A Randomized Controlled Trial Investigating the Effects of Neurofeedback, Methylphenidate, and Physical Activity on Event-Related Potentials in Children with Attention-Deficit/Hyperactivity Disorder

Change in Sleep Latency as a Mediator of the Effect of Physical Activity Intervention on Executive Functions Among Children with ADHD: A Secondary Analysis from a Randomized Controlled Trial

This study aimed to explore the potential mediating role of sleep quality in the effect of physical activity (PA) intervention for improving executive functions (EFs) in children with attention-deficit hyperactivity disorder (ADHD). Participants aged 6 to 12 years old with a formal ADHD diagnosis were recruited from a local hospital. A total of 80 eligible children with ADHD were randomized to an intervention group for 12 consecutive weeks of PA training (three times per week, 60 min per session) (n = 40; Mage = 8.37, 75% boys) or a wait-list control group (n = 40; Mage = 8.29, 80% boys). Three core EFs (inhibitory control, working memory, and cognitive flexibility) were assessed by neurocognitive tasks, and sleep quality was measured by the Chinese version of the Pittsburgh Sleep Quality Index. The bootstrapping method was used to test PA intervention effects on EFs and on potential variables of sleep quality after intervention and to test whether there were indirect effects of the intervention on EFs via mediators of sleep. The results showed that the PA intervention had a direct effect on sleep latency reduction (β = - 0.26, 95%CI - 0.47 to - 0.06) and cognitive flexibility improvement (decrease in completion time) (β = - 0.30, 95%CI - 0.50 to - 0.09). Furthermore, change in sleep latency significantly mediated the effects of PA intervention on cognitive flexibility (β = - 0.084, 95%CI - 0.252 to - 0.001). The findings suggest that sleep latency could be a crucial behavioral mediator of PA intervention in improving cognitive flexibility among children with ADHD.

Methylphenidate dose-response in children with ADHD: evidence from a double-blind, randomized placebo-controlled titration trial

Methylphenidate (MPH) is highly efficacious in reducing symptoms of attention-deficit/hyperactivity disorder (ADHD) in children. Generally increased doses are found to result in better symptom control; however, it remains unclear whether this pattern can be observed at the individual level, given the large heterogeneity in individual dose-response relationships and observed placebo responses. A double-blind, randomized, placebo-controlled cross-over trial was used to compare weekly treatment with placebo and 5, 10, 15 and 20 mg of MPH twice daily on parent and teacher ratings of child ADHD symptoms and side effects. Participants were 5-13-year-old children with a DSM-5 diagnosis of ADHD (N = 45). MPH response was assessed at group and individual levels and predictors of individual dose-response curves were examined. Mixed model analysis showed positive linear dose-response curves at group level for parent and teacher rated ADHD symptoms and parent rated side effects, but not for teacher rated side effects. Teachers reported all dosages to improve ADHD symptoms compared to placebo, while parents only reported > 5 mg/dose as effective. At the individual level, most (73-88%) children, but not all, showed positive linear dose-response curves. Higher severity of hyperactive-impulsive symptoms and lower internalizing problems, lower weight, younger age and more positive opinions towards diagnosis and medication partly predicted steeper linear individual dose-response curves. Our study confirms that increased doses of MPH yield greater symptom control at a group level. However, large interindividual variation in the dose-response relationship was found and increased doses did not lead to greater symptom improvement for all children. This trial was registered in the Netherlands trial register (# NL8121).

Efficacy of non-pharmacological interventions on executive functions in children and adolescents with ADHD: A systematic review and meta-analysis

OBJECTIVE

Although front-line doctors recommend medications, this kind of treatment has limited efficacy in improving executive functions (EFs) in children and adolescents with attention-deficit/hyperactivity disorder (ADHD). This study explored the effects of non-pharmacological intervention on EFs in children and adolescents with ADHD.

METHODS

In accordance with the Preferred Reporting Items for Systematic Review and Meta-analyses guidelines, we searched seven electronic databases: APA PsycINFO, CINAHL Complete, EMBASE, ERIC, Medline, Pubmed, and Web of Science, from inception to March 2022. Two authors independently screened studies for eligibility, extracted data, and assessed bias risk using the Physiotherapy Evidence Database scale. Our analyses included randomized controlled trials and non-randomized comparison studies of non-pharmacological interventions and assessed EFs through neurocognitive tasks in children and adolescents between 5 and 18 years.

