Interference Control in Children with Attention Deficit/Hyperactivity Disorder

The relationship between the use of Touch Screen Devices and interference suppression in children aged 5-11

OBJECTIVE

To investigate the relation between the use of Touch Screen Devices (TSDs), such as smartphones and tablets, and interference suppression as assessed by the Bivalent Shape Task (BST) in 5-11-year-old children.

METHODS

Thirty-eight children from a Dutch primary school were included. Interference suppression was measured in the incongruent level of the BST. TSD use was measured by a standardized interview. The dataset was analyzed using multilevel analysis because of its nested structure.

RESULTS

Children with moderate to high TSD use showed a longer reaction time (RT) as age progresses in the incongruent level (T = 2.40, p = .017), compared to children with no to low TSD use. Furthermore, an interaction between TSD use, age, gender, and the incongruent level demonstrated an increased RT in boys with moderate to high TSD use compared to boys with no to low TSD use as age increases (T = -2.23, p = .026).

CONCLUSION

The RT in response of interfering stimuli seems to be negatively influenced by TSD use as age progresses in children aged 5-11. Moreover, a gender-specific effect could be observed. Given the potential impact of these findings, more research would be helpful to further explore causal mechanisms.

Differential Impact of WM Load on Attention in Young Adults Versus Children and Adolescents

Background: This study aimed to examine how concurrent working memory (WM) loads affect selective attention, and to explore developmental differences between young adults and children/adolescents aged 10 to 14 years. Methods: We employed a modified Stroop task with verbal or spatial WM loads to assess their impact on attention. Results: In adults, we found increased Stroop effects when WM load overlapped with target processing and decreased Stroop effects when WM load overlapped with distractor processing. Conversely, in children/adolescents, WM loads did not significantly impact target or distractor processing, indicating no change in Stroop effects under dual-task conditions. Interestingly, results from the correlational analyses revealed that as participants' ages increase, the interference effect under the WM load that shares resources with distractor processing in the attention task decreases. Conclusions: Our findings suggest that the interaction between attention and WM differs across developmental stages. While adults showed distinctive effects of concurrent WM loads on attention processing depending on the cognitive resources utilized, children/adolescents failed to show the interaction between the two cognitive systems. Furthermore, a significant relationship between age and the effects of WM load on attention was observed, providing insights into the development of the interaction between WM and attention.

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.

Two sides of the same coin: ADHD affects reactive but not proactive inhibition in children

Children with attention-deficit/hyperactivity disorder (ADHD) present a deficit in inhibitory control. Still, it remains unclear whether it comes from a deficit in reactive inhibition (ability to stop the action in progress), proactive inhibition (ability to exert preparatory control), or both.We compared the performance of 39 children with ADHD and 42 typically developing children performing a Simon choice reaction time task. The Simon task is a conflict task that is well-adapted to dissociate proactive and reactive inhibition. Beyond classical global measures (mean reaction time, accuracy rate, and interference effect), we used more sophisticated dynamic analyses of the interference effect and accuracy rate to investigate reactive inhibition. We studied proactive inhibition through the congruency sequence effect (CSE).Our results showed that children with ADHD had impaired reactive but not proactive inhibition. Moreover, the deficit found in reactive inhibition seems to be due to both a stronger impulse capture and more difficulties in inhibiting impulsive responses. These findings contribute to a better understanding of how ADHD affects inhibitory control in children.

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.

Lateral prefrontal activity as a compensatory strategy for deficits of cortical processing in Attention Deficit Hyperactivity Disorder

Attention Deficit Hyperactivity Disorder (ADHD) is the most common neuropsychiatric disorder in childhood and is characterized by a delay of cortical maturation in frontal regions. In order to investigate interference control, which is a key function of frontal areas, a functional MRI study was conducted on 17 ADHD boys and 17 typically developing (TD) boys, while solving the multi source interference task (MSIT). This task consists of two conditions, a “congruent condition” and an “incongruent condition”. The latter requires to inhibit information that interferes with task-relevant stimuli. Behavioral results showed that ADHD subjects committed more errors than TD children. In addition, TD children presented a larger MSIT effect -a greater difference in reaction times between the incongruent and the congruent conditions- than ADHD children. Associated to the MSIT effect, neuroimaging results showed a significant enhancement in the activation of the right lateral prefrontal cortex (rlPFC) in ADHD than in TD subjects. Finally, ADHD subjects presented greater functional connectivity between rlPFC and bilateral orbitofrontal cortex than the TD group. This difference in connectivity correlated with worse performance in both groups. Our results could reflect a compensatory strategy of ADHD children resulting from their effort to maintain an adequate performance during MSIT.

