Hyperactivity in boys with attention-deficit/hyperactivity disorder (ADHD): The role of executive and non-executive functions

Effects of rope skipping exercise on working memory and cardiorespiratory fitness in children with attention deficit hyperactivity disorder

Introduction

Children with Attention Deficit Hyperactivity Disorder (ADHD) exhibit deficits in working memory (WM) and cardiorespiratory fitness (CRF), both of which are closely associated with the core symptoms of ADHD. This study aimed to investigate the effects of rope skipping exercise (RSE) on the WM and CRF of children with ADHD, to provide a theoretical foundation for the optimization of exercise intervention programs tailored to children with ADHD.

Methods

This study recruited 55 children (age range 6-12 years) and randomly assigned them into three groups: the ADHD with RSE (AWRSE, n=22, mean age: 10.18 ± 1.10 years), the ADHD with sports game (SG) (AWSG, n=16, mean age: 9.38 ± 0.96 years), and the typically developing (TD) control group (CG, n=17, mean age: 8.94 ± 0.56 years). The AWRSE underwent a RSE intervention, while the other two groups participated in SG. The exercise intervention lasted for 8 weeks, with sessions held twice a week for 60 minutes each, at a moderate-to-vigorous-intensity (64-95% HRmax). All children in each group underwent pre-test and post-test, including height, weight, BMI, n-back, and 20mSRT. One-way analysis of variance (Ony-way ANOVA) and paired sample t-test were used to analyze inter- and intra-group differences respectively.

Results

Before the intervention, children with ADHD exhibited a significantly lower VO2max compared to the TD children (p<0.05), and there was no significant difference in the other indicators between the groups (p>0.05). After the intervention, no significant inter-group differences were found across all indices for the three groups of children (p > 0.05). The AWRSE had significant improvements in the accuracy of 1-back task, Pacer (laps), and VO2max (p<0.05), with the level of CRF approaching that of TD children. A significant decrease in response time for the 1-back task was observed in the CG.

Conclusion

An 8-week RSE intervention is an effective therapeutic approach for children with ADHD, significantly enhancing their WM and CRF.

Executive Functioning and Emotion Regulation in Children with and without ADHD

Difficulties with emotion regulation affect the majority of youth with attention-deficit/hyperactivity disorder (ADHD) and predict greater functional impairment than ADHD symptoms alone. Deficits in executive functioning are also present for most children with ADHD, and have been linked with emotion regulation difficulties in both clinical and neurotypical populations throughout development. The current study was the first to assess all three core executive functions (working memory, inhibitory control, set shifting) simultaneously in a clinically-diverse sample of children with and without ADHD and common comorbidities and investigate the extent to which they uniquely predict emotion dysregulation. A sample of 151 children ages 8-13 years (M = 10.36, SD = 1.52; 52 girls; 70.2% White/Non-Hispanic) were assessed using a criterion battery of executive functioning tasks, teacher-reported ADHD symptoms, and parent-reported emotion regulation. Results of the bias-corrected, bootstrapped conditional effects path model revealed that better-developed working memory predicted better emotion regulation (β = 0.23) and fewer ADHD symptoms (β = -0.21 to -0.37), that ADHD symptoms (β = -0.18 to -0.20) independently predicted emotion dysregulation, and that working memory exerted indirect effects on emotion regulation through both inattention and hyperactivity/impulsivity (β = 0.04-0.07). Sensitivity analyses indicated that these effects were generally robust to control for age, sex, executive function interrelations, and inclusion/exclusion of children with co-occurring ASD. These findings underscore the importance of working memory (relative to inhibitory control and set shifting) and its relations with ADHD symptoms for understanding children's emotion regulation skills, and may help explain the limited efficacy of first-line ADHD treatments, which do not target working memory, for improving emotion regulation skills.

