Maturational delay in ADHD: evidence from CPT

Online search strategies utilized in feigning attention deficit/hyperactivity disorder (ADHD) while performing a continuous performance test (CPT)

BACKGROUND

The availability of information regarding neuropsychological tests threatens their confidentiality. This concern may be particularly relevant to Attention-Deficit/Hyperactivity Disorder (ADHD) considering its widespread online coverage. The present study explored simulators' online search strategies.

METHOD

Simulators (n = 39) searched for information before undergoing an evaluation which included performing a continuous performance test (CPT). Their search strategies were analyzed, and their performance was compared to that of ADHD patients (n = 36) and healthy controls (n = 38).

RESULTS

Most simulators reached high-risk websites that provided written and video-based information regarding the test. Sixty percent, comprised mostly of 3rd-year students, reached Google Scholar. These students were also easier to detect as simulators. Common strategies included performing the CPT in accordance with typical ADHD symptoms and avoiding the endorsement of both unusual and stereotypical symptoms.

CONCLUSION

Simulators can access online information that contains key test data. Higher education may increase the ability to reach academic research while decreasing the ability to convincingly feign impairment. While additional research is needed to examine coaching effects on neuropsychological testing, the risk to test security that many websites pose should be acknowledged and steps, including ones taken by test publishers, should be undertaken to minimize it.

Machine Learning and Deep Learning Approaches in Lifespan Brain Age Prediction: A Comprehensive Review

The concept of 'brain age', derived from neuroimaging data, serves as a crucial biomarker reflecting cognitive vitality and neurodegenerative trajectories. In the past decade, machine learning (ML) and deep learning (DL) integration has transformed the field, providing advanced models for brain age estimation. However, achieving precise brain age prediction across all ages remains a significant analytical challenge. This comprehensive review scrutinizes advancements in ML- and DL-based brain age prediction, analyzing 52 peer-reviewed studies from 2020 to 2024. It assesses various model architectures, highlighting their effectiveness and nuances in lifespan brain age studies. By comparing ML and DL, strengths in forecasting and methodological limitations are revealed. Finally, key findings from the reviewed articles are summarized and a number of major issues related to ML/DL-based lifespan brain age prediction are discussed. Through this study, we aim at the synthesis of the current state of brain age prediction, emphasizing both advancements and persistent challenges, guiding future research, technological advancements, and improving early intervention strategies for neurodegenerative diseases.

Impact of Distractors on Sustained Attention and Inhibition in Children With ADHD

OBJECTIVE

This study examines the impact of visual and auditory distractors on attention and inhibition in children with and without ADHD.

METHOD

The study used the MOXO d-CPT child version. The sample consisted of 208 children aged 8 to 12 years, including 64 with ADHD and 144 controls.

RESULTS

Children with ADHD and controls differed in their reaction to distracting stimuli; visual distractors cause a higher decrease in sustained attention and inhibitory control in the ADHD group. Moreover, auditory distractors generate improved performance in the control group but not in the ADHD group. In addition, age-related effects were found in both sustained attention and inhibitory control in all children, regardless of whether the ADHD condition was present.

CONCLUSIONS

The findings indicate that children with ADHD performed poorer compared to controls, and that distractors differently affected the performance of the two groups.

BOLD Activation During the Application of MOXO-CPT in School Patients With and Without Attention Deficit Hyperactivity Disorder

INTRODUCTION

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder that affects 3% of children in the world.

OBJECTIVE

In this work, we seek to compare the different brain activations of pediatric patients with and without ADHD.

METHODS

A functional resonance examination with BOLD contrast was applied using the MOXO-CPT test (Continuous Performance test with single and double visual-auditory distractors).

RESULTS

Differences in BOLD activation were observed indicating that control children regularly presented negative BOLD activations that were not found in children with ADHD. Inhibitory activity in audiovisual association zones in control patients was greater than in patients with ADHD. The inhibition in the frontal and motor regions in the controls contrasted with the overactivation of the motor areas in patients with ADHD, this, together with the detection of cerebellar activation which attempted to modulate the responses of the different areas that lead to executive failure in patients with ADHD.

CONCLUSIONS

In view of these results, it can be argued that the lack of inhibition of ADHD patients in their executive functions led to a disorganization of the different brain systems.

Behavior Rating Inventory of Executive Function in Preschool (BRIEF-P) and Attention-Deficit and Hyperactivity Disorders (ADHD): A Systematic Review and Meta-Analysis of Floor and Ceiling Effects

BACKGROUND

ADHD is a neurodevelopmental disorder that is accompanied by executive challenges.

OBJECTIVES

To obtain evidence of the usefulness of the BRIEF-P and to analyze the possible ceiling and floor effect of its scores in the assessment of executive function in preschoolers with signs compatible with a possible diagnosis of ADHD.

METHOD

A search was performed in Science Direct, NCBI (PubMed), and ProQuest Education Journals during the period 2012-2022. We included studies that evaluated samples of individuals with symptomatology compatible with ADHD, with an age range between 2 and 6 years, published in English or Spanish. Of a total of 2538 articles, only seven met the inclusion criteria. The risk of bias was assessed using the QUADAS-2 questionnaire. The main variables were age and executive functioning.

