Relationship between reaction time variability and motor skill development in ADHD

Slower and more variable reaction times to computerized tasks have been documented in children diagnosed with attention deficit/hyperactivity disorder (ADHD). Recent research supports a role for attentional lapses in generating abnormally variable and slow responses. However, given the association between ADHD and impairments in motor control, we hypothesized that slower or more variable reaction times might also correlate with motor development. The aim of this case-control study was to explore the relationship between motor function, reaction speed and variability, and ADHD. After comprehensive educational and clinical assessments, motor skill development was evaluated in 35 children ages 9 to 14 (19 with ADHD) using the Physical and Neurological Examination for Subtle Signs (PANESS) test battery. Finger-sequencing speed and variability were quantified with goniometers. Reaction times were measured with 20 trials each of computerized simple and choice (binary) tasks. Compared to healthy controls, children with ADHD had slower and more variable reaction times, and these findings correlated with impaired motor development (PANESS) and slow and variable finger sequencing (goniometers). Further studies of motor development in ADHD may identify factors influencing speed and variability of reaction times.     

Brain Development During the Preschool Years

The preschool years represent a time of expansive mental growth, with the initial expression of many psychological abilities that will continue to be refined into young adulthood. Likewise, brain development during this age is characterized by its ??blossoming?? nature, showing some of its most dynamic and elaborative anatomical and physiological changes. In this article, we review human brain development during the preschool years, sampling scientific evidence from a variety of sources. First, we cover neurobiological foundations of early postnatal development, explaining some of the primary mechanisms seen at a larger scale within neuroimaging studies. Next, we review evidence from both structural and functional imaging studies, which now accounts for a large portion of our current understanding of typical brain development. Within anatomical imaging, we focus on studies of developing brain morphology and tissue properties, including diffusivity of white matter fiber tracts. We also present new data on changes during the preschool years in cortical area, thickness, and volume. Physiological brain development is then reviewed, touching on influential results from several different functional imaging and recording modalities in the preschool and early school-age years, including positron emission tomography (PET), electroencephalography (EEG) and event-related potentials (ERP), functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG), and near-infrared spectroscopy (NIRS). Here, more space is devoted to explaining some of the key methodological factors that are required for interpretation. We end with a section on multimodal and multidimensional imaging approaches, which we believe will be critical for increasing our understanding of brain development and its relationship to cognitive and behavioral growth in the preschool years and beyond.     

An optimal adjustment procedure to minimize experiment time in decisions with multiple alternatives

Decisions between multiple alternatives typically conform to Hick’s Law: Mean response time increases log-linearly with the number of choice alternatives. We recently demonstrated context effects in Hick’s Law, showing that patterns of response latency and choice accuracy were different for easy versus difficult blocks. The context effect explained previously observed discrepancies in error rate data and provided a new challenge for theoretical accounts of multialternative choice. In the present article, we propose a novel approach to modeling context effects that can be applied to any account that models the speed–accuracy trade-off. The core element of the approach is “optimality” in the way an experimental participant might define it: minimizing the total time spent in the experiment, without making too many errors. We show how this approach can be included in an existing Bayesian model of choice and highlight its ability to fit previous data as well as to predict novel empirical context effects. The model is shown to provide better quantitative fits than a more flexible heuristic account.     

Psychometric assessment of the Mindful Attention Awareness Scale (MAAS) among Chinese adolescents

The Mindful Attention Awareness Scale (MAAS) has the longest empirical track record as a valid measure of trait mindfulness. Most of what is understood about trait mindfulness comes from administering the MAAS to relatively homogenous samples of Caucasian adults. This study rigorously evaluates the psychometric properties of the MAAS among Chinese adolescents attending high school in Chengdu, China. Classrooms from 24 schools were randomly selected to participate in the study. Three waves of longitudinal data (N = 5,287 students) were analyzed. MAAS construct, nomological, and incremental validity were evaluated as well as its measurement invariance across gender using latent factor analyses. Participants' mean age was 16.2 years (SD = 0.7), and 51% were male. The 15-item MAAS had adequate fit to the one-dimensional factor structure at Wave 1, and this factor structure was replicated at Wave 2. A 6-item short scale of the MAAS fit well to the data at Wave 3. The MAAS maintained reliability (Cronbach's α = .89-.93; test-restest r = .35-.52), convergent/discriminant validity, and explained additional variance in mental health measures beyond other psychosocial constructs. Both the 15- and 6-item MAAS scales displayed at least partial factorial invariance across gender. The findings suggest that the MAAS is a sound measure of trait mindfulness among Chinese adolescents. To reduce respondent burden, the MAAS 6-item short-scale provides an option to measure trait mindfulness.     

