Gender differences among children with ADHD on continuous performance tests: a meta-analytic review

Sex Differences in Diagnosis and Treatment Timing of Comorbid Depression/Anxiety and Disease Subtypes in Patients With ADHD: A Database Study

OBJECTIVE

Our study examined the impact of sex, ADHD subtype, and comorbid illnesses (depression/anxiety) on the timing of diagnosis and treatment for ADHD.

METHOD

To analyze ADHD patients, four health databases were used to assess subtype, comorbid mood, and antidepressant or anxiolytic drug exposure. Analyses were stratified by sex and age. Standardized mean differences measured intergroup differences.

RESULTS

Females with ADHD were identified at older ages and had higher rates of depression and anxiety diagnoses and treatments before and after their initial ADHD diagnosis. Predominantly inattentive ADHD patients were diagnosed later and more likely to receive mood disorder diagnosis and treatment than hyperactive impulsive ADHD patients.

CONCLUSIONS

Results suggest a more complex ADHD presentation in females, potentially causing late diagnosis and delayed treatment.

The experience of effort in ADHD: a scoping review

Background

Mental effort plays a critical role in regulating cognition. However, the experience of mental effort may differ for individuals with Attention-Deficit/Hyperactivity Disorder (ADHD), a disorder for which sustained mental effort 'avoidance' or 'dislike' is a criterion in the DSM. We conducted a scoping review to characterize the literature on the experiences of effort in ADHD.

Methods

This systematic scoping review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Extension for Scoping Reviews and Joanna Briggs Methodology. PsycINFO (OVID), PsycINFO (ProQuest) and PubMed were searched for studies published in English before February 14, 2023. Studies must have included an ADHD population or a measure of ADHD symptomatology, in addition to a self-report measure of the experience of effort or the use of an effort preference paradigm. Two researchers reviewed all abstracts, and one researcher reviewed full-text articles.

Results

Only 12 studies met the inclusion criteria. Several gaps and inconsistencies in the research were identified in terms of method, definitions of effort, measurements of ADHD, and sample characteristics. Moreover, the pattern of results on the experience of effort was mixed.

Conclusion

Despite its diagnostic and conceptual significance, the experience of mental effort in ADHD is not well studied. Critical gaps were identified in the existing literature. A three-facet conceptualization of effort is proposed-specifically, task-elicited effort, volitionally exerted effort, and the affect associated with engaging in effort - to guide future explorations of the experience of effort in ADHD.

Sex-differential patterns of neuropsychological functioning in adults with attention-deficit/hyperactivity disorder

BACKGROUND

The sex-differential prevalence of attention-deficit/hyperactivity disorder (ADHD) varies across the lifespan, but little is known about sex differences in executive functions in adults with ADHD.

METHODS

We assessed 261 adults, aged 18-40 years, diagnosed with ADHD (170 males [assigned at birth], aged 25.81 ± 5.49; 91 females, aged 27.76 ± 5.42) and 308 neurotypical adults (176 males, aged 24.62 ± 5.14; 132 female, aged 25.37 ± 5.42) via psychiatric interviews to confirm ADHD and other psychiatric diagnoses. They were assessed by the Cambridge Neuropsychological Testing Automated Battery (CANTAB) on Reaction Time (arousal/processing speed), Rapid Visual Information Processing (sustained attention), Spatial Span (spatial memory), Spatial Working Memory, Intradimentional/Extradimensional Shift (set-shifting), and Stocking of Cambridge (spatial planning). The primary analyses were adjusted for age, full-scale IQ, and co-occurring psychiatric conditions.

RESULTS

Adults with ADHD had various co-occurring psychiatric conditions without sex differences in ADHD-neurotypical differences. Both adult males and females with ADHD performed poorer in all CANTAB tasks than same-sex neurotypical adults. Significant sex-moderating effects were observed in neuropsychological performance, including greater ADHD-neurotypical differences in arousal for females than males and in location memory for spatial tasks in males than females.

CONCLUSION

There were no sex-moderating effects in the presence of co-occurring psychiatric conditions in adult ADHD. However, there were sex-moderating effects on how ADHD related to neuropsychological functioning in adulthood. ADHD was associated with more challenges in arousal/processing speed in females and more challenges in strategy use or inhibition in spatial memory in males.

Differences in Ex-Gaussian Parameters from Response Time Distributions Between Individuals with and Without Attention Deficit/Hyperactivity Disorder: A Meta-analysis

Attention Deficit Hyperactivity Disorder (ADHD) is one of the most prevalent neurodevelopmental disorders in childhood and adolescence. Differences in reaction times (RT) in cognitive tasks have been consistently observed between ADHD and typical participants. Instead of estimating means and standard deviations, fitting non-symmetrical distributions like the ex-Gaussian, characterized by three parameters (µ, σ, and τ), account for the whole RT distributions. A meta-analysis is performed with all the available literature using ex-Gaussian distributions for comparisons between individuals with ADHD and controls. Results show that τ and σ are generally greater for ADHD samples, while µ tends to be larger for typical groups but only for younger ages. Differences in τ are also moderated by ADHD subtypes. τ and σ show, respectively, quadratic and linear relationships with inter-stimulus intervals from Continuous Performance Test and Go/No Go tasks. Furthermore, tasks and cognitive domains influence the three parameters. Interpretations of ex-Gaussian parameters and clinical implications of these findings are also discussed. Fitting ex-Gaussian distributions to RT data is a useful way to explore differences between individuals with ADHD and healthy controls.

A systematic review of the utility of continuous performance tests among adults with ADHD

OBJECTIVE

The clinical utility of continuous performance tests (CPTs) among adults with attention-deficit/hyperactivity disorder (ADHD) has increasingly been brought under question. Therefore, the objective of this study was to systematically review the literature to investigate the clinical utility of various commercially available CPTs, including the Conner's Continuous Performance Test (CCPT), Test of Variables of Attention (TOVA), Gordon Diagnostic System (GDS), and Integrated Visual and Auditory Continuous Performance Test (IVA) in the adult ADHD population.

METHODS

This systematic review followed the a priori PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Articles were gathered from PsycINFO, PsycARTICLES, Academic Search Complete, and Google Scholar on 11 April 2022. Sixty-nine articles were included in the final review. Risk of bias was assessed using the National Institute of Health Quality Assessment Took for Observational Cohort and Cross-Sectional Studies.

RESULTS

Most articles demonstrated high risk of bias, and there was substantial heterogeneity across studies. Overall, the reviewed CPTs appeared to have limited diagnostic utility and classification accuracy. Although many studies showed differing scores between adults with ADHD and comparison groups, findings were not consistent. Characteristics of CPT performances among adults with ADHD were mixed, with little consistency and no evidence of a clear profile of performances; however, CCPT commission errors appeared to have the most utility when used a treatment or experimental outcome measure, compared to other CCPT scores.

CONCLUSION

Overall, CPTs should not be used in isolation as a diagnostic test but may be beneficial when used as a component of a comprehensive assessment.

Developmental deviation in delay discounting as a transdiagnostic indicator of risk for child psychopathology

BACKGROUND

The tendency to prefer smaller, immediate rewards over larger, delayed rewards is known as delay discounting (DD). Developmental deviations in DD may be key in characterizing psychiatric and neurodevelopmental disorders. Recent work empirically supported DD as a transdiagnostic process in various psychiatric disorders. Yet, there is a lack of research relating developmental changes in DD from mid-childhood to adolescence to psychiatric and neurodevelopmental disorders. Additionally, examining the interplay between socioeconomic status/total household income (THI) and psychiatric symptoms is vital for a more comprehensive understanding of pediatric pathology and its complex relationship with DD.

METHODS

The current study addresses this gap in a robust psychiatric sample of 1843 children and adolescents aged 5-18 (M = 10.6, SD = 3.17; 1,219 males, 624 females). General additive models (GAMs) characterized the shape of age-related changes in monetary and food reward discounting for nine psychiatric disorders compared with neurotypical youth (NT; n = 123). Over 40% of our sample possessed a minimum of at least three psychiatric or neurodevelopmental disorders. We used bootstrap-enhanced Louvain community detection to map DD-related comorbidity patterns. We derived five subtypes based on diagnostic categories present in our sample. DD patterns were then compared across each of the subtypes. Further, we evaluated the effect of cognitive ability, emotional and behavioral problems, and THI in relation to DD across development.

