Interference control in 6–11 year‐old children with and without ADHD: behavioral and ERP study

An event-related potential study of P300 in preschool children with attention deficit hyperactivity disorder

Objective

To study the characteristics of event related potential P300 in preschool children with attention deficit hyperactivity disorder (ADHD) aged 4-6 years (4≤ age <6), and to explore the differences in cognitive function compared with healthy children. To explore a new method for the study of cognitive function in preschool children with ADHD.

Methods

A total of 73 preschool children aged 4-6 years were selected from the outpatient clinic of Neurology Department, the ADHD-specialized Clinic and Health Care Department of the Children's Hospital Affiliated to the Capital Institute of Pediatrics from March 2021 to May 2024. They were divided into the ADHD group (45 cases) and healthy children group (28 cases). Event related potential P300 was measured in all children and the amplitude and latency of the wave were compared between the two groups separately.

Results

The latency of P300 at all the recording electrodes (Fz, Cz, Pz, Oz, C3, C4) in the ADHD group was significantly longer than controls (p < 0.05). The wave amplitudes of children with ADHD were significantly higher than controls at Pz and Oz points.

Conclusion

The differences between two groups in P300 test show that preschool children with ADHD present longer latency at central line of the brain and bilateral central lobes compared with healthy children, and higher amplitude at the central parietal lobe and central occipital lobe. It may suggest that attention cognition has already impaired in preschool children with ADHD.

Knowledge over Time of Action Codes for Perceived Objects: An Exploratory Study on Developmental Children

Over the past 20 years, there has been a growing interest in the processing of tool objects, and in the spatial S-R correspondence effects obtained with pictures of manipulable objects. Beyond the original affordance activation account, a location coding account has been proposed for such behavioral effects, which states that the location of the visually salient portion of an object speeds up spatially aligned motor responses and slows down misaligned ones. Furthermore, an additional action coding account has been proposed, according to which it is the direction of the action of the perceived object (e.g., "pouring tea leftward" when the spout of a teapot is leftward-oriented) that biases motor performance. We investigated this action coding account of S-R correspondence effects by comparing the reaction time (RT) performance of two groups: younger (6 to 9 years old) and older (10 to 13 years old) children. We assumed that knowledge of tool objects and the activation of action codes from object perception is proportional to age. Therefore, a larger correspondence effect was hypothesized for the older relative to the younger children's group. Consistently, a 34 ms correspondence effect was observed in the older children relative to the younger ones (18 ms). The results support the view that action direction is a constitutive feature of tool objects, which is subject to experience, and thus, to increasing knowledge over time.

The Impact of Sex on Cognitive Control in ADHD: Girls Slow to Inhibit, Boys Inhibit Less, and Both Show Higher Response Variability

OBJECTIVE

To determine whether girls and boys with ADHD show distinct impairments in components of cognitive control across multiple tasks (go/no-go, stop signal, and flanker) and performance metrics (response speed, variability, and errors).

METHOD

A total of 300 children, ages 8 to 12 years with ADHD (n = 210, 58 girls) or typically developing (TD; n = 99, 37 girls), completed all tasks. Traditional response measures (e.g., mean and standard deviation of reaction time, inhibition errors, and stop signal reaction time) and ex-Gaussian modeling of reaction times (mu, sigma, and tau) were analyzed.

RESULTS

Girls showed intact response inhibition in the context of slower response speed, while boys made more inhibition errors and did not slow their response speed. Both girls and boys with ADHD showed higher response variability and poorer interference control than TD children.

CONCLUSION

Girls and boys with ADHD show distinct impairments in cognitive control that may be important for understanding the pathophysiology of ADHD.

Cross-modal conflict deficit in children with attention-deficit/hyperactivity disorder

The difference between the audiovisual incongruent condition and the audiovisual congruent condition is known as cross-modal conflict, which is an important behavioral index to measure the conflict control function. Previous studies have found conflict control deficits in children with attention-deficit/hyperactivity disorder (ADHD), but it is not clear whether and how cross-modal conflict occurs in children with ADHD at different processing levels. The current study adopted the cross-modal matching paradigm to recruit 25 children with ADHD (19 boys and 6 girls) and 24 TD children (17 boys and 7 girls), aiming to investigate the cross-modal conflict effect at the perception and response levels of children with ADHD. The results showed that both groups of children showed significant cross-modal conflict, and there was no significant difference between the ADHD and TD groups in the number of error trials and mean response time. However, the cross-modal conflict effect caused by auditory distractors was different between the ADHD and TD groups; the TD group had stronger auditory conflict at the response level, whereas the ADHD group had weaker auditory conflict. This indicates that the ADHD group had a deficit of auditory conflict at the response level.

