Head-Down Tilt Bed Rest Improves Executive Function Amongst Younger Adults: A Pilot Project

Purpose Microgravity has been shown to be a significant stressor on the cardiovascular system and the brain due to the redistribution of fluids that occurs in the absence of gravitational force, but there is scarce literature surrounding the effects of microgravity on cerebral hemodynamics and cognition. Understanding the early effects that simulated gravity has on cognitive function is essential for developing proper physical and cognitive countermeasures to assure safe and effective cognitive/decisions making while astronauts prepare for the initial launch or when they arrive in a microgravity environment. Therefore, this study aims to determine how an acute simulation of microgravity would alter cerebral oxygenation and executive functions. Methods Sixty-five young healthy participants (22±6 years, 21 females) completed a thirty (30) minute horizontal (00 tilt) followed by a 90-min -6° head-down-tilt (HDT) protocol. Cerebral oxygenation in the prefrontal cortex was monitored throughout the testing session using near-infrared spectroscopy. Cognition was also measured using a computerized Stroop Task. Results Our results demonstrate that cerebral oxygenation was higher during HDT compared to the horizontal supine position (9.11±1.3 vs 7.51±1.8, p=0.02). For the cognitive results, the non-executive performance of the Stroop task remained stable during HDT (652.46± 19.3 vs. 632.49±14.5, p=0.09). However, reaction time during the executive task performance was improved after the HDT (1058±195 msec to 950±158 msec, p<0.01). Conclusion Our results suggest that an acute bout of simulated microgravity can enhance executive functioning.

The Impact of Organizational Spirituality on Successful Policy Implementation in the Light of Mediating and Moderating Variables with the Islamic Approach

In this study, it has been attempted to identify the factors affecting policy executive performance with the Islamic approach and then to evaluate the relationship between them. The statistical population includes the staff and managers of the selected governmental organizations in Yazd. The sampling was done by cluster sampling method. The research was applied in terms of purpose and correlational in terms of the research method, which was collected through using a valid and reliable questionnaire and survey method. Due to the sample size required, 392 questionnaires were distributed. The results of the validity and reliability of the questionnaire were also acceptable. The constructs of the conceptual framework variables were identified using exploratory factor analysis. The identified factor structure was then considered as the base of the definition of hypotheses that indicate confirmation of the relationships between structures and components. These assumptions were tested through confirmatory factor analysis using LISREL 8.5 software. In this study, PLS software was used to measure the fit of the research model. The results indicated that the dimensions of spirituality had a direct impact on job satisfaction, work-family interaction, organizational culture, organizational commitment, and servant leadership. In addition, job satisfaction, organizational culture and servant leadership had a direct and significant impact on policy executive performance.

Quantifying ADHD symptoms in open-ended everyday life contexts with a new virtual reality task

Objective: In the assessment of attention deficit hyperactivity disorder (ADHD) there is a need for methods that would reflect ADHD symptoms in naturalistic yet controlled situations objectively. Method: We developed a novel virtual reality task, EPELI (Executive Performance in Everyday LIving), and used it to quantify goal-directed behavior in ADHD children (n = 38) and typically developing controls (n = 38) in everyday home situations. Results: The ADHD group exhibited higher percentage of irrelevant actions out of all actions, reflecting lower attentional-executive efficacy, and more controller movements and more total game actions, both indicative of hyperactivity-impulsivity. Five main EPELI measures combined exhibited excellent discriminatory ability, with area under curve being 88 %. The efficacy measure of EPELI was strongly correlated with parent evaluations of everyday executive problems (r = .57) and ADHD symptoms (r = .55). Conclusion: Virtual reality assessment can successfully quantify ADHD symptoms in a rich naturalistic context.

