The role of inattention and hyperactivity/impulsivity in the fine motor coordination in children with ADHD

Neurocognitive training enhances the outcomes of children with attention deficit hyperactivity disorder: A preliminary study

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder characterized by diverse clinical manifestations including inattention, hyperactivity and impulsivity.

OBJECTIVE

The present study aims to investigate the effects of neurocognitive training (NT), a personalized and specialized exercise programme on symptoms, attention and dynamic balance in treatment-naïve children diagnosed with ADHD.

METHODS

Fourteen treatment-naïve children aged 7-12 years diagnosed with ADHD were enrolled in the intervention group. The NT intervention was administered weekly for 10 consecutive weeks, supplemented by a structured home exercise programme for 6 days a week over the same 10-week period. ADHD-related symptoms, attention and dynamic balance were assessed in pre-treatment, post-treatment, 6 months, and 12 months. Fifteen typically developing (TD) children, matched for age, underwent evaluation only once to establish baseline normative values.

RESULTS

Following the NT (post-treatment), significant improvements were observed in hyperactivity-impulsivity scores, oppositional-defiant behaviours and dynamic balance when compared to the TD children (p < 0.05). In the ADHD group, a significant difference was found in the long term (12-month follow-up) in hyperactivity-impulsivity, oppositional-defiant behaviours and dynamic balance (p < 0.05).

CONCLUSION

The findings suggest that the NT yields favourable effects on hyperactivity-impulsivity, oppositional defiant behaviours and dynamic balance in children diagnosed with ADHD, with these improvements appearing to be sustained over the long term.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04707040.

Stimulant Drugs and Stimulant Use Disorder

The authors aim to summarize several key points of stimulant drugs and stimulant use disorder, including their indications, short-term and long-term adverse effects, current treatment strategies, and association with opioid medications. The global prevalence of stimulant use has seen annual increase in the last decade. Multiple studies have shown that stimulant use and stimulant use disorder are associated with a range of individual and public health issues. Stimulant misuse has led to a significant increase of overdose deaths in the United States.

Effects of the Specific Eye Fixation Training on Fine Visuomotor Coordination in Children with Attention Deficit Hyperactivity Disorder

This study investigated the effects of quiet eye training (QET) on the neuropsychological functioning and fine motor performance of children with attention deficits. The participant cohort consisted of 106 children with attention deficit hyperactivity disorder (ADHD) between the ages of 8 and 12 years. The children were assigned to either the QET group (n = 54) or the control group (n = 52). The QET group went through a 5-week intervention in which the performance of blocks of targeting tasks was preceded by watching split-screen video footage featuring the gaze and body movements of a skilled model performing a throwing motion. Both groups underwent pre-test and post-test assessments, which included the reaction test of alertness, go/no-go inhibition test, and motor performance series test. The QET group demonstrated significant improvements in attentional engagement, inhibitory control, and fine motor skills, which require precise and fast visuomotor coordination. These results highlight the potential benefits of QET intervention in ameliorating attention deficits and enhancing fine aiming motor skills in children with ADHD. However, task specificity was evident, indicating that the intervention effects were most pronounced for the hand fine motor aiming tasks requiring both precision and speed.

Fine Motor Skills in Children with Tourette Syndrome and their Unaffected First-degree Siblings

Background

The exact etiology of Tourette Syndrome (TS) remains unclear, making the search for impaired neuropsychological functions possibly connected to the underlying cause of TS as important as it is challenging. One neuropsychological domain of interest is fine motor skills.

Method

This study compared fine motor skill performance on the Purdue Pegboard Task (PPT) in 18 children with TS, 24 unaffected first-degree siblings and 20 controls. A set of screening questionnaires was administered to determine comorbid psychiatric illness.

Results

Children with TS, their siblings and controls did not differ significantly in fine motor skills as measured with the PPT. Performance on the PPT was not correlated with tic severity; however, we found an inverse correlation with severity of attention-deficit/hyperactivity disorder (ADHD) symptoms, as assessed by parent reported ADHD symptoms. Children with TS were found to have significantly higher parent reported ADHD symptoms compared to controls, yet only two out of the 18 participants had been diagnosed with ADHD.