Enhancement of visual dominance effects at the response level in children with attention-deficit/hyperactivity disorder

Previous studies have widely demonstrated that individuals with attention-deficit/hyperactivity disorder (ADHD) exhibit deficits in conflict control tasks. However, there is limited evidence regarding the performance of children with ADHD in cross-modal conflict processing tasks. The current study aimed to investigate whether children with ADHD have poor conflict control, which has an impact on sensory dominance effects at different levels of information processing under the influence of visual similarity. A total of 82 children aged 7 to 14 years, including 41 children with ADHD and 41 age- and sex-matched typically developing (TD) children, were recruited. We used the 2:1 mapping paradigm to separate levels of conflict, and the congruency of the audiovisual stimuli was divided into three conditions. In C trials, the target stimulus and the distractor stimulus were identical, and the bimodal stimuli corresponded to the same response keys. In PRIC trials, the distractor stimulus differed from the target stimulus and did not correspond to any response keys. In RIC trials, the distractor stimulus differed from the target stimulus, and the bimodal stimuli corresponded to different response keys. Therefore, we explicitly differentiated cross-modal conflict into a preresponse level (PRIC > C), corresponding to the encoding process, and a response level (RIC > PRIC), corresponding to the response selection process. Our results suggested that auditory distractors caused more interference during visual processing than visual distractors caused during auditory processing (i.e., typical auditory dominance) at the preresponse level regardless of group. However, visual dominance effects were observed in the ADHD group, whereas no visual dominance effects were observed in the TD group at the response level. A possible explanation is that the increased interference effects due to visual similarity and children with ADHD made it more difficult to control conflict when simultaneously confronted with incongruent visual and auditory inputs. The current study highlights how children with ADHD process cross-modal conflicts at multiple levels of information processing, thereby shedding light on the mechanisms underlying ADHD.

Dissociable effects of positive feedback on the capture and inhibition of impulsive behavior in adolescents with ADHD versus typically developing adolescents

The present study investigated how enhancing motivation by delivering positive feedback (a smiley) after a successful trial could affect interference control in adolescents with Attention Deficit Hyperactivity Disorder (ADHD) and in their typically developing (TD) peers. By using a Simon task within the theoretical framework of the "activation-suppression" model, we were able to separately investigate the expression and the inhibition of impulsive motor behavior. The experiment included 19 adolescents with ADHD and 20 TD adolescents in order to explore whether data found in adolescents with ADHD were similar to those found in TD adolescents. Participants performed the Simon task in two conditions: a condition with feedback delivered after each successful trial and a condition with no feedback. The main findings were that increasing motivation by delivering positive feedback increased impulsive response in both groups of adolescents. It also improved the efficiency of impulsive motor action inhibition in adolescents with ADHD but deteriorated it in TD adolescents. We suggest that 1/increased motivation could lead adolescents to favor fast responses even if incorrect, and 2/the differential effect of feedback on the selective suppression of impulsive motor action in both groups could be due to different baseline DA levels.

Hearts, flowers, and fruits: All children need to reveal their post-error slowing

Slowing down responses after errors (i.e., post-error slowing [PES]) is an established finding in adults. Yet PES in young children is still not well understood. In this study, we investigated (a) whether young children show PES in tasks with different types of cognitive conflict and differing demands on executive functions, (b) whether PES is adaptive and efficient in the sense that it is associated with better task performance, and (c) whether PES correlates between tasks. We tested 4- to 6-year-old children on the Funny Fruits task (FF; n = 143), a Stroop-like task that incorporates semantic conflict and taxes children's inhibition skills, and the Hearts and Flowers task (HF; n = 170), which incorporates spatial conflict and taxes children's inhibition skills in its incongruent block and taxes both inhibition and cognitive flexibility (rule-switching) skills in its mixed block. A subgroup of children were tested on both FF and HF (n = 74). Results revealed that, first, children showed PES in FF and both blocks of HF, indicating that PES occurs in both types of conflict and under varying executive demands. Second, PES was associated with task accuracy, but only for FF and the mixed HF. Third, a between-task association in PES emerged only between FF and the mixed HF. Together, these findings indicate that PES is still a developing strategy in young children; it is present but only adaptive for, and correlates between, semantic inhibition and spatial flexibility.