CONCLUSIONS

Executive deficits in early-age individuals with symptoms compatible with ADHD are more extensive than just deficits in working memory. A floor effect has been found in tests associated with hot executive functions and a ceiling effect in cold executive functions. This makes it necessary to use different tests to assess executive performance in preschoolers with ADHD-compatible symptomatology and to design intervention proposals accordingly. The BRIEF-P is an instrument that facilitates obtaining a sensitive and discriminative executive profile, although it should be used in combination with other neuropsychological performance tests.

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.

Developmental trajectory of hot and cold executive functions in children with and without attention deficit-hyperactivity disorder (ADHD)

BACKGROUND

Children with attention deficit hyperactivity disorder (ADHD) have a delayed development. Two main cognitive models of ADHD are executive (cold) and motivational (hot) models. In this study, we aimed to compare the development of hot and cold executive functions in children with and without ADHD.

METHODS AND PROCEDURES

Forty-six children with ADHD symptoms (56% boys) and forty-four typically developing controls (54% boys), in three age groups of 6-8, 8-10 and 10-12 years, were participated in the study. Go/No-Go Task (GNGT), One-Back Test (OBT) and Shifting Attention Test (SAT), Delay Discounting Test (DDT) and Balloon Analogue Risk Task (BART) were used for assessment.

OUTCOMES AND RESULTS

Children with ADHD showed lower performance in GNG, OBT, SAT, and BART, but intact performance in DDT. The tasks' performance was significantly different between three age groups in GNG and SAT, but similar in OBT and BART. The interaction effect was significant only for the BART measures.

CONCLUSIONS AND IMPLICATIONS

Children with ADHD compared to typically developing children, experience impaired hot and cold executive functions. The cognitive delay was found only in risky decision making as a hot executive function.

Growth rates of human induced pluripotent stem cells and neural stem cells from attention-deficit hyperactivity disorder patients: a preliminary study

Attention-deficit hyperactivity disorder (ADHD) is a neurodevelopmental polygenic disorder that affects more than 5% of children and adolescents around the world. Genetic and environmental factors play important roles in ADHD etiology, which leads to a wide range of clinical outcomes and biological phenotypes across the population. Brain maturation delays of a 4-year lag are commonly found in patients, when compared to controls of the same age. Possible differences in cellular growth rates might reflect the clinical observations in ADHD patients. However, the cellular mechanisms are still not elucidated. To test this hypothesis, we analysed the proliferation of induced pluripotent stem cells (iPSCs) and neural stem cells (NSCs) derived from male children and adolescents diagnosed with ADHD and with genetic predisposition to it (assessed using polygenic risk scores), as well as their respective matched controls. In the current pilot study, it was noticeable that NSCs from the ADHD group proliferate less than controls, while no differences were seen at the iPSC developmental stage. Our results from two distinct proliferation methods indicate that the functional and structural delays found in patients might be associated with these in vitro phenotypic differences, but start at a distinct neurodevelopmental stage. These findings are the first ones in the field of disease modelling of ADHD and might be crucial to better understand the pathophysiology of this disorder.

Validating Embedded Validity Indicators of Feigned ADHD-Associated Cognitive Impairment Using the MOXO-d-CPT

BACKGROUND

The current study aimed to validate the utility of previously established validity indicators derived from MOXO-d-CPT's continuous performance test.

METHOD

Healthy simulators feigned impairment after searching online for relevant information, an ecologically valid coaching condition (n = 39). They were compared to ADHD patients (n = 36) and healthy controls (n = 38).

RESULTS

Simulators performed significantly worse than ADHD patients in all MOXO-d-CPT indices, as well as a scale that integrates their contributions (feigned ADHD scale). Three indices (attention, hyperactivity, and impulsivity) and the latter scale exhibited adequate discriminative capacity. Higher education was associated with an exaggerated impairment among simulators, easing their detection.

CONCLUSION

Similarity between the current study and a previous study which examned the utlity of the MOXO-d-CPT validity indicators, increases our confidence in the efficacy of the latters embedded validity indicators. Though the findings provide initial validation of these validity indicators, generalizing beyond highly functioning participants necessitates further research.

Electroencephalography complexity in resting and task states in adults with attention-deficit/hyperactivity disorder

Analysing EEG complexity could provide insight into neural connectivity underlying attention-deficit/hyperactivity disorder symptoms. EEG complexity was calculated through multiscale entropy and compared between adults with attention-deficit/hyperactivity disorder and their peers during resting and go/nogo task states. Multiscale entropy change from the resting state to the task state was also examined as an index of the brain’s ability to change from a resting to an active state. Thirty unmedicated adults with attention-deficit/hyperactivity disorder were compared with 30 match-paired healthy peers on the multiscale entropy in the resting and task states as well as their multiscale entropy change. Results showed differences in multiscale entropy between individuals with attention-deficit/hyperactivity disorder and their peers during the resting state as well as the task state. The multiscale entropy measured from the comparison group was larger than that from the attention-deficit/hyperactivity disorder group in the resting state, whereas the reverse pattern was found during the task state. Our most robust finding showed that the multiscale entropy change from individuals with attention-deficit/hyperactivity disorder was smaller than that from their peers, specifically at frontal sites. Interestingly, individuals without attention-deficit/hyperactivity disorder performed better with decreasing multiscale entropy changes, demonstrating higher accuracy, faster reaction time and less variability in their reaction times. These data suggest that multiscale entropy could not only provide insight into neural connectivity differences between adults with attention-deficit/hyperactivity disorder and their peers but also into their behavioural performance.