An Examination of Relations Among Working Memory, ADHD Symptoms, and Emotion Regulation

Emotion regulation difficulties are present in many, if not most, children with attention-deficit/hyperactivity disorder (ADHD) and confer risk for a host of adverse outcomes. Little is known, however, regarding the neurocognitive and behavioral mechanisms that underlie these difficulties. A well-characterized, clinically evaluated sample of 145 children ages 8-13 years (M = 10.33, SD = 1.47; 55 girls; 69% White/non-Hispanic) were administered multiple, counterbalanced working memory tests and assessed for emotion dysregulation and ADHD symptoms via multiple-informant reports. Bias-corrected, bootstrapped conditional effects modeling indicated that underdeveloped working memory exerted significant direct effects on emotion regulation in all tested models as well as indirect effects on emotion regulation via parent-reported hyperactive/impulsive symptoms (95% CIs excluded zero). Interestingly, hyperactive/impulsive symptoms also predicted emotion dysregulation when controlling for the influence of working memory. Inattention failed to predict emotion regulation difficulties in all tested models (all 95% CIs included zero). This pattern of results replicated across parent and teacher models and were robust to control for mono-informant bias, age, and gender. These findings suggest that emotion dysregulation in ADHD reflects, in part, both a direct outcome of underdeveloped working memory and an affective outcome of hyperactive and/or impulsive symptomatology, both attributable to and independent of the role of underlying working memory deficits.

A Review of Working Memory Training in the Management of Attention Deficit Hyperactivity Disorder

Attention deficit hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders among children. Working memory deficits underlie many of the behavioural symptoms of ADHD. Alongside psychostimulant medications, strategies to improve working memory may play an important adjuvant role in the management of ADHD. In this study, we review the role of working memory deficits in ADHD, the evidence surrounding working memory training strategies in the management of the condition, and the factors affecting the success of these strategies in alleviating ADHD symptoms. More specifically, we review several non-pharmacological interventions that target working memory deficits in ADHD, with special emphasis on cognitive working memory training. We conclude that the development of evidence-based interventions such as computerised cognitive training (CCT) could provide an alternative or adjunct to the use of psychostimulants, especially in cases where side effects are a major issue.

Is There a Functional Relation Between Set Shifting and Hyperactivity in Children with Attention-Deficit/Hyperactivity Disorder (ADHD)?

OBJECTIVE

Replicated evidence indicates that children with attention-deficit/hyperactivity disorder (ADHD) show disproportionate increases in hyperactivity/physical movement when their underdeveloped executive functions are taxed. However, our understanding of hyperactivity's relation with set shifting is limited, which is surprising given set shifting's importance as the third core executive function alongside working memory and inhibition. The aim of this study was to experimentally examine the effect of imposing set shifting and inhibition demands on objectively measured activity level in children with and without ADHD.

METHOD

The current study used a validated experimental manipulation to differentially evoke set shifting, inhibition, and general cognitive demands in a carefully phenotyped sample of children aged 8-13 years with ADHD (n = 43) and without ADHD (n = 34). Activity level was sampled during each task using multiple, high-precision actigraphs; total hyperactivity scores (THS) were calculated.

RESULTS

Results of the 2 × 5 Bayesian ANOVA for hyperactivity revealed strong support for a main effect of task (BF10 = 1.79 × 1018, p < .001, ω2 = .20), such that children upregulated their physical movement in response to general cognitive demands and set shifting demands specifically, but not in response to increased inhibition demands. Importantly, however, this manipulation did not disproportionally increase hyperactivity in ADHD as demonstrated by significant evidence against the task × group interaction (BF01 = 18.21, p = .48, ω2 = .002).

CONCLUSIONS

Inhibition demands do not cause children to upregulate their physical activity. Set shifting produces reliable increases in children's physical movement/hyperactivity over and above the effects of general cognitive demands but cannot specifically explain hyperactivity in children with ADHD.