Linking Mild Childhood Adversity with Conflict and False Feedback Monitoring

It was proposed that dimensions of childhood adversity (i.e., deprivation and threat) have distinct effects on neural development and function. Present study examined the relationships between mild deprivation/threat and performance monitoring among undergraduate students without psychiatric diagnoses. By using event-related potentials (ERPs), 78 participants underwent a modified Flanker task in which false feedback on approximately 10% of the correct response trials was administered. The dynamic stages of performance monitoring in this task were differentiated into interference monitoring, feedback processing, and behavior adjustment. Childhood adversity was assessed by a Childhood Trauma Questionnaire (CTQ), which was further divided into subscales of neglect (as a proxy for deprivation dimension) and abuse (as a proxy for threat dimension). Our results showed that higher score of childhood neglect was associated with more interference cost indicated by longer RT to interference trials at the behavioral level, and altered interference monitoring indicated by smaller N2 amplitude to interference trials at the neural level. Meanwhile, higher score of childhood abuse was related to smaller P3 amplitude to unexpected negative feedback. These results suggested that mild childhood deprivation might be associated with altered processing of interference monitoring, while mild childhood threat might be linked to lower electrophysiological response to unexpected negative feedback among young adults without psychiatric disorders.

The development of allocentric spatial frame in the auditory system

The ability to encode space is a crucial aspect of interacting with the external world. Therefore, this ability appears to be fundamental for the correct development of the capacity to integrate different spatial reference frames. The spatial reference frame seems to be present in all the sensory modalities. However, it has been demonstrated that different sensory modalities follow various developmental courses. Nevertheless, to date these courses have been investigated only in people with sensory impairments, where there is a possible bias due to compensatory strategies and it is complicated to assess the exact age when these skills emerge. For these reasons, we investigated the development of the allocentric frame in the auditory domain in a group of typically developing children aged 6-10 years. To do so, we used an auditory Simon task, a paradigm that involves implicit spatial processing, and we asked children to perform the task in both the uncrossed and crossed hands postures. We demonstrated that the crossed hands posture affected the performance only in younger children (6-7 years), whereas at 10 years of age children performed as adults and were not affected by such posture. Moreover, we found that this task's performance correlated with age and developmental differences in spatial abilities. Our results support the hypothesis that auditory spatial cognition's developmental course is similar to the visual modality development as reported in the literature.

Atypical Developmental Trajectories of Early Perception Among School-Age Children With Attention Deficit Hyperactivity Disorder During a Visual Search Task

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by cognitive deficits associated with attention. Prior studies have revealed the potential impact of ADHD on basic perception and cognitive ability in patients with ADHD. In this study, bilateral posterior P1 and N1 were measured in 122 Chinese children aged 7-12 years (64 with ADHD) to investigate the developmental characteristics of early perception during visual processing in school-age children with ADHD. For children with ADHD, a larger P1 activity with an atypical developmental pattern was evoked and observed for the visual search performance. These findings offer new insights into the mechanisms of cognitive developmental deficits and intervention techniques in children with ADHD.

Differential response to pharmacological intervention in ADHD furthers our understanding of the mechanisms of interference control

The deficit in "interference control" found in children with Attention Deficit Hyperactivity Disorder (ADHD) could be due to two distinct processes, which are not disentangled in most studies: a larger susceptibility to activating prepotent response impulses and a deficit in suppressing them. Here, we investigated the effect of 1/ADHD and 2/ methylphenidate (MPH), on these two components of interference control. We compared interference control between untreated children with ADHD, children with ADHD under MPH, and typically developing children performing a Simon task. The main findings were that 1/ children with ADHD were more susceptible to reacting impulsively and less efficient at suppressing impulsive actions, and 2/ MPH improved the selective inhibition of impulsive actions but did not modify the strength of response impulse. This work provides an example of how pharmacological interventions and selective responses to them can be used to investigate and further our understanding of cognitive processing.