RESULTS

Higher discounting was found in six of the nine disorders we examined relative to NT. DD was consistently elevated across development for most disorders, except for depressive disorders, with age-specific DD differences compared with NTs. Community detection analyses revealed that one comorbidity subtype consisting primarily of Attention-Deficit/Hyperactivity Disorder (ADHD) Combined Presentation and anxiety disorders displayed the highest overall emotional/behavioral problems and greater DD for the food reward. An additional subtype composed mainly of ADHD, predominantly Inattentive Presentation, learning, and developmental disorders, showed the greatest DD for food and monetary rewards compared with the other subtypes. This subtype had deficits in reasoning ability, evidenced by low cognitive and academic achievement performance. For this ADHD-I and developmental disorders subtype, THI was related to DD across the age span such that participants with high THI showed no differences in DD compared with NTs. In contrast, participants with low THI showed significantly worse DD trajectories than all others. Our results also support prior work showing that DD follows nonlinear developmental patterns.

CONCLUSIONS

We demonstrate preliminary evidence for DD as a transdiagnostic marker of psychiatric and neurodevelopmental disorders in children and adolescents. Comorbidity subtypes illuminate DD heterogeneity, facilitating the identification of high-risk individuals. Importantly, our findings revealed a marked link between DD and intellectual reasoning, with children from lower-income households exhibiting lower reasoning skills and heightened DD. These observations underscore the potential consequences of compromised self-regulation in economically disadvantaged individuals with these disorders, emphasizing the need for tailored interventions and further research to support improved outcomes.

Time-Perception Deficits in Attention-Deficit/Hyperactivity Disorder: A Systematic Review and Meta-Analysis

The present meta-analysis quantified the deficit in time perception in Attention-Deficit/Hyperactivity Disorder (ADHD) throughout the lifespan and examined potential moderators of this deficit. Our sample of 824 effect sizes showed a mean g of 0.688 that was moderated by the age of the sample and working memory. Separate moderator analyses for samples below or above the age of 18 showed that the link with working memory only applied to the samples below the age of 18, whereas an effect of ADHD subtype only applied to samples 18 and above. The discussion highlights the implications for remediation and avenues for future research.

ADHD-related sex differences in frontal lobe white matter microstructure and associations with response control under conditions of varying cognitive load and motivational contingencies

Children with attention-deficit/hyperactivity disorder (ADHD) demonstrate reduced response inhibition, increased response time variability, and atypical frontal lobe white matter microstructure with emerging evidence of sex differences. This study aims to examine whether frontal lobe white matter microstructure is differentially impacted in ADHD by sex and whether this relates to Go/No-Go (GNG) task performance. Diffusion tensor imaging (DTI) from 187 children (8-12 years), including ADHD (n = 94) and typically developing controls (TD; n = 93). Participants completed three GNG tasks with varying cognitive demands and incentives (standard, cognitive, and motivational). Fractional anisotropy (FA) was examined as an index of white matter microstructure within bilateral frontal lobe regions of interest. Children with ADHD showed reduced FA in primary motor (M1) and supplementary motor area (SMA) regardless of sex. Sex-based dissociation for the effect of diagnosis was observed in medial orbitofrontal cortex (mOFC), with higher FA in girls with ADHD and lower FA in boys with ADHD. Both diagnosis and sex contributed to performance on measures of response inhibition and reaction time (RT) variability, with all children with ADHD demonstrating poorer performance on all GNG tasks, but boys with ADHD demonstrating more impulsivity on standard and motivational behavioral paradigms compared to girls with ADHD. Analyses revealed associations between reduced FA in M1, SMA, and mOFC and increased response inhibition and RT variability with some sex-based differences. These findings provide novel insights regarding the brain basis of ADHD and associated impairments in response inhibition and RT variability, and contribute to our understanding of sexual dimorphic behavioral outcomes.

Degrading stimuli by reducing image resolution impairs performance in a rodent continuous performance test

Attention is a cognitive domain often disrupted in neuropsychiatric disorders and continuous performance tests (CPTs) are common clinical assays of attention. In CPTs, participants produce a behavioral response to target stimuli and refrain from responding to non-target stimuli. Performance in CPTs is measured as the ability to discriminate between targets and non-targets. Rodent versions of CPTs (rCPTs) have been validated with both anatomical and pharmacological studies, providing a translational platform for understanding attention function. In humans, stimulus degradation, the inclusion of visual noise in the image to reduce resolution, in CPTs impairs performance. Reduced image contrast, changes in the relative luminescence of elements in the image, has been used in rCPTs to test similar constructs, but, to our knowledge, reduced image resolution has not been tested in an rCPT. In this study, we tested multiple levels of stimulus degradation in a touchscreen version of the rCPT in mice. We found that stimulus degradation significantly decreased performance in males and females. Specifically, we found decreased stimulus discrimination and increases in hit reaction time and reaction time variability. These findings are in line with the effects of stimulus degradation in human studies. These data extend the utility and translational value of the family of rCPTs by demonstrating that stimulus degradation in the form of reduced image resolution produces qualitatively similar behavioral responses in mice as those in previous human studies.

Gender Differences in Auditory and Visual Attentional Performance in Children with and without ADHD

OBJECTIVE

Despite the relatively high prevalence of attention deficit hyperactivity disorder (ADHD), the impairment of ADHD in women is underestimated due to the different ways the phenomenon manifests compared to traditional male symptoms. In order to close the gender gap in diagnosis and treatment, this study aims to explore the impact of gender on auditory and visual attention in children with and without ADHD.

METHOD

A total of 220 children with and without ADHD participated in this study. Their auditory and visual attention performances were analyzed by comparative computerized auditory and visual subtests.

RESULTS

Auditory and visual attention performance in children with and without ADHD did affect by gender, including typically developing (TD) boys are better than TD girls at distinguishing visual targets from non-target stimuli. When performing attention tasks, TD girls generally maintained a cautious response, which was different from TD boys, who generally adopted positive response methods. ADHD girls suffered from more serious auditory inattention problems than ADHD boys; however, ADHD boys suffered from more auditory and visual impulsive problems than ADHD girls. The internal attention problems of female ADHD children were broader than that of their male ADHD peers and were also more severe, especially in problems of auditory omission and auditory response acuity.

CONCLUSIONS

ADHD children had a significant gap in auditory and visual attention performance compared to TD children. The research results support the impact of gender on the performance of auditory and visual attention in children with and without ADHD.

The student-teacher relationship and ADHD symptomatology: A meta-analysis

Children with attention-deficit/hyperactivity disorder (ADHD) typically experience significant academic and social impairments, including problem behaviors in the classroom. Existing research suggests students who present with ADHD symptoms are more likely to have relationships with their teachers that are low in closeness and high in conflict. However, research about the quality of relationships between teachers and students with ADHD symptoms remains quantitatively un-synthesized. The present meta-analysis quantitatively describes the overall quality of student-teacher relationships for children who present with ADHD symptoms according to the relational dimensions of closeness and conflict. Database searches of PsycInfo, ERIC, and ProQuest (theses and dissertations) were conducted to collect a sample of 27 quantitative studies for statistical analyses. A total of 47 effect sizes (N = 17,236) were included in the analyses. Results confirm the trends seen in the literature. Children with symptoms of ADHD tended to have relationships with their teachers that were low in closeness (r = -0.170) and high in conflict (r = 0.414). Additionally, eight moderator analyses were conducted (i.e., grade level, informant types, informant consistency, sample type, reported comorbidity, gender, and ADHD presentation) to assess their effect on the link between ADHD symptoms and student-teacher relationship quality. The results of this meta-analysis provide insight into the quality of relationships that students who exhibit ADHD symptoms form with their teachers also may inform intervention programs that aim to best support students.

