Saccade eye movements as a quantitative measure of frontostriatal network in children with ADHD

The use of eye-tracking technology in supporting children and adolescents with attention deficit/hyperactivity disorder: a comprehensive review

MATERIALS AND METHODS

Through the analysis of 74 studies, we examine how eye-tracking technology has been applied to address ADHD-related challenges, the specific methods used, and the correlations between eye-tracking metrics and ADHD symptoms in youth.Results and conclusions: The findings suggest that eye-tracking offers a non-invasive and reliable approach to objectively assess domains such as visual processing characteristics, early detection or interventions. By discussing both the achievements and limitations of the reviewed studies, this paper not only consolidates existing knowledge but also proposes avenues for future research to enhance support for children and adolescents with ADHD.

Can attention-deficit/hyperactivity disorder be considered a form of cerebellar dysfunction?

Attention-deficit/hyperactivity disorder (ADHD) is a heterogenous disorder, commonly described for presenting difficulties in sustained attention, response inhibition, and organizing goal-oriented behaviors. However, along with its traditionally described executive dysfunction, more than half of the children diagnosed with ADHD have been reported to show difficulties with gross and fine motor skills, albeit motor impairments in ADHD continue to be a neglected area of clinical attention. The rapidly growing field of the clinical cognitive neuroscience of the cerebellum has begun to relate cerebro-cerebellar circuits to neurodevelopmental disorders. While the cerebellum's role in motor function, such as balance, motor coordination, and execution, is well recognized, ongoing research has evidenced its additional and fundamental role in neurocognitive development and executive function, including attention and social cognition, which are all areas of impairment commonly found in ADHD. Interestingly, neuroimaging studies have consistently shown differences in cerebellar volume and functional connectivity between ADHD and typically developing children. Furthermore, methylphenidate is known to act at the cerebellar level, as intrinsic cerebellar dopaminergic systems involved in attention and motor function have been identified. This article reviews some of the main findings linking cerebellar dysfunction to ADHD behavioral symptoms and incorporates the cerebellum as a possible neurological basis and differentiating indicator within the condition. We suggest considering more rigorous assessments in future ADHD studies, including cerebellar-associated skill evaluations to correlate with symptom severity and other detected outcomes, such as executive dysfunction, and study possible associative patterns that may serve as more objective measures for this diagnosis.

Unexpected sounds induce a rapid inhibition of eye-movement responses

Unexpected sounds have been shown to trigger a global and transient inhibition of motor responses. Recent evidence suggests that eye movements may also be inhibited in a similar way, but it is not clear how quickly unexpected sounds can affect eye-movement responses. Additionally, little is known about whether they affect only voluntary saccades or also reflexive saccades. In this study, participants performed a pro-saccade and an anti-saccade task while the timing of sounds relative to stimulus onset was manipulated. Pro-saccades are generally reflexive and stimulus-driven, whereas anti-saccades require the generation of a voluntary saccade in the opposite direction of a peripheral stimulus. Unexpected novel sounds inhibited the execution of both pro- and anti-saccades compared to standard sounds, but the inhibition was stronger for anti-saccades. Novel sounds affected response latencies as early as 150 ms before the peripheral cue to make a saccade, all the way to 25 ms after the cue to make a saccade. Interestingly, unexpected sounds also reduced anti-saccade task errors, indicating that they aided inhibitory control. Overall, these results suggest that unexpected sounds yield a global and rapid inhibition of eye-movement responses. This inhibition also helps suppress reflexive eye-movement responses in favor of more voluntarily generated ones.

Motor actions across psychiatric disorders: A research domain criteria (RDoC) perspective

The motor system is critical for understanding the pathophysiology and treatment of mental illness. Abnormalities in the processes that allow us to plan and execute movement in a goal-directed, context-appropriate manner (i.e., motor actions) are especially central to clinical motor research. Within this context, the NIMH Research Domain Criteria (RDoC) framework now includes a Motor Actions construct within the recently incorporated Sensorimotor Systems Domain, providing a useful framework for conducting research on motor action processes. However, there is limited available resources for understanding or implementing this framework. We address this gap by providing a comprehensive critical review and conceptual integration of the current clinical literature on the subconstructs comprising the Motor Actions construct. This includes a detailed discussion of each Motor Action subconstruct (e.g., action planning/execution) and its measurement across different units of analysis (e.g., molecules to behavior), the temporal and conceptual relationships among the Motor Action subconstructs (and other relevant RDoC domain constructs), and how abnormalities in these Motor Action subconstructs manifest in mental illness. Together, the review illustrates how motor system dysfunction is implicated in the pathophysiology of many psychiatric conditions and demonstrates shared and distinct mechanisms that may account for similar manifestations of motor abnormalities across disorders.

Eye-tracking training improves visuospatial working memory of children with attention-deficit/hyperactivity disorder and autism spectrum disorder

Given the close connection between eye movement and frontal lobe functions and some evidence supporting the effect of eye-tracking training on enhancing cognitive performance mediated by the frontal lobe, this study aimed to explore if after-school eye-tracking training can improve the visuospatial working memory (VSWM) and cognitive flexibility performance in children with attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). This study is a non-randomized cluster trial. Forty children from eight primary schools were selected, half receiving eye-tracking training for 20 sessions over 9 months, while the other half served as a waitlist control. They were matched on demographic characteristics and baseline cognitive performance. Their VSWM and cognitive flexibility were assessed at the beginning and end of the study. Results showed that children who received eye-tracking training, but not those on a waitlist, exhibited significant improvements in the total score and working memory span of the VSWM tests, and the correct responses in cognitive flexibility tests. Specifically, VSWM performance at higher span levels (5 or above) yielded a greater improvement. The findings suggest that eye-tracking training can be a feasible and effective after-school program for improving working memory and cognitive flexibility performance in children with ADHD and ASD. This study was prospectively registered at ClinicalTrials.gov (https://clinicaltrials.gov/, trial number: NCT05428657).

Utilizing artificial intelligence-based eye tracking technology for screening ADHD symptoms in children

Objective

To explore the potential of using artificial intelligence (AI)-based eye tracking technology on a tablet for screening Attention-deficit/hyperactivity disorder (ADHD) symptoms in children.