RESULTS

Sixty-seven studies with 3147 participants met the inclusion criteria. The final meta-analysis included 74 independent interventions categorized into six categories: cognitive training, EF-specific curriculum, game-based training, mindfulness practice, neurofeedback training, and physical exercise. Overall, non-pharmacological interventions (combined) produced significant moderate to large effects on overall EFs in children and adolescents with ADHD (g=0.673). Physical exercise had a large positive effect on domain-specific EFs, including inhibitory control (g=0.900) and cognitive flexibility (g=1.377). Cognitive training had a large training effect on working memory (g=0.907), and an EF-specific curriculum had a small to moderate beneficial effect on planning performance (g=0.532).

CONCLUSION

Non-pharmacological interventions, particularly physical exercise, cognitive training, and an EF-specific curriculum, appear to have beneficial effects on EFs in children and adolescents with ADHD.

Evaluation of Neurofeedback Learning in Patients with ADHD: A Systematic Review

NFB has a clear potential as a recognised treatment option for ADHD, but suffers from a lack of clarity about its efficacy, still unresolved after multiple controlled trials. Comparing learners and non-learners based on the evolution of patient-level indicators during the trial serves as a 'natural' control, and can help elucidate the mechanisms of NFB. We present a systematic review motivated by the need to establish the state of the art of patient learning during NFB treatment in current clinical literature. One particularly striking question we would like to answer here is whether existing NFB papers study learning variability, since only individual performance differences can give us information about mechanisms of learning. The results show that very few clinical trial reports have dealt with the heterogeneity of NFB learning, nor analysed whether NFB efficacy is dependent on NFB learning, even though NFB is believed to be a treatment based on learning to perform. In this systematic review we examine not only what has been reported, but also provide a critical analysis of possible flaws or gaps in existing studies, and discuss why no generalized conclusions about NFB efficacy have yet been made. Future research should focus on finding reliable ways of identifying the performers and studying participants' individual learning trajectories as it might enhance prognosis and the allocation of clinical resources.

Effects of different physical activity interventions on children with attention-deficit/hyperactivity disorder: A network meta-analysis of randomized controlled trials

Background

Previous studies have shown that physical activity interventions positively affect core symptoms and executive functioning in children with attention-deficit/hyperactivity disorder (ADHD). However, comparisons between different physical activity interventions still need to be made. This study is the first to analyze the effects of 10 different types of physical activity on children with ADHD through a network meta-analysis.

Methods

PubMed, Embase, Web of Science, and Cochrane Library databases were searched for randomized controlled trials on the effects of physical activity interventions on children with ADHD. The search time frame was from database creation to October 2022. Two investigators independently performed literature screening, extraction, and quality assessment. Network meta-analysis was performed with Stata 15.1.

Results

A total of 31 studies were included, and the results indicated that perceptual-motor training was the most effective in terms of motor ability and working memory (SUCRA = 82.7 and 73.3%, respectively). For attention problems and cognitive flexibility, aquatic exercise was the most effective (SUCRA = 80.9 and 86.6%, respectively). For social problems, horsemanship was the most effective (SUCRA = 79.4%). For inhibition switching, cognitive-motor training was the most effective (SUCRA = 83.5%).

Conclusion

Our study revealed that aquatic exercise and perceptual-motor training had a superior overall performance. However, the effects of various physical activity interventions on different indicators in children with ADHD can vary depending on the individual and the intervention's validity. To ensure an appropriate physical activity intervention is selected, it is important to assess the severity of symptoms exhibited by children with ADHD beforehand.

Methylphenidate, Guanfacine, and Combined Treatment Effects on Electroencephalography Correlates of Spatial Working Memory in Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

The combination of d-methylphenidate and guanfacine (an α-2A adrenergic agonist) may be an effective alternative to either agent as monotherapy in children with attention-deficit/hyperactivity disorder (ADHD). This study investigated the neural mechanisms underlying medication effects using cortical source analysis of electroencephalography (EEG) data.