Assessment of goal-directed behavior and prospective memory in adult ADHD with an online 3D videogame simulating everyday tasks

The diagnosis of ADHD is based on real-life attentional-executive deficits, but they are harder to detect in adults than in children and objective quantitative measures reflecting these everyday problems are lacking. We developed an online version of EPELI 3D videogame for naturalistic and scalable assessment of goal-directed action and prospective memory in adult ADHD. In EPELI, participants perform instructed everyday chores in a virtual apartment from memory. Our pre-registered hypothesis predicted weaker EPELI performances in adult ADHD compared to controls. The sample comprised 112 adults with ADHD and 255 neurotypical controls comparable in age (mean 31, SD = 8 years), gender distribution (71% females) and educational level. Using web-browser, the participants performed EPELI and other cognitive tasks, including Conner's Continuous Performance Test (CPT). They also filled out questionnaires probing everyday executive performance and kept a 5-day diary of everyday prospective memory errors. Self-reported strategy use in the EPELI game was also examined. The ADHD participants' self-ratings indicated clearly more everyday executive problems than in the controls. Differences in the EPELI game were mostly seen in the ADHD participants' higher rates of task-irrelevant actions. Gender differences and a group × gender interaction was found in the number of correctly performed tasks, indicating poorer performance particularly in ADHD males. Discriminant validity of EPELI was similar to CPT. Strategy use strongly predicted EPELI performance in both groups. The results demonstrate the feasibility of EPELI for online assessment and highlight the role of impulsivity as a distinctive everyday life problem in adult ADHD.

Synesthesia has specific cognitive processing during Go/No-go paradigms

Grapheme-color synesthesia is a consistent and automatic perception of non-physical color when presented with a grapheme. Many previous studies focused on the synesthetic visual system, but other cognitive functions in grapheme-color synesthetes have remained unclear. Therefore, the objective of the present study was to investigate the characteristics of cognitive processing for motor execution and inhibition during Go/No-go paradigms in grapheme-color synesthesia using event-related potentials (ERPs). Six grapheme-color synesthetes and 24 non-synesthetes performed visual, auditory, and somatosensory Go/No-go paradigms. Omission errors were higher in grapheme-color synesthetes than non-synesthetes. Group-trial interactions (i.e., synesthetes-non-synesthetes × Go-No-go) were observed for the latency of the visual N2 component and amplitude of the somatosensory N2 component. Latencies of auditory and somatosensory P3 components were shorter in grapheme-color synesthetes than non-synesthetes. These findings suggest that grapheme-color synesthetes have specific cognitive processing in motor execution and inhibition as well as synesthetic color perception. Our data advance understanding of cognitive processing in grapheme-color synesthesia.

Evaluating Processing Speed and Reaction Time Outcome Measures in Children and Adolescents with Down Syndrome

Reliable and valid cognitive outcome measures, including examiner-administered and computer-facilitated assessments of processing speed and reaction time, are necessary for future clinical trials that include individuals with Down syndrome (DS). The current study evaluated the score distributions and psychometric properties of four examiner-administered and three computerized processing speed and reaction time measures. Participants included 97 individuals with DS, aged 6 to 17 (M = 12.6, SD = 3.3). Two examiner-administered measures (Differential Ability Scales-II Rapid Naming and Cat/dog Stroop Congruent) met most predetermined psychometric criteria. Other assessments demonstrated good test-retest reliability and had negligible practice effects but lacked adequate feasibility. Recommendations for using processing speed and reaction time assessments in research and suggestions for modifications of measures are discussed.

Establishment of an objective index for the diagnosis of attention deficit/hyperactivity disorder by the continuous performance test "MOGRAZ"

OBJECTIVE

The diagnosis of attention deficit/hyperactivity disorder (AD/HD) in Japan is mainly based on information obtained from caregivers. There is therefore a need to establish an objectivity index that can be easily used in clinical practice. The purpose of the study was to create a predictive model for the diagnosis of AD/HD using the MOGRAZ, a visual continuous performance test developed in Japan.

METHODS

We collected data from an AD/HD group and a non-AD/HD group. The AD/HD group included 75 children with predominantly inattentive type AD/HD and 48 with combined type AD/HD who were aged 6 to 12 years and diagnosed at our department. The non-AD/HD group included 153 Japanese children aged 6 to 11 years enrolled in regular classes at a public elementary school. In both groups, multiple logistic regression analysis was performed using the results of MOGRAZ, age, and sex as parameters, and algorithms for a predictive diagnostic model of AD/HD were created.

RESULTS

The area under the receiver operating characteristic curve (ROC-AUC) between the predominantly inattentive type AD/HD subgroup and non-AD/HD group was 0.884 (95% confidence interval: 0.837-0.932), and the ROC-AUC between the combined type AD/HD subgroup and non-AD/HD group was 0.914 (95% CI: 0.869-0.959).

CONCLUSION

The prediction model using the MOGRAZ score allowed us to create an objectivity index to determine the diagnosis of AD/HD that can be easily used in clinical practice. We plan additional verification of this prediction model with additional participants.

Efficacy of Continuous Performance Testing in Adult ADHD in a Clinical Sample Using QbTest

OBJECTIVE

Continuous performance tests are widely used to aid diagnostic decision making and measure symptom reduction in adult ADHD clinical populations. The diagnostic accuracy of the Quantified Behavior Test plus (QbTest+), developed to identify ADHD populations as an objective measure of ADHD symptoms, was explored.

METHODS

The utility of the QbTest+ was investigated in a clinical cohort of 69 adult patients referred to a specialist ADHD clinic in the UK.

RESULTS

Scores from the QbTest+ failed to differentiate between patients diagnosed with ADHD and those who did not receive a diagnosis after full clinical assessment.

CONCLUSIONS

Based on our findings, we recommend clinicians are cautious when interpreting results of the QbTest+ in clinical populations. This study highlights the need for investigation into the lack of validation of commonly used objective measures in ADHD populations.

Sex Differences in Substance Use, Prevalence, Pharmacological Therapy, and Mental Health in Adolescents with Attention-Deficit/Hyperactivity Disorder (ADHD)

Sex differences are poorly studied within the field of mental health, even though there is evidence of disparities (with respect to brain anatomy, activation patterns, and neurochemistry, etc.) that can significantly influence the etiology and course of mental disorders. The objective of this work was to review sex differences in adolescents (aged 13–18 years) diagnosed with ADHD (according to the DSM-IV, DSM-IV-TR and DSM-5 criteria) in terms of substance use disorder (SUD), prevalence, pharmacological therapy and mental health. We searched three academic databases (PubMed, Web of Science, and Scopus) and performed a narrative review of a total of 21 articles. The main conclusions of this research were (1) girls with ADHD are more at risk of substance use than boys, although there was no consensus on the prevalence of dual disorders; (2) girls are less frequently treated because of underdiagnosis and because they are more often inattentive and thereby show less disruptive behavior; (3) together with increased impairment in cognitive and executive functioning in girls, the aforementioned could be related to greater substance use and poorer functioning, especially in terms of more self-injurious behavior; and (4) early diagnosis and treatment of ADHD, especially in adolescent girls, is essential to prevent early substance use, the development of SUD, and suicidal behavior.

Maternal stress, child behavior and the promotive role of older siblings

Background

In the first years of their lives, children develop the cognitive, social and emotional skills that will provide the foundations for their lifelong health and achievements. To increase their life prospects and reduce the long-term effects of early aversive conditions, it is therefore crucial to understand the risk factors that negatively affect child development and the factors that are instead beneficial. In this study, we tested (i) the effects of different social and environmental stressors on maternal stress levels, (ii) the dynamic relationship between maternal stress and child behavior problems during development, and (iii) the potential promotive (i.e. main) or protective (i.e. buffering) effect of siblings on child behavior problems during development.

Methods

We used longitudinal data from 373 mother–child pairs (188 daughters, 185 sons) from pregnancy until 10 years of age. We assessed maternal stress and child behavior problems (internalizing and externalizing) with validated questionnaires, and then used linear mixed models, generalized linear mixed models and longitudinal cross-lagged models to analyze the data.

Results

Our results showed that higher maternal stress levels were predicted by socio-environmental stressors (i.e. the lack of sufficient social areas in the neighborhood). Moreover, prenatal maternal stress reliably predicted the occurrence of behavior problems during childhood. Finally, the presence of older siblings had a promotive function, by reducing the likelihood that children developed externalizing problems.