Transcranial Direct Current Stimulation Improves Executive Dysfunctions in ADHD: Implications for Inhibitory Control, Interference Control, Working Memory, and Cognitive Flexibility

Objective: This study examined effects of transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) and orbitofrontal cortex (OFC) on major executive functions (EFs), including response inhibition, executive control, working memory (WM), and cognitive flexibility/task switching in ADHD. Method: ADHD children received (a) left anodal/right cathodal DLPFC tDCS and (b) sham stimulation in Experiment 1 and (a) left anodal DLPFC/right cathodal OFC tDCS, (b) left cathodal DLPFC/right anodal OFC tDCS, and (c) sham stimulation in Experiment 2. The current intensity was 1 mA for 15 min with a 72-hr interval between sessions. Participants underwent Go/No-Go task, N-back test, Wisconsin Card Sorting Test (WCST), and Stroop task after each tDCS condition. Results: Anodal left DLPFC tDCS most clearly affected executive control functions (e.g., WM, interference inhibition), while cathodal left DLPFC tDCS improved inhibitory control. Cognitive flexibility/task switching benefited from combined DLPFC-OFC, but not DLPFC stimulation alone. Conclusion: Task-specific stimulation protocols can improve EFs in ADHD.

Aggravation of symptom severity in adult attention-deficit/hyperactivity disorder by latent Toxoplasma gondii infection: a case-control study

Toxoplasma gondii (T. gondii) has a high worldwide prevalence and an underestimated impact on neuropsychiatric disorders. Previous studies related T. gondii to disorders associated with the dysfunctional dopaminergic system. However, an association between T. gondii infection and adult attention-deficit/hyperactivity disorder (ADHD) has not yet been studied. In a sex- and age-matched case-control study, we investigated the seropositivity, serointensity, and avidity of latent T. gondii infection in adult ADHD patients and examined the influence of those variables on the symptomatology of ADHD. Of 140 participants, 20.0% were seropositive for anti-T. gondii IgG and 0% for anti-T. gondii IgM. T. gondii seropositivity was associated with 2.8-fold increase in the odds of ADHD in a confounder-adjusted multivariable analysis. Age and consumption of raw/undercooked meat were confirmed as significant predictors of T. gondii seropositivity. Multiple linear regression analysis of self-rated ADHD-related symptom severity in all participants revealed a significant association with T. gondii seropositivity, elevated IgG titers (serointensity), and stronger anti-T. gondii IgG avidity. Overall symptom severity was increased in seropositive ADHD patients compared to seronegative subjects with ADHD. In particular, hyperactivity was significantly associated with serointensity. We conclude that there is a high rate of T. gondii seropositivity in adults with ADHD. Additionally, our results suggest a clinical impact of latent T. gondii infection on ADHD-related symptoms in a serointensity- and avidity-dependent manner.

ADHD and hyperactivity: The influence of cognitive processing demands on gross motor activity level in children

Excessive gross motor activity is a prominent feature of children with ADHD, and accruing evidence indicates that their gross motor activity is significantly higher in situations associated with high relative to low working memory processing demands. It remains unknown, however, whether children's gross motor activity rises to an absolute level or accelerates incrementally as a function of increasingly more difficult cognitive processing demands imposed on the limited capacity working memory (WM) system - a question of both theoretical and applied significance. The present investigation examined the activity level of 8- to 12-year-old children with ADHD (n = 36) and Typically Developing (TD) children (n = 24) during multiple experimental conditions: a control condition with no storage and negligible WM processing demands; a short-term memory (STM) storage condition; and a sequence of WM conditions that required both STM and incrementally more difficult higher-order cognitive processing. Relative to the control condition, all children, regardless of diagnostic status, exhibited higher levels of gross motor activity while engaged in WM tasks that required STM alone and STM combined with upper level cognitive processing demands, and children with ADHD were motorically more active under all WM conditions relative to TD children. The increase in activity as a consequence of cognitive demand was similar for all experimental conditions. Findings suggest that upregulation of physical movement rises and remains relatively stable to promote arousal related mechanisms when engaged in cognitive activities involving WM for all children, and to a greater extent for children with ADHD.