METHOD

A total of 172 children with ADHD (aged 7-14; 118 boys) completed an 8-week randomized, double-blind, comparative study with 3 treatment arms: d-methylphenidate, guanfacine, or their combination. EEG modulations of brain oscillations at baseline and end point were measured during a spatial working memory task from cortical sources localized within the anterior cingulate (midfrontal) and primary visual cortex (midoccipital), based on previously reported ADHD and control differences. Linear mixed models examined treatment effects on EEG and performance measures.

RESULTS

Combined treatment decreased midoccipital EEG power across most frequency bands and task phases. Several midoccipital EEG measures also showed significantly greater changes with combined treatment than with monotherapies. D-methylphenidate significantly increased midoccipital theta during retrieval, while guanfacine produced only trend-level reductions in midoccipital alpha during maintenance and retrieval. Task accuracy improved with combined treatment, was unchanged with d-methylphenidate, and worsened with guanfacine. Treatment-related changes in midoccipital power correlated with improvement in ADHD severity.

CONCLUSION

These findings show that combined treatment ameliorates midoccipital neural activity associated with treatment-related behavioral improvements and previously implicated in visuo-attentional deficits in ADHD. Both monotherapies had limited effects on EEG measures, with guanfacine further showing detrimental effects on performance. The identified midoccipital EEG profile may aid future treatment monitoring for children with ADHD.

CLINICAL TRIAL REGISTRATION INFORMATION

Single Versus Combination Medication Treatment for Children With Attention Deficit Hyperactivity Disorder (Project1); https://clinicaltrials.gov/; NCT00429273.

DIVERSITY & INCLUSION STATEMENT

We worked to ensure race, ethnic, and/or other types of diversity in the recruitment of human participants. We worked to ensure sex and gender balance in the recruitment of human participants. One or more of the authors of this paper self-identifies as a member of one or more historically underrepresented racial and/or ethnic groups in science. While citing references scientifically relevant for this work, we also actively worked to promote sex and gender balance in our reference list. We actively worked to promote inclusion of historically underrepresented racial and/or ethnic groups in science in our author group. We actively worked to promote sex and gender balance in our author group.

Additive effects of EEG neurofeedback on medications for ADHD: a systematic review and meta-analysis

To elucidate possible additive effects of electroencephalogram-based neurofeedback (EEG-NF) on medications against the core symptoms of attention-deficit/hyperactivity disorder (ADHD), randomized controlled trials (RCTs) were retrieved from electronic databases including PubMed, EMBASE, ClinicalKey, Cochrane CENTRAL, ScienceDirect, and ClinicalTrials.gov from inception to March 2022. The primary outcomes were changes in ADHD symptoms (i.e., global, inattention, hyperactivity/impulsivity) assessed with validated rating scales, while secondary outcome was all-cause discontinuation rate. Meta-analysis of five RCTs involving 305 participants [Median age = 9.285 years (range 8.6-11.05)] with a median follow-up of 12 weeks showed additive effects of EEG-NF on medications from parents' observations against ADHD global symptoms (Hedges' g = 0.2898, 95%CI [0.0238; 0.5557]) and inattention symptoms (Hedges' g = 0.3274, 95%CI [0.0493; 0.6055]). However, additive effects failed to sustain six months after EEG-NF intervention. Besides, there was no difference in improvement of hyperactivity/impulsivity from parents' observation, attentional performance, and all-cause discontinuation rate between the two groups. Our results supported additional benefits of combining EEG-NF with medications compared to medication alone in treating global symptoms and symptoms of inattention in ADHD patients. Nevertheless, given a lack of evidence showing a correlation between underlying physiological changes and small effect sizes in our preliminary results, further studies are warranted to support our findings.