Conclusions

Overall, our results confirm the negative effects that maternal stress during pregnancy may have on the offspring, and suggest an important main effect of older siblings in promoting a positive child development.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13261-2.

Developmental Changes of Autistic Symptoms, ADHD Symptoms, and Attentional Performance in Children and Adolescents with Autism Spectrum Disorder

This study followed up ADHD/autistic symptoms and attentional performance in children/adolescents with ASD and typically developing ones (TD) over 5-7 years. The participants were stratified by age at baseline into child (< 12 years) and adolescent (12-19 years) groups. ADHD symptoms, especially hyperactivity, and attentional functions significantly improved during follow-up, more in children than in adolescents, in both ASD and TD. Significantly more omission errors and perseverations were noted in ASD than TD through the follow-up. Children with ASD had more improvement in reaction time while adolescents with ASD had less improvement in commission errors and detectability than TD. No correlation of attentional functions and ADHD symptoms in ASD implied different neural mechanisms of ADHD symptoms between ASD and ADHD.

Frontal corticostriatal functional connectivity reveals task positive and negative network dysregulation in relation to ADHD, sex, and inhibitory control

Frontal corticostriatal circuits (FCSC) are involved in self-regulation of cognition, emotion, and motor function. While these circuits are implicated in attention-deficit/hyperactivity disorder (ADHD), the literature establishing FCSC associations with ADHD is inconsistent. This may be due to study variability in considerations of how fMRI motion regression was handled between groups, or study specific differences in age, sex, or the striatal subregions under investigation. Given the importance of these domains in ADHD it is crucial to consider the complex interactions of age, sex, striatal subregions and FCSC in ADHD presentation and diagnosis. In this large-scale study of 362 8-12 year-old children with ADHD (n = 165) and typically developing (TD; n = 197) children, we investigate associations between FCSC with ADHD diagnosis and symptoms, sex, and go/no-go (GNG) task performance. Results include: (1) increased striatal connectivity with age across striatal subregions with most of the frontal cortex, (2) increased frontal-limbic striatum connectivity among boys with ADHD only, mostly in default mode network (DMN) regions not associated with age, and (3) increased frontal-motor striatum connectivity to regions of the DMN were associated with greater parent-rated inattention problems, particularly among the ADHD group. Although diagnostic group differences were no longer significant when strictly controlling for head motion, with motion possibly reflecting the phenotypic variance of ADHD itself, the spatial distribution of all symptom, age, sex, and other ADHD group effects were nearly identical to the initial results. These results demonstrate differential associations of FCSC between striatal subregions with the DMN and FPN in relation to age, ADHD, sex, and inhibitory control.

Clinical characteristics, neuroimaging findings, and neuropsychological functioning in attention-deficit hyperactivity disorder: Sex differences

Recent clinical studies, in both children/adolescents and adults, have shown the extreme neuropsychological heterogeneity of attention-deficit hyperactivity disorder (ADHD): specific neuropsychological deficits have been found only in a minority of individuals, with no direct correlation between discrete cognitive performances and the trajectory of clinical symptoms. Deficits in specific neuropsychological functions may be common in ADHD, but nevertheless no cognitive or neuropsychological profile may fully explain the disorder. Sex differences in the ADHD presentation, both at a neuropsychological and clinical level, also contribute to this clinical and neuropsychological heterogeneity. At a neuropsychological level, females with ADHD may show greater working memory problems, poorer vocabulary skills and worse visual spatial reasoning. Structural and functional imaging study also show discrete differences across sex; however, the great majority of clinical studies mainly or exclusively include male participants with insufficient data to draw firm conclusions on sex differences within the disorder. Here, we report the recent literature data, discussing still open research questions about the clinical presentation, neuroimaging findings, and neuropsychological functioning in ADHD with a focus on the impact of sex differences-a deeper insight in these unresolved issues may have relevant clinical and therapeutic implications for tailored, effective, and long-lasting interventions.

Neurodevelopmental Disorders Among Publicly or Privately Insured Children in the United States

IMPORTANCE

Neurodevelopmental disorders are associated with poor health and social outcomes. Population-based data on incidence, age at diagnosis, and demographic variations are essential to identify modifiable risk factors and inform the planning of services and interventions.

OBJECTIVES

To assess the incidence and timing of diagnosis of neurodevelopmental disorders during childhood in the US and to evaluate differences by population characteristics.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study used nationwide data on birth cohorts nested in the 2000-2014 Medicaid Analytic eXtract and the 2003-2015 IBM MarketScan Research Database on 2 070 541 publicly and 1 309 900 privately insured children enrolled at birth. Data were analyzed between May 1, 2020, and June 30, 2021.

MAIN OUTCOMES AND MEASURES

Neurodevelopmental disorders, autism spectrum disorders, attention-deficit/hyperactivity disorder, learning disabilities, speech or language disorders, developmental coordination disorders, intellectual disabilities, and behavioral disorders were identified based on validated algorithms. Kaplan-Meier analyses were used to estimate the incidence and timing of diagnosis, stratified by child's sex, birth year, maternal age at delivery, and race and ethnicity.

RESULTS

The cohorts comprised 2 070 541 publicly insured children (1 045 426 boys [50.5%]) and 1 309 900 privately insured children (667 607 boys [51.0%]) enrolled at birth. By 8 years of age, 23.9% of publicly insured children and 11.0% of privately insured children received a diagnosis of 1 or more neurodevelopmental disorders (autism spectrum disorder, 1.6% and 1.3%; attention-deficit/hyperactivity disorder, 14.5% and 5.8%; learning disability, 1.2% and 0.6%; speech or language disorder, 8.4% and 4.5%; developmental coordination disorder, 0.9% and 0.7%; intellectual disability, 0.7% and 0.1%; and behavioral disorder, 8.4% and 1.5%). Risks were substantially higher among boys (incidence of ≥1 neurodevelopmental disorder by age 8 years for boys vs girls: 30.7% vs 16.7% among publicly insured children and 15.0% vs 6.7% among privately insured children) and White children (30.2% vs 9.1% among Asian children, 23.0% among Black children, 15.4% among Hispanic children, and 22.7% among children of unknown race or ethnicity; information on race and ethnicity was available only for publicly insured children). The association of maternal age and birth year with incidence of neurodevelopmental disorders varied by outcome. Except for attention-deficit/hyperactivity disorder, the diagnosis tended to be established somewhat earlier for privately insured children. The association of race and ethnicity with age at diagnosis varied by outcome. Co-occurring neurodevelopmental disorders were common, especially among children with autism spectrum disorder and intellectual disability (>70% had ≥1 other disorder).

CONCLUSIONS AND RELEVANCE

In this population-based cohort study, a relatively high incidence of and co-occurrence of neurodevelopmental disorders as well as the disparity in incidence and timing of diagnosis by insurance type and race and ethnicity were found. These findings represent important public health concerns and underscore the need for timely and accessible developmental assessments and educational services to help reduce the burden of these disorders.

Preliminary Study of the Applicability of Software in the investigation of Sustained Auditory Attention

Introduction The use of auditory behavioral tests, which specifically assess sustained attention, is necessary, due to its relationship with learning, language production, cognitive development and school performance.

Objective To evaluate how children performed using software developed to investigate the ability of sustained auditory attention, and to compare the scores obtained in this format with those of the original, non-computerized test.

Methods This cross-sectional study included 52 children of both genders, aged 6 to 11 years, with normal hearing and no history of complaints regarding inattention and/or hyperactivity. The computerized test was administered to all 52 children. The total error score (inattention and impulsivity) and the vigilance decrement were used to define the children's performance when using the software. The scores obtained in the two formats (computer software and original on compact disc) were then compared.

Results Statistically significant differences were found in the scores for innattention, impulsivity, and total error score (inattention and impulsivity) when comparing genders, and a negative correlation coefficient was found when comparing ages. Increased scores were found for all variables of the sustained auditory attention ability test (SAAAT) compared with the original format.

