stressor on immune function. Proliferation to PWM followed a similar pattern but was not statistically significant. Blood pressure responses were negatively correlated with proliferation values suggesting that stressor predictability may attenuate stress-associated immune decreases by reducing sympathetic arousal.     

Attentional deficits in fibromyalgia and its relationships with pain,emotional distress and sleep dysfunction complaints

Cognitive complaints are common among subjects with fibromyalgia (FM). Yet, few studies have been able to document these deficits with cognitive tasks. A main limitation of existing studies is that attention has been broadly defined and the tasks used to measure attention are not designed to cover all the main components of the attentional system. Research on attention has identified three primary functions of attention, known as alerting, orienting and executive functioning. This study used the attentional network test-interactions task to explore whether and which of the three attentional networks are altered in FM. Results showed that FM patients have impaired executive control (greater interference), reduced vigilance (slower overall reaction time) and greater alertness (higher reduction in errors after a warning cue). Vigilance and alertness showed several relations with depression, anxiety and sleep quality. Sleep dysfunction was a significant predictor for alertness, whereas there were no significant predictors for vigilance. These findings highlight that the treatment of sleep difficulties in FM patients may help with some of their cognitive complaints.     

Is preschool executive function causally related to academic achievement?

The primary objective of this study was to reevaluate the well-established result that preschoolers' performance on executive function tasks are positively associated with their performance on academic achievement tests. The current study replicated the previously established concurrent associations between children's performance on EF tasks and academic achievement tests. Specifically, children's performance on measures of inhibitory and motor control were positively associated with their performance on tests of reading, writing, and mathematics achievement (rs?=?.2?.5); moreover, although diminished in magnitude, most of these associations held up even after including an earlier measure of academic achievement as a covariate (rs?=?.1?.3). However, the application of an alternative analytic method, fixed effects analysis, a method that capitalizes on repeated measures data to control for all time stable measured and unmeasured covariates, rendered the apparent positive associations between executive function and academic achievement nonsignificant (rs?=?.0?.1). Taken together, these results suggest that the well-replicated association between executive function abilities and academic achievement may be spurious. Results are discussed with respect to the importance of utilizing analytic methods and research designs that facilitate strong causal inferences between executive function and academic achievement in early childhood, as well as the limitations of making curriculum development recommendations and/or public policy decisions based on studies that have failed to do so.     

Interference control in adolescents with Mild-to-Borderline Intellectual Disabilities and/or behavior disorders

The aim of this study was to investigate interference control in adolescents with Mild to Borderline Intellectual Disability (MBID) by addressing two key questions. First, as MBID is often associated with comorbid behavior disorders (BD), we investigated whether MBID and BD both affect interference control. Second, we studied whether interference control deficits are associated to problems in everyday executive functioning. Four groups of adolescents with and without MBID and/or BD performed the Eriksen flanker task, requiring participants to respond to a central target while ignoring interfering flanking stimuli. Their teachers rated behavior on the Behavior Rating Inventory Executive Function (BRIEF). We found pronounced effects of MBID but not BD on flanker interference control. In contrast, we observed pronounced effects of BD, but not MBID, on the BRIEF. In addition, flanker interference scores and BRIEF scores did not correlate. These results are taken to suggest that adolescents with MBID are characterized by deficits in interference control that do not become manifest in ratings of everyday executive functioning. In contrast, adolescents with BD are not characterized by deficits in interference control but do show elevated ratings of deficits in everyday executive function.     

Neurodevelopmental Disorders Across the Lifespan: A Neuroconstructivist Approach.

Objectives. To investigate neuropsychological and neurobehavioral outcome in children with arterial ischemic stroke (AIS).

Background. Childhood stroke can have consequences on motor, cognitive, and behavioral development. We present a cross-sectional study of neuropsychological and neurobehavioral outcome at least one year poststroke in a uniquely homogeneous sample of children who had experienced AIS.

Method. Forty-nine children with AIS aged 6 to 18 years were recruited from a specialist clinic. Neuropsychological measures of intelligence, reading comprehension, attention, and executive function were administered. A triangulation of data collection included questionnaires completed by the children, their parents, and teachers, rating behavior, executive functions, and emotions.

Key Findings. Focal neuropsychological vulnerabilities in attention (response inhibition and dual attention) and executive function were found, beyond general intellectual functioning, irrespective of hemispheric side of stroke. Difficulties with emotional and behavioral regulation were also found. Consistent with an “early plasticity” hypothesis, earlier age of stroke was associated with better performance on measures of executive function.

Conclusions. A significant proportion of children poststroke are at long-term risk of difficulties with emotional regulation, executive function, and attention. Data also suggest that executive functions are represented in widespread networks in the developing brain and are vulnerable to unilateral injury.     

Psychometric Support for an Abbreviated Version of the Behavior Rating Inventory of Executive Function (BRIEF) Parent Form

The objectives of this study were to systematically develop and evaluate the psychometric properties of an abbreviated version of the Behavior Rating Inventory of Executive Function (BRIEF) Parent Report; a questionnaire widely used by pediatric neuropsychologists. A total of 24 items from the original BRIEF Parent Form were selected for the short-form, which was then evaluated in three complementary samples, according to six a priori psychometric criteria. The short-form generally demonstrated appropriate psychometric qualities, with convincing evidence for the reliability and validity of the three composite indices: Behavioral Regulation, Metacognition, and the Global Executive Composite. Potential clinical applications include screening at-risk children in medical clinics to facilitate appropriate referrals for further psychological consultation. In research settings, the short-form can be easily integrated into studies involving mass collection of data (e.g., large-scale epidemiological research), facilitating advancements in the scientific understanding of neuropsychological morbidity in medically involved populations.     

Executive function outcomes of children with traumatic brain injury sustained before three years

Traumatic brain injury (TBI) is a common cause of disability in childhood. While the outcomes of TBI sustained in school years has been heavily researched, very little is known about the impact of TBI in infants and young children. The aim of this study was to investigate the impact of TBI on executive function (EF) in children who sustained a TBI before 3 years of age. A group of 55 children, 19 with a mild TBI, 16 children with a moderate-severe TBI, and 20 uninjured comparison children participated. The EF of children aged 3 to 6 years were compared using child-based measures of attentional control and information processing. Parents completed questionnaires rating their child's EF. Severity groups differed on the child-based EF measure of attentional control with children with TBI performing below the control group. There were no significant group differences for information processing or parent-rated EF. It appears that children who sustain a TBI before the age of 3 years display impairments in some areas of attentional control 3–4 years postinjury. The findings fit with the existing EF literature for older children.     

Attention,Response Inhibition,and Face-Information Processing in Children: The Role of Task Characteristics,Age, and Gender

The aim of the study was to assess: (a) developmental changes in attention, response inhibition, and face-information processing using the new Balloons task and (b) to evaluate the association between measures derived from the task with reported behavior problems. One hundred and thirty-four typically developing children (53 boys and 81 girls) were tested with the Balloons. Their parents and teachers completed the Child Behavior Checklist. Our results validate the Balloons as a reliable task with significant effects of manipulations in difficulty level (speed, processing load, and processing type). The results suggest that face-information processing undergoes significant changes during the age period between 7 and 13 years with significant gender differences. Modest but significant correlations were found between the Balloons' measures and behavior problems.