Executive Functioning and Activity in Children: a Multimethod Examination of Working Memory, Inhibition, and Hyperactivity

Two primary methods of quantifying executive functioning include self- or other-reports (i.e., questionnaire-based EF) and cognitive test performance (i.e., task-based EF). Despite their lack of concordance with one another and relatively inconsistent associations with attention-deficit/hyperactivity disorder (ADHD) symptoms, both approaches have been utilized in attempts to advance our understanding of the role of EF in symptoms of ADHD. The current study is the first to incorporate a direct assessment of behavior (i.e., actigraphy) to further clarify the relation between EF and hyperactivity using a multi-method approach in a sample of children with a range of ADHD symptoms. Fifty-two children between the ages of 8 and 12 completed a testing session during which performance on working memory and inhibition computerized tasks, as well as actigraphy data, were collected. Additionally, parent reports of hyperactivity/impulsivity, working memory, and inhibition were obtained. As expected, questionnaire-based measures of working memory and inhibition were strongly associated with parent-reported hyperactivity/impulsivity, whereas only the latter was associated significantly with mechanically assessed movement. In contrast, task-based working memory performance was more strongly associated with parent-reported hyperactivity/impulsivity relative to task-based inhibition. Further, both task-based working memory and task-based inhibition were similarly associated with mechanically-assessed movement. Finally, compared to questionnaire-based EF, both measures of task-based EF accounted for more variance in objectively-assessed movement. Collectively, these results highlight the measurement issues in the present literature, the importance of careful task and questionnaire design, and the value that alternative approaches (e.g., actigraphy) may provide with respect to advancing our understanding of EF.

Executive Functioning Heterogeneity in Pediatric ADHD

Neurocognitive heterogeneity is increasingly recognized as a valid phenomenon in ADHD, with most estimates suggesting that executive dysfunction is present in only about 33%-50% of these children. However, recent critiques question the veracity of these estimates because our understanding of executive functioning in ADHD is based, in large part, on data from single tasks developed to detect gross neurological impairment rather than the specific executive processes hypothesized to underlie the ADHD phenotype. The current study is the first to comprehensively assess heterogeneity in all three primary executive functions in ADHD using a criterion battery that includes multiple tests per construct (working memory, inhibitory control, set shifting). Children ages 8-13 (M = 10.37, SD = 1.39) with and without ADHD (N = 136; 64 girls; 62% Caucasian/Non-Hispanic) completed a counterbalanced series of executive function tests. Accounting for task unreliability, results indicated significantly improved sensitivity and specificity relative to prior estimates, with 89% of children with ADHD demonstrating objectively-defined impairment on at least one executive function (62% impaired working memory, 27% impaired inhibitory control, 38% impaired set shifting; 54% impaired on one executive function, 35% impaired on two or all three executive functions). Children with working memory deficits showed higher parent- and teacher-reported ADHD inattentive and hyperactive/impulsive symptoms (BF₁₀ = 5.23 × 10⁴), and were slightly younger (BF₁₀ = 11.35) than children without working memory deficits. Children with vs. without set shifting or inhibitory control deficits did not differ on ADHD symptoms, age, gender, IQ, SES, or medication status. Taken together, these findings confirm that ADHD is characterized by neurocognitive heterogeneity, while suggesting that contemporary, cognitively-informed criteria may provide improved precision for identifying a smaller number of neuropsychologically-impaired subtypes than previously described.