Conclusion Females performed worse than males in all aspects except for vigilance decrement when using the SAAAT software developed to evaluate the ability of SAAAT vigilance; younger children made more errors when using the SAAAT software; inattention errors were more frequent than impulsivity. Overall, higher values were obtained using the SAAAT software, when compared with the original version.

Prevalence of mental disorders in school children and adolescents in China: diagnostic data from detailed clinical assessments of 17,524 individuals

BACKGROUND

To date, no national-scale psychiatric epidemiological survey for children and adolescents has been conducted in China. In order to inform government officials and policymakers and to develop a comprehensive plan for service providers, there was a clear need to conduct an up-to-date systematic nationwide psychiatric epidemiological survey.

METHODS

We conducted a two-stage large-scale psychiatric point prevalence survey. Multistage cluster stratified random sampling was used as the sampling strategy. Five provinces were selected by comprehensively considering geographical partition, economic development, and rural/urban factors. In Stage 1, the Child Behavior Checklist was used as the screening tool. In Stage 2, Mini-International Neuropsychiatric Interview for Children and Adolescents and a diagnostic process based on the Diagnostic and Statistical Manual were used to make the diagnoses. Sampling weights and poststratification weights were employed to match the population distributions. Exploratory analyses were also performed using socio-demographic factors. Prevalence in socio-demographic factor subgroups and overall were estimated. Rao-Scott adjusted chi-square tests were utilized to determine if between-group differences were present. Factor interactions were checked by logistic regression analyses.

RESULTS

A total of 73,992 participants aged 6-16 years of age were selected in Stage 1. In Stage 2, 17,524 individuals were screened and diagnosed. The weighted prevalence of any disorder was 17.5% (95% CI: 17.2-18.0). Statistically significant differences in prevalence of any psychiatric disorder were observed between sexes [χ² (1, N = 71,929) = 223.0, p < .001], age groups [χ² (1, N = 71,929) = 18.6, p < .001] and developed vs. developing areas [χ² (1, N = 71,929) = 2,129.6, p < .001], while no difference was found between rural and urban areas [χ² (1, N = 71,929) = 1.4, p = .239]. Male, younger individuals, children, and adolescents from developed areas had higher prevalence of any psychiatric disorder. The prevalence of any psychiatric disorder was found to decrease with the age in the male group, while the female group increased with the age. Individuals diagnosed with attention-deficit hyperactivity disorder, oppositional defiant disorder, a tic disorder, conduct disorder, and major depression disorder had the highest rates of comorbidity.

CONCLUSIONS

The prevalence of any psychiatric disorder we found is the highest ever reported in China. These results urgently need to be addressed by public mental health service providers and policymakers in order to provide access to the necessary treatments and to reduce the long-term negative impact of these conditions on families and the society as a whole.

Heterogeneity in maternal and child mental health responses to the COVID-19 pandemic

We used latent profile analysis on a longitudinal dataset to examine changes in maternal and child mental health during COVID-19 and factors that may protect against declines in mental health. Participants were 183 low-income mothers (M = 36 years) with young children (M = 5.31 years) in the City of Toronto with data collected prior to and during the pandemic in 2020. Mothers reported on their own stress, anxiety and depression and their children's emotional, conduct, hyperactivity, peer, and prosocial problems at both timepoints. We found heterogeneity in mental health changes, with 5 distinct patterns of change for mothers, and 4 distinct patterns of change for children during COVID-19. The majority (83%) of mothers experienced significant declines in at least one aspect of mental health. In contrast, the majority of children (65%) experienced either no change or improvements in mental health. Interestingly, patterns of change across these groups were not differentiated by demographic characteristics such as income, education, and family composition. However, for mothers, a higher degree of satisfaction with social support was associated with membership in a profile with better mental health both prior to, and during the pandemic. For children, having a stable history of early childhood education, and care was associated with membership in a profile that showed improvements in mental health during the pandemic. We discuss how our results support the need for proactive and global interventions for at-risk families with raised mental health concerns, and the benefits that stable early childhood education and care may provide for young children.

Characterization of a differential reinforcement of low rates of responding task in non-deprived male and female rats: Role of Sigma-1 receptors

Impulsive action can be defined as the inability to withhold a response and represents one of the dimensions of the broad construct impulsivity. Here, we characterized a modified differential reinforcement of low rates of responding (DRL) task developed in our laboratory, in which impulsive action is measured in ad libitum fed/watered subjects. Specifically, we first determined the effects of both sex and estrous cycle on impulsive action by systematically comparing male and estrous-synchronized female subjects. In addition, we evaluated the convergent validity of this modified DRL task by testing the effects of the D2R/5HT2AR antagonist, aripiprazole, and the noncompetitive NMDAR antagonist, MK-801. Finally, we tested the effects of the selective antagonist BD-1063 and agonist PRE-084 of Sigma-1 receptor (Sig-1R) on impulsive action using this modified DRL task. We found that female rats showed and increased inability to withhold a response when compared to males, and this effect was driven by the metestrus/diestrus phase of the estrous cycle. In addition, aripiprazole and MK-801 fully retained their capability to reduce and increase impulsive action, respectively. Finally, the selective Sig-1R antagonist, BD-1063 dose-dependently reduced the inability to withhold a response in both sexes, though more potently in female rats. In summary, we show that impulsive action, as measured in a modified DRL task which minimizes energy-homeostatic influences, is a function of both sex and estrous cycle. Furthermore, we validate the convergent validity of the task and provide evidence that Sig-1R antagonism may represent a novel pharmacological strategy to reduce impulsive action.

Behavioral and Neurophysiological Markers of ADHD in Children, Adolescents, and Adults: A Large-Scale Clinical Study

This study aimed to re-evaluate the possible differences between attention-deficit/hyperactivity disorder (ADHD) subjects and healthy controls in the context of a standard Go/NoGo task (visual continuous performance test [VCPT]), frequently used to measure executive functions. In contrast to many previous studies, our sample comprises children, adolescents, and adults. We analyzed data from 447 ADHD patients and 227 healthy controls. By applying multivariate linear regression analyses, we controlled the group differences between ADHD patients and controls for age and sex. As dependent variables we used behavioral (number of omission and commission errors, reaction time, and reaction time variability) and neurophysiological measures (event-related potentials [ERPs]). In summary, we successfully replicated the deviations of ADHD subjects from healthy controls. The differences are small to moderate when expressed as effect size measures (number of omission errors: d = 0.60, reaction time variability: d = 0.56, contingent negative variation (CNV) and P3 amplitudes: -0.35 < d < -0.47, ERP latencies: 0.21 < d < 0.29). Further analyses revealed no substantial differences between ADHD subtypes (combined, inattentive, and hyperactive/impulsive presentation), subgroups according to high- and low-symptomatic burden or methylphenidate intake for their daily routine. We successfully replicated known differences between ADHD subjects and controls for the behavioral and neurophysiological variables. However, the small-to-moderate effect sizes limit their utility as biomarkers in the diagnostic procedure. The incongruence of self-reported symptomatic burden and clinical diagnosis emphasizes the challenges of the present clinical diagnosis with low reliability, which partially accounts for the low degree of discrimination between ADHD subjects and controls.

Sex-specific frontal-striatal connectivity differences among adolescents with externalizing disorders

BACKGROUND

Sex-specific neurobiological underpinnings of impulsivity in youth with externalizing disorders have not been well studied. The only report of functional connectivity (FC) findings in this area demonstrated sex differences in fronto-subcortical connectivity in youth with attention-deficit/hyperactivity disorder (ADHD).

METHODS

The current study used functional magnetic resonance imaging(fMRI) to examine sex differences in resting-state seed-based FC, self-rated impulsivity, and their interactions in 11-12-year-old boys (n = 43) and girls (n = 43) with externalizing disorders. Generalized linear models controlling for pubertal development were used. Seeds were chosen in the ventral striatum, medial prefrontal cortex, middle frontal gyrus and amygdala.

RESULTS

Impulsivity scores were greater in boys than girls (p < 0.05). Boys showed greater positive connectivity within a ventromedial prefrontal-ventral striatal network. In addition, boys demonstrated weaker connectivity than girls within two medial-lateral prefrontal cortical networks. However, only boys showed greater medial-lateral prefrontal connectivity correlated with greater impulsivity.