Theories of Change and Mediators of Psychotherapy Effectiveness in Adolescents With Externalising Behaviours: A Systematic Review

BACKGROUND

Externalising behaviours are becoming a remarkably prevalent problem during adolescence, often precipitating both externalising and internalising disorders in later adulthood. Psychological treatments aim to increase the social functioning of adolescents in order for them to live a more balanced life and prevent these negative trajectories. However, little is known of the intervening variables and mediators involved in these treatments' change mechanisms. We conducted a systematic review, exploring the available evidence on mediators of psychological treatments for externalising behaviours and symptoms amongst adolescents (10 to 19 years old).

METHODS

A systematic search was performed on Medline and PsycINFO databases, which identified studies from inception to February 23, 2020. Eligible studies included randomised controlled trials that enrolled adolescents with externalising symptoms and behaviours as, at least, one of the primary outcomes. A group of 20 reviewers from the COST-Action TREATme (CA16102) were divided into 10 pairs. Each pair independently screened studies for inclusion, extracted information from the included studies, and assessed the methodological quality of the included studies and the requirements for mediators, following Kazdin's criteria. Risk of bias of RCTs was assessed by the Mixed Methods Appraisal Tool. Extracted data from the included studies were reported using a narrative synthesis.

RESULTS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA), after removing duplicates, 3,660 articles were screened. Disagreements were resolved by consensus. In a second stage, 965 full-text articles were assessed for eligibility. A total of 14 studies fulfilled all inclusion criteria. The majority were related to systemic psychological treatment approaches. Two types of mediators were identified as potentially being involved in the mechanisms of change for better social improvements of adolescents: to increase healthier parent-adolescent relationships and parental discipline. However, there were significant and non-significant results amongst the same mediators, which led to discussing the results tentatively.

CONCLUSIONS

Family variables were found to be the largest group of investigated mediators, followed by relational, behavioural, and emotional variables. No cognitive or treatment-specific mediators were identified. Both adequate behavioural control of adolescents' peer behaviour and a better positive balance in their relationships with their parents seemed to buffer the effects of externalising behaviours in adolescents. Several methodological limitations concerning mediation testing design, outcome measures, and mediator selection have been identified.

ETHICS AND DISSEMINATION

Ethical approval was not required. PROSPERO registration number: CRD42021231835.

Eye Tracking During a Continuous Performance Test: Utility for Assessing ADHD Patients

OBJECTIVE

The use of continuous performance tests (CPTs) for assessing ADHD related cognitive impairment is ubiquitous. Novel psychophysiological measures may enhance the data that is derived from CPTs and thereby improve clinical decision-making regarding diagnosis and treatment. As part of the current study, we integrated an eye tracker with the MOXO-dCPT and assessed the utility of eye movement measures to differentiate ADHD patients and healthy controls.

METHOD

Adult ADHD patients and gender/age-matched healthy controls performed the MOXO-dCPT while their eye movements were monitored (n = 33 per group).

RESULTS

ADHD patients spent significantly more time gazing at irrelevant regions, both on the screen and outside of it, than healthy controls. The eye movement measures showed adequate ability to classify ADHD patients. Moreover, a scale that combined eye movement measures enhanced group prediction, compared to the sole use of conventional MOXO-dCPT indices.

CONCLUSIONS

Integrating an eye tracker with CPTs is a feasible way of enhancing diagnostic precision and shows initial promise for clarifying the cognitive profile of ADHD patients. Pending replication, these findings point toward a promising path for the evolution of existing CPTs.

Time Perception Deficits in Children and Adolescents with ADHD: A Meta-analysis

OBJECTIVE

Prior studies have reported time perception impairment in children and adolescents with ADHD but the results were inconsistent.

METHOD

The current meta-analysis reviews 27 empirical studies published in English after year 2000 that compared time perception competence among children and adolescents with and without ADHD.

RESULTS

Results from 1620 participants with ADHD and 1249 healthy controls showed significant timing deficits in ADHD. Children/adolescents with ADHD perceived time less accurately (Hedges' g > 0.40), less precisely (Hedges' g = 0.66) and had higher tendency to overestimate time than their healthy counterparts. Moderator analyses indicated that the discrepancy of time perception between groups was not affected by the type of timing tasks nor the modality of stimuli used in the tasks. Nonetheless, results were moderated by age and gender.

CONCLUSION

These findings may update current understanding of the underlying neuropsychological deficits in ADHD and provide insight for future research in clinical assessments and treatments for ADHD.