Methods

We recruited 112 children diagnosed with ADHD (ADHD group; mean age: 9.40 ± 1.70 years old) and 325 typically developing children (TD group; mean age: 9.45 ± 1.59 years old). We designed a data-driven end-to-end convolutional neural network appearance-based model to predict eye gaze to permit eye-tracking under low resolution and sampling rates. The participants then completed the eye tracking task on a tablet, which consisted of a simple fixation task as well as 14 prosaccade (looking toward target) and 14 antisaccade (looking away from target) trials, measuring attention and inhibition, respectively.

Results

Two-way MANOVA analyses demonstrated that diagnosis and age had significant effects on performance on the fixation task [diagnosis: F(2, 432) = 8.231, ***p < 0.001; Wilks' Λ = 0.963; age: F(2, 432) = 3.999, *p < 0.019; Wilks' Λ = 0.982], prosaccade task [age: F(16, 418) = 3.847, ***p < 0.001; Wilks' Λ = 0.872], and antisaccade task [diagnosis: F(16, 418) = 1.738, *p = 0.038; Wilks' Λ = 0.938; age: F(16, 418) = 4.508, ***p < 0.001; Wilks' Λ = 0.853]. Correlational analyses revealed that participants with higher SNAP-IV score were more likely to have shorter fixation duration and more fixation intervals (r = -0.160, 95% CI [0.250, 0.067], ***p < 0.001), poorer scores on adjusted prosaccade accuracy, and poorer scores on antisaccade accuracy (Accuracy: r = -0.105, 95% CI [-0.197, -0.011], *p = 0.029; Adjusted accuracy: r = -0.108, 95% CI [-0.200, -0.015], *p = 0.024).

Conclusion

Our AI-based eye tracking technology implemented on a tablet could reliably discriminate eye movements of the TD group and the ADHD group, providing a potential solution for ADHD screening outside of clinical settings.

Spatial bias in anti-saccade endpoints following bilateral dorsal posterior parietal lesions

Anti-saccades are eye movements in which the saccade is executed in the opposite direction of a visual target and are often hypometric. Because the visual target and saccade goal are decoupled, it has been suggested that competition between the two locations occurs and needs to be resolved. It has been hypothesized that the hypometria of anti-saccades reflects this spatial competition by revealing a bias towards the visual target. To confirm that this hypometria is not simply due to reduced gain, we tested 10 healthy subjects on three different anti-saccade spatial configuration tasks: 90° away across hemifields, 90° away within the same hemifield and 180° away (classic, diagonally opposite). Specifically, we examined whether saccade endpoints showed evidence for the visual target location's interference with anti-saccade programming and execution processes. Among other neural substrates involved in anti-saccades production, the dorsal posterior parietal cortex (PPC) has been implicated in the spatial inhibition of contralateral visual target. To gain insight into the neural processes involved in spatial competition during anti-saccades, we also tested one patient with a bilateral dorsal PPC lesion. In all spatial configurations, we observed that anti-saccade endpoints demonstrated a spatial bias towards the visual target for all participants, likely due to an incomplete inhibition of the visual target location. This spatial bias was exacerbated in our patient, which suggests that the dorsal PPC contributes to the amalgamation of the two competing spatial representations.

Motor Capabilities in Children with ADHD Are Improved after Brief Visuopostural Training

Children with ADHD show poor motor control. The aim of the present study was to test whether children with ADHD improved their motor performances (oculomotor as well as posture) after a short visuopostural training period. Two groups (G1 trained and G2 non-trained), each comprising 15 children with ADHD matched in IQ (intelligence quotient), sex, and age, participated in the study. Eye movements and postural sway were measured before (T1) and after (T2) 10 min of visuopostural training for the trained group and after 10 min of resting for the non-trained group. Training consisted of a visual search task performed while the child was standing on an unstable platform. At T1, oculomotor and postural abilities were statistically similar for both groups of children with ADHD (trained and non-trained). At T2, significant improvements in both oculomotor and postural capabilities were observed for the trained group but not for the non-trained group. These findings suggest that a short visuopostural training period could help children with ADHD to learn how to focus their visual attention in order to improve motor performance. Visuopostural training could allow a better integration of sensory inputs via central mechanisms, leading to improvement in both oculomotor and postural control. Further studies on a larger number of children with ADHD will be needed to confirm these findings and explore the eventual possible persistence of the training effect.

EyeT4Empathy: Dataset of foraging for visual information, gaze typing and empathy assessment

We present a dataset of eye-movement recordings collected from 60 participants, along with their empathy levels, towards people with movement impairments. During each round of gaze recording, participants were divided into two groups, each one completing one task. One group performed a task of free exploration of structureless images, and a second group performed a task consisting of gaze typing, i.e. writing sentences using eye-gaze movements on a card board. The eye-tracking data recorded from both tasks is stored in two datasets, which, besides gaze position, also include pupil diameter measurements. The empathy levels of participants towards non-verbal movement-impaired people were assessed twice through a questionnaire, before and after each task. The questionnaire is composed of forty questions, extending a established questionnaire of cognitive and affective empathy. Finally, our dataset presents an opportunity for analysing and evaluating, among other, the statistical features of eye-gaze trajectories in free-viewing as well as how empathy is reflected in eye features.

The Eyes Have It: A Meta-analysis of Oculomotor Inhibition in Attention-Deficit/Hyperactivity Disorder

BACKGROUND

Diminished inhibitory control is one of the main characteristics of attention-deficit/hyperactivity disorder (ADHD), and impairments in oculomotor inhibition have been proposed as a potential biomarker of the disorder. The present meta-analysis summarizes the effects reported in studies comparing oculomotor inhibition in ADHD patients and healthy control subjects.

METHODS

Inhibitory outcomes were derived from oculomotor experimental paradigms including the antisaccade (AS), memory-guided saccade, and prolonged fixation tasks. Temporal and spatial measures were also extracted from these tasks and from visually guided saccade tasks as secondary outcomes. Data were available from k = 31 studies (N = 1567 participants). Summary effect sizes were computed using random-effects models and a restricted maximum-likelihood estimator.