CONCLUSIONS

The findings provide evidence supporting sex differences in both ventral striatal-ventromedial prefrontal and medial-lateral prefrontal functional networks in youth with externalizing disorders. These important networks are thought to be implicated in impulse control. Medial-lateral prefrontal connectivity may represent a male-specific biomarker of impulsivity.

How children with neurodevelopmental disorders can benefit from the neurocognitive effects of exercise

Exercise is an integral part of children's lives, and research in educational settings has found that regular engagement promises improvements in executive function (i.e. top-down control of goal-directed behavior). Based on recent advances in understanding the moderators and the neurocognitive mechanisms of these effects, we highlight a potential application of exercise in the treatment of executive dysfunction. Even though different neurodevelopmental disorders are characterized by a heterogeneity in core symptoms, children affected by these disorders often face common executive function deficits. So far, exercise has not been recognized as an alternative or additional treatment for this specific cognitive impairment. The limited experimental evidence in children with neurodevelopmental disorders provides a first indication that regular exercise engagement benefits executive function. However, we identified key research questions that need to be answered before a prescription of exercise to children with executive dysfunction can be encouraged in clinical practice.

The Visuo-Motor Attention Test in Boys with Attention Deficit Hyperactivity Disorder (ADHD): Methylphenidate-Placebo Randomized Controlled Trial

To assess the visuomotor attention ability in children with ADHD and controls and their response to placebo and Methylphenidate (MPH) treatment. 36 boys with ADHD and 36 age matched typical controls were administered the visuomotor attention test (VMAT) as a baseline and following a week of MPH(IR) or placebo administered to the study group, in a randomized crossover design. A significant difference between the study and control groups was found on several VMAT measures. No performance difference between ADHD dimensional sub-types was observed at the baseline assessment. Under MPH treatment a significant improvement in VMAT measures was observed and particularly in the combined and predominantly hyperactive (C\HI) type. The VMAT results obtained in the present study are consistent with previous findings. ADHD subtypes appear similarly short of visuomotor attention resources; a visuomotor test can be used in the assessment of gains derived from MPH treatment.

Gender differences in externalizing and internalizing problems in Singaporean children and adolescents with attention-deficit/hyperactivity disorder

BACKGROUND

Studies on gender differences in attention-deficit/hyperactivity disorder (ADHD) comorbidities in the Asian populations have been limited and previous studies have shown inconclusive findings. Singapore is a city-state country in Southeast Asia with a population of 5.7 million. This study examined gender differences in internalizing and externalizing problems in Singaporean children and adolescents with ADHD. The plausible social factors underlying the gender differences were discussed.

METHODS

A total of 773 participants (aged 6 to 18, 88% males) newly diagnosed with ADHD were recruited from the largest public child and adolescent psychiatric center in Singapore. Their internalizing and externalizing problems were assessed using the Child Behavioral Checklist and Teacher's Report Form by parents and teachers respectively. Demographics and relevant social factors were collected using parent questionnaires.

RESULTS

Females with ADHD were reported to have less delinquent and aggressive behavior but more depressive symptoms than their male counterparts, similar to findings in the Western literature. Gender remained a significant predictor of externalizing problem after controlling for other factors. Lower socioeconomic status and parental use of physical punishment were significant predictors of both internalizing and externalizing problems.

CONCLUSIONS

Gender differences in ADHD comorbidities do exist in the Asian clinical population. The lack of externalizing symptoms in females with ADHD has made timely referral and diagnosis challenging. More research is needed in understanding the gender differences in ADHD and the biopsychosocial mechanism underlying the differences in order to improve the detection of ADHD in females.

Maternal Ferritin Levels during Pregnancy and ADHD Symptoms in 4-Year-Old Children: Results from the INMA-INfancia y Medio Ambiente (Environment and Childhood) Prospective Birth Cohort Study

Ferritin status during prenatal brain development may influence the risk of attention deficit and hyperactivity disorder (ADHD) symptoms in childhood. We investigated the association of maternal ferritin in pregnancy and ADHD-like symptoms in offspring. A total of 1095 mother-child pairs from three birth cohorts of the INMA Project (Spain) were studied. Maternal plasma ferritin in pregnancy was measured at 11.57 weeks of gestation. Children′s ADHD-like symptoms at ages 4–5 years were assessed using the ADHD Rating Scale-IV. The count model of the zero-inflated Poisson regression model showed a significant inverse association between ferritin (continuous variable) and inattention, β = −0.19 (−0.32, −0.07), for boys. Comparing ferritin level by tertiles, significant differences were observed between the first tertile ([1.98, 20.92]) and the second ([20.92, 38.79]) and third tertiles ([38.79, 216.5]) (mg/L).The number of symptoms was lower for those in the third tertile, β = −0.3 (−0.55, −0.5), and for those in the second one, β = −0.37 (−0.6, −0.14). The model stratification by sex also showed this inverse association for boys only, β = −0.21 (−0.34, −0.08). No associations were found between ferritin level and hyperactivity or total ADHD symptoms. High ferritin levels during pregnancy show a protective association with child inattentive-type ADHD symptoms.

Exploring the Variability in Reaction Times of Preschoolers at Risk of Attention-Deficit/Hyperactivity Disorder: an ex-Gaussian Analysis

Reaction times (RTs) are typically slower and more variable in individuals with attention-deficit/hyperactivity disorder (ADHD). Analysis of the ex-Gaussian RT distribution, which is described by mu, sigma (mean and standard deviation, respectively, of the normal distribution) and tau (that of exponential distribution), reveals that individuals with ADHD do not display overall slower RTs but have a high proportion of extremely slow RTs, represented by a high tau value. Although this is a vital component for describing ADHD-related RT variability in school-aged children, adolescents, and adults, it has not been thoroughly studied at the preschool age. We assessed 65 preschoolers at risk of ADHD and 98 typically developing preschoolers with the Conners' Kiddie Continuous Performance Test (K-CPT) and parental and teacher reports of ADHD symptoms. We found that preschoolers at risk of ADHD had greater values for RT standard deviation, sigma, and tau than typically developing preschoolers at long inter-stimulus intervals (ISIs) (3 s), but not at short ISIs (1.5 s). This suggests that attention problems in preschool children may only be apparent in the tasks with a relatively slow event rate. Our study demonstrates that the ex-Gaussian tau value is essential for describing the inattentive component of task performance in preschoolers with heightened ADHD symptoms. Furthermore, the fact that the tau effect was modulated by ISI suggests that the longer duration (3 s vs. 1.5 s) is a non-optimal energetic state in preschoolers at risk of ADHD, and that this might account for the subtle attentional flaw in task performance.

A Machine-Based Prediction Model of ADHD Using CPT Data

Despite the popularity of the continuous performance test (CPT) in the diagnosis of attention-deficit/hyperactivity disorder (ADHD), its specificity, sensitivity, and ecological validity are still debated. To address some of the known shortcomings of traditional analysis and interpretation of CPT data, the present study applied a machine learning-based model (ML) using CPT indices for the Prediction of ADHD.Using a retrospective factorial fitting, followed by a bootstrap technique, we trained, cross-validated, and tested learning models on CPT performance data of 458 children aged 6–12 years (213 children with ADHD and 245 typically developed children). We used the MOXO-CPT version that included visual and auditory stimuli distractors. Results showed that the ML proposed model performed better and had a higher accuracy than the benchmark approach that used clinical data only. Using the CPT total score (that included all four indices: Attention, Timeliness, Hyperactivity, and Impulsiveness), as well as four control variables [age, gender, day of the week (DoW), time of day (ToD)], provided the most salient information for discriminating children with ADHD from their typically developed peers. This model had an accuracy rate of 87%, a sensitivity rate of 89%, and a specificity rate of 84%. This performance was 34% higher than the best-achieved accuracy of the benchmark model. The ML detection model could classify children with ADHD with high accuracy based on CPT performance. ML model of ADHD holds the promise of enhancing, perhaps complementing, behavioral assessment and may be used as a supportive measure in the evaluation of ADHD.