Rethinking hyperactivity in pediatric ADHD: Preliminary evidence for a reconceptualization of hyperactivity/impulsivity from the perspective of informant perceptual processes

Hyperactivity is a core ADHD symptom that has been both positively and negatively associated with cognition and functional outcomes. The reason for these conflicting findings is unclear but may relate to subjective assessments that conflate excess physical movement (hyperactivity) with verbally intrusive/impulsive behaviors. The current study adopted a model-driven, rational-empirical approach to distinguish excess physical movement symptoms from other, auditorily perceived behaviors assessed under the "hyperactivity/impulsivity" umbrella. We then tested this alternative conceptualization's fit, reliability, replicability, convergent/divergent validity via actigraphy, and generalizability across informants (parents, teachers) in a well-characterized, clinically evaluated sample of 132 children ages 8-13 years (M = 10.34, SD = 1.51; 47 girls; 67% White/non-Hispanic). The current DSM hyperactivity/impulsivity item pool can be reliably reclassified by knowledgeable judges into items reflecting excess physical movement (visual hyperactivity) and auditory interruptions (verbal intrusion). This bifactor structure showed evidence for multidimensionality and superior model fit relative to traditional hyperactivity/impulsivity models. The resultant visual hyperactivity factor was reliable, replicable, and showed strong convergent validity evidence via associations with objectively assessed hyperactivity. The verbal intrusion factor also showed evidence for reliability and explained a substantive portion of reliable variance, but demonstrated lower estimated replicability. These findings provide preliminary support for conceptualizing ADHD symptoms from the perspective of their cognitive-perceptual impact on others, as well as differentiating excess physical movement (hyperactivity) from other behaviors assessed under the hyperactivity/impulsivity umbrella. "Verbal intrusion" appears to provide a better explanation than "impulsivity" for the reliable, non-hyperactivity variance assessed by these items, but the current item set appears insufficient for replicable measurement of this construct. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Evidence against emotion inference deficits in children with ADHD

Inconsistent evidence suggests that pediatric attention deficit/hyperactivity disorder (ADHD) may be associated with impairments in the ability to use context clues to infer the emotion states of others. However, the evidence base for these impairments is comprised of data from laboratory-based tests of emotion inference that may be confounded by demands on nonaffective cognitive processes that have been linked with ADHD. The current study builds on our previous study of facial affect recognition to address this limitation and investigate a potential mechanism underlying children's ability to infer emotion state from context clues. To do so, we used a fully crossed, counterbalanced experimental design that systematically manipulated emotion inference and working memory demands in 77 carefully phenotyped children ages 8-13 (M_age = 10.46, SD = 1.54; 66% Caucasian/Non-Hispanic; 42% female) with ADHD (n = 42) and without ADHD (n = 35). Results of Bayesian mixed-model ANOVAs indicated that using context clues to infer the emotion state of others competed for neurocognitive resources with the processes involved in rehearsing/maintaining information within working memory (BF₁₀ = 1.57 × 10¹⁹, d = 0.72). Importantly, there was significant evidence against the critical Group × Condition interaction for response times (BF₀₁ = 4.93), and no significant evidence for this interaction for accuracy (BF₀₁ = 2.40). In other words, children with ADHD do not infer emotions more slowly than children without ADHD (d = 0.13), and their small magnitude impairment in accuracy (d = 0.30) was attributable to their generally less accurate performance on choice-response tasks (i.e., across both emotion and control conditions). Taken together, the evidence indicates that emotion inference abilities are likely unimpaired in pediatric ADHD and that working memory is implicated in the ability to infer emotion from context for all children-not just children with ADHD. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Are emotion recognition abilities intact in pediatric ADHD?