RESULTS

Among inhibitory outcomes, direction errors in AS, after correcting for publication bias, showed a moderate effect and large between-study heterogeneity (k = 18, n = 739, g = 0.57, 95% confidence interval [CI] [0.27, 0.88], I²= 74%); anticipatory saccades in memory-guided saccade showed a large effect and low heterogeneity (k = 11, n = 487; g = 0.86, 95% CI [0.64, 1.08], I² = 17.7%); and saccades during prolonged fixation evidenced large effect size and heterogeneity (k = 6, n = 325 g = 1.11, 95% CI [0.56, 1.65], I² = 79.1%) partially related to age. Among secondary outcomes, saccadic reaction time in AS (k = 22, n = 932, g = 0.34, 95% CI [0.06, 0.63], I² = 53.12%) and coefficient of variability in visually guided saccade (k = 5, n = 282, g = 0.53, 95% CI [0.28, 0.78], I² = 0.01%) indicated significant effects with small to moderate effects sizes.

CONCLUSIONS

ADHD groups commit more oculomotor inhibition failures than control groups. The substantial effects support the conclusion that oculomotor disinhibition is a relevant ADHD-related mechanism. Moderate effects observed in saccadic reaction time variability suggest that fluctuant performance in oculomotor tasks is another relevant characteristic of ADHD.

Evidence towards a continuum of impairment across neurodevelopmental disorders from basic ocular-motor tasks

Findings of genetic overlap between Schizophrenia, Attention-Deficit/Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD) contributed to a renewed conceptualization of these disorders as laying on a continuum based on aetiological, pathophysiological and neurodevelopmental features. Given that cognitive impairments are core to their pathophysiology, we compared patients with schizophrenia, ADHD, ASD, and controls on ocular-motor and manual-motor tasks, challenging crucial cognitive processes. Group comparisons revealed inhibition deficits common to all disorders, increased intra-subject variability in schizophrenia and, to a lesser extent, ADHD as well as slowed processing in schizophrenia. Patterns of deviancies from controls exhibited strong correlations, along with differences that posited schizophrenia as the most impaired group, followed by ASD and ADHD. While vector correlations point towards a common neurodevelopmental continuum of impairment, vector levels suggest differences in the severity of such impairment. These findings argue towards a dimensional approach to Neurodevelopmental Disorders' pathophysiological mechanisms.

Eye-tracking training improves the learning and memory of children with learning difficulty

Children who experience difficulty in learning at mainstream schools usually are provided with remediation classes after school to facilitate their learning. The present study aims to evaluate an innovative eye-tracking training as possible alternative remediation. Our previous findings showed that children who received eye-tracking training demonstrated improved attention and inhibitory control, and the present randomized controlled study aims to evaluate if eye-tracking training can also enhance the learning and memory of children. Fifty-three primary school students with learning difficulty (including autism spectrum disorder, attention-deficit/hyperactivity disorder, specific learning disorder, specific language impairment and borderline intellectual functioning) were recruited and randomly assigned to either the Eye-tracking Training group or the after-school remediation class. They were assessed on their learning and memory using the Hong Kong List Learning Test before and after 8-month training. Twenty weekly parallel sessions of training, 50 min per session, were provided to each group. Children who received the eye-tracking training, not those in the control group, showed a significant improvement in memory as measured by the delayed recall. In addition, the Eye-Tracking Training group showed significantly faster learning than the control group. Also, the two groups showed a significant improvement in their reading abilities. In sum, eye-tracking training may be effective training for enhancing the learning and memory of children with learning difficulties.

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.

Oculomotor deficits in attention deficit hyperactivity disorder (ADHD): A systematic review and comprehensive meta-analysis

Atypical motor coordination and cognitive processes, such as response inhibition and working memory, have been extensively researched in individuals with attention deficit hyperactivity disorder (ADHD). Oculomotor neural circuits overlap extensively with regions involved in motor planning and cognition, therefore studies of oculomotor function may offer unique insights into motor and cognitive control in ADHD. We performed a series of pairwise meta-analyses based on data from 26 oculomotor studies in ADHD to examine whether there were differences in performance on visually-guided saccade, gap, antisaccade, memory-guided, pursuit eye movements and fixation tasks. These analyses revealed oculomotor disturbances in ADHD, particularly for difficulties relating to saccade inhibition, memorizing visual target locations and initiating antisaccades. There was no evidence for pursuit eye movement disturbances or saccade dysmetria. Investigating oculomotor abnormalities in ADHD may provide insight into top-down cognitive control processes and motor control, and may serve as a promising biomarker in ADHD research and clinical practice.

Eye-Tracking Training Improves Inhibitory Control in Children with Attention-Deficit/Hyperactivity Disorder

Disinhibition is a common sign among children with attention-deficit/hyperactivity disorder (ADHD). The present study examined the effect of computerized eye-tracking training to improve inhibitory control in ADHD children. Thirty-two ADHD children (mean age = 8.4 years) were recruited. Half of the participants underwent 240 min of eye-tracking training over two weeks (i.e., experimental group), while the other half did not receive any training (i.e., control group). After training, the experimental group exhibited significant improvements in neuropsychological tests of inhibition, such as faster reaction time in the incongruent condition of the Flanker test, more unique designs in the Category Fluency and Five-Point Tests, and a faster completion time in Trail 2 of the Children's Color Trail Test. The control group did not show significant changes in any of these tests. Our findings support the use of eye-tracking training to improve the inhibitory control of ADHD children.

Computerized Eye-Tracking Training Improves the Saccadic Eye Movements of Children with Attention-Deficit/Hyperactivity Disorder

Abnormal saccadic eye movements, such as longer anti-saccade latency and lower pro-saccade accuracy, are common in children with attention-deficit/hyperactivity disorder (ADHD). The present study aimed to investigate the effectiveness of computerized eye-tracking training on improving saccadic eye movements in children with ADHD. Eighteen children with ADHD (mean age = 8.8 years, 10 males) were recruited and assigned to either the experimental (n = 9) or control group (n = 9). The experimental group underwent an accumulated 240 min of eye-tracking training within two weeks, whereas the control group engaged in web game playing for the same amount of time. Saccadic performances were assessed using the anti- and pro-saccade tasks before and after training. Compared to the baseline, only the children who underwent the eye-tracking training showed significant improvements in saccade latency and accuracy in the anti- and pro-saccade tasks, respectively. In contrast, the control group exhibited no significant changes. These preliminary findings support the use of eye-tracking training as a safe non-pharmacological intervention for improving the saccadic eye movements of children with ADHD.