ADHD Symptomatology, Executive Function and Cognitive Performance Differences between Family Foster Care and Control Group in ADHD-Diagnosed Children

Children in foster care have a high prevalence of attention deficit and hyperactivity disorder (ADHD) diagnosis, together with other difficulties in inattentive/hyperactive behaviors, executive and cognitive processes. Early exposure to adversity is a risk factor for developing ADHD via neurodevelopmental pathways. The goal of this research is (a) to study the cognitive and executive performance and inattentive/hyperactive behavior of ADHD-diagnosed children living in foster families in Spain, and (b) to analyze the role of placement variables in their performance. The sample was composed of 102 ADHD-diagnosed children aged 6- to 12-years-old, divided into two groups: 59 children living with non-relative foster families and 43 children not involved with protection services. Children’s executive function–inhibition, working memory, flexibility, attention, intellectual capacity, verbal comprehension, perceptive reasoning, working memory and processing speed were assessed using objective testing measures. At the same time, parents and teachers reported on children’s inattentive, hyperactive and impulsive behaviors. Children in foster care obtained lower scores in the general ability index than the control group after controlling the age at assessment. However, no differences were found in executive processes. Regarding placement factors, children with shorter exposure to adversities in their birth families and more time in foster care showed better executive performance. Professionals should consider the placement history of children in foster care and its influence on their symptomatology and cognitive capacities.

Uric Acid Associates With Executive Function in Children and Adolescents With Hypertension

Observational studies show that serum uric acid levels associate with cardiometabolic risk factors and subclinical target organ damage. The aim of the present study is to investigate the association of traditional cardiometabolic risk factors and uric acid with the executive performance in children and adolescents. Ninety-nine children and adolescents aged 5 to 18 years referred for assessment of primary hypertension were included. Traditional cardiometabolic risk factors, uric acid, and ambulatory blood pressure parameters were assessed. Executive performance was assessed by the validated Behavior Rating Inventory of Executive Function parent questionnaire. Serum uric acid correlated with cardiometabolic parameters, daytime and nighttime systolic blood pressure. High uric acid levels and ambulatory hypertension were associated with behavior regulation independently of other cardiometabolic risk factors or presence of metabolic syndrome. Participants with combined hypertension and high uric acid levels presented the lowest behavior regulation performance. Children with high uric acid had worse behavior regulation indices T scores with estimated marginal means 56.47 (95% CI, 51.68–61.27) compared with 49.22 (95% CI, 45.91–52.53) in those with low uric acid levels ( P =0.023, adjusted for age, sex, nighttime systolic blood pressure, daytime and nighttime heart rate). Mediation analysis showed that part of the effect of high uric acid levels on behavior regulation was mediated by nighttime systolic blood pressure. In conclusion, we found a positive association of serum uric acid with worse executive performance in children at risk for primary hypertension. Extending these cross-sectional findings with longitudinal studies may determine whether high uric acid levels increases the risk of cognitive decline in youth.

Evoked Potentials Differentiate Developmental Coordination Disorder From Attention-Deficit/Hyperactivity Disorder in a Stop-Signal Task: A Pilot Study

Developmental Coordination Disorder and Attention-Deficit/Hyperactivity Disorder are unique neurodevelopmental disorders with overlaps in executive functions and motor control. The conditions co-occur in up to 50% of cases, raising questions of the pathological mechanisms of DCD versus ADHD. Few studies have examined these overlaps in adults with DCD and/or ADHD. Therefore, to provide insights about executive functions and motor control between adults with DCD, ADHD, both conditions (DCD + ADHD), or typically developed controls, this study used a stop-signal task and parallel EEG measurement. We assessed executive performance via go accuracy and go reaction time, as well as motor response inhibition via stop-signal reaction time. This was complemented with analysis of event-related potentials (ERPs). Based on existing investigations of adults with DCD or ADHD, we expected (1) groups would not differ in behavioral performance on stop and go trials, but (2) differences in ERPs, particularly in components N200 (index of cognitive control) and P300 (index of attention and inhibition) would be evident. The sample included N = 50 adults with DCD (n = 12), ADHD (n = 9), DCD + ADHD (n = 7), and control participants (n = 22). We replicated that there were no between-group differences for behavioral-level executive performance and motor response inhibition. However, on a physiological level, ERP components N200 and P300 differed between groups, particularly during successful response inhibition. These ERPs reflect potential endophenotypic differences not evident in overt behavior of participants with ADHD and/or DCD. This suggests a disorder specific employment of inhibition or general executive functions in groups of adults with DCD, DCD + ADHD, ADHD, or control participants.