Literacy and Numeracy Underachievement in Boys and Girls With ADHD

Objective: To determine literacy and numeracy outcomes, among children with and without ADHD by gestational age and gender. Method: De-identified linked population data from the Western Australian Monitoring of Drug Dependence Systems, Western Australian Literacy and Numeracy Assessment database, and the Midwives Notification System used information on 6,819 children with ADHD compared with 14,451 non-ADHD children. Results: Twenty-three percent of boys and 28% of girls with ADHD had numeracy scores below the benchmark in School Year 3, compared with 11% of children without ADHD. These differences were also evident in reading, writing, and spelling through primary school. Children with ADHD and reduced gestational age were at a greater risk of not meeting numeracy and reading benchmarks, compared with children born at term. Conclusion: Children with ADHD are disadvantaged from an early age in key areas of learning, and this risk increased with reduction in gestational age at birth.

Literacy and Numeracy Underachievement in Boys and Girls With ADHD

Objective: The aim was to determine literacy and numeracy outcomes, among children with and without ADHD by gestational age and gender. Method: De-identified linked population data from the Western Australian Monitoring of Drugs of Dependence System and Western Australian Literacy and Numeracy Assessment databases, and the Midwives Notification System used information on 6,819 children with ADHD compared with 14,451 non-ADHD children. Results: A total of 23% of boys and 28% of girls with ADHD had numeracy scores below the benchmark in School Year 3, compared with 11% of children without ADHD. These differences were also evident for reading, writing, and spelling through primary school. Children with ADHD and reduced gestational age were at a greater risk of not meeting numeracy and reading benchmarks, compared with children born at term. Conclusion: Children with ADHD are disadvantaged from an early age in key areas of learning, and this risk increased with reduction in gestational age at birth.

Cross-lateralisation in children with attention-deficit/hyperactivity disorder and motor skill performance

Cross‐lateralisation and increased motor difficulties have been reported in children with attention‐deficit/hyperactivity disorder (ADHD). Nevertheless, the question of how crossed (i.e. mixed preference) or uncrossed (i.e. same side preference) lateralisation impacts motor performance in children with ADHD has yet to be examined. In this study, previously validated observational measures of hand and foot preference were used to identify right‐handed children with ADHD who display cross‐ (n = 29) and uncross‐lateralisation (n = 31). An uncross‐lateralised typically developing (TD) group (n = 32) was also identified, and included as a control. Motor performance was assessed with seven valid and reliable fine and gross motor tasks performed with both preferred and non‐preferred limbs. Group, task and sex‐related effects were examined. Findings revealed that male (but not female) cross‐lateralised children with ADHD performed significantly worse, respectively, in two of the fine motor tasks (spiral tracing [p < .01], and dot filling [p < .05]). Results suggest that cross‐lateralised hand and foot preference may affect complex motor skills in male children with ADHD. Furthermore, characteristics of ADHD may manifest differently in male and female children. Findings highlight the importance of considering both hand and foot preference when targeting motor interventions for children with ADHD.

Auditory and Visual Executive Functions in Children and Response to Methylphenidate: A Randomized Controlled Trial

Objectives: The aim of the study was to assess auditory and visually based executive functions (EFs) and the effect of methylphenidate (MPH) in children with ADHD. Methods: Thirty-six boys between the ages of 8.3 and 9.7 years with ADHD and 36 matched controls were included. The study group was randomized into MPH and placebo for 7 days each in a crossover design. A Cued Choice Reaction Time (CCRT) test that included incongruent cuing was administered at baseline and following 1 and 2 weeks. Results: The difference between the study and control groups was more evident with visual cues and incongruent cuing. Increased gains by children with predominantly hyperactive-impulsive\combined (HI\C) type of ADHD were observed under MPH. Conclusions: The differences between children with ADHD and typical children are more pronounce under incongruent auditory cuing . The gains attributable to MPH are more specific to tasks involving auditory and visual EFs and in children with HI\C type ADHDs.

The Influence of Methylphenidate on Hyperactivity and Attention Deficits in Children With ADHD: A Virtual Classroom Test

Objective: This study compares the performance in a continuous performance test within a virtual reality classroom (CPT-VRC) between medicated children with ADHD, unmedicated children with ADHD, and healthy children. Method:N = 94 children with ADHD (n = 26 of them received methylphenidate and n = 68 were unmedicated) and n = 34 healthy children performed the CPT-VRC. Omission errors, reaction time/variability, commission errors, and body movements were assessed. Furthermore, ADHD questionnaires were administered and compared with the CPT-VRC measures. Results: The unmedicated ADHD group exhibited more omission errors and showed slower reaction times than the healthy group. Reaction time variability was higher in the unmedicated ADHD group compared with both the healthy and the medicated ADHD group. Omission errors and reaction time variability were associated with inattentiveness ratings of experimenters. Head movements were correlated with hyperactivity ratings of parents and experimenters. Conclusion: Virtual reality is a promising technology to assess ADHD symptoms in an ecologically valid environment.

Continuous Performance Test Is Sensitive to a Single Methylphenidate Challenge in Preschool Children With ADHD

Objective: There is a lack of evidence-based diagnostic paradigms and personalized interventions for preschoolers with ADHD. This study aimed to evaluate the performance of preschoolers diagnosed with ADHD on a continuous performance test (CPT) before and after a single methylphenidate (MPH) challenge. Method: The Test of Variables of Attention (TOVA)-a CPT-was administered to 61 preschoolers (5.64 ± 0.69 years; 74% boys) with ADHD before and after a single MPH challenge (0.3 or 0.5 mg/kg). Baseline TOVA performance was correlated with Conners' Rating Scales (CRS) and compared with post-MPH TOVA performance. Results: A high rate of omission errors and several significant correlations between TOVA values and CRS scores were found at baseline. A single MPH administration improved TOVA performance significantly and was well tolerated. Conclusion: TOVA assessment may assist in the evaluation of the effect of MPH in preschoolers with ADHD and may help in planning interventions for them.

Gender Differences in Objective and Subjective Measures of ADHD Among Clinic-Referred Children

Attention deficit hyperactivity disorder (ADHD), one of the most prevalent childhood disorders today, is generally more likely to be diagnosed and treated in boys than in girls. However, gender differences in ADHD are currently poorly understood, partly because previous research included only a limited proportion of girls and relied mainly on subjective measures of ADHD, which are highly vulnerable to reporter's bias. To further examine gender differences in ADHD and to address some of the shortcomings of previous studies, this study examined gender differences in subjective and objective measures of ADHD among clinic-referred children with ADHD. Participants were 204 children aged 6-17 years-old with ADHD (129 boys, 75 girls). A retrospective analysis was conducted using records of a clinical database. Obtained data included parent and teacher forms of the Conners ADHD rating scales, Child Behavior Checklist (CBCL), Teacher's Report Form (TRF), and child's continuous performance test (CPT) scores. Results showed that according to parents' and teachers' reports of ADHD-related symptoms (Conners ADHD rating scales), girls had more inattention problems than boys, but no differences were identified in the level of hyperactivity and impulsivity symptoms. CPT data, however, revealed higher impulsivity among boys. We did not find gender differences in the level of distractibility during CPT performance. Specifically, the effects of distractors type (visual environmental stimuli, auditory stimuli, or a combination of them) and distractors load (one or two distracting stimuli at a time) on CPT performance did not differ between boys and girls with ADHD. These findings suggest that gender effects on ADHD symptoms may differ between subjective and objective measures. Understanding gender differences in ADHD may lead to improved identification of girls with the disorder, helping to reduce the gender gap in diagnosis and treatment.

Specific Effects of Individualized Cognitive Training in Children with Attention-Deficit/Hyperactivity Disorder (ADHD): The Role of Pre-Training Cognitive Impairment and Individual Training Performance

Objective: We investigated the impact of the pre-training neuropsychological (NP) impairment and of the training progress on the NP and behavioural outcome after computerized cognitive training (CogT) in children with ADHD. Method: Thirty-one participants underwent individualized CogT (focussing on one or two cognitive domains: working memory, inhibition, attention) over 12 weeks. NP tests and behaviour ratings served as outcome measures. Results: After CogT, significant improvements emerged according to parents' ratings, but only on very few NP test measures. Children with milder/no pre-training NP impairment showed larger improvements on behavioural ratings than more impaired children. A steeper training performance slope was related to better behavioural outcomes. Conclusion: We find partial support for specific effects of CogT, but the assumption that an individually tailored selection of training tasks would be particularly beneficial for children with ADHD with NP deficits was not confirmed. Trial registration number: NCT02358941.