Effect of a visual tracking intervention on attention and behavior of children with Attention Deficit Hyperactivity Disorder

Attention deficit hyperactivity disorder is characterized by several cognitive and behavioral problems such as inattention and impulsivity, abnormal control of eye movements and relocation, visual fixation and visuospatial perception. There is a link between core motor functions such as oculomotor function and cognition to the extent that the oculomotor system acts as a mediator between the motor and cognitive functions. Therefore, the effects of eye-tracking intervention were investigated on attention in these children. Thirty - nine boys with ADHD, 6 to 10 years of age were recruited and randomized to receive current occupational therapy (control group), or occupational therapy accompanied with eye-tracking exercises (experimental group). They were evaluated using the Conner's Parent Rating Scale, the Continuous Performance Task-2, and the Test of Visual-Motor Skills-Revised before and after the intervention. Significant improvements in the mean scores of cognitive problems (F=9/22), coping behavior (F=6.03) and hyperactivity (F=9.77) were detected in the posttest between the two groups (p<0.05). Furthermore, in the Continuous Performance Test scores, detectability (F=5.68), omission errors (F=17.89), commission errors (F=19.45), reaction time (F=8.95), variability (F=7.07), and preservation (F=6.33) showed significant differences between control and experimental groups (p<0.01). It appears that eye-tracking interventions designed based on the isolation of neck and eye movement might have an important role in improving cognitive function and coping behaviors in these children. It seems that these exercises could increase eye movement control; improve cognitive function and response inhibition.

Inhibiting saccades to a social stimulus: a developmental study

Faces are an important source of social signal throughout the lifespan. In adults, they have a prioritized access to the orienting system. Here we investigate when this effect emerges during development. We tested 139 children, early adolescents, adolescents and adults in a mixed pro- and anti-saccades task with faces, cars or noise patterns as visual targets. We observed an improvement in performance until about 15 years of age, replicating studies that used only meaningless stimuli as targets. Also, as previously reported, we observed that adults made more direction errors to faces than abstract patterns and cars. The children showed this effect too with regards to noise patterns but it was not specific since performance for cars and faces did not differ. The adolescents, in contrast, made more errors for faces than for cars but as many errors for noise patterns and faces. In all groups latencies for pro-saccades were faster towards faces. We discuss these findings with regards to the development of executive control in childhood and adolescence and the influence of social stimuli at different ages.

Saccade eye movement in children with attention deficit hyperactivity disorder

Objects: This study aims to investigate the saccade/anti-saccade eye movement in children with attention deficit/hyperactivity disorder (ADHD).Methods: Twelve children (8.8 ± 0.8 years) diagnosed with ADHD (DSM-V) and 12 control (9.1 ± 0.3 years) were invited to participate in the experiment where the iView Hi-SPEED eyetracker, with the sample rate at 500 Hz Binocular, was employed. The visual guided saccade (VGS) task was used to collect saccade latency and accuracy values. The anti-saccade task was used to collect saccade latency and accuracy values as well as the percentage of direction errors (PDE).Results: Children with ADHD showed a significant difference in latency in the 7.5° target and imprecision in both targets (7.5° and 15°) during the VGS task. Moreover, the ADHD group exhibited shorter latency (15° target) and significantly higher numbers in the Percentage of Direction Errors in the anti-saccade tasks than the control group.Conclusions: The results suggest that children with ADHD have the following difficulties: precise oculomotor control, oculomotor response inhibition function and basic visual attention.

Diagnosis of oculomotor anomalies in children with learning disorders

This systematic review presents the existing scientific evidence for oculomotor anomalies in children with three different types of learning disorders - namely, dyslexia, dyspraxia and attention deficit-hyperactivity disorder (ADHD). This review was registered in the PROSPERO database (registration number: 139317). The QUADAS-2 tool was used to systematically evaluate the quality of the diagnostic tests used in the evaluated studies and to confirm whether the oculomotor alterations observed in the different groups of children with various learning disorders had a consistent diagnostic basis. Using this tool, the design of the articles was well elaborated, although concerns exist regarding the selection of patients and the diagnostic criteria for the binocular conditions. All the studies reviewed conclude that a pattern of oculomotor anomalies exist in the groups of children with these three types of learning disorders compared to healthy children. However, there is a concern regarding the diagnostic methodology, as no clear range of normality for the parameters used to characterise ocular motility was identified and no gold standard or reference test has been defined. In future studies, this range of normality must be developed for different oculomotor skills, and a reference test (possibly video-oculography) for the measurement of these skills must be established.

Dorsolateral prefrontal cortex hyperactivity during inhibitory control in children with ADHD in the antisaccade task

Children with ADHD show significant deficits in response inhibition. A leading hypothesis suggests prefrontal hypoactivation as a possible cause, though, there is conflicting evidence. We tested the hypoactivation hypothesis by analyzing the response inhibition process within the oculomotor system. Twenty-two children diagnosed with ADHD and twenty control (CTRL) children performed the antisaccade task while undergoing an fMRI study with concurrent eye tracking. This task included a preparatory stage that cued a prosaccade (toward a stimuli) or an antisaccade (away from a stimuli) without an actual presentation of a peripheral target. This allowed testing inhibitory control without the confounding activation from an actual response. The ADHD group showed longer reaction times and more antisaccade direction errors. While both groups showed activations in saccade network areas, the ADHD showed significant hyperactivation in the dorsolateral prefrontal cortex during the preparatory stage. No other areas in the saccade network had significant activation differences between groups. Further ADHD group analysis OFF and ON stimulant medication did not show drug-related activation differences. However, they showed a significant correlation between the difference in OFF/ON preparatory activation in the precuneus, and a decrease in the number of antisaccade errors. These results do not support the hypoactivity hypothesis as an inhibitory control deficit general explanation, but instead suggest less efficiency during the inhibitory period of the antisaccade task in children. Our findings contrast with previous results in ADHD adults showing decreased preparatory antisaccade activity, suggesting a significant age-dependent maturation effect associated to the inhibitory response in the oculomotor system.

