The decimal effect: behavioral and neural bases for a novel influence on intertemporal choice in healthy individuals and in ADHD.

We identify a novel contextual variable that alters the evaluation of delayed rewards in healthy participants and those diagnosed with attention deficit/hyperactivity disorder (ADHD). When intertemporal choices are constructed of monetary outcomes with rounded values (e.g., $25.00), discount rates are greater than when the rewards have nonzero decimal values (e.g., $25.12). This finding is well explained within a dual system framework for temporal discounting in which preferences are constructed from separate affective and deliberative processes. Specifically, we find that round dollar values produce greater positive affect than do nonzero decimal values. This suggests that relative involvement of affective processes may underlie our observed difference in intertemporal preferences. Furthermore, we demonstrate that intertemporal choices with rounded values recruit greater brain responses in the nucleus accumbens to a degree that correlates with the size of the behavioral effect across participants. Our demonstration that a simple contextual manipulation can alter self-control in ADHD has implications for treatment of individuals with disorders of impulsivity. Overall, the decimal effect highlights mechanisms by which the properties of a reward bias perceived value and consequent preferences.

A quantitative analysis of fidgeting in ADHD and its relation to performance and sustained attention on a cognitive task.

Introduction: Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder where hyperactivity often manifests as fidgeting, a non-goal-directed motoric action. Many studies demonstrate fidgeting varies under different conditions as a self-regulating mechanism for attention and alertness during cognitively demanding tasks. Fidgeting has also been associated with reaction time variability. However, a lack of standard variables to define and quantify fidgeting can lead to discrepancies in data and interpretability issues across studies. Furthermore, little is known about fidgeting in adults with ADHD compared to youth. This study aims to design a framework to quantify meaningful fidgeting variables and to apply them to test the relation between fidgeting and performance on a cognitive task, the Flanker, in adults with ADHD. Method: Our study included 70 adult participants diagnosed with ADHD, aged 18-50 years (30.5 ± 7.2 years). Screening included a structured clinical interview, childhood, current self and current observer ratings of ADHD symptoms. Actigraphy devices were attached to the left wrist and right ankle during completion of a cognitive control, attention task (the Flanker). Laboratory testing was subsequently completed on a single day. The relation between task performance, reaction time variability and fidgeting was examined. Results and Discussion: Our analysis revealed increased fidgeting during correct trials as defined by our new variables, consistent with previous observations. Furthermore, differences in fidgeting were observed between early and later trials while the percentage of correct trials were not significantly different. This suggests a relation between the role of fidgeting and sustaining attention. Participants with low reaction time variability, that is, those with more consistent reaction times, fidgeted more during later trials. This observation supports the theory that fidgeting aids arousal and improves sustained attention. Finally, a correlation analysis using ADHD-symptom rating scales validated the relevance of the fidget variables in relation to ADHD symptom severity. These findings suggest fidgeting may be a compensatory mechanism that aids in sustained attention for those with ADHD, although alternative explanations exist. Conclusion: Our study suggests that fidgeting may aid in sustained attention during the attention-demanding, cognitive control processes for adults with ADHD, with more fidgeting observed during correct trials and among participants with lower reaction time variability. Furthermore, the newly defined fidget variables were validated through a significant correlation with ADHD rating scales. By sharing our implementation of fidget variables, we hope to standardize and encourage further quantitative research into the role of fidgeting in ADHD.

A study on the effectiveness of videoconferencing on teaching parent training skills to parents of children with ADHD.

OBJECTIVE: Many geographic locations are without services and staff available to provide treatment for children with attention deficit hyperactivity disorder (ADHD). This is a randomized controlled trial to evaluate the effectiveness of group parent training on ADHD treatment delivered via videoconferencing. SUBJECTS AND METHODS: Twenty-two subjects were enrolled in the study, with 9 subjects in the videoconference session (treatment group) and 13 in the face-to-face session (control group). The parent child relationship questionnaire for child and adolescents (PCQ-CA), Vanderbilt assessment scales (parent and teacher versions), children global assessment scale, clinical global impression-severity score, clinical global impression-improvement score, and social skills rating system assessed the effectiveness of the treatment. A Likert scale evaluated parents' acceptance of the training modality. Our results showed that the parent training program significantly improved parents' disciplinary practices based on the PRQ-CA, parent ratings of ADHD, oppositional defiant disorder, and conduct disorder symptoms, and the children's global functioning. RESULTS: The treatment effects did not differ between the videoconference and face-to-face groups; however, the videoconference group evidenced statistically greater improvement on the hyperactive symptoms of Vanderbilt assessment scales. Our findings suggest that parent training through a videoconferencing modality may be as effective as face-to-face training and is well accepted by parents. CONCLUSIONS: Parent training via videoconferencing may be an important tool for addressing ADHD in geographic locations that do not have access to appropriate treatment providers.

Associations of Irritability With Functional Connectivity of Amygdala and Nucleus Accumbens in Adolescents and Young Adults With ADHD.