Extant studies suggest that children with attention-deficit/hyperactivity disorder (ADHD) may make more errors and respond more slowly on tasks that require them to identify emotions based on facial affect. It is unclear, however, whether these findings reflect a unique deficit in emotion recognition, or more general difficulty with choice-response tasks (i.e., tasks that require participants to select among a set of competing options). In addition, ADHD is associated with executive dysfunction, but there is inconsistent evidence regarding the extent to which top-down cognitive control is involved in emotion recognition. The current study used a series of four counterbalanced tasks to systematically manipulate emotional content and working memory demands to determine (a) whether children with ADHD exhibit a unique facial affect recognition deficit and (b) the extent to which facial affect recognition is an automatic versus controlled process that depends in part on working memory. Bayesian results from a carefully phenotyped sample of 64 children ages 8 to 13 (M = 10.42, SD = 1.56; 26 girls; 67% Caucasian/non-Hispanic) with ADHD (n = 35) and without ADHD (n = 29) indicated that working memory is involved in children's ability to efficiently infer emotional state from facial affect (BF₁₀= 4.59 × 10¹⁴). Importantly, there was significant evidence against deficits in emotion recognition for children with ADHD. The ADHD/non-ADHD groups were statistically equivalent in terms of recognition accuracy (BF₀₁ = 1.32 × 10⁵⁴, d = -0.18), and the ADHD group's slower recognition speed was parsimoniously explained by difficulty with choice-response tasks rather than unique to emotional stimuli (BF₁₀ = 3.23, d = 0.31). These findings suggest that emotion recognition abilities are intact in children with ADHD, and highlight the need to control for impaired bottom-up (choice-response) and top-down abilities (working memory) when investigating emotional functioning in ADHD. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Dopaminergic Genes Polymorphisms and Prefrontal Cortex Efficiency Among Obese People - Whether Gender is a Differentiating Factor?

BACKGROUND

Obesity is a chronic condition associated with poorer cognitive functioning. Wisconsin Card Sorting Test (WCST) is a useful tool for evaluating executive functions. In this study, we assessed the association between dopaminergic gene polymorphisms: DAT1 (SLC6A3), COMTVal158Met, DRD4 (48-bp variable number of tandem repeats - VNTR) and WCST parameters to investigate the functions of the frontal lobes in obese individuals.

OBJECTIVE

To find the significant correlations between polymorphisms of DAT1, COMTVal158Met, DRD4 and executive functions in obese subjects.

METHODS

The analysis of the frequency of individual alleles was performed in 248 obese patients (179 women, 69 men). Evaluation of the prefrontal cortex function (operating memory and executive functions) was measured with the Wisconsin Card Sorting Test (WCST). Separate analyzes were performed in age subgroups to determine different activities and regulation of genes in younger and older participants.

RESULTS

Scores of WCST parameters were different in the subgroups of women and men and in the age subgroups. Regarding the COMT gene, patients with A/A and G/A polymorphisms showed significantly better WCST results in WCST_P, WCST_CC and WCST_1st. Regarding DAT1 men with L/L and L/S made less non-perseverative errors, which was statistically significant. In DRD4, significantly better WCST_1st results were found only in older women with S allele.

CONCLUSION

Obtained results indicate the involvement of dopaminergic transmission in the regulation of prefrontal cortex function. Data analysis indicates that prefrontal cortex function may ensue, from different elements such as genetic factors, metabolic aspects of obesity, and hormonal activity (estrogen).

Transcranial direct current stimulation in attention-deficit hyperactivity disorder: A meta-analysis of neuropsychological deficits

Transcranial direct current stimulation (tDCS) is a promising method for altering cortical excitability with clinical implications in neuropsychiatric diseases. Its application in neurodevelopmental disorders especially attention-deficit hyperactivity disorder (ADHD), is in early stage and promising but its effectiveness has not been systematically examined yet. We conducted a meta-analysis on the effectiveness of tDCS on the most studied neuropsychological symptoms of ADHD, which is the first reported meta-analysis of tDCS studies on ADHD. Data from 10 randomized controlled studies (including 11 separate experiments) targeting inhibitory control, and/or working memory (WM) in ADHD were included. Results show that overall tDCS significantly improved inhibitory control. Sub-analyses further show that dorsolateral prefrontal cortex (dlPFC) (but not right inferior frontal gyrus) tDCS and anodal (but not cathodal) tDCS significantly improved inhibitory control with a small effect size. Anodal dlPFC-tDCS had the largest significant effect on inhibitory control with a small-to-medium effect size. Additionally, a significant improving effect of tDCS on inhibitory control accuracy (but not response time) and WM speed (but not accuracy) were found. Overall, this meta-analysis supports a beneficial effect of tDCS on inhibitory control and WM in ADHD with a small-to-medium effect size. TDCS seems to be a promising method for improving neuropsychological and cognitive deficits in ADHD. However, there might be a dissociation between neuropsychological deficits and clinical symptoms of ADHD and therefore, the significance of this meta-analysis for clinical purposes is limited. Future studies should systematically evaluate the role of inter-individual factors (i.e., ADHD subtype, types of the deficit) and stimulation parameters (i.e., site, polarity, intensity, duration, repetition rate) on tDCS efficacy in ADHD population and examine whether benefits are long-term.