Probing oculomotor inhibition with the minimally delayed oculomotor response task

The ability to not execute (i.e. to inhibit) actions is important for behavioural flexibility and frees us from being slaves to our immediate sensory environment. The antisaccade task is one of several used to investigate behavioural inhibitory control. However, antisaccades involve a number of important processes besides inhibition such as attention and working memory. In the minimally delayed oculomotor response (MDOR) task, participants are presented with a simple target step, but instructed to saccade not to the target when it appears (a prosaccade response), but when it disappears (i.e. on target offset). Varying the target display duration prevents offset timing being predictable from the time of target onset, and saccades prior to the offset are counted as errors. Antisaccade error rate and latency are modified by alterations in fixation conditions produced by inserting a gap between fixation target offset and stimulus onset (the gap paradigm; error rate increases, latency decreases) or by leaving the fixation target on when the target appears (overlap paradigm; error rate decreases, latency increases). We investigated the effect of gaps and overlaps on performance in the MDOR task. In Experiment 1 we confirmed that, compared to a control condition in which participants responded to target onsets, in the MDOR task saccade latency was considerably increased (increases of 122-272 ms depending on target display duration and experimental condition). However, there was no difference in error rate or saccade latency between gap and synchronous (fixation target offset followed immediately by saccade target onset) conditions. In Experiment 2, in a different group of participants, we compared overlap and synchronous conditions and again found no statistically significant differences in error rate and saccade latency. The timing distribution of errors suggested that most were responses to target onsets, which we take to be evidence of inhibition failure. We conclude that the MDOR task evokes behaviour that is consistent across different groups of participants. Because it is free of the non-inhibitory processes operative in the antisaccade task, it provides a useful means of investigating behavioural inhibition.

The development of inhibitory saccadic trajectory deviations correlates with measures of antisaccadic inhibition

Chronological age is related positively to a participant's ability to inhibit distracting information. Inhibition can be measured using the trajectory deviation of a saccade. Saccadic curvature away from distracting visual information is controlled through top-down inhibition mediated by the frontal eye fields. In the present study, we aimed to further test the saccadic trajectory deviation paradigm's sensitivity to the development of frontal inhibitory procuresses by comparing its measure of saccadic inhibition with that of a widely used paradigm, namely, the antisaccade task. We show that the later 'inhibition' phase of the trajectory deviation function correlated strongly with the measure of antisaccadic inhibition obtained in the same individuals. As expected, the earlier 'capture' phase of the trajectory deviation function, which does not represent the involvement of frontal structures, did not correlate with antisaccadic inhibition. Further, both measures of frontal inhibition increased with chronological age.

Disinhibition in children with attention-deficit/hyperactivity disorder: Changes in [oxy-Hb] on near-infrared spectroscopy during "rock, paper, scissors" task

OBJECTIVE

Attention-deficit/hyperactivity disorder (AD/HD) is a common developmental disorder. Many reports have suggested that symptoms of AD/HD are related to frontal lobe dysfunctions, particularly disinhibition. However, measuring neurological findings with biomarkers during frontal functional tasks has sometimes been difficult in children with AD/HD. This study aimed to investigate frontal inhibitory function objectively in children with AD/HD during "rock, paper, scissors" (RPS) tasks, as a familiar game for Japanese children, using near-infrared spectroscopy (NIRS).

SUBJECTS AND METHODS

Eighteen children with AD/HD were compared with 27 typically developing children (TDC). Children from each group were divided into two age groups: younger, 6-10years; and older, 11-16years. Changes in oxygenated hemoglobin [oxy-Hb] were measured in the prefrontal region using NIRS during a 'to lose' RPS task, in which subjects were asked to present the RPS signal that would lose in response to one of the three signals displayed randomly on a computer screen every 2.0s.

RESULTS

The rate of correct performance with both TDC and AD/HD increased with age. Only in the older group, the rate of correct performance was significantly higher with TDC than with AD/HD. However, children with AD/HD in both age groups showed significantly lower [oxy-Hb] activity in the prefrontal region during the 'to lose' RPS task, particularly in the dorsolateral area.

CONCLUSIONS

Our results suggest that prefrontal region activation during the 'to lose' RPS task could offer a biomarker for diagnosing AD/HD, and may help in the early treatment of AD/HD.

Oculomotor Abnormalities in Children with Attention-Deficit/Hyperactivity Disorder Are Improved by Methylphenidate

BACKGROUND

There are relatively few studies of saccadic eye movements in children with attention-deficit/hyperactivity disorder (ADHD). The aim of this study was to examine inhibitory abilities of eye movements in children with ADHD and to explore the effect of methylphenidate (MPH) on eye movement performance.

METHODS

Thirty-one children with ADHD (mean age 9.9 ± 0.4 years) and 31 sex-, age-, and IQ-matched children with normal development were examined. Saccades elicited not only by the gap, step, overlap, and antisaccade paradigms but also a simple fixation paradigm have been recorded using an eye tracker. The latency of each type of saccade, the error rate of antisaccades, and the number of saccades made during fixation have been measured.

RESULTS

Children with ADHD and naive to treatment with respect to controls showed significantly shorter mean latency of voluntary saccades (overlap paradigm), more frequent errors during the antisaccade paradigm, and higher number of saccades made during fixation. After 1 month of MPH treatment, all these parameters changed significantly and reached control values.

CONCLUSION

Taken together, these results suggest that oculomotor abilities are poor in children with ADHD, which may correlate with deficits in inhibitory mechanisms. Treatment with MPH improves oculomotor performances through adaptive strategies, which may involve brain structures related to cognitive inhibition.

Developmental changes in autonomic emotional response during an executive functional task: A pupillometric study during Wisconsin card sorting test

OBJECTIVE

The autonomic nervous system has a deep relationship with the cognitive network when performing cognitive tasks. We hypothesize that autonomic emotional responses can affect cognitive function, especially executive function. The aim of this study was to clarify the involvement of the autonomic system during an executive functional task via developmental changes assessed using pupillometry.

SUBJECTS AND METHODS

Subjects were 16 healthy children and 9 healthy adults. Children were divided into 3 groups (Group A, 7-9years; Group B, 10-14years; Group C, 15-17years). Pupil diameter was recorded using an eye mark recorder during cognitive shift (CS) during the Wisconsin card sorting test (WCST). The rate of pupil variations was integrated and compared within each group, focusing on performance during CS.

RESULTS

Categories achieved (CA) in the behavioral results of WCST increased with age, with significant differences between Group A and other groups. The change of pupillary diameter was increased with CS and decreased at the correct answers after CS in adults. Changes of pupillary diameter with CS showed a linear increase with age, and the pattern of the pupillary response at the age of 10-14years was comparable to adults. The integrated rate of pupil diameter with CS increased with age, and there was a significant difference between Group A and adults. In addition, the degree of mydriasis correlated with the number of CA.