Influence of emotional stimulus valence on inhibitory control in adults with and without ADHD

Human behavior is influenced both by approach and avoidance automatic reactions to positive and negative stimulus, respectively, but these reactions have not been well studied in attention-deficit/hyperactivity disorder (ADHD) patients. Moreover, studies employing spatial stimulus-response compatibility tasks in ADHD and healthy control (HC) subjects are scarce and inconclusive. The present study investigated inhibitory control and emotional processing in ADHD adults with a modified stimulus-response compatibility task in which spatial and emotional features of affective stimuli had to be processed together to select the correct response. Manual responses to figures of Favorite and Rival soccer team players were measured, and compatible or incompatible responses were chosen according to the soccer team figure. Eighteen HC participants and sixteen ADHD adults performed the task. We found an ordinary spatial compatibility effect for the Favorite soccer team and a reversed one for the Rival team in the ADHD group but not in the HC group. The effects may be due to stronger approach and withdrawal reactions toward the Favorite soccer team and away from the Rival one, respectively, indicating poor inhibitory control for the ADHD group. These results show that differences between ADHD and HC subjects become prominent when response selection involves both emotional and spatial features of the stimulus.

Do neurocognitive deficits in decision making differentiate conduct disorder subtypes?

The present study aimed to test whether neurocognitive deficits involved in decision making underlie subtypes of conduct-disorder (CD) differentiated on the basis of callous-unemotional (CU) traits. Eighty-five participants (M age = 10.94 years) were selected from a sample of 1200 children based on repeated assessment of CD and CU traits. Participants completed a multi-method battery of well-validated measures of risky decision making and associated constructs of selective attention and future orientation (Stroop, Stoplight, and Delay-Discounting Tasks). Findings indicated that impaired decision making, selective attention, and future orientation contribute to the antisocial presentations displayed by children with CD, irrespective of level of CU traits. Youth high on CU traits without CD showed less risky decision making, as indicated by their performance on the Stoplight laboratory task, than those high on both CD and CU traits, suggesting a potential protective factor against the development of antisocial behavior.

Auditory interference control in children with learning disability: An exploratory study

OBJECTIVES

The current study aimed to compare the auditory interference control of participants with Learning Disability (LD) to a control group on two versions of an auditory Stroop task.

METHODS

A group of eight children with LD (clinical group) and another group of eight typically developing children (control group) served as participants. All the participants were involved in a semantic and a gender identification-based auditory Stroop task. Each participant was presented with eight different words (10 times) that were pre-recorded by a male and a female speaker. The semantic task required the participants to ignore the speaker's gender and attend to the meaning of the word, and vice-versa for the gender identification task. The participants' performance accuracy and reaction time (RT) was measured on both the tasks.

RESULTS

Control group participants significantly outperformed the clinical group participants on both the tasks with regard to performance accuracy as well as RT.

CONCLUSION

The results suggest that children with LD have problems in suppressing irrelevant auditory stimuli and focusing on the relevant auditory stimuli. This can be attributed to the auditory processing problems in these children.

Pathophysiology of ADHD and associated problems-starting points for NF interventions?

Attention deficit hyperactivity disorder (ADHD) is characterized by severe and age-inappropriate levels of hyperactivity, impulsivity and inattention. ADHD is a heterogeneous disorder, and the majority of patients show comorbid or associated problems from other psychiatric disorders. Also, ADHD is associated with cognitive and motivational problems as well as resting-state abnormalities, associated with impaired brain activity in distinct neuronal networks. This needs to be considered in a multimodal treatment, of which neurofeedback (NF) may be a promising component. During NF, specific brain activity is fed-back using visual or auditory signals, allowing the participants to gain control over these otherwise unaware neuronal processes. NF may be used to directly improve underlying neuronal deficits, and/or to establish more general self-regulatory skills that may be used to compensate behavioral difficulties. The current manuscript describes pathophysiological characteristics of ADHD, heterogeneity of ADHD subtypes and gender differences, as well as frequently associated behavioral problems such as oppositional defiant/conduct or tic disorder. It is discussed how NF may be helpful as a treatment approach within these contexts.

Nonword reading and Stroop interference: what differentiates attention-deficit/hyperactivity disorder and reading disability?

BACKGROUND

Attention deficits and impaired reading performance co-occur more often than expected by chance; however, the underlying mechanism of this association still remains rather unexplored.

