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.     

Prenatal Treatment of Congenital Adrenal Hyperplasia—Not Standard of Care

Congenital adrenal hyperplasia (CAH) due to steroid 21-hydroxylase deficiency is a common autosomal recessive disorder due to mutations in the CYP21A2 gene. Since genetic counselors play a crucial role in educating families about inherited disorders, they need to have thorough knowledge regarding the pathophysiology of CAH especially the effects on the fetus, the complex genetics of this disorder, and the controversies surrounding experimental prenatal dexamethasone treatment. Affected female fetuses may have varying degree of virilization of the external genitalia. Starting in the 1980's, supraphysiologic glucocorticoid treatment was used to decrease the virilization of the external genitalia of affected female fetuses. However, recent clinical observations, animal studies and greater awareness of the details of human fetal adrenal physiology raise concerns regarding the safety of this prenatal treatment. We review the pathophysiology of CAH, the safety and ethical considerations of prenatal dexamethasone treatment and the views of multiple medical societies that conclude that this experimental therapy should only be done in prospective trials approved by ethical review boards.     

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.     

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.     

Acquired equivalence of cues by presentation in a common context in rats

It is well established that humans and other animals may treat two perceptually different cues alike, if the cues have been individually paired with a common antecedent or a common consequence. Recently, Molet et al. (Psychon Bull Rev 18:618–623, 2011) reported evidence for a new form of acquired equivalence in human conditional discrimination, namely context-mediated equivalence. In the present research, using a flavor conditioning procedure, we asked whether rats would show similar context-mediated equivalence to demonstrate that this new form of acquired equivalence is a general phenomenon. Rats experienced two flavor cues A and B each presented either in the same context, X, or each in its own distinctive context, X or Y. Subsequently, the rats experienced B with sucrose in a third context, Z, and then the generalization of conditioning to A was assessed. When tested in Context Z, consumption of A was more marked when A and B had both been presented in the same context than when they had been presented in two different contexts. Thus, importantly, in the absence of the training context, cues that shared a common context at different times came to be treated as equivalent. This represents the first evidence of context-mediated equivalence in a nonhuman species.     

An invariant dimensional liability model of gender differences in mental disorder prevalence: evidence from a national sample

Epidemiological studies of categorical mental disorders consistently report that gender differences exist in many disorder prevalence rates and that disorders are often comorbid. Can a dimensional multivariate liability model be developed to clarify how gender impacts diverse, comorbid mental disorders? We pursued this possibility in the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC; N = 43,093). Gender differences in prevalence were systematic such that women showed higher rates of mood and anxiety disorders, and men showed higher rates of antisocial personality and substance use disorders. We next investigated patterns of disorder comorbidity and found that a dimensional internalizing-externalizing liability model fit the data well, where internalizing is characterized by mood and anxiety disorders, and externalizing is characterized by antisocial personality and substance use disorders. This model was gender invariant, indicating that observed gender differences in prevalence rates originate from women and men's different average standings on latent internalizing and externalizing liability dimensions. As hypothesized, women showed a higher mean level of internalizing, while men showed a higher mean level of externalizing. We discuss implications of these findings for understanding gender differences in psychopathology and for classification and intervention.     

Compensatory nonconformity: Self-uncertainty and low implicit self-esteem increase adoption and expression of minority opinions

The present studies tested whether people, particularly those who are most vulnerable to self-threats as indicated by low implicit self-esteem, adopt and express minority opinions to compensate for self-uncertainty. In Studies 1 through 3, low implicit self-esteem participants who were made to feel uncertain about themselves as individuals (versus uncertain about a self-irrelevant issue in Study 1, certain about themselves in Study 2, or uncertain about their group memberships in Study 3) expressed more disagreement with others' opinions. Additionally, Study 3 demonstrated that this effect is specific to minority opinions and does not emerge on majority opinions. In Study 4, the relation between self-uncertainty and disagreement with others' opinions was strongest among participants with both low implicit and high explicit self-esteem, who respond to self-threats in particularly defensive ways.