CONCLUSION

These findings suggest that autonomic emotional response play an important role as a part of the process for executive function.

The role of speed in ADHD-related working memory deficits: A time-based resource-sharing and diffusion model account

Several recent commentaries suggest that, for psychological science to move beyond "homuncular" explanations for cognitive control, it is critically important to examine the role of basic and computationally well-defined processes (e.g. cognitive processing speed). Correlational evidence has previously linked slow speed to working memory (WM) deficits in ADHD, but the directionality of this relationship has not been investigated experimentally and the mechanisms through which speed may influence WM are unclear. Herein, we demonstrate in school-aged children with and without ADHD, that manipulating speed (indexed with the diffusion model) within a WM paradigm reduces WM capacity due to an increase in cognitive load, in a manner that is consistent with predictions of the time-based resource-sharing model of WM. Results suggest slow speed is a plausible cause of WM deficits in ADHD, provide a mechanistic account of this relationship, and urge the exploration of non-executive neurocognitive processes in clinical research on etiology.

Longitudinal Visuomotor Development in a Malaria Endemic Area: Cerebral Malaria and Beyond

Paediatric cerebral malaria is the most serious complication of Plasmodium falciparum infection. While the majority recover, long-term cognitive impairment has been highlighted as a significant and neglected problem. Persistent or serious deficits in processes such as attention or behavioural inhibition should be manifest in changes to performance on oculomotor tasks. Therefore we investigated the impact of cerebral malaria on the development of reflexive pro-saccades and antisaccades. In a longitudinal study, 47 children previously admitted with retinopathy-confirmed cerebral malaria (mean age at admission 54 months), were compared with 37 local healthy controls (mean ages at first study visit 117 and 110 months respectively). In each of three or four test sessions, over a period of up to 32 months, participants completed 100 prosaccade tasks and 100 antisaccade tasks. Eye movements were recorded using infrared reflectance oculography; prosaccade, correct antisaccade and error prosaccade latency, and antisaccade directional error rate were calculated. Hierarchical linear modelling was used to investigate the effect of age and the influence of cerebral malaria on these parameters. Data were also collected from an independent, older group (mean age 183 months) of 37 local healthy participants in a separate cross-sectional study. Longitudinal data exhibited the expected decrease in latency with age for all saccade types, and a decrease in the antisaccade directional error rate. Hierarchical linear modelling confirmed that age had a statistically significant effect on all parameters (p< = 0.001). However, there were no statistically significant differences between the cerebral malaria and control groups. Combining groups, comparison with the literature demonstrated that antisaccade directional error rate for the Malawi sample was significantly higher than expected, while latencies for all saccade types were indistinguishable from published. The high directional error rate was also confirmed in the older, healthy Malawian participants from the cross sectional study. Our observation of similar oculomotor performance in cerebral malaria and control groups at long follow-up periods suggests that cerebral malaria survivors are not at a generally increased risk of persistent cognitive deficits. Our data raise questions about the prevailing hypothesis that cerebral malaria has gross impacts on the development of processes such as attention and behavioural inhibition. More importantly, our novel finding of a clear difference in antisaccade performance between all of the Malawi participants and published data suggests that the Malawian paediatric population as a whole faces serious challenges to cognitive development beyond cerebral malaria.

Usefulness of the measurement of saccadic refixation in the diagnosis of attention-deficit hyperactivity disorder/hyperkinetic disorder in adults

Background:

The aim of the research is to evaluate the usefulness of the measurement of saccadic refixation in the diagnosis of attention-deficit hyperactivity disorder (ADHD)/hyperkinetic disorder (HKD) in adults.

Methods:

Seventy-eight individuals were examined: 40 with ADHD/HKD and 38 healthy ones. A noninvasive eye movement examination using the Saccadometer (Advanced Clinical Instrumentation, Cambridge, UK) was applied. Two saccadic tests, prosaccades task (PT) and antisaccades task (AT), were carried out.

Results:

Based on the results, we can assume that selected parameters, such as latency, standard deviation of latency, promptness, and correctness (directional errors), in individuals with ADHD/HKD differ statistically in the relevant parameters from the healthy ones. The latency and the standard deviation of latency in ADHD/HKD participants are greater when compared to healthy ones. ADHD/HKD participants have a greater number of directional errors in comparison to healthy ones.

Conclusions:

The standard deviation of latency prosaccades is a good parameter for distinguishing people from both groups. An important and innovative solution in this study in comparison to the studies of other authors, who reached similar results, is the use of an automatically calibrating system (autonomous) adapted for clinical use as well as a quantitative analysis of the saccadic parameters.

Antisaccade-related brain activation in children with attention-deficit/hyperactivity disorder--A pilot study

While antisaccade paradigms invoke circuitry associated with cognitive control and attention-deficit/hyperactivity disorder (ADHD), there is a dearth of functional magnetic resonance imaging (fMRI) investigations using antisaccade tasks among children with ADHD. Neural correlates associated with antisaccade performance were examined with fMRI in 11 children with ADHD (10 medicated) matched to 11 typically developing children. Significantly greater brain activation in regions in right dorsolateral prefrontal cortex and caudate nucleus was observed in children with ADHD relative to the control group. This pattern separated the children into their respective groups in a taxonomic manner. Sensitivity analyses probing comorbidity and medication-specific effects showed that results were consistent; however, the caudate nucleus difference was only detectable in the full sample, or in subsets with a more relaxed cluster threshold. Antisaccade performance did not significantly differ between the groups, perhaps as a result of greater brain activation or medication effects in the ADHD group. Thus, antisaccade paradigms may have sensitivity and specificity for the investigation of cognitive control deficits and associated neural correlates in ADHD, and may contribute towards the development of new treatment approaches for children with the disorder.

Electroencephalogram valid rate in simple reaction time task as an easy index of children's attention functions

BACKGROUND

Electroencephalogram (EEG) signal artifacts occur often in children, but an EEG valid rate (VR), constructed by excluding the artifacts, might be meaningful to evaluate children's neuropsychological functions. The aim of this study was to develop an easy screening index, the EEGVR, and to investigate attention function in children using this index.