Conclusion

This study suggests that fine motor skill impairment in children with TS may be more strongly correlated with comorbid ADHD than to TS and tics.

Cilia in the Striatum Mediate Timing-Dependent Functions

Almost all brain cells contain cilia, antennae-like microtubule-based organelles. Yet, the significance of cilia, once considered vestigial organelles, in the higher-order brain functions is unknown. Cilia act as a hub that senses and transduces environmental sensory stimuli to generate an appropriate cellular response. Similarly, the striatum, a brain structure enriched in cilia, functions as a hub that receives and integrates various types of environmental information to drive appropriate motor response. To understand cilia's role in the striatum functions, we used loxP/Cre technology to ablate cilia from the dorsal striatum of male mice and monitored the behavioral consequences. Our results revealed an essential role for striatal cilia in the acquisition and brief storage of information, including learning new motor skills, but not in long-term consolidation of information or maintaining habitual/learned motor skills. A fundamental aspect of all disrupted functions was the "time perception/judgment deficit." Furthermore, the observed behavioral deficits form a cluster pertaining to clinical manifestations overlapping across psychiatric disorders that involve the striatum functions and are known to exhibit timing deficits. Thus, striatal cilia may act as a calibrator of the timing functions of the basal ganglia-cortical circuit by maintaining proper timing perception. Our findings suggest that dysfunctional cilia may contribute to the pathophysiology of neuro-psychiatric disorders, as related to deficits in timing perception.

Bibliometric Analysis of Psychomotricity Research Trends: The Current Role of Childhood

Psychomotricity is a wide broad term, which encompasses different bodily action approaches to support children and adolescents to achieve their highest potential. A search on the Web of Science (WoS) Core Collection database was performed on this topic, using traditional bibliometric laws. Finally, 118 publications (112 articles and 6 reviews) documents were found. Annual publications presented an exponentially growing trend (R² = 84.7%). Spain was the most productive country/region worldwide. Paola Magioncalda, Matteo Martino y Víctor Arufe Giraldez were highlighted as the most prolific co-authors. "Retos Nuevas Tendencias en Educación Física, Deporte y Recreación" was the most productive journal and the "International Journal of Environmental Research and Public Health", was the second most productive; the third in the list was the most productive in the JCR ranking. Thus, research on psychomotricity is experiencing exponential growth, causing this topic to generate great interest among researchers, publishers and journals. The most cited paper was "Neurocognitive Effects of Alcohol Hangover". The author keywords that were first raised together with psychomotricity were related to rehabilitation and psychomotor development, while the current trend was focused on physical activity and early childhood education.

Reduced Modular Segregation of White Matter Brain Networks in Attention Deficit Hyperactivity Disorder

OBJECTIVE

Despite studies reporting alterations in the brain networks of patients with ADHD, alterations in the modularity of white matter (WM) networks are still unclear.

METHOD

Based on the results of module division by generalized Louvain algorithm, the modularity of ADHD was evaluated. The correlation between the modular changes of ADHD and its clinical characteristics was analyzed.

RESULTS

The participation coefficient and the connectivity between modules of ADHD increased, and the modularity coefficient decreased. Provincial hubs of ADHD did not change, and the number of connector hubs increased. All results showed that the modular segregation of WM networks of ADHD decreased. Modules with reduced modular segregation are mainly responsible for language and motor functions. Moreover, modularity showed evident correlation with the symptoms of ADHD.

CONCLUSION

The modularity changes in WM network provided a novel insight into the understanding of brain cognitive alterations in ADHD.

The Contributions of Cognitive Abilities to the Relationship between ADHD Symptoms and Academic Achievement

The main objective of this study was to examine whether increased levels of inattentive (INA) and hyperactive/impulsive (H/I) behaviours were associated with lower scores on standardized tests of achievement in basic reading, spelling, and math skills, after accounting for certain known background risk factors and cognitive processes. Clinical assessment data from a rigorously diagnosed, stimulant-medication-naïve sample of 354 elementary school-aged children experiencing academic difficulties and behavioural symptoms of inattention and/or hyperactivity/impulsivity were analyzed. Although higher scores of INA were significantly associated with lower scores in reading, spelling, and math, these associations did not persist when cognitive variables were added to the models. H/I was associated with math achievement, along with cognitive and background variables. Overall, cognitive variables accounted for the majority of the variance across basic reading, spelling, and math skills. Additionally, the only background demographic variables associated with academic achievement were age and sex for spelling and math. This finding highlights the importance of looking beyond observable INA and H/I behaviours to determine the underlying factors influencing academic achievement. Accurate identification of deficits in specific academic skills and the underlying factors influencing achievement in these skills are essential components in determining appropriate recommendations and targeted interventions.