Ready for a Learner's Permit? Clinical Neuropsychological Off-road Tests and Driving Behaviors in a Simulator among Adolescents with ADHD and ASD

A simulator driving test (SDT) and two neuropsychological tests, the Useful Field of View (UFOV) test and the Test of Variables of Attention (TOVA) were evaluated with regard to validity for fitness to drive on 51 young clients diagnosed with attention deficit hyperactivity disorder (ADHD), 33 of whom also had autism spectrum disorder (ASD), and 38 adolescents without a neurodevelopmental diagnosis. The results show generally much greater variability and significantly poorer performance in the SDT and the TOVA for clients with ADHD/ASD compared with the control group. The SDT results were strongly intratest correlated, but had no interest correlation with either the UFOV test or the TOVA. The greater variability among clients with ADHD/ASD suggests greater effort and susceptibility to motivational issues and decline in sustained attention over several tests. In conclusion, the SDT is sensitive and has good face validity, and the TOVA is sensitive to neuropsychological aspects of safe driving. The SDT and the TOVA thus complement each other, and discrepancy between test scores calls for special consideration.

Acute and chronic sleep deprivation in residents: Cognition and stress biomarkers

OBJECTIVES

Insufficient sleep affects circadian hormonal profiles and inflammatory markers and may modulate attention, executive functioning and decision-making. Medical professionals and specifically resident physicians, who are involved in long-term nightshift schedules during their post-graduate training, are prone to acute and chronic sleep deprivation and disruption, putting them at risk for making medical errors. The aim of the study was to evaluate the impact of chronic and acute-on-chronic sleep deprivation and disruption among residents on selected physiological and cognitive measures.

METHODS

Thirty-three medical and surgical residents were evaluated twice - at baseline and after a 26-hour shift. Eighteen young attending physicians who did not engage in nightshift schedules served as controls and were evaluated once. Measures included morning cortisol and high-sensitivity C-reactive protein (hs-CRP), computerised tests of attention and behaviour, the Behaviour Rating Inventory of Executive Function, a risk-taking questionnaire and the Pittsburgh Sleep Quality Index.

RESULTS

Residents, but not attendings, reported chronic sleep disruption and deprivation. Residents at baseline exhibited reduced morning cortisol levels and elevated hs-CRP levels, compared to attendings. Residents at baseline had impaired global executive function compared to attendings. A nightshift with acute sleep deprivation further reduced residents' executive function. Residents at baseline and after a nightshift demonstrated increased impulsivity and slower processing time than attendings. Residents and attendings did not differ in risk-taking tendencies which were assessed in a separate cohort.

CONCLUSIONS

In a real-life setting, resident physicians exhibit increased low-grade systemic inflammation (hs-CRP) and impaired HPA-axis function. Their chronic sleep curtailment is associated with greater impulsivity, slower cognitive processing, and impaired executive function. Future research is warranted to understand how improving working schedule by increasing sleep duration may minimise the short-term and potential long-term risks to physicians in training.

The effect of attention-deficit/hyperactivity disorder (ADHD) on driving behavior and risk perception

OBJECTIVE

To examine the effect of attention-deficit/hyperactivity disorder (ADHD) on differences in driving behavior and risk perception, in experienced drivers.

METHODS

A total of 147 experienced drivers participated in the study. Drivers with ADHD (n = 91) were compared to an age-matched control group of drivers (n = 56) with no neuropsychiatric diagnoses. A simulator driving test (SDT) was used in the study and included a driving scenario with various traffic environments to examine any differences in number of collisions, number of speedings, risk index (based on 12 risky situations), speed adaptation (based on 19 road sections), mean speed, and preferred speed, between the two groups. The participants also completed a questionnaire about their driving behavior.

RESULTS

No differences in the simulator driving test were found between the ADHD group and the control group. No adverse effects of ADHD were found for any of the measures, i.e., collisions, number of speeding, risk index, speed adaptation, mean speed and preferred speed. The only significant group difference was that drivers with ADHD rated themselves lower on concentration.

CONCLUSIONS

Participants with ADHD and the control group drove remarkably similarly in the simulator driving test and rated themselves similarly regarding how they drive. The results contribute to state that ADHD drivers are less deviant than asserted by previous research.

Possible Age-Related Progression of Attentional Impairment in ADHD and Its Attenuation by Past Diagnosis and Treatment

Objective: The aim of the study is to evaluate attentional impairment in different age groups with ADHD. Method: In all, 58 children, 73 adolescents, and 104 adults with ADHD were evaluated using the Test of Variables of Attention (TOVA). Subjects with comorbidities or psychotropic treatment were not included. Results: Considering Response Time Variability (RTV), adults were 10.6 and 4.0 times more likely to be severely impaired (standard score < 40) than children and adolescents, respectively. Adults were twice as likely as adolescents to be very impaired (standard score< 70) in Omissions. Considering d' (decrement of attentional performance over time), all severely impaired participants were adults. Age predicted impairment in Attention Performance Index (API), RTV, and d', but not Omissions or Commissions. Past treatment with stimulants predicted less impairment in d', past diagnosis predicted less impairment in RTV, and each predicted less impairment in Omissions and API. Conclusion: Adults had more attentional impairment than children and adolescents. Past diagnosis and treatment were associated with less ADHD-related attentional impairment.