A systematic review of tools used to screen and assess for externalising behaviour symptoms in low and middle income settings

BACKGROUND

Mental health issues, often manifested as behavioural difficulties, in children are estimated to be high in low and middle-income countries (LMIC) settings. There is a paucity of definitive data due to a lack of well-validated tools to use across settings. This review aims to provide evidence on what tools are used and which have been adapted and validated in LMIC settings.

METHODS

We performed a systematic review to identify tools used to assess or screen externalising behaviour problems in children and adolescents in LMIC and assess their cultural adaptations. We searched for studies measuring externalising behaviour in children from 0 to 19 years published up to September 2018. Articles were assessed to identify tools used and analysed using the Ecological Validity Framework.

RESULTS

We identified 82 articles from over 50 LMICs who had studied externalising behaviour in children. Twenty-seven tools were identified, with a predominance of studies using tools from the USA and Europe. Most studies did not describe an adaptation and evaluation process, with only one study following recommended criteria. New tools were identified which both screen and assess externalising behaviour which have not yet been utilised across settings.

CONCLUSIONS

Although tools from the USA and Europe are often utilised to screen and assess for externalising behaviour problems in children in LMICs, the conceptual frameworks behind the use of these tools in other cultural contexts are not always carefully examined. In order to have valid data across cultures, we should aim to adapt and validate tools before use. Provision of processes to validate tools across LMIC settings would be beneficial.

Conflict processing in kindergarten children: New evidence from distribution analyses reveals the dynamics of incorrect response activation and suppression

The development of cognitive control is known to follow a long and protracted development. However, whether the interference effect in conflict tasks in children would entail the same core processes as in adults, namely an automatic activation of incorrect response and its subsequent suppression, remains an open question. We applied distributional analyses to reaction times and accuracy of 5- and 6-year-old children performing three conflict tasks (flanker, Simon, and Stroop) in a within-participants design. This revealed both strong commonalities and differences between children and adults. As in adults, fast responses were more error prone than slow ones on incompatible trials, indicating a fast "automatic" activation of the incorrect response. In addition, the strength of this activation differed across tasks, following a pattern similar to that of adults. Moreover, modeling the data with a drift diffusion model adapted for conflict tasks allowed one to better assess the origin of the typical slowing down observed in children. Besides showing that advanced distribution analyses can be successfully applied to children, the current results support the notion that interference effects in 5- and 6-year-olds are driven by mechanisms very similar to the ones at play in adults but with different time courses.

Altered patterns of resting-state functional connectivity between the caudate and other brain regions in medication-naïve children with attention deficit hyperactivity disorder

BACKGROUND

Structural and functional alterations occur in the caudate of patients with attention-deficit/hyperactivity disorder (ADHD). Here we aimed to investigate the functional connectivity between the dorsal caudate and other brain regions in ADHD children.

METHODS

Resting-state functional connectivity from 30 ADHD and 33 age- and gender-matched "normal" children were measured by functional Magnetic Resonance Imaging.

RESULTS

Positive connectivity with dorsal caudate was observed in the prefrontal areas, cingulate cortex and temporal lobe. Negative functional connectivity was observed in the precuneus, occipital cortices and cerebellum. The connectivity of left dorsal caudate to left inferior frontal gyrus was correlated with severity of ADHD.

CONCLUSIONS

Connectivity of dorsal caudate with several brain regions was identified in ADHD children.