Effects of Comorbid Developmental Coordination Disorder and Symptoms of Attention Deficit Hyperactivity Disorder on Physical Activity in Children Aged 4-5 Years

Developmental coordination disorder (DCD) is often comorbid with attention-deficit/hyperactivity disorder (ADHD). While children with DCD engage in less moderate-to-vigorous physical activity (MVPA) compared to typically developing (TD) children, research pertaining to how ADHD affects this relationship is limited. We investigated the effect of ADHD on MVPA among children at risk for DCD (DCDr). 507 children aged 4-5 years (DCDr = 233, TD = 274) participated. Motor skills were assessed using the Movement Assessment Battery for Children-2nd edition (DCDr; ≤ 16th percentile), ADHD symptoms were assessed using the Child Behaviour Checklist, and Actigraph accelerometers measured MVPA over seven days. DCD did not negatively affect MVPA, however, after adjusting for ADHD symptoms, the effect of DCD became significant and was driven by symptoms of inattention. Symptoms of ADHD may be suppressing the negative effects of DCD on MVPA, highlighting the importance of assessing and controlling for ADHD symptoms in this population.

The performance and predictors of Chinese character writing in children with attention deficit hyperactivity disorder

Writing difficulties are common in children with attention deficit hyperactivity disorder (ADHD). Preliminary evidence suggests that early character writing ability is fundamental for later writing composition and academic achievement. Critical factors of different character writing tasks in children with ADHD, however, remain unclear. This study aims to describe the performance and identify predictors of Chinese character writing in children with ADHD. Thirty Mandarin Chinese-speaking children with ADHD (7.16 ± 0.59 years) and thirty matched peers (7.21 ± 0.57 years) were recruited from northern Taiwan. They were evaluated with the Battery of Chinese Basic Literacy (BCBL); the Chinese version of the Test of Nonverbal Intelligence, fourth edition (C-TONI-4); the Chinese version of the Peabody Picture Vocabulary Test-Revised (C-PPVT-R); orthographic awareness test; character naming test; and the Bruininks Oseretsky Test of Motor Proficiency, second edition (BOT-2). The results showed that Mandarin Chinese-speaking children with ADHD scored lower than their typically developing peers on both dictation and copying subtests. After controlling for age, orthographic awareness and inattention were identified as important predictors of character dictation; while, manual dexterity was a critical predictor of character copying in children with ADHD. The results demonstrated that character writing problems may exist in Mandarin Chinese-speaking children with ADHD, and cognitive-linguistic and fine-motor skills have varying contributions to Chinese character writing tasks.

A rapid systematic review of attention-deficit/hyperactivity disorder (ADHD) and high order writing: Current findings and implications for intervention

BACKGROUND

Theoretical writing models and empirical studies have suggested a possible strong association between attention-deficit/hyperactivity disorder (ADHD) and high order writing (e.g., planning, text production, and revising).

AIM

A rapid systematic review was conducted to examine this relationship with the aim of informing writing interventions specific to the ADHD population.

METHOD

A systematic search for empirical studies on ADHD and high order writing performance from the last two decades identified 18 eligible studies.

RESULTS

Most studies showed that, compared to their peers, students with ADHD have more significant difficulties in high order writing performance. Writing quality and writing process (e.g., planning and editing) were identified as a challenge for ADHD students and may be more challenging than writing productivity and meta-cognitive knowledge of writing. Individuals' inattention, short-term memory, working memory, executive functions, reading, oral language skills, and externalising behavioural problems were identified as significant predictors of high order writing performance.

CONCLUSIONS AND IMPLICATIONS

The findings support theoretical writing models that propose writing as a complex process influenced by multiple cognitive factors, which are commonly impaired in individuals with ADHD. Interventions specific to the identified problems are discussed.