METHODS

The EEG was carried out during a 4 min simple reaction time (SRT) task as standard procedure in 50 children, consisting of 26 with attention-deficit-hyperactivity disorder (ADHD; mean age, 9.8 years; range, 8-11.3 years) and 24 without (mean age, 10.1 years; range, 7.8-12 years). An easy index was derived from the valid rate (VR) of EEG using area under the receiver operating characteristic curve. The index was applied to regroup the 50 children into high VR (HVR) and low VR (LVR) groups, while the Comprehensive Non-verbal Attention Test (CNAT) and four behavioral questionnaires were compared between the two groups in order to investigate the validity of this index.

RESULTS

The EEGVR at 75% was optimal to identify HVR and LVR (sensitivity, 0.769; specificity, 0.792). The LVR group had significantly lower scores on both CNAT and the behavioral questionnaires, although the demographic variables and full-scale intelligence quotient (FSIQ) were similar between the two groups.

CONCLUSIONS

The EEGVR in an SRT task might be an easy and effective index to screen the attention function of children, and could consequently contribute to the early diagnosis of ADHD.

Gap Effect Abnormalities during a Visually Guided Pro-Saccade Task in Children with Attention Deficit Hyperactivity Disorder

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder that starts in early childhood and has a comprehensive impact on psychosocial activity and education as well as general health across the lifespan. Despite its prevalence, the current diagnostic criteria for ADHD are debated. Saccadic eye movements are easy to quantify and may be a quantitative biomarker for a wide variety of neurological and psychiatric disorders, including ADHD. The goal of this study was to examine whether children with ADHD exhibit abnormalities during a visually guided pro-saccadic eye-movement and to clarify the neurophysiological mechanisms associated with their behavioral impairments. Thirty-seven children with ADHD (aged 5–11 years) and 88 typically developing (TD) children (aged 5–11 years) were asked to perform a simple saccadic eye-movement task in which step and gap conditions were randomly interleaved. We evaluated the gap effect, which is the difference in the reaction time between the two conditions. Children with ADHD had a significantly longer reaction time than TD children (p < 0.01) and the gap effect was markedly attenuated (p < 0.01). These results suggest that the measurement of saccadic eye movements may provide a novel method for evaluating the behavioral symptoms and clinical features of ADHD, and that the gap effect is a potential biomarker for the diagnosis of ADHD in early childhood.

The role of prefrontal catecholamines in attention and working memory

While much progress has been made in identifying the brain regions and neurochemical systems involved in the cognitive processes disrupted in mental illnesses, to date, the level of detail at which neurobiologists can describe the chain of events giving rise to cognitive functions is very rudimentary. Much of the intense interest in understanding cognitive functions is motivated by the hope that it might be possible to understand these complex functions at the level of neurons and neural circuits. Here, we review the current state of the literature regarding how modulations in catecholamine levels within the prefrontal cortex (PFC) alter the neuronal and behavioral correlates of cognitive functions, particularly attention and working memory.

Functional connectivity within the default mode network is associated with saccadic accuracy in Parkinson's disease: a resting-state FMRI and videooculographic study

In addition to the skeleto-motor deficits, patients with Parkinson's disease (PD) frequently present with oculomotor dysfunctions such as impaired smooth pursuit and saccadic abnormalities. There is increasing evidence for an impaired cortical function to be responsible for oculomotor deficits that are associated with lack of inhibitory control; however, these pathomechanisms still remain poorly understood. By means of "task-free" resting-state functional magnetic resonance imaging (rs-fMRI), functional connectivity changes in PD within the default mode network (DMN) have been reported. The aim of this study was to investigate whether altered functional connectivity within the DMN was correlated with oculomotor parameter changes in PD. Twelve PD patients and 13 matched healthy controls underwent rs-fMRI at 1.5 T and videooculography (VOG) using Eye-Link-System. Rs-fMRI seed-based region-to-region connectivity analysis was performed, including medial prefrontal cortex (mPFC), medial temporal lobe (MTL), posterior cingulate cortex (PCC), and hippocampal formation (HF); while VOG examination comprised ocular reactive saccades, smooth pursuit, and executive tests. Rs-fMRI analysis demonstrated a decreased region-to-region functional connectivity between mPFC and PCC as well as increased connectivity between bilateral HF in PD compared with controls. In VOG, patients and controls differed in terms of executive tests outcome, smooth pursuit eye movement, and visually guided reactive saccades but not in peak eye velocity. A significant relationship was observed between saccadic accuracy and functional connectivity strengths between MTL and PCC. These results suggest that PD-associated changes of DMN connectivity are correlated with PD-associated saccadic hypometria, in particular in the vertical direction.

Hyperbilirubinemia: subcortical mechanisms of cognitive and behavioral dysfunction

Although development of the full syndrome of kernicterus is relatively rare, neonatal jaundice continues to occur frequently. Controversy remains concerning whether or not infants with moderate elevations in bilirubin are at risk for neurodevelopmental disorders in later childhood. Sites of brain pathology associated with bilirubin neurotoxicity are identified and well established. Based on these regions of brain involvement, we apply neuroscientific principles of brain-behavior relationships to predict types of cognitive features that may accompany hyperbilirubinemia. We address a range of neurodevelopmental abnormalities that can arise as a function of elevated neonatal bilirubin levels affecting these brain regions, even in the absence of full kernicterus syndrome. Moreover, we explain the neuropathologic mechanisms that would drive these abnormalities. We thus attempt to establish a blueprint for future investigations of these conditions, to improve neurodevelopmental outcomes.

Saccadic eye movement applications for psychiatric disorders

OBJECTIVE

The study presented here analyzed the patterns of relationship between oculomotor performance and psychopathology, focusing on depression, bipolar disorder, schizophrenia, attention-deficit hyperactivity disorder, and anxiety disorder.

METHODS

Scientific articles published from 1967 to 2013 in the PubMed/Medline, ISI Web of Knowledge, Cochrane, and SciELO databases were reviewed.

RESULTS

Saccadic eye movement appears to be heavily involved in psychiatric diseases covered in this review via a direct mechanism. The changes seen in the execution of eye movement tasks in patients with psychopathologies of various studies confirm that eye movement is associated with the cognitive and motor system.

CONCLUSION

Saccadic eye movement changes appear to be heavily involved in the psychiatric disorders covered in this review and may be considered a possible marker of some disorders. The few existing studies that approach the topic demonstrate a need to improve the experimental paradigms, as well as the methods of analysis. Most of them report behavioral variables (latency/reaction time), though electrophysiological measures are absent.