Can working memory training work for ADHD? Development of central executive training and comparison with behavioral parent training

OBJECTIVE

Working memory deficits have been linked experimentally and developmentally with attention-deficit/hyperactivity disorder (ADHD)-related symptoms/impairments. Unfortunately, substantial evidence indicates that extant working memory training programs fail to improve these symptoms/impairments. We hypothesized that this discrepancy may reflect insufficient targeting, such that extant protocols do not adequately engage the specific working memory components linked with the disorder's behavioral/functional impairments.

METHOD

The current study describes the development, empirical basis, and initial testing of central executive training (CET) relative to gold-standard behavioral parent training (BPT). Children with ADHD ages 8-13 (M = 10.43, SD = 1.59; 21 girls; 76% Caucasian/non-Hispanic) were treated using BPT (n = 27) or CET (n = 27). Detailed data analytic plans for the pre/post design were preregistered. Primary outcomes included phonological and visuospatial working memory, and secondary outcomes included actigraphy during working memory testing and two distal far-transfer tasks. Multiple feasibility/acceptability measures were included.

RESULTS

The BPT and CET samples did not differ on any pretreatment characteristics. CET was rated as highly acceptable by children and was equivalent to BPT in terms of feasibility/acceptability as evidenced by parent-reported high satisfaction, low barriers to participation, and large ADHD symptom reductions. CET was superior to BPT for improving working memory (Group × Time d = 1.06) as hypothesized. CET was also superior to BPT for reducing actigraph-measured hyperactivity during visuospatial working memory testing and both distal far-transfer tasks (Group × Time d = 0.74).

CONCLUSIONS

Results provide strong support for continued testing of CET and, if replicated, would support recent hypotheses that next-generation ADHD cognitive training protocols may overcome current limitations via improved targeting. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Are Episodic Buffer Processes Intact in ADHD? Experimental Evidence and Linkage with Hyperactive Behavior

Working memory deficits are present in a substantial proportion of children with ADHD, and converging evidence links these deficits with ADHD-related behavioral and functional impairments. At the same time, working memory is not a unitary construct, and evidence is lacking regarding the role of several components of this system in ADHD. Preclinical behavioral studies are needed to fractionate the multicomponent working memory system, determine which specific subcomponent(s) are impaired in ADHD, and more importantly link these subcomponent(s) with specific ADHD-related behavioral symptoms/functional impairments. The current study reflects one piece of that puzzle, and focuses on the episodic buffer component of working memory. Across multiple testing days, a well-characterized sample of 86 children ages 8-13 (M=10.52, SD=1.54; 34 girls; 64% Caucasian/Non-Hispanic) with ADHD (n=49) and without ADHD (n=37) completed three counterbalanced working memory tests that were identical in all aspects except the key subcomponent process (phonological, visuospatial, episodic buffer). Gross motor movement during these and control tasks were measured using 4 high-precision actigraphs. There was no evidence of group differences in gender, age, SES, or IQ. Bayesian mixed-model ANOVAs indicated that the ADHD group performed significantly worse on all three working memory tests (d=1.17-1.44) and was significantly more hyperactive than controls (d=0.66-1.05) during the visuospatial and episodic buffer tests. In contrast, the ADHD and Non-ADHD groups were equivalent with regard to effects of episodic buffer demands on performance and hyperactive behavior. The most parsimonious conclusion is that the episodic buffer is likely intact in ADHD, and unrelated to ADHD hyperactivity symptoms.