METHOD

In two consecutive studies, children aged 8 to 12 years with attention-deficit/hyperactivity disorder (ADHD) and children with reading disability (RD) were examined using a 2 (ADHD versus no ADHD) × 2 (RD versus no RD) factorial design. To further delineate deficient interference control from reading processes, we used a newly developed self-paced word/nonword reading task (Experiment 1, n = 68) and a modified computerized Stroop paradigm, including an orthographic phonological neighbor (OPN) condition (Experiment 2, n = 84).

RESULTS

RD (compared to non-RD groups) was associated with impairments in both word and nonword reading, while children with ADHD also showed impaired nonword reading. In the Stroop task, RD, but not ADHD, had a significant impact on task performance. Interestingly, a significant interaction between ADHD, RD, and task condition emerged, which was due to particularly slower reaction times to nonwords in children with RD only, while task performance in children with comorbid ADHD and RD resembled that of ADHD only.

CONCLUSIONS

Thus, our results demonstrate that impairments in nonword reading were not specific to RD but were also present in children with ADHD. In addition, RD and not ADHD was characterized by poor interference control in the Stroop task. These findings question whether unique cognitive deficits are specific to either ADHD or RD.

Interference control in adolescents with mild-to-borderline intellectual disabilities and/or behavior disorders

The aim of this study was to investigate interference control in adolescents with Mild to Borderline Intellectual Disability (MBID) by addressing two key questions. First, as MBID is often associated with comorbid behavior disorders (BD), we investigated whether MBID and BD both affect interference control. Second, we studied whether interference control deficits are associated to problems in everyday executive functioning. Four groups of adolescents with and without MBID and/or BD performed the Eriksen flanker task, requiring participants to respond to a central target while ignoring interfering flanking stimuli. Their teachers rated behavior on the Behavior Rating Inventory Executive Function (BRIEF). We found pronounced effects of MBID but not BD on flanker interference control. In contrast, we observed pronounced effects of BD, but not MBID, on the BRIEF. In addition, flanker interference scores and BRIEF scores did not correlate. These results are taken to suggest that adolescents with MBID are characterized by deficits in interference control that do not become manifest in ratings of everyday executive functioning. In contrast, adolescents with BD are not characterized by deficits in interference control but do show elevated ratings of deficits in everyday executive function.

Interference control in adult ADHD: no evidence for interference control deficits if response speed is controlled by delta plots

Several theoretical accounts assume that interference control deficits belong to the core symptoms of adult ADHD. However, findings of increased interference effects in adult ADHD patients compared with healthy adults may be confounded with the simultaneous finding of generally slower responses in the patient group. The current study compared the magnitude of the interference effect in the Stroop task between a group of adults with ADHD and a healthy adult control group in a procedure that accounted for differences in overall response speed by using delta plots. The amount of interference did not differ between patient and control group at comparable reaction time levels. These results challenge the conclusions of the previous studies, in that they indicate that interference control is not impaired in adult ADHD.

Beyond interference control impairment in ADHD: evidence from increased intraindividual variability in the color-stroop test

The present study investigates intraindividual variability (IIV) in the Color-Stroop test and in a simple reaction time (SRT) task. Performance level and variability in reaction times (RTs)-quantified with different measures such as individual standard deviation (ISD) and coefficient of variation (ICV), as well as ex-Gaussian parameters (mu, sigma, tau)-were analyzed in 24 children with attention deficit/hyperactivity disorder (ADHD) and 24 typically developing children (TDC). Children with ADHD and TDC presented equivalent Color-Stroop interference effects when mean RTs were considered, and the two groups did not differ in the SRT task. Interestingly, compared to TDC, children with ADHD were more variable in their responses, showing increased ISD and ICV in the Color-Stroop interference condition and in the SRT task. Moreover, children with ADHD exhibited higher tau values-that is, more frequent abnormally long RTs-in the Color-Stroop interference condition than did the TDC, but comparable tau values in the SRT, suggesting more variable responses. These results speak in favor of a general deficit in more basic and central processes that only secondarily may affect the efficiency of inhibitory processes in children with ADHD. Overall the present findings confirm the role of IIV as a cornerstone in the ADHD cognitive profile and support the search for fine-grained analysis of performance fluctuations.