Relationship between intraindividual auditory and visual attention in children with ADHD

BACKGROUND AND AIM

Most previous attention-deficit/hyperactivity disorder (ADHD) studies have used only a single sensory modality (usually vision) to investigate attentional problems, although patients with ADHD might display deficits of auditory attention similar to their visual attention. This study explored intraindividual auditory and visual attention in children with and without ADHD to examine the relationship between these two dimensions of attention.

METHODS

Attentional performances of 140 children (70 children with ADHD and 70 typically developing peers) were measured through the Test of Variables of Attention (TOVA) in the present study.

RESULTS

For both groups, most attentional indices showed significant differences between the two modalities (d ranging from 0.32 to 0.72). The correlation coefficients of most of the attentional variables in children with ADHD were lower than their typically developing peers. All attentional indices of children with ADHD (ranging from 12.8%-55.7%) were much higher than those of their typically developing peers (ranging from 1.4%-8.6%).

CONCLUSION

These results not only indicate that typically developing children display more consistent attentional performance, but also support the view that children with ADHD may show attention deficiency in one modality but not necessarily in the other.

A novel quantitative electroencephalography subtype with high alpha power in ADHD: ADHD or misdiagnosed ADHD?

This study investigated quantitative electroencephalography (QEEG) subtypes as auxiliary tools to assess Attention Deficit Hyperactivity Disorder (ADHD). A total of 74 subjects (58 male and 16 female) were assessed using the Korean version of the Diagnostic Interview Schedule for Children Version IV and were assigned to one of three groups: ADHD, ADHD-Not Otherwise specified (NOS), and Neurotypical (NT). We measured absolute and relative EEG power in 19 channels and conducted an auditory continuous performance test. We analyzed QEEG according to the frequency range: delta (1–4 Hz), theta (4–8 Hz), slow alpha (8–10 Hz), fast alpha (10–13.5 Hz), and beta (13.5–30 Hz). The subjects were then grouped by Ward’s method of cluster analysis using the squared Euclidian distance to measure dissimilarities. We discovered four QEEG clusters, which were characterized by: (a) elevated delta power with less theta activity, (b) elevated slow alpha relative power, (c) elevated theta with deficiencies of alpha and beta relative power, and (d) elevated fast alpha and beta absolute power. The largest proportion of participants in clusters (a) and (c) were from the ADHD group (48% and 47%, respectively). Conversely, group (b) mostly consisted of the participants from the NOS group (59%), while group (d) had the largest proportion of participants from the NT group (62%). These results indicate that children with ADHD does not neurophysiologically constitute a homogenous group. We also identified a new subtype with increased alpha power in addition to those commonly reported in ADHD. Given the QEEG characteristics with increased alpha power, we should consider the possibility that this subtype may be caused by childhood depression. In conclusion, we believe that these QEEG subtypes of ADHD are expected to provide valuable information for accurately diagnosing ADHD.

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.

Longitudinal Trajectories of Sustained Attention Development in Children and Adolescents with ADHD

The present study characterizes changes in sustained attention ability over ages 9-14, and whether longitudinal trajectories of attention development differ between persistent ADHD, remitted ADHD and control groups. The Sustained Attention to Response Task (SART) was administered to 120 children with ADHD and 123 controls on three occasions between ages 9 and 14. Trajectories of sustained attention development, indicated by changes in SART performance (standard deviation of response time [SDRT], omission errors, and ex-Gaussian parameters sigma and tau), were examined using generalized additive mixed models. For all measures there was a significant main effect of age; response time variability and number of omission errors improved linearly as children aged. However, children with ADHD had significantly greater SDRT, tau and omission errors than controls across waves. There were no significant group differences in sigma, indicating that the greater overall response time variability (SDRT) observed in ADHD was likely driven by more intermittent long responses (larger tau). Trajectories of sustained attention performance did not differ between children with persistent ADHD or ADHD in remission. Longitudinal trajectories of sustained attention development are comparable between ADHD and controls, however children with ADHD (regardless of remission status) display a performance deficit equivalent to typical controls 1-3 years younger. Findings highlight the need for continued clinical support for children in remission from ADHD and provide support for tau as an endophenotype of ADHD.

The Course of Neurocognitive Functioning and Prediction of Behavioral Outcome of ADHD Affected and Unaffected Siblings

Longitudinal studies on the course of neurocognitive functioning of children with ADHD and their unaffected siblings are scarce. Also, it is unclear to what extent that course is related to ADHD outcomes. A carefully phenotyped large sample of 838 Caucasian participants (ADHD-combined type: n = 339, unaffected siblings: n = 271, controls: n = 228; mean age at baseline = 11.4 years, mean age at follow-up = 17.3 years, SD = 3.2) was used to investigate differences in the course of neurocognitive functioning of ADHD affected and unaffected siblings versus controls, and to investigate the relationship between neurocognitive change and ADHD outcomes. At baseline, an aggregated measure of overall neurocognitive functioning and eight neurocognitive measures of working memory, timing (speed/variability), motor control, and intelligence were investigated. Outcomes at follow-up were dimensional measures of ADHD symptom severity and the Kiddie-Global Assessment Scale (K-GAS) for overall functioning. At follow up, affected and unaffected siblings trended to, or fully caught up with performance levels of controls on four (44.4%) and five (55.6%) of the nine dependent variables, respectively. In contrast, performance in remaining key neurocognitive measures (i.e. verbal working memory, variability in responding) remained impaired at follow-up. Change in neurocognitive functioning was not related to ADHD outcomes. Our results question the etiological link between neurocognitive deficits and ADHD outcomes in adolescents and young adults.

