The impact of transcranial direct current stimulation on attention bias modification in children with ADHD

Individuals with attention deficit-hyperactivity disorder (ADHD) struggle with the interaction of attention and emotion. The ventromedial prefrontal cortex (vmPFC) and dorsolateral prefrontal cortex (dlPFC) are assumed to be involved in this interaction. In the present study, we aimed to explore the effect of stimulation applied over the dlPFC and vmPFC on attention bias in individuals with ADHD. Twenty-three children with ADHD performed the emotional Stroop and dot probe tasks during transcranial direct current stimulation (tDCS) in 3 conditions: anodal dlPFC (F3)/cathodal vmPFC (Fp2), anodal vmPFC (Fp2)/cathodal dlPFC (F3), and sham stimulation. Findings suggest reduction of attention bias in both real conditions based on emotional Stroop task and not dot probe task. These results were independent of emotional states. The dlPFC and vmPFC are involved in attention bias in ADHD. tDCS can be used for attention bias modification in children with ADHD.

Transcranial random noise stimulation (tRNS) improves hot and cold executive functions in children with attention deficit-hyperactivity disorder (ADHD)

Children with attention deficit-hyperactivity disorder (ADHD) have impaired hot and cold executive functions, which is thought to be related to impaired ventromedial and dorsolateral prefrontal cortex (vmPFC and dlPFC) functions. The present study aimed to assess the impact concurrent stimulation of dlPFC and vmPFC through transcranial random noise stimulation (tRNS), a non-invasive brain stimulation tool which enhances cortical excitability via application of alternating sinusoidal currents with random frequencies and amplitudes over the respective target regions on hot and cold executive functions. Eighteen children with ADHD received real and sham tRNS over the left dlPFC and the right vmPFC in two sessions with one week interval. The participants performed Circle Tracing, Go/No-Go, Wisconsin Card Sorting, and Balloon Analogue Risk Tasks during stimulation in each session. The results showed improved ongoing inhibition, prepotent inhibition, working memory, and decision making, but not set-shifting performance, during real, as compared to sham stimulation. This indicates that simultaneous stimulation of the dlPFC and the vmPFC improves hot and cold executive functions in children with ADHD.

Neural symphony of risky decision making in children with ADHD: Insights from transcranial alternating current stimulation and cognitive modeling

BACKGROUND

The ventromedial prefrontal cortex (vmPFC) and dorsolateral prefrontal cortex (dlPFC) are key brain regions involved in risky decision making, affected in individuals with attention deficit hyperactivity disorder (ADHD). This study aims to examine how entrainment of these areas impacts the process and outcome of risky decision making in children with ADHD.

METHODS

Eighteen children with ADHD performed the balloon analogue risk-taking task (BART) during five different sessions of tACS (1.5 mA, 6 Hz), separated by one-week intervals, via (1) two channels with synchronized stimulation over the left dlPFC and right vmPFC, (2) the same electrode placement with anti-phase stimulation, (3) stimulation over the left dlPFC only, (4) stimulation over right vmPFC only, and (5) sham stimulation. Four-parameter and constant-sensitivity models were used to model the data.

RESULTS

The study showed that synchronized stimulation was associated with a reduction in positive prior belief, risk propensity, and deterministic selection. Desynchronized stimulation was associated with accelerated learning from initial selections. Isolated stimulation of the dlPFC leads to riskier decision enhanced learning updates and risk propensity, whereas isolated stimulation of the vmPFC facilitated faster learning and increased probabilistic selection.

CONCLUSION

The results highlight the important roles of the dlPFC and vmPFC and their communication in decision making, showcasing their impact on various aspects of the decision-making process. The findings provide valuable insights into the complex interplay between cognitive and emotional factors in shaping our choices.

The effect of comprehensive working memory training on executive functions and behavioral symptoms in children with attention deficit-hyperactivity disorder (ADHD)

This study aimed to evaluate the effect of working memory training on executive functions and behavioral symptoms in children with ADHD. Thirty children with ADHD were randomly assigned to active control or Active Memory Intervention (AMIN) group. Executive functions and rating scales were used for assessment in three baseline, post-intervention, and 1-month follow-up sessions. The results show AMIN improves working memory and inhibitory control as well as ameliorates ADHD symptoms at home and school. Working memory training is beneficial and transferable intervention in children with ADHD.