Treatment biomarkers for ADHD: Taking stock and moving forward

The development of treatment biomarkers for psychiatric disorders has been challenging, particularly for heterogeneous neurodevelopmental conditions such as attention-deficit/hyperactivity disorder (ADHD). Promising findings are also rarely translated into clinical practice, especially with regard to treatment decisions and development of novel treatments. Despite this slow progress, the available neuroimaging, electrophysiological (EEG) and genetic literature provides a solid foundation for biomarker discovery. This article gives an updated review of promising treatment biomarkers for ADHD which may enhance personalized medicine and novel treatment development. The available literature points to promising pre-treatment profiles predicting efficacy of various pharmacological and non-pharmacological treatments for ADHD. These candidate predictive biomarkers, particularly those based on low-cost and non-invasive EEG assessments, show promise for the future stratification of patients to specific treatments. Studies with repeated biomarker assessments further show that different treatments produce distinct changes in brain profiles, which track treatment-related clinical improvements. These candidate monitoring/response biomarkers may aid future monitoring of treatment effects and point to mechanistic targets for novel treatments, such as neurotherapies. Nevertheless, existing research does not support any immediate clinical applications of treatment biomarkers for ADHD. Key barriers are the paucity of replications and external validations, the use of small and homogeneous samples of predominantly White children, and practical limitations, including the cost and technical requirements of biomarker assessments and their unknown feasibility and acceptability for people with ADHD. We conclude with a discussion of future directions and methodological changes to promote clinical translation and enhance personalized treatment decisions for diverse groups of individuals with ADHD.

Results of Neurofeedback in Treatment of Children with ADHD: A Systematic Review of Randomized Controlled Trials

Attention-deficit/hyperactivity disorder (ADHD) is one of the most prevalent disorders in children and adolescents. Neurofeedback, a nonpharmaceutical treatment, has shown promising results. To review the evidence of efficacy of neurofeedback as a treatment for children and adolescents with ADHD. A systematic review of the specific scientific studies published in 1995-2021, identifying and analyzing randomized controlled trials (RCT). A total of 1636 articles were identified and 165 met inclusion criteria, of which 67 were RCTs. Neurofeedback training was associated with significant long-term reduction in symptoms of ADHD. Though limitations exist regarding conclusions about the specific effects of neurofeedback, the review documents improvements in school, social, and family environments.

Comparison of Vitamin D, Neurofeedback, and Neurofeedback Combined with Vitamin D Supplementation in Children with Attention-Deficit/Hyperactivity Disorder

Background: Nowadays, some treatments such as neurofeedback and Vitamin D Supplementation are of great importance in the treatment of attention-deficit/hyperactivity disorder (ADHD). To determine the efficacy of the combined treatment, the present trial was conducted to investigate the effectiveness of each one of them with combined neurofeedback and vitamin D supplementation in the reduction of ADHD symptom in children suffering from this disorder. Methods: In this study from March 2020 to June 2020, we enrolled a total of 120 patients (6-15 years old) who were referred to the Mehr psychiatric hospital (affiliated to Lorestan University of Medical Sciences). Patients were then randomly categorized into three experimental groups and one control group. The first, the second, and the third experimental groups consumed vitamin D pearl, neurofeedback combined with vitamin D, and neurofeedback for 12 weeks, respectively. The control group was given no treatment. Vitamin D serum level was evaluated at baseline, 4, 8, and 12 weeks in all participants. For data collection, the Parent Attention-Deficit/Hyperactivity Disorder Rating Scale-IV (ADHD-RS-IV) was applied. The obtained information was analyzed using repeated measure variance analysis. Results: The mean scores were significantly different across the groups. Repeated measure variance analysis showed that the mean score was lower in the combined group in comparison with the other three groups (P<0.05). Conclusion: Combined treatment could be considered as more effective compared to separate treatments. In addition, in this study, by applying the combined intervention, the duration of treatment decreased significantly.

Neural Effects of Physical Activity and Movement Interventions in Individuals With Developmental Disabilities-A Systematic Review

Individuals with developmental disabilities present with perceptuo-motor, social communication, and cognitive impairments that often relate to underlying atypical brain structure and functioning. Physical activity/movement interventions improve behavioral performance of individuals with and without developmental disabilities. Majority of the evidence on potential neural mechanisms explaining the impact of physical activity/movement interventions is based on studies in individuals with typical development; there is a dearth of systematic reviews synthesizing the neural effects of physical activity/movement interventions in individuals with developmental disabilities. In this systematic review, we have gathered evidence on the neural effects of physical activity/movement interventions from 32 papers reporting substantial neural effects and behavioral improvements in individuals with developmental disabilities. Chronic intervention effects (multiple sessions) were greater than acute intervention effects (single session). Specifically, using electroencephalogram, functional magnetic resonance imaging, diffusion tensor imaging, and functional near-infrared spectroscopy, studies found physical activity/movement intervention-related changes in neural activity, indicating normalization of cortical arousal in individuals with attention-deficit /hyperactivity disorder (ADHD), increased social brain connectivity in individuals with autism spectrum disorder (ASD), and more efficient executive functioning processes in individuals with a wide range of other developmental disabilities. Despite promising results, more research is clearly needed in this area with larger sample sizes, using standardized neuroimaging tools/variables, and across multiple diagnoses to further explore the neural mechanisms underlying physical activity/movement interventions and to replicate findings from the present review.