Working Memory and Motor Activity: A Comparison Across Attention-Deficit/Hyperactivity Disorder, Generalized Anxiety Disorder, and Healthy Control Groups

Converging findings from recent research suggest a functional relationship between attention-deficit/hyperactivity disorder (ADHD)-related hyperactivity and demands on working memory (WM) in both children and adults. Excessive motor activity such as restlessness and fidgeting are not pathognomonic symptoms of ADHD, however, and are often associated with other diagnoses such as generalized anxiety disorder (GAD). Further, previous research indicates that anticipatory processing associated with anxiety can directly interfere with storage and rehearsal processes of WM. The topographical similarity of excessive motor activity seen in both ADHD and anxiety disorders, as well as similar WM deficits, may indicate a common relationship between WM deficits and increased motor activity. The relationship between objectively measured motor activity (actigraphy) and PH and visuospatial WM demands in adults with ADHD (n = 21), adults with GAD (n = 21), and healthy control adults (n = 20) was examined. Although all groups exhibited significant increases in activity from control to WM conditions, the ADHD group exhibited a disproportionate increase in activity, while activity exhibited by the GAD and healthy control groups was not different. Findings indicate that ADHD-related hyperactivity is uniquely related to WM demands, and appear to suggest that adults with GAD are no more active relative to healthy control adults during a cognitively demanding laboratory task.

Hyperactivity in boys with attention-deficit/hyperactivity disorder: The influence of underlying visuospatial working memory and self-control processes

Changes in motor activity were examined across control and executive function (EF) tasks that differ with regard to demands placed on visuospatial working memory (VS-WM) and self-control processes. Motor activity was measured via actigraphy in 8- to 12-year-old boys with (n=15) and without (n=17) attention-deficit/hyperactivity disorder (ADHD) during the completion of VS-WM, self-control, and control tasks. Results indicated that boys with ADHD, relative to typically developing boys, exhibited greater motor activity across tasks, and both groups' activity was greater during EF tasks relative to control tasks. Lastly, VS-WM performance, relative to self-control performance, accounted for significantly more variance in activity across both VS-WM and self-control tasks. Collectively, findings suggest that ADHD-related hyperactivity is positively related to increased cognitive demands and appears to be better explained by deficient VS-WM rather than insufficient self-control.

Is hyperactivity ubiquitous in ADHD or dependent on environmental demands? Evidence from meta-analysis

Hyperactivity, or excess gross motor activity, is considered a core and ubiquitous characteristic of ADHD. Alternate models question this premise, and propose that hyperactive behavior reflects, to a large extent, purposeful behavior to cope with environmental demands that interact with underlying neurobiological vulnerabilities. The present review critically evaluates the ubiquity and environmental modifiability of hyperactivity in ADHD through meta-analysis of 63 studies of mechanically measured activity level in children, adolescents, and adults with ADHD relative to typically developing groups. Random effects models corrected for publication bias confirmed elevated gross motor activity in ADHD (d=0.86); surprisingly, neither participant age (child vs. adult) nor the proportion of each ADHD sample diagnosed with the inattentive subtype/presentation moderated this effect. In contrast, activity level assessed during high cognitive load conditions in general (d=1.14) and high executive functioning demands in particular (d=1.39) revealed significantly higher effect sizes than activity level during low cognitive load (d=0.36) and in-class schoolwork (d=0.50) settings. Low stimulation environments, more rigorous diagnostic practices, actigraph measurement of movement frequency and intensity, and ADHD samples that included fewer females were also associated with larger effects. Overall, the results are inconsistent with DSM-5 and ADHD models that a) describe hyperactivity as ubiquitous behavior, b) predict a developmental decline in hyperactivity, or c) differentiate subtypes/presentations according to perceived differences in hyperactive behavior. Instead, results suggest that the presence and magnitude of hyperactive behavior in ADHD may be influenced to a considerable extent by environmental factors in general, and cognitive/executive functioning demands in particular.