Vigilance, Inhibitory Control and Regional Cerebral Blood Oxygenation in the PFC - Differences in ADHD Types of Presentations

It is commonly believed that proven abnormalities in the structure and functioning of the prefrontal lobes affect cognitive deficits in children with ADHD. The purpose of the current study was to assess vigilance, inhibitory control, and regional cerebral blood oxygenation (rCBO2) in the prefrontal cortex (PFC) of children with ADHD. The study included 150 children with ADHD and 51 typically developing (TD) children aged 9-12 years. Children with ADHD showed a deficit in vigilance (assessed by the shortened version of the Mackworth clock task), inhibitory control (the Stroop task), different rCBO2 patterns in the PFC, as well as lower cortical activation during cognitive tasks. These differences are discussed in the context of the types of ADHD presentations.

Dysregulation of synaptic pruning as a possible link between intestinal microbiota dysbiosis and neuropsychiatric disorders

The prenatal and early postnatal stages represent a critical time window for human brain development. Interestingly, this window partly overlaps with the maturation of the intestinal flora (microbiota) that play a critical role in the bidirectional communication between the central and the enteric nervous systems (microbiota-gut-brain axis). The microbial composition has important influences on general health and the development of several organ systems, such as the gastrointestinal tract, the immune system, and also the brain. Clinical studies have shown that microbiota alterations are associated with a wide range of neuropsychiatric disorders including autism spectrum disorder, attention deficit hyperactivity disorder, schizophrenia, and bipolar disorder. In this review, we dissect the link between these neuropsychiatric disorders and the intestinal microbiota by focusing on their effect on synaptic pruning, a vital process in the maturation and establishing efficient functioning of the brain. We discuss in detail how synaptic pruning is dysregulated differently in the aforementioned neuropsychiatric disorders and how it can be influenced by dysbiosis and/or changes in the intestinal microbiota composition. We also review that the improvement in the intestinal microbiota composition by a change in diet, probiotics, prebiotics, or fecal microbiota transplantation may play a role in improving neuropsychiatric functioning, which can be at least partly explained via the optimization of synaptic pruning and neuronal connections. Altogether, the demonstration of the microbiota's influence on brain function via microglial-induced synaptic pruning addresses the possibility that the manipulation of microbiota-immune crosstalk represents a promising strategy for treating neuropsychiatric disorders.

The Utility of the CPT in the Diagnosis of ADHD in Individuals with Substance Abuse: A Systematic Review

BACKGROUND

Early identification of attention-deficit/hyperactivity disorder (ADHD) in individuals with substance use disorders (SUD) is important because ADHD has an adverse effect on the development and course of SUD. Given the limited validity of self-report measures of ADHD in individuals with SUD, it is important to investigate the utility of the continuous performance test (CPT) in classifying ADHD in adults with SUD.

OBJECTIVE

This review aims to examine the quantitative similarities and differences in CPT performance of adults with ADHD, SUD, and their comorbidity to determine if a distinct neurocognitive profile exists for each.

METHOD

A systematic review of CPT studies that included patients with the comorbidity of ADHD and SUD and a comparison group of one of the disorders alone was conducted. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used.

RESULTS

Eight studies were identified with sample sizes ranging from n = 17 to n = 386. The comorbidity of ADHD and SUD was, mostly, not associated with higher rates of commission and omission errors than either disorder alone. However, the comorbidity of ADHD and SUD was more likely to be associated with increased deficits in response time variability compared with individuals with ADHD alone.

CONCLUSIONS

This review highlights the shortage of large-scale CPT research involving patients with ADHD and SUD. The CPT might be sensitive to attentional deficits, but it lacks specificity for the classification of adult ADHD, SUD, or their comorbidity, and the CPT is thus not useful in discriminating comorbid ADHD and SUD from either disorder alone. Future CPT research should explore whether specific attentional deficits account for the development and persistence of SUD. Such research should also reach beyond traditional CPT measures and include other cognitive and behavioral deficits that were associated with ADHD, such as distractibility and hyperactivity.

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.