Developmental Trajectories of Attention in Normal Korean Population

Objectives

This study aimed to investigate the trajectory of change of diverse attention and working memory in Koreans from 4 to 40 years of age.

Methods

The data of 912 subjects from 4 to 15 years of age obtained from a previous standardization study of the computerized comprehensive attention test were merged with the newly obtained data of 150 subjects aged 16 to 40 years from this study. We evaluated the various kinds of attention, in which each subtest had five indicators. Working memory, with parameters such as number of correct responses and span, was also measured.

Results

Our findings indicated that attention developed as age increased, and it decreased or was maintained after a certain age. Selective and sustained attention developed rapidly in children and adolescents, until mid-teens or 20 s when it ceased development. Divided attention, however, developed up to approximately age 20. In addition, working memory developed until mid-teens or 20 s.

Conclusion

We presented the standardized data on diverse kinds of attention and working memory in children, adolescents, and adults in Korea. We could recognize any patterns of change in attention and working memory with increasing age.

ADHD and Gender: subjective experiences of children in Chile

Abstract Although research on ADHD has tended to ignore gender differentials, recent contributions produced mainly from epidemiology have revealed that this diagnostic category seems to be strongly related to gender. However, these contributions seem to limit their scope to the study of the symptoms as well as cognitive, affective and social functioning of children, leaving aside subjective aspects associated with the ADHD practices of diagnosis and treatment. Thus, this article aims to explore how the gender dimension crosses the subjective experience of children diagnosed with ADHD. Based on open interviews conducted with children between the ages of 7 and 13, we show general trends that articulate gender and characteristics associated with the ADHD diagnosis, while at the same time, with children’s experiences that dislocate such trends. The findings were grouped according to four emerging axes: (1) locations, (2) abilities, (3) approches, (4) interactions. Thus, we will show how the experience of boys and girls is multiple in relation to the diagnosis and it is not possible to be reduced to a gender binary perspective.

Sex differences in network controllability as a predictor of executive function in youth

Executive function is a quintessential human capacity that emerges late in development and displays different developmental trends in males and females. Sex differences in executive function in youth have been linked to vulnerability to psychopathology as well as to behaviors that impinge on health, wellbeing, and longevity. Yet, the neurobiological basis of these differences is not well understood, in part due to the spatiotemporal complexity inherent in patterns of brain network maturation supporting executive function. Here we test the hypothesis that sex differences in impulsivity in youth stem from sex differences in the controllability of structural brain networks as they rewire over development. Combining methods from network neuroscience and network control theory, we characterize the network control properties of structural brain networks estimated from diffusion imaging data acquired in males and females in a sample of 879 youth aged 8-22 years. We summarize the control properties of these networks by estimating average and modal controllability, two statistics that probe the ease with which brain areas can drive the network towards easy versus difficult-to-reach states. We find that females have higher modal controllability in frontal, parietal, and subcortical regions while males have higher average controllability in frontal and subcortical regions. Furthermore, controllability profiles in males are negatively related to the false positive rate on a continuous performance task, a common measure of impulsivity. Finally, we find associations between average controllability and individual differences in activation during an n-back working memory task. Taken together, our findings support the notion that sex differences in the controllability of structural brain networks can partially explain sex differences in executive function. Controllability of structural brain networks also predicts features of task-relevant activation, suggesting the potential for controllability to represent context-specific constraints on network state more generally.

Let's call the whole thing off: evaluating gender and sex differences in executive function

The executive functions allow for purposeful, deliberate, and intentional interactions with the world-attention and focus, impulse control, decision making, and working memory. These measures have been correlated with academic outcomes and quality of life, and are impacted by deleterious environmental events throughout the life span, including gestational and early life insults. This review will address the topic of sex differences in executive function including a discussion of differences arising in response to developmental programming. Work on gender differences in human studies and sex differences in animal research will be reviewed. Overall, we find little support for significant gender or sex differences in executive function. An important variable that factors into the interpretation of potential sex differences include differing developmental trajectories. We conclude by discussing future directions for the field and a brief discussion of biological mechanisms.

ADHD-related sex differences in fronto-subcortical intrinsic functional connectivity and associations with delay discounting

Background

Attention-deficit/hyperactivity disorder (ADHD) is associated with atypical fronto-subcortical neural circuitry and heightened delay discounting, or a stronger preference for smaller, immediate rewards over larger, delayed rewards. Recent evidence of ADHD-related sex differences in brain structure and function suggests anomalies in fronto-subcortical circuitry may differ among girls and boys with ADHD. The current study examined whether the functional connectivity (FC) within fronto-subcortical neural circuitry differs among girls and boys with ADHD compared to same-sex typically developing (TD) controls and relates to delay discounting.

Methods

Participants include 8–12-year-old children with ADHD (n = 72, 20 girls) and TD controls (n = 75, 21 girls). Fronto-subcortical regions of interest were functionally defined by applying independent component analysis to resting-state fMRI data. Intrinsic FC between subcortical components, including the striatum and amygdala, and prefrontal components, including ventromedial prefrontal cortex (vmPFC), anterior cingulate cortex (ACC), and anterior dorsolateral prefrontal cortex (dlPFC), was compared across diagnostic groups overall and within sex. Correlations between intrinsic FC of the six fronto-subcortical pairs and delay discounting were also examined.

Results

Both girls and boys with ADHD show atypical FC between vmPFC and subcortical regions including the striatum (stronger positive FC in ADHD) and amygdala (weaker negative FC in ADHD), with the greatest diagnostic effects among girls. In addition, girls with ADHD show atypical intrinsic FC between the striatum and dlPFC components, including stronger positive FC with ACC and stronger negative FC with dlPFC. Further, girls but not boys, with ADHD, show heightened real-time delay discounting. Brain–behavior correlations suggest (1) stronger negative FC between the striatal and dlPFC components correlated with greater money delay discounting across all participants and (2) stronger FC between the amygdala with both the dlPFC and ACC components was differentially related to heightened real-time discounting among girls and boys with and without ADHD.

Conclusions

Our findings suggest fronto-subcortical functional networks are affected in children with ADHD, particularly girls, and relate to delay discounting. These results also provide preliminary evidence of greater disruptions in fronto-subcortical FC among girls with ADHD that is not due to elevated inattention symptom severity, intellectual reasoning ability, age, or head motion.

Electronic supplementary material

The online version of this article (10.1186/s11689-018-9254-9) contains supplementary material, which is available to authorized users.

Association of Low Lead Levels with Behavioral Problems and Executive Function Deficits in Schoolers from Montevideo, Uruguay

The negative effect of lead exposure on children's intelligence is well-documented. Less is known about the impact of lead on the use of executive functions to self-regulate behavior. We measured blood lead level (BLL) in a sample of first grade children from Montevideo, Uruguay (n = 206, age 6.7 ± 0.5 years, 59.7% boys). Behavior was assessed with teacher versions of the Conners Rating Scale (CRS) and the Behavior Rating Inventory of Executive Functions (BRIEF). Mean BLL was 4.2 ± 2.1 μg/dL; 10% had mild-to-severe ratings of Attentional Deficit with Hyperactivity Disorder (ADHD) (T score > 65). In negative binomial regression, BLL was not associated with CRS sub-scales, but was associated with a poorer ability to inhibit inappropriate behaviors, prevalence ratio (PR) [95% CI]: 1.01 [1.00, 1.03] as measured by the BRIEF. In covariate-adjusted models, the association with BLL was attenuated. When stratified by sex, the covariate-adjusted association between BLL, hyperactivity, poorer inhitibion, emotional control, and behavioral regulation was marginally significant for girls but not boys. In summary, among children with low lead-exposure, we found some, but nonetheless modest, evidence of a relationship between higher BLL and child behavior. If confirmed by larger studies and other objective measures of behavior, such links could have implications for learning and social interaction, particularly among girls.