The design and analysis of state-trace experiments

State-trace analysis (Bamber, 1979) addresses a question of interest in many areas of psychological research: Does 1 or more than 1 latent (i.e., not directly observed) variable mediate an interaction between 2 experimental manipulations? There is little guidance available on how to design an experiment suited to state-trace analysis, despite its increasing use, and existing statistical methods for state-trace analysis are problematic. We provide a framework for designing and refining a state-trace experiment and statistical procedures for the analysis of accuracy data using Klugkist, Kato, and Hoijtink's (2005) method of estimating Bayes factors. The statistical procedures provide estimates of the evidence favoring 1 versus more than 1 latent variable, as well as evidence that can be used to refine experimental methodology.     

Time Course of Treatment Effect of OROS(R) Methylphenidate in Children With ADHD

Objective: The authors evaluated the time course of the treatment effect of Osmotic-Release Oral System methylphenidate (OROS(?) MPH) HCl (Concerta(?), Raritan, NJ) CII in children with ADHD. Method: Data were combined from two double-blind, randomized, placebo-controlled, cross-over, analog classroom studies in children (9-12 years) with ADHD. Participants received an individualized dose of placebo or OROS(?) MPH on two laboratory school days. Permanent Product Math Test and Swanson, Kotkin, Agler, M-Flynn, and Pelham scores were evaluated 0.5 hr before dosing and 1, 2, 4, 10, 11, and 12.5 hr post dose. Analysis used a repeated-measures mixed model. Results: Treatment effects were present at all postdose assessment points (p < .0001 for all comparisons, n = 139). Adverse events were similar to previous reports for OROS(?) MPH. Conclusion: A robust treatment effect occurred with OROS(?) MPH; onset was at 1 hr and persisted for at least 12.5 hr after dosing.     

Prospective teachers' conceptions of assessment: a cross-cultural comparison

This paper examines the responses of two sample of prospective teachers (New Zealand, n = 324; and Spain, n = 672) to the Teachers' Conceptions of Assessment inventory (English and Spanish respectively). The inventory captures four major intentions for assessment (i.e., improvement, irrelevance, school and student accountability). The conceptions of prospective teachers about the nature and purpose of assessment are relevant, given that (a) much educational assessment is carried out in classrooms; and (b) prospective teachers enter the teacher education programs with significant prior school experience of assessment as pupils. Results of confirmatory factor analysis indicated that the original model was inadmissible and that the best-fitting revised model was only configurally invariant between the two samples. It would appear that lack of teaching experience results in different responses for prospective teachers to those of practicing teachers. Moreover, differences in societal and cultural priorities for assessment use most likely explain the lack of invariance between samples.     

Decision making in the Balloon Analogue Risk Task (BART): Anterior cingulate cortex signals loss aversion but not the infrequency of risky choices

The inferior frontal gyrus/anterior insula (IFG/AI) and anterior cingulate cortex (ACC) are key regions involved in risk appraisal during decision making, but accounts of how these regions contribute to decision making under risk remain contested. To help clarify the roles of these and other related regions, we used a modified version of the Balloon Analogue Risk Task (Lejuez et al., Journal of Experimental Psychology: Applied, 8, 75-84, 2002) to distinguish between decision-making and feedback-related processes when participants decided to pursue a gain as the probability of loss increased parametrically. Specifically, we set out to test whether the ACC and IFG/AI regions correspond to loss aversion at the time of decision making in a way that is not confounded with either reward-seeking or infrequency effects. When participants chose to discontinue inflating the balloon (win option), we observed greater ACC and mainly bilateral IFG/AI activity at the time of decision as the probability of explosion increased, consistent with increased loss aversion but inconsistent with an infrequency effect. In contrast, we found robust vmPFC activity when participants chose to continue inflating the balloon (risky option), consistent with reward seeking. However, in the cingulate and in mainly bilateral IFG regions, blood-oxygenation-level-dependent activation decreased when participants chose to inflate the balloon as the probability of explosion increased, findings that are consistent with a reduced loss aversion signal. Our results highlight the existence of distinct reward-seeking and loss-averse signals during decision making, as well as the importance of distinguishing between decision and feedback signals.