Association between fluoride exposure and behavioural outcomes of school-age children: a pilot study in China

To assess the association between fluoride exposure and children's behavioural outcomes, we recruited 325 resident school-age children (7-13 years old) lived in Tongxu County of Henan Province in China. We measured urinary fluoride (UF) concentrations using the ion-selective electrode method. Children's behavioural outcomes were assessed by Conners' Parent Rating Scale-Revised, including conduct problems, learning problems, psychosomatic problems, impulsive-hyperactive, anxiety, and ADHD index. It turned out that each 1.0 mg/L increment in UF concentration corresponded with an elevation in the psychosomatic problem score of 4.01 (95% CI: 2.74, 5.28) and a 97% (OR = 1.97, 95% CI: 1.19, 3.27) increase in the prevalence of psychosomatic problems after adjusting for potential influencing factors. The sensitivity analysis results were consistent with those observed in our preliminary analysis. Our study suggests that fluoride exposure is positively related to the behavioural problem in school-age children, psychosomatic problem in particular.

The investigation of foot structure within children who have attention-deficit hyperactivity disorder: a case-controlled study

The impairments in motor performance could be related to the foot structure in children with attention-deficit/hyperactivity disorder (ADHD) while considering the close relationship between foot structure and lower extremity alignment. This study aimed to investigate the foot structure and its relationships between disease severity, physical activity and psychiatric traits in children with ADHD. Children with ADHD (n = 50; mean age: 12.02 ± 1.83 years) and typically developing peers (n = 30; mean age: 12.86 ± 2.56 years) were included. The static footprint analysis was collected by using digital images. The ImageJ program was used to calculate Clarke's angle, Staheli arch index (SAI) and Chippaux-Smirak index (CSI). The Turgay DSM-IV disruptive behavior disorders rating scale (T-DSM-IV-S), physical activity questionnaire for older children (PQ-C), children's depression inventory and state-trait anxiety inventory for children were all used to assess symptoms of ADHD, physical activity, depression, stress and anxiety, respectively. Approximately 52-53% of children with ADHD had mild to severe flatfoot, while only 8-13% of typically developing peers had flatfoot based on SAI and CSI (P = 0.01). Significant correlation was found between Clarke's angle and PQ-C (r = 0.21, P = 0.04). Besides, T-DSM-IV-S was significantly correlated with SAI (r = 0.24, P = 0.01) and CSI (r = 0.25, P = 0.01) in children with ADHD. Children with ADHD had a significantly greater tendency of flatfoot compared to typically developing peers. Besides, the deterioration of the foot structure of children with ADHD was associated with disease severity.

Executive Function Training for Preschool Children With ADHD: A Randomized Controlled Trial

OBJECTIVE

This randomized controlled study explored the efficacy, feasibility, and acceptability of executive function training (EFT) for preschool children with ADHD.

METHOD

The current study design was an 8 week randomized parallel groups, single-blinded trial, using EFT-P. A total of 96 children with an ADHD diagnosis at age 4 to 5 years old were randomized into the intervention group and waitlist group. In the intervention group, 46 out of 50 participants completed the 8-week program, compared with 39 out of 46 in the waiting group. The level of ADHD symptoms and the executive function (EF) were evaluated by both neuropsychological tests from NEPSY Second Edition (NEPSY-II) and Behavior Rating Inventory of Executive Function Preschool version (BRIEF-P).

RESULTS

The EFT is feasible to administer and is acceptable for preschool children, with a 93% retention rate. Results showed that following the intervention, the visual-motor precision (p = .024), ADHD diagnostic state (p = .01), and oppositional defiant symptoms (p = .023) improved significantly in preschool children. However, the symptoms of ADHD and other EF evaluations were found to be insignificant.

CONCLUSION

The EFT is feasible, acceptable, and potentially effective to reduce symptoms and improve EF for preschool children with ADHD. The next step is to extend the program time and provide more frequent practice of activities between the children and the therapist and/or parent, to improve the effectiveness.

How effective is fine motor training in children with ADHD? A scoping review

Background

Motor deficiencies are observed in a large number of children with ADHD. Especially fine motor impairments can lead to academic underachievement, low self-esteem and frustration in affected children. Despite these far-reaching consequences, fine motor deficiencies have remained widely undertreated in the ADHD population. The aim of this review was to systematically map the evidence on existing training programs for remediating fine motor impairments in children with ADHD and to assess their effectiveness.