A Systematic Literature Review and Meta-analysis on Effectiveness of Neurofeedback for Obsessive-Compulsive Disorder

To evaluate the evidences related to the effectiveness of neurofeedback treatment for people with OCD. A literature review and meta-analysis of current controlled trials for patients with OCD symptoms was conducted across different databases. So, the primary outcome measure was OCD symptoms in subjects based on DSM IV. Y-BOCS was considered as primary outcomes. Nine met inclusion criteria (including 1211 patients). Analysis showed there was an important benefit of neurofeedback treatment in comparison to other treatments (MD = -6.815; 95% CI = [-9.033, -4.598]; P < 0.001). The results provide preliminary evidence that NFB is efficacious method for OCD and suggest that more clinical trials are needed to compare common treatment such as medication, neurological, and behavioral interventions.

Sensory processing and P300 event-related potential correlates of stimulant response in children with attention-deficit/hyperactivity disorder: A critical review

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder associated with considerable impairment in psychiatric and functional domains. Although stimulant medication can reduce core symptoms of inattention, hyperactivity, and impulsivity, a subgroup of patients does not respond to this intervention. A precision medicine approach has been proposed, whereby biomarkers are used to identify an effective treatment approach for a given individual. This review synthesizes the existing literature on event-related potential (ERP) correlates of stimulant response in children diagnosed with ADHD, with the goal of evaluating the potential for ERP to inform precision medicine care in this population. Forty-three articles were examined and results tentatively suggest that stimulant medications normalize the amplitude of the P300 component, and this is also associated with behavioral improvement. In contrast, results generally indicate that stimulants do not significantly alter early processing components, although there are some exceptions to this finding. Implications for research, theory, and clinical work are considered and concrete recommendations for future directions are provided. While recognizing limitations of existing literature (e.g., homogenous samples, variable methodologies), we conclude that ERP methods represent a promising approach for precision medicine care of patients with ADHD.

Long-term effects of theta/beta neurofeedback on EEG power spectra in children with attention deficit hyperactivity disorder

OBJECTIVE

Neurofeedback has been proposed as an effective alternative for pharmacological treatment in children with attention-deficit/hyperactivity disorder (ADHD), with potentially long-term and delayed benefits. However, the specificity of such long-term behavioral improvements remains inconclusive and therefore additional research into the neurophysiological effects of neurofeedback is needed. We compared long-term effects of theta/beta neurofeedback (NFB) to methylphenidate (MPH) and physical activity (PA, semi-active control intervention) on electroencephalogram (EEG) power spectra. Based on the vigilance stabilization model, we hypothesized further reductions in theta and alpha power in the NFB compared to the control groups.

METHOD

EEG power spectra (theta, alpha and beta) during resting and task conditions were recorded at pre-, post-intervention and 6-months follow-up in 67 children, aged 7-13 (NFB: n = 24, MPH: n = 23, or PA: n = 20).

RESULTS

Analyses revealed no power spectra differences at follow-up between MPH and NFB (range p = .165-.905) and PA and NFB (range p = .172-.822).

CONCLUSIONS

No evidence was found for the specificity of theta/beta NFB at follow-up.

SIGNIFICANCE

This was the first study into long-term neurophysiological effects of theta/beta NFB. Future studies are encouraged to explore both specific and non-specific mechanisms of NFB.

CLINICAL TRIALS REGISTRATION

Train Your Brain? Exercise and neurofeedback intervention for ADHD, https://clinicaltrials.gov/show/NCT01363544, Ref. No. NCT01363544.

Physical exercise in attention deficit hyperactivity disorder - evidence and implications for the treatment of borderline personality disorder

A growing body of literature indicates a