Effects of Exercise on Cognitive Performance in Children and Adolescents with ADHD: Potential Mechanisms and Evidence-based Recommendations

Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder with a complex symptomatology, and core symptoms as well as functional impairment often persist into adulthood. Recent investigations estimate the worldwide prevalence of ADHD in children and adolescents to be ~7%, which is a substantial increase compared to a decade ago. Conventional treatment most often includes pharmacotherapy with central nervous stimulants, but the number of non-responders and adverse effects call for treatment alternatives. Exercise has been suggested as a safe and low-cost adjunctive therapy for ADHD and is reported to be accompanied by positive effects on several aspects of cognitive functions in the general child population. Here we review existing evidence that exercise affects cognitive functions in children with and without ADHD and present likely neurophysiological mechanisms of action. We find well-described associations between physical activity and ADHD, as well as causal evidence in the form of small to moderate beneficial effects following acute aerobic exercise on executive functions in children with ADHD. Despite large heterogeneity, meta-analyses find small positive effects of exercise in population-based control (PBC) children, and our extracted effect sizes from long-term interventions suggest consistent positive effects in children and adolescents with ADHD. Paucity of studies probing the effect of different exercise parameters impedes finite conclusions in this regard. Large-scale clinical trials with appropriately timed exercise are needed. In summary, the existing preliminary evidence suggests that exercise can improve cognitive performance intimately linked to ADHD presentations in children with and without an ADHD diagnosis. Based on the findings from both PBC and ADHD children, we cautiously provide recommendations for parameters of exercise.

Age-Related Changes in Distractibility: Developmental Trajectory of Sustained Attention in ADHD

OBJECTIVE

This study investigated age-related changes in sustained attention in children with ADHD and in their typically developed peers.

METHOD

The study used a Continuous Performance Test (CPT) that includes visual and auditory stimuli serving as distractors. The rate of omission errors was used as a measurement of difficulty in sustained attention. Participants were children and adolescents aged 7 to 18 years (478 with ADHD and 361 without ADHD).

RESULTS

Both groups of adolescents (with and without ADHD) showed reduced distractibility than younger children from the same group. However, distractibility tended to diminish in non-ADHD adolescents, but not in adolescents with ADHD.

CONCLUSION

Although part of the difficulties in ADHD could be explained by developmental delay that improves with time, other deficits, such as increased distractibility causing more omission errors, do not show a clear developmental trajectory. The results suggest that deficits in inhibitory control might be the core of ADHD.

Delayed myelination and neurodevelopment in male seizure-prone versus seizure-resistant rats

OBJECTIVE

Aberrant myelination and developmental delay have been reported in epilepsy. However, it is unclear whether these are linked to intrinsic mechanisms that support a predisposition toward seizures and the development of epilepsy. Thus, we compared rates of myelination and neurodevelopment in male rats selectively bred for enhanced susceptibility to kindling epileptogenesis (FAST) with male rats bred for resistance (SLOW).

METHODS

Myelin-specific gene expression was compared in the brainstem, cerebellum, and cerebral hemisphere of FAST and SLOW rats on postnatal days (PNDs) 5, 11, 17, 23, and 90 to determine strain-specific myelination rates. Myelin protein levels were also compared at PNDs 5 and 23 in the brainstem. Relative rates of neurodevelopment were evaluated between PNDs 5 and 21 using physical growth landmarks and neuromotor tests including righting reflex, cliff avoidance, negative geotaxis, and locomotor activity.

RESULTS

Myelin-specific mRNA expression was significantly down-regulated in FAST rats on PNDs 5 and 11 in all 3 brain structures, indicating relatively delayed myelination. Likewise, corresponding protein levels were significantly lower in FAST brainstem on PND 5. Developmental delay was evident in the FAST strain such that only 9% of FAST pups, compared to 81% of SLOW, had open eyes by PND 13, locomotor activity was significantly reduced between PNDs 12 and 16, and neuromotor task acquisition was delayed between PNDs 5 and 10.

SIGNIFICANCE

Relative delays in myelination and neurodevelopment co-occurred in the seizure-prone FAST strain in the absence of seizures. These findings suggest these symptoms are not seizure-induced and may be mechanistically linked to an underlying pathophysiology supporting a predisposition toward developing epilepsy.

Attention Deficit Hyperactivity Disorder in Neurofibromatosis Type 1: Evaluation with a Continuous Performance Test

Background and Purpose

The objective of this study was to determine if the MOXO visual- and vocal-distractors-based continuous performance test distinguishes patients with attention deficit hyperactivity disorder (ADHD) and neurofibromatosis type 1 (NF1) from those without NF1.

Methods

Thirty-five patients (16 males; mean age 9.91 years) attending a multidisciplinary NF1 clinic completed the MOXO test. The findings were compared to 532 healthy age-matched standardized control subjects (285 males) without ADHD.

Results

The overall performance in the MOXO text was significantly worse in the NF1 group than in controls (p<0.01), but no group-specific pattern was identified. Impulsivity and hyperactivity were significantly more prominent in males than females (p<0.01). Compared to controls, the NF1 group exhibited significantly more failures to respond to target stimuli in the presence of visual distractors.

Conclusions

MOXO scores are abnormal in patients with NF1, but the test cannot differentiate between NF1 with ADHD characteristics and ADHD. The test highlights sex differences in ADHD characteristics in NF1. Overreactivity to visual distractors may form part of the attention deficit in NF1.