Methods

The scoping review followed the PRISMA-ScR guidelines. In March 2020, PsycINFO, MEDLINE (PubMed), Web of Science, Google Scholar and The Cochrane Database of Systematic Reviews were searched for evidence. The eligibility criteria and the data charting process followed the PICO framework, complemented by study design. The investigated population included children with a formal ADHD diagnosis (either subtype) or elevated ADHD symptoms aged between 4 and 12 years, both on and off medication. All training interventions aiming at improving fine motor skills, having a fine motor component or fine motor improvements as a secondary outcome were assessed for eligibility; no comparators were specified.

Results

Twelve articles were included in the final report, comprising observational and experimental studies as well as a review. Both offline and online or virtual training interventions were reported, often accompanied by physical activity and supplemented by training sessions at home. The training programs varied in length and intensity, but generally comprised several weeks and single or multiple training sessions per week. All interventions including more than one session were effective in the treatment of fine motor deficiencies in children with ADHD and had a wide range of additional positive outcomes. The effects could be maintained at follow-up.

Conclusions

Fine motor training in children with ADHD can be very effective and multiple approaches including specific fine motor and cognitive training components, some kind of physical activity, feedback mechanisms, or multimodal treatments can be successful. Training programs need to be tailored to the specific characteristics of the ADHD population. A mHealth approach using serious games could be promising in this context due to its strong motivational components.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02916-5.

Resting Theta/Beta Ratios Mediate the Relationship Between Motor Competence and Inhibition in Children With Attention Deficit/Hyperactivity Disorder

Despite that previous studies have supported relationships between motor ability and inhibitory function, and between resting brain theta/beta power ratios (TBR) and inhibition in children with attention deficit/hyperactivity disorder (ADHD), little research has examined the mechanism within these relationships. The purpose of this study was to investigate whether TBR would mediate the relationship between motor ability and inhibitory function. A total of 71 children with ADHD were recorded resting electroencephalographic (EEG) data during eyes-open. Motor abilities were evaluated by Movement Assessment Battery for Children-2 (MABC-2) and inhibitory ability were assessed by a modified Eriksen’s flanker task. The results of mediation analyses revealed that TBR could completely mediate the relationship between motor competence and response speed (indirect effect = −0.0004, 95% CI [−0.0010, −0.0001]) and accuracy (indirect effect = 0.0003, 95% CI [0.0000, 0.0010]) in the incongruent condition of the flanker task. This study suggests that TBR may be one of the mechanisms between motor ability and inhibition function in children with ADHD.

Executive Functioning Rating Scale as a Screening Tool for ADHD: Independent Validation of the BDEFS-CA

Objective: This study provides independent examination of the validity of the Barkley Deficits of Executive Functioning Scale-Children and Adolescents (BDEFS-CA) in a sample of children diagnosed with ADHD (n = 50) and typically developing controls (n = 50). Method: Parents of participants completed the BDEFS-CA and the Conners 3 rating scales. Validity of BDEFS-CA was examined using a confirmatory factor analysis, correlational analyses with Conners 3 ratings, and receiver operating characteristic (ROC) curve analysis of diagnostic accuracy. Results: Findings support the construct, concurrent, and discriminant validity of the BDEFS-CA in a mixed sample. Conclusion: Findings provide independent examination of the validity of the BDEFS-CA as a measure of executive dysfunction and a screening tool for ADHD.

Atypical cortical activation during fine motor tasks in autism spectrum disorder

Individuals with autism spectrum disorder (ASD) often have difficulty with coordinated fine motor skills, but the degree of difficulty significantly varies from person to person. To elucidate the cause of this diversity, we monitored brain activity during fine movement tasks (tying bowknots) by near-infrared spectroscopy in 17 adults with ASD and 18 adults with typical development matched for age, gender, and intelligence quotient (IQ). We also examined the relationship between brain activation and developmental characteristics, including ASD severity, using the Autism-Spectrum Quotient and the Multi-dimensional Scale for Pervasive Developmental Disorder and Attention-Deficit/Hyperactivity Disorder. Although participants in the ASD group did not show significant clumsiness, their right prefrontal cortexes were relatively less activated, particularly in individuals with poor social skills and inattention. Our study indicates that individuals with ASD traits may use different strategies when performing fine movements; that is, they less use the brain areas responsible for processing visual image or planning behaviors.