Smooth pursuit and fixation ability in children with Tourette syndrome

OBJECTIVE

The smooth pursuit eye movements and fixation ability of children aged 8 to 16 years with Tourette syndrome (TS) were examined.

BACKGROUND

Although several studies have examined the saccadic ability of patients with TS, there have been only a few studies examining pursuit ability in TS.

METHOD

Pursuit gain (eye velocity/target velocity) and intrusive saccades during fixation were measured in children with TS-only, TS+attention deficit hyperactivity disorder (ADHD), and TS+ADHD+obsessive compulsive disorder (OCD), and in controls (8 to 16 y). Two pursuit tasks and 1 fixation task were used. In random pursuit 1 (RP1), each step and ramp cycle began from fixation; in random pursuit 2 (RP2), each cycle followed the next. In the fixation task, children were required to maintain fixation on a center dot and ignore distractor stimuli.

RESULTS

All children had significantly higher pursuit gains in RP2 than in RP1 when pursuing a 30 degrees/s moving target. In addition, in RP2, the TS+ADHD+OCD group displayed significantly higher pursuit gains relative to the TS-only, TS+ADHD, and control groups. In the fixation task, the TS+ADHD group exhibited significantly more intrusive saccades than the TS+ADHD+OCD and control groups.

CONCLUSIONS

Our findings support an enhanced oculomotor ability in the TS+ADHD+OCD group and the presence of an online gain control mechanism during ongoing pursuit. These findings are discussed in more detail.

Down syndrome and attention-deficit/hyperactivity disorder (ADHD)

Clinicians might minimize the prevalence of behavioral disorders among mentally retarded people. Decreased attention, hyperactivity, and impulsivity are frequently reported in children with Down syndrome, yet the exact prevalence of attention-deficit/hyperactivity disorder (ADHD) has not been clearly estimated in this population. The objective of this study was to estimate the prevalence of ADHD in children with Down syndrome and to emphasize the possible relationship between ADHD symptoms and the level of mental retardation and common medical comorbidity. In this study, the prevalence of ADHD among Down syndrome children was very high, reaching 43.9%. No significant correlation was found between ADHD symptoms and the level of mental retardation, but significant correlation was found with ophthalmologic problems. We conclude that children with Down syndrome are at increased risk for ADHD. When evaluating children with Down syndrome for attention deficits, psychiatric comorbidity as well as medical problems should be carefully taken into consideration.

Summer treatment program for children with attention deficit hyperactivity disorder: Japanese experience in 5 years

In 2005 we established the first American-style summer treatment program (STP) for children with attention deficit hyperactivity disorder (ADHD) located outside North America. This program was based on methods established by professor Pelham and has been used in a number of studies and at a number of sites in the USA. A total of 137 children diagnosed with ADHD, ranging in age from 6 to 12 years, participated in at least one of five annual summer treatment programs in Kurume city, Japan, during 2005-2009. The duration of the STP was 2 weeks in 2005, 2008, and 2009; 3 weeks in 2006 and 2007. A set of evidence-based behavioral modification techniques comprising the STP behavioral program (e.g., point system, daily report card, positive reinforcement, time out) was used. We also assessed the cognitive function of individual children before and after STP using the CogState(R) batteries. Every year, regardless of the duration of the STP, most children showed positive behavioral changes in multiple domains of functioning, demonstrated by significant improvement in points earned daily, which reflect behavior frequencies. Cognitive functions, particularly the rate of anticipatory errors in executive function, significantly improved after the STP, suggesting that STP has positive effects not only on behavioral aspects but also on some cognitive functions. Further studies are necessary to confirm this finding by studying sequential cognitive function of age-matched children who do not attend STP.

Medio-frontal and anterior temporal abnormalities in children with attention deficit hyperactivity disorder (ADHD) during an acoustic antisaccade task as revealed by electro-cortical source reconstruction

BACKGROUND

Attention Deficit Hyperactivity Disorder (ADHD) is one of the most prevalent disorders in children and adolescence. Impulsivity is one of three core symptoms and likely associated with inhibition difficulties. To date the neural correlate of the antisaccade task, a test of response inhibition, has not been studied in children with (or without) ADHD.

METHODS

Antisaccade responses to visual and acoustic cues were examined in nine unmedicated boys with ADHD (mean age 122.44 ± 20.81 months) and 14 healthy control children (mean age 115.64 ± 22.87 months, three girls) while an electroencephalogram (EEG) was recorded. Brain activity before saccade onset was reconstructed using a 23-source-montage.

RESULTS

When cues were acoustic, children with ADHD had a higher source activity than control children in Medio-Frontal Cortex (MFC) between -230 and -120 ms and in the left-hemispheric Temporal Anterior Cortex (TAC) between -112 and 0 ms before saccade onset, despite both groups performing similarly behaviourally (antisaccades errors and saccade latency). When visual cues were used EEG-activity preceding antisaccades did not differ between groups.

CONCLUSION

Children with ADHD exhibit altered functioning of the TAC and MFC during an antisaccade task elicited by acoustic cues. Children with ADHD need more source activation to reach the same behavioural level as control children.

ADHD: volumetry, motor, and oculomotor functions

The use of quantitative neuroimaging (volumetry), motor, and oculomotor assessments for studying children with attention-deficit/hyperactivity disorder (ADHD) has grown dramatically in the past 20 years. Most evidence to date suggests that anomalous basal ganglia development plays an important role in early manifestation of ADHD; however, widespread cerebellar and cortical delays are also observed and are associated with the behavioral (cognitive, motor, oculomotor) phenotype in children with ADHD. These motor and "executive" control systems appear to develop in parallel, such that both systems display a similar protracted developmental trajectory, with periods of rapid growth in elementary years and continued maturation into young adulthood. Development of each system is dependent on the functional integrity and maturation of related brain regions, suggesting a shared neural circuitry that includes frontostriatal systems and the cerebellum (i.e., those identified as anomalous in studies of volumetry in ADHD). Motor and oculomotor paradigms provide unique opportunities to examine executive control processes that exist at the interface between movement and cognition in children with ADHD, also linking cognition and neurological development. The observed pattern of volumetric differences, together with the known parallel development of motor and executive control systems, appears to predict motor and oculomotor anomalies in ADHD, which are highly relevant, yet commonly overlooked in clinical settings.