Immersive virtual reality for improving cognitive deficits in children with ADHD: a systematic review and meta-analysis

Virtual reality (VR) shows great potential in treating and managing various mental health conditions. This includes using VR for training or rehabilitation purposes. For example, VR is being used to improve cognitive functioning (e.g. attention) among children with attention/deficit-hyperactivity disorder (ADHD). The aim of the current review and meta-analysis is to evaluate the effectiveness of immersive VR-based interventions for improving cognitive deficits in children with ADHD, to investigate potential moderators of the effect size and assess treatment adherence and safety. The meta-analysis included seven randomised controlled trials (RCTs) of children with ADHD comparing immersive VR-based interventions with controls (e.g. waiting list, medication, psychotherapy, cognitive training, neurofeedback and hemoencephalographic biofeedback) on measures of cognition. Results indicated large effect sizes in favour of VR-based interventions on outcomes of global cognitive functioning, attention, and memory. Neither intervention length nor participant age moderated the effect size of global cognitive functioning. Control group type (active vs passive control group), ADHD diagnostic status (formal vs. informal) and novelty of VR technology were not significant moderators of the effect size of global cognitive functioning. Treatment adherence was similar across groups and there were no adverse effects. Results should be cautiously interpreted given the poor quality of included studies and small sample.

Reading mind from the eyes in individuals with attention deficit-hyperactivity disorder (ADHD): A meta-analysis

OBJECTIVES

Individuals with ADHD struggle with social impairments. The present study aimed to find out the inconsistent results of theory of mind skill in individuals with ADHD.

METHODS

The current meta-analysis reviewed 17 empirical studies that compared theory of mind in individuals with and without ADHD based on reading mind from the eyes test (RMET).

RESULTS

Finding from 1620 participants with ADHD and 1249 healthy controls showed a significant impairment in theory of mind in individuals with ADHD (Hedges' g = 0.66). Moderator analyses indicated that the impaired theory of mind was not affected by age and gender.

CONCLUSION

These findings describe impaired theory of mind in individuals with ADHD and provide an insight to pay attention to theory of mind in respective clinical assessments and treatments.

Transcranial direct current stimulation (tDCS) alters the pattern of information processing in children with ADHD: Evidence from drift diffusion modeling

OBJECTIVE

Performance accuracy and reaction time in cognitive tasks are routinely used to evaluate the efficacy of tDCS to affect cognitive task performance. tDCS alters the excitability of targeted brain areas and thereby alters performance of cognitive tasks. The drift diffusion model (DDM) provides some additional measures to explore information processing style, such as (non)decision time, bias for decision, and speed of information processing. DDM parameters are informative for the study of cognitive impairments in children with ADHD. In the present study, we aimed to evaluate the impact of tDCS on cognitive performance via DDM measures.

METHODS

This study conducted DDM modeling and reanalysis of two exploratory, single-blinded, within-subject design experiments, which were published earlier. In the first experiment, twenty- four children with ADHD performed a Go/ No- Go task during anodal or sham tDCS over the right dlPFC. In the second experiment, twenty- five children with ADHD performed the 1- back working memory task during anodal or sham tDCS over the left dlPFC. We reanalyzed the data after DDM modeling.

RESULTS

The conventional performance measures revealed no significant effect of tDCS on No- Go accuracy in the first experiment and 1-back accuracy in the second experiment. The 1-back reaction time and speed-accuracy tradeoff were however improved under the real stimulation condition. The DDM measures identified increased No-Go- bias and decision time with respect to inhibitory control, and an increased threshold and amount of information required for response in the 1- back test.

CONCLUSION

In children with ADHD, anodal tDCS over the right dlPFC induces more conservative and less impulsive decisions. Furthermore, anodal tDCS over the left dlPFC enhanced efficacy of working memory performance with respect to agility and capacity. The experimental results show that drift diffusion modeling is useful for evaluation of the impact of tDCS on the style of information processing.