Reduced fine motor competence in children with ADHD is associated with atypical microstructural organization within the superior longitudinal fasciculus

Recent work in healthy adults suggests that white matter organization within the superior longitudinal fasciculus (SLF) may, at least partly, explain individual differences in fine motor skills. The SLF is also often implicated in the neurobiology underlying attention deficit hyperactivity disorder (ADHD) as part of the attention network connecting frontal and parietal regions. While ADHD is primarily characterized by inattention, impulsivity and/or hyperactivity, atypical fine motor control is a common comorbid feature. This study aimed to investigate the association between reduced fine motor skills in ADHD and microstructural properties within the SLF. Participants were 55 right-handed children with ADHD and 61 controls aged 9-11 years. Fine motor control was assessed using the Grooved Pegboard task. Children underwent high angular resolution diffusion MRI. Following pre-processing, constrained spherical deconvolution tractography was performed to delineate the three SLF branches bilaterally. Children with ADHD showed significantly poorer fine motor performance relative to controls in the non-dominant hand, indicated by significantly slower left handed Grooved Pegboard task performance. This slower response time for the non-dominant (left) hand was significantly associated with reduced apparent fibre density within the right SLF I, and reduced right SLF I, II and III volume. This finding was independent of spatial attention performance. These data support previous reports indicating that children with ADHD have poorer fine motor performance than controls in their non-dominant hand, and indicates that the neurobiological basis for impaired fine motor control may involve white matter properties within the contralateral SLF. This suggests that white matter properties in fronto-parietal areas may have broader implications than attention.

The Potential Role of Dopamine in Mediating Motor Function and Interpersonal Synchrony

Motor functions in general and motor planning in particular are crucial for our ability to synchronize our movements with those of others. To date, these co-occurring functions have been studied separately, and as yet it is unclear whether they share a common biological mechanism. Here, we synthesize disparate recent findings on motor functioning and interpersonal synchrony and propose that these two functions share a common neurobiological mechanism and adhere to the same principles of predictive coding. Critically, we describe the pivotal role of the dopaminergic system in modulating these two distinct functions. We present attention deficit hyperactivity disorder (ADHD) as an example of a disorder that involves the dopaminergic system and describe deficits in motor and interpersonal synchrony. Finally, we suggest possible directions for future studies emphasizing the role of dopamine modulation as a link between social and motor functioning.

Neural generators involved in visual cue processing in children with attention-deficit/hyperactivity disorder (ADHD)

Event-related potentials (ERP) studies report alterations in the ongoing visuo-attentional processes in children with attention-deficit/hyperactivity disorder (ADHD). We hypothesized that the neural generators progressively recruited after a cue stimulus imply executive-related areas well before engagement in executive processing in children with ADHD compared to typically developed children (TDC). We computed source localization (swLORETA) of the ERP and ERSP evoked by the Cue stimulus during a visual Cue-Go/Nogo paradigm in 15 ADHD compared to 16 TDC. A significant difference in N200/P200 amplitude over the right centro-frontal regions was observed between ADHD and TDC, supported by a stronger contribution of the left visuo-motor coordination area, premotor cortex, and prefrontal cortex in ADHD. In addition, we recorded a greater beta power spectrum in ADHD during the 80-230 ms interval, which was explained by increased activity in occipito-parieto-central areas and lower activity in the left supramarginal gyrus and prefrontal areas in ADHD. Successive analysis of the ERP generators (0-500 ms with successive periods of 50 ms) revealed significant differences beginning at 50 ms, with higher activity in the ventral anterior cingulate cortex, premotor cortex, and fusiform gyrus, and ending at 400-500 ms with higher activity of the dorsolateral prefrontal cortex and lower activity of the posterior cingulate cortex in ADHD compared to TDC. The areas contributing to ERP in ADHD and TDC differ from the early steps of visuo-attentional processing and reveal an overinvestment of the executive networks interfering with the activity of the dorsal attention network in children with ADHD.