OBJECTIVE: Irritability is a common characteristic in ADHD. We examined whether dysfunction in neural connections supporting threat and reward processing was related to irritability in adolescents and young adults with ADHD. METHOD: We used resting-state fMRI to assess connectivity of amygdala and nucleus accumbens seeds in those with ADHD (n = 34) and an age- and gender-matched typically-developing comparison group (n = 34). RESULTS: In those with ADHD, irritability was associated with atypical functional connectivity of both seed regions. Amygdala seeds showed greater connectivity with right inferior frontal gyrus and caudate/putamen, and less connectivity with precuneus. Nucleus accumbens seeds showed altered connectivity with middle temporal gyrus and precuneus. CONCLUSION: The irritability-ADHD presentation is associated with atypical functional connectivity of reward and threat processing regions with cognitive control and emotion processing regions. These patterns provide novel evidence for irritability-associated neural underpinnings in adolescents and young adults with ADHD. The findings suggest cognitive and behavioral treatments that address response to reward, including omission of an expected reward and irritability, may be beneficial for ADHD.

Irritability Predicts Hyperactive/Impulsive Symptoms Across Adolescence for Females.

Irritability is common in Attention-Deficit Hyperactivity Disorder (ADHD), but little is known about whether irritability predicts the course of ADHD symptoms over time. Adolescence is a dynamic period of emotional development as well as shifts in ADHD symptoms; an important goal is to identify youth at risk of increasing or persisting symptoms. We examined irritability as a longitudinal predictor of change in adolescents' ADHD symptoms, as well as how this link may differ in females versus males. The sample included 108 youth (72 males) age 12-16 years (M = 14.21 years, SD = 1.44 years), 62 of whom met criteria for ADHD. Approximately 18 months later, 80 participants (48 males) were followed up at Time 2. A dimensional approach was used to examine changes over time in parent-reported inattentive and hyperactive/impulsive symptoms. Longitudinal path analysis revealed that irritability at Time 1 predicted higher relative hyperactive/impulsive symptoms at Time 2 after controlling for age and longitudinal stability in all variables. A multiple-group analysis examining moderation by sex/gender revealed that this association was significant only for females. These results suggest that irritability may play a key role in the persistence and worsening of hyperactive/impulsive symptoms across adolescence for females, with potential implications for the diagnosis and treatment of females with ADHD.

Neural basis of working memory in ADHD: Load versus complexity.

Working memory (WM) deficits are key in attention deficit hyperactivity disorder (ADHD). Nevertheless, WM is not universally impaired in ADHD. Additionally, the neural basis for WM deficits in ADHD has not been conclusively established, with regions including the prefrontal cortex, cerebellum, and caudate being implicated. These contradictions may be related to conceptualizations of WM capacity, such as load (amount of information) versus operational-complexity (maintenance-recall or manipulation). For instance, relative to neurotypical (NT) individuals, complex WM operations could be impaired in ADHD, while simpler operations are spared. Alternatively, all operations may be impaired at higher loads. Here, we compared the impact of these two components of WM capacity: load and operational-complexity, between ADHD and NT, behaviorally and neurally. We hypothesized that the impact of WM load would be greater in ADHD, and the neural activation would be altered. Participants (age-range 12-23 years; 50 ADHD (18 females); 82 NT (41 females)) recalled three or four objects (load) in forward or backward order (operational-complexity) during functional magnetic resonance imaging scanning. The effects of diagnosis and task were compared on performance and neural engagement. Behaviorally, we found significant interactions between diagnosis and load, and between diagnosis, load, and complexity. Neurally, we found an interaction between diagnosis and load in the right striatum, and between diagnosis and complexity in the right cerebellum and left occipital gyrus. The ADHD group displayed hypo-activation compared to NT group during higher load and greater complexity. This informs mechanisms of functional problems related to WM in adolescents and young adults with ADHD (e.g., academic performance) and remedial interventions (e.g., WM-training).

Will working memory training generalize to improve off-task behavior in children with attention-deficit/hyperactivity disorder?

Computerized working memory and executive function training programs designed to target specific impairments in executive functioning are becoming increasingly available, yet how well these programs generalize to improve functional deficits in disorders, such as attention-deficit/hyperactivity disorder (ADHD), beyond the training context is not well-established. The aim of this study was to examine the extent to which working memory (WM) training in children with ADHD would diminish a core dysfunctional behavior associated with the disorder, "off-task" behavior during academic task performance. The effect of computerized WM training (adaptive) was compared to a placebo condition (nonadaptive) in a randomized, double-blind, placebo-controlled design in 26 children (18 males; age, 7 to 14 years old) diagnosed with ADHD. Participants completed the training in approximately 25 sessions. The Restricted Academic Situations Task (RAST) observational system was used to assess aspects of off-task behavior during the completion of an academic task. Traditional measures of ADHD symptoms (Conners' Parent Rating Scale) and WM ability (standardized WM tests) were also collected. WM training led to significant reductions in off-task ADHD-associated behavior on the RAST system and improvement on WM tests. There were no significant differences between groups in improvement on parent rating scales. Findings lend insight into the generalizability of the effects of WM training and the relation between deficits in WM and off-task behavioral components of ADHD. These preliminary data suggest WM training may provide a mechanism for indirectly altering academic performance in children with ADHD.