Inattention in primary school is not good for your future school achievement-A pattern classification study

Inattention in childhood is associated with academic problems later in life. The contribution of specific aspects of inattentive behaviour is, however, less known. We investigated feature importance of primary school teachers’ reports on nine aspects of inattentive behaviour, gender and age in predicting future academic achievement. Primary school teachers of n = 2491 children (7–9 years) rated nine items reflecting different aspects of inattentive behaviour in 2002. A mean academic achievement score from the previous semester in high school (2012) was available for each youth from an official school register. All scores were at a categorical level. Feature importances were assessed by using multinominal logistic regression, classification and regression trees analysis, and a random forest algorithm. Finally, a comprehensive pattern classification procedure using k-fold cross-validation was implemented. Overall, inattention was rated as more severe in boys, who also obtained lower academic achievement scores in high school than girls. Problems related to sustained attention and distractibility were together with age and gender defined as the most important features to predict future achievement scores. Using these four features as input to a collection of classifiers employing k-fold cross-validation for prediction of academic achievement level, we obtained classification accuracy, precision and recall that were clearly better than chance levels. Primary school teachers’ reports of problems related to sustained attention and distractibility were identified as the two most important features of inattentive behaviour predicting academic achievement in high school. Identification and follow-up procedures of primary school children showing these characteristics should be prioritised to prevent future academic failure.

Aiding the diagnosis of AD/HD in childhood: Using actigraphy and a continuous performance test to objectively quantify symptoms

The current gold standard for the diagnosis of AD/HD is based on subjective reports from teachers, parents, and clinicians. These measures can be problematic as they are open to rater biases and also fail to account for the developmental nature of symptoms. The current study examined the diagnostic accuracy of two objective measures, a computer-based Continuous Performance Task and actigraphy (e.g. motion tracking device) in differentiating children with AD/HD (N=70) from healthy controls (N=70). It was predicted that task-unrelated movement (measured via actigraphy) during a CPT and CPT performance would have high classification accuracy in differentiating children with AD/HD from healthy controls, and that the inclusion of age would increase this accuracy. Results indicated that total energy expenditure from the task-unrelated wrist and ankle movement during the CPT was higher in children with AD/HD than controls, and that CPT performance was poorer in AD/HD than controls. Discriminant function analyses revealed that the CPT Full-Scale Response Control Quotient and wrist and ankle energy expenditure provided optimal classification accuracy - correctly classifying 86% of cases, with sensitivity of 81.4% and specificity of 91.4%. The prediction that classification accuracy would increase with the inclusion of age was not supported by the data. When taken in conjunction with other clinical assessments, these findings suggest that actigraphy during a CPT and CPT performance may increase the probability of a correct AD/HD diagnosis.

Positive Illusions? The Accuracy of Academic Self-Appraisals in Adolescents With ADHD

OBJECTIVE

Children with attention deficit/hyperactivity disorder (ADHD) overestimate their academic competencies (AC) relative to performance and informant indicators (i.e., positive illusory bias; PIB). Do adolescents with ADHD exhibit this PIB and does it render self-views inaccurate? We examined the magnitude of the AC-PIB in adolescents with and without ADHD, the predictive accuracy of parent and adolescent AC ratings, and whether executive functions (EF) predict the AC-PIB.

METHOD

Adolescents (49 ADHD; 47 typically developing) completed math and EF tests, and self-rated their AC. Parents rated their adolescents' AC and EF.

RESULTS

Adolescents with ADHD performed more poorly on the math task (vs. comparison group) but had a larger AC-PIB relative to parents' ratings. EFs predicted the PIB within the full sample. Adolescents' AC ratings, regardless of ADHD status, were more predictive of math performance than their parents' AC ratings.

CONCLUSION

Adolescents with ADHD appear self-aware in their AC despite a modest PIB; nuanced self-appraisals may depend on EFs.

The effect of alpha-linolenic acid supplementation on ADHD symptoms in children: a randomized controlled double-blind study

Background: Attention deficit-hyperactivity disorder (ADHD) is the most common neuro-developmental disorder in childhood. Its pharmacologic treatment mostly includes methylphenidate, yet many parents seek alternative, “natural,” therapeutic options, commonly omega-3 fatty acids. Previous studies of supplementation with fish oil or long-chain omega-3 fatty acids to children with ADHD yielded mixed results. The use of alpha-linolenic acid (ALA), a medium-chained, plant-based omega-3 fatty acid (18:3 n-3), has not been sufficiently examined in this population.

Methods: Forty untreated children with ADHD, aged 6–16 years, were randomized to receive either 2 g/day of oil containing 1 g ALA or placebo, for 8 weeks. Before and after supplementation, the children underwent a physician assessment of ADHD symptoms and a computerized continuous performance functions test. The children’s parents and teachers filled out Conners’ and DSM questionnaires.

Results: Seventeen (42.5%) children completed the study, eight in the supplementation group, nine in the placebo group. Main drop-out reasons were capsule size, poor compliance, and a sense of lack of effect. No significant difference was found in any of the measured variables tested before and after supplementation, in both study groups. No between-group difference was found in the changes of the various measures of ADHD symptoms throughout the study period.

Conclusion: Supplementation of 2 g/day of oil containing 1 g ALA did not significantly reduce symptoms in children with ADHD. Future studies in this field should consider an alternative method to deliver the oil, a higher dose, and a larger sample size.