Arousal and Executive Alterations in Attention Deficit Hyperactivity Disorder (ADHD)

Attention deficit hyperactivity disorder (ADHD) is the most common neurobehavioral disorder in childhood and can significantly affect a child's personal and social development and academic achievement. Taking into account the model of attentional networks proposed by Posner et al., the aim of the present study was to review the literature regarding two main explicative models of ADHD, i.e., the inhibition model and the cognitive-energetic model, by discussing behavioral and neurological evidence of both models and the limitations of each model. The review highlights evidence that favors the energetic model and points to an unstable arousal as a potential pathogenetic factor in ADHD.

Neuropsychological classification based on brain mapping performance in Thai children with and without ADHD

This study investigated the cognitive strengths and weaknesses of Attention Deficit Hyperactivity Disorder (ADHD) patients by using quantitative electroencephalography (QEEG) to analyze brain mapping outcomes in relation to neuropsychological assessments. A total of 305 participants with and without ADHD were recruited. The theta relative power of QEEG was analyzed using stepwise multiple regression, and twelve scalp regions were compared between groups using independent t-tests. Increased power was found at the T5 scalp region in the ADHD group and at the F4 region in the non-ADHD group. Decreased power was found at the F7 region in the ADHD group and at the F3 region in the non-ADHD group. Six of the twelve brain locations had significantly higher theta relative power in the ADHD group than in the non-ADHD group. These brain mapping outcomes can be easily translated to neuropsychological functions, such as attention, executive function, memory, spatial ability, and language, to better understand or predict the potential behavior of ADHD patients.

Human Brain Imaging Links Dopaminergic Systems to Impulsivity

Molecular and functional imaging techniques have been used and combined with pharmacological probes to evaluate the role of dopamine in impulsivity. Overall, strong evidence links striatal dopaminergic function with impulsivity, measured by self-reports and laboratory tests of cognitive control and reward-based decision-making. The combination of molecular imaging using positron emission tomography (PET) with functional magnetic resonance imaging (fMRI) specifically implicates striatal D2-type dopamine receptors (i.e., D2 and D3) and corticostriatal connectivity in cognitive control. Low levels of striatal and midbrain D2-type receptor availability correlate with self-reported impulsivity, whereas striatal D2-type receptor availability shows positive correlation with motor response inhibition and cognitive flexibility. Impulsive choice on reward-based decision-making tasks also is related to deficits in striatal D2-type dopamine receptor availability, and there is evidence for an inverted U-shaped function in this relationship, reflecting an optimum of striatal dopaminergic activity. Findings from studies of clinical populations that present striatal dopamine D2-type receptor deficits as well as healthy control research participants identify D2-type receptors as therapeutic targets to improve cognitive control.

Gender and hand dominance on fine motor skills among Grade 1–7 learners with attention-deficit hyperactivity disorder

Children diagnosed with attention-deficit/hyperactivity disorder encounter difficulties in many activities in their daily lives that require motor coordination skills. The aim of this study was to establish whether children with attention-deficit/hyperactivity disorder have deficits in fine motor skills. Eighty male and female learners diagnosed with attention-deficit/hyperactivity disorder matched with 80 non-attention-deficit/hyperactivity disorder from the North West and Limpopo provinces (South Africa), aged 7–13  years, participated in the study. All participants completed the grooved pegboard test, the maze coordination task, and the finger tapping test. These instruments measure various functions of motor speed and eye–hand coordination. The findings reveal that children with attention-deficit/hyperactivity disorder performed significantly poorer than the control group with regard to the grooved pegboard and maze coordination tasks, but not with the finger tapping task. There were no gender differences in all the tests. Performance on the maze coordination task with the non-dominant hand was poorer for the attention-deficit/hyperactivity disorder group with regard to the time taken to complete the task. However, no hand dominance differences were found on the grooved pegboard and finger tapping tests. The study revealed a relationship between attention-deficit/hyperactivity disorder symptomatology and motor problems with regard to complex tasks of accuracy, but not on a simple task of motor speed. It is, therefore, recommended that since children with attention-deficit/hyperactivity disorder show motor deficiencies, motor skill training should be considered as part of the intervention, as these skills are needed for many daily activities and academic competencies.