Neuronal Intra-Individual Variability Masks Response Selection Differences between ADHD Subtypes-A Need to Change Perspectives

Due to the high intra-individual variability in attention deficit/hyperactivity disorder (ADHD), there may be considerable bias in knowledge about altered neurophysiological processes underlying executive dysfunctions in patients with different ADHD subtypes. When aiming to establish dimensional cognitive-neurophysiological constructs representing symptoms of ADHD as suggested by the initiative for Research Domain Criteria, it is crucial to consider such processes independent of variability. We examined patients with the predominantly inattentive subtype (attention deficit disorder, ADD) and the combined subtype of ADHD (ADHD-C) in a flanker task measuring conflict control. Groups were matched for task performance. Besides using classic event-related potential (ERP) techniques and source localization, neurophysiological data was also analyzed using residue iteration decomposition (RIDE) to statistically account for intra-individual variability and S-LORETA to estimate the sources of the activations. The analysis of classic ERPs related to conflict monitoring revealed no differences between patients with ADD and ADHD-C. When individual variability was accounted for, clear differences became apparent in the RIDE C-cluster (analog to the P3 ERP-component). While patients with ADD distinguished between compatible and incompatible flanker trials early on, patients with ADHD-C seemed to employ more cognitive resources overall. These differences are reflected in inferior parietal areas. The study demonstrates differences in neuronal mechanisms related to response selection processes between ADD and ADHD-C which, according to source localization, arise from the inferior parietal cortex. Importantly, these differences could only be detected when accounting for intra-individual variability. The results imply that it is very likely that differences in neurophysiological processes between ADHD subtypes are underestimated and have not been recognized because intra-individual variability in neurophysiological data has not sufficiently been taken into account.

Event-related potential measures of executive functioning from preschool to adolescence

Executive functions are a collection of cognitive abilities necessary for behavioural control and regulation, and are important for school success. Executive deficits are common across acquired and developmental disorders in childhood and beyond. This review aims to summarize how studies using event-related potential (ERP) can provide insight into mechanisms underpinning how executive functions develop in children from preschool to adolescence. We specifically focus on ERP components that are considered to be well-established markers of executive functioning, including the ability to resist distraction (inhibition, N200), hold scenes in mind (visuospatial working memory, contralateral delay activity), attend to specific stimuli (information processing, P300), follow rules (response monitoring, error-related negativity [ERN], and error-related positivity [Pe]), and adjust to feedback (outcome monitoring, feedback-related negativity). All of these components show developmental changes from preschool to adolescence, in line with behavioural and neuroimaging findings. These ERP markers also show altered developmental trajectories in the context of atypical executive functions. As an example, deficits in executive function are prominently implicated in attention-deficit-hyperactivity disorder. Therefore, this review highlights ERP studies that have investigated the above ERP components in this population. Overall, ERPs provide a useful marker for the development and dysfunction of executive skills, and provide insight into their neurophysiological basis.

Characterizing cognitive control abilities in children with 16p11.2 deletion using adaptive 'video game' technology: a pilot study

Assessing cognitive abilities in children is challenging for two primary reasons: lack of testing engagement can lead to low testing sensitivity and inherent performance variability. Here we sought to explore whether an engaging, adaptive digital cognitive platform built to look and feel like a video game would reliably measure attention-based abilities in children with and without neurodevelopmental disabilities related to a known genetic condition, 16p11.2 deletion. We assessed 20 children with 16p11.2 deletion, a genetic variation implicated in attention deficit/hyperactivity disorder and autism, as well as 16 siblings without the deletion and 75 neurotypical age-matched children. Deletion carriers showed significantly slower response times and greater response variability when compared with all non-carriers; by comparison, traditional non-adaptive selective attention assessments were unable to discriminate group differences. This phenotypic characterization highlights the potential power of administering tools that integrate adaptive psychophysical mechanics into video-game-style mechanics to achieve robust, reliable measurements.

Do Young Children Modulate Their Cognitive Control?

Abstract. Dynamic, trial-by-trial modulations of inhibitory control are well documented in adults but rarely investigated in children. Here, we examined whether 5-to-7 year-old children, an age range when inhibitory control is still partially immature, achieve such modulations. Fifty three children took flanker, Simon, and Stroop tasks. Above and beyond classic congruency effects, the present results showed two crucial findings. First, we found evidence for sequential modulations of congruency effects in these young children in the three conflict tasks. Second, our results showed both task specificities and task commonalities. These findings in young children have important implications as they suggest that, to be modulated, inhibitory control does not require full maturation and that the precise pattern of trial-by-trial modulations may depend on the nature of conflict.