Adverse effects of heavy prenatal maternal smoking on attentional control in children with ADHD

OBJECTIVE

Exposure to heavy maternal cigarette smoking in pregnancy and severe maternal psychosocial stress during pregnancy appear to be important risk factors for the development of ADHD. This study aimed to determine whether these perinatal risk factors were associated with neuropsychological deficits commonly seen in ADHD.

METHOD

We examined the effect of these two risk factors on measures of attentional control, motor inhibition, visual-motor integration, and fine motor coordination in a group of 81 children with ADHD, aged from 8 to 18 years. The neuropsychological battery included the Connors' Continuous Performance Test (CPT), the Stroop Color-Word Interference Test, the Beery Visual-Motor Integration Test, and the Purdue Pegboard Test.

RESULTS

Heavy maternal smoking during pregnancy was associated with slower reaction times (p < .002), and reaction time variability (p < .007) on the CPT.

CONCLUSIONS

This study suggests a persistent negative effect of heavy prenatal maternal smoking on attentional control in children with ADHD. Future studies should examine the neurobiological basis and determine the degree to which inherited genetic susceptibility factors contribute to this finding.

Auditory conflict processing in ADHD

BACKGROUND

Impaired cognitive control has been implicated as an important developmental pathway to attention deficit/hyperactivity disorder (ADHD). Cognitive control is crucial to suppress interference resulting from conflicting information and can be measured by Stroop-like tasks. This study was conducted to gain insight into conflict processing in children with ADHD.

METHODS

Event-related potentials (ERPs) were recorded in an auditory Stroop task. Twenty-four children with ADHD were compared with 24 control children (aged 8-12 years).

RESULTS

No deficit in interference control was found on the auditory Stroop task in children with ADHD. Children with ADHD responded more slowly, less accurately and more variably compared to controls. No differences between the groups occurred in the early conflict-related ERPs. However, the difference between the congruent and the incongruent condition in the 450-550 ms time window was absent in the ADHD group compared to controls. In addition, the conflict sustained potential was found frontally in the ADHD group but parietally in the control group.

CONCLUSIONS

These ERP findings suggest that children with ADHD evaluate conflict to a lesser extent and differ in the way their brains select appropriate responses during conflict compared with controls.

Perceptual and motor inhibition in adolescents/young adults with childhood-diagnosed ADHD

OBJECTIVE

This study examined perceptual and motor inhibition in a longitudinal sample of adolescents/young adults who were diagnosed with ADHD in childhood, and as a function of the relative persistence of ADHD.

METHOD

Ninety-eight participants diagnosed with ADHD in childhood were reevaluated approximately 10 years later. Eighty-five never-ADHD controls similar in age, IQ, sociodemographic background, and gender distribution served as a comparison group. Participants were administered a psychiatric interview and the Stimulus and Response Conflict Tasks (Nassauer & Halperin, 2003).

RESULTS

Participants with childhood ADHD demonstrated slower and less accurate responses to both control and conflict conditions relative to the comparison group, as well as more variable responses in both conditions of the motor inhibition task; there was no specific effect of childhood ADHD on perceptual or motor inhibition. ADHD persisters and partial remitters did not differ in overall accuracy, speed or variability in responding, but relative to partial remitters, persisters demonstrated greater slowing in response to perceptual conflict.

CONCLUSIONS

These findings are consistent with theories positing state regulation, but not inhibitory control deficits in the etiology of ADHD, and suggest that improved perceptual inhibition may be associated with better outcome for ADHD.

Differences in Neurophysiological Markers of Inhibitory and Temporal Processing Deficits in Children and Adults with ADHD

We compared ADHD-related temporal processing and response inhibition deficits in children and adults using event-related potentials (ERPs) during cued continuous performance tasks (CPT, O-X-version, plus a more demanding flanker version). ERP markers of temporal processing (Cue CNV) and inhibition (NoGo P300) were obtained in matched groups of children (32 with ADHD, mean age 11.2 years, and 31 controls, mean age 11.1 years) and adults (22 ADHD, mean age 42.7 years, and 22 controls, mean age 44.0 years). ERP markers and performance reflected both age and ADHD status. Performance was poorer, and Cue CNV and NoGo P300 were weaker in ADHD children and adults compared to their matched controls. ADHD-related ERP differences in children were more prominent at posterior scalp sites but more pronounced at anterior scalp sites in adults, paralleling the prominent topographic changes of both ERP markers with development. The fact that differences in the same test and the same processing period appear in both children and adults, but that they present in different aspects of performance and different scalp topographies, leads to the conclusion that some ADHD-related deficits persist into adulthood despite alterations of their qualitative aspects.