Different effects of methylphenidate and atomoxetine on the behavior and brain transcriptome of zebrafish

Attention deficit-hyperactivity disorder (ADHD) is a prevalent neuropsychiatric disorder found in children. It is characterized by inattention, hyperactivity, and impulsivity. Methylphenidate (MPH) and atomoxetine (ATX) are commonly prescribed for the treatment of ADHD. In the present study, we examined the behavioral and brain transcriptome changes in MPH-treated and ATX-treated zebrafish. In behavioral analysis, zebrafish showed opposite response to each treatment. MPH-treated fish showed higher anxiety-like behavior while ATX-treated fish showed lower anxiety-like behavior. Further, we performed RNA sequencing analysis of zebrafish brain to elucidate the underlying biological pathways associated with MPH and ATX treatment. Interestingly, we found that shared differentially expressed genes in MPH-treated and ATX-treated fish were instrumental in cholesterol biosynthesis pathway and were regulated in opposite manner. Our findings highlight the contrast between MTH and ATX, and may suggest the alterations in clinical practice for these medications and drug development for ADHD.

The negative attribution processes of mothers of children with attention deficit/hyperactivity disorder

The objective of this study was to investigate the attribution processes of mothers regarding children's prosocial behaviors, inattention, and hyperactivity/impulsivity (symptoms of attention deficit/hyperactivity disorder, ADHD) using two paradigms. The first paradigm involved multidimensional attributions. The second paradigm concerned making attributions of children's identical behaviors based on information such as consensus, distinctiveness, and consistency. The participants were 64 mothers of children with ADHD (7-13 years old) and 64 mothers with typical/normal children (7-12 years old). The results showed that mothers of typical children exhibited positive attribution styles or person attributions whereas mothers of children with ADHD exhibited negative attribution styles. Mothers of children with ADHD tended to make personal attributions of children's negative behaviors (e.g., inattention and hyperactivity/impulsivity; HI) but made situational attributions of prosocial behaviors. The results of this study can be used in future studies of the effects of intervention on children with ADHD or in studies related to neurophysiology.

Effectiveness of reboxetine in treatment of outpatient children and adolescents with attention deficit-hyperactivity disorder with comorbid anxiety disorders

OBJECTIVE

Some previous studies have reported that ADHD is often comorbid with anxiety disorders. The aim of the present study was to evaluate the effectiveness of reboxetine in treating outpatient children and adolescents with ADHD and comorbid anxiety disorders.

METHOD

In this open-label study, 25 outpatient children and adolescents, aged 6-16 years were selected by convenient sampling and underwent treatment with 4mg reboxetine for four weeks. Data were collected at baseline, two weeks and four weeks after the start of the medication using Conners' Parent Questionnaire, Hamilton's Rating Scale for Anxiety, Clinical Global Assessment Scale, Clinical Global Impression-Severity Scale and Side Effects Form. Data were analyzed using repeated measure, analyses of variance (ANOVA), Tukey post hoc test and paired t-test.

RESULTS

There were significant reduction in the total score of ADHD (F = 31.441; P <0.001) at the end of the treatment compared to baseline (Table 1). The differences between T0 and T2 in the subscales of attention deficit, hyperactivity and confrontation (F = 20.691; P <0.001, F = 28.810; P < 0.001, and F = 17.463; P <0.001, respectively) were also significant. Findings also indicated significant differences between T0 and T1 (P<0.01) and T1 and T2 (P<0.01) in all of the subscales except for confrontation. A significant improvement was observed in the severity of ADHD and anxiety disorders during different courses of the treatment (p<0.001). No significant changes were observed in systolic and diastolic blood pressure and pulse and weight of the patients during the study. The most common complications were headache and anorexia.

CONCLUSIONS

The short-term treatment with reboxetine was effective in improving ADHD with comorbid anxiety disorders. Therefore, reboxetine could be used as a treatment option for ADHD in those children who experience comorbid anxiety disorders or in those who are non-responsive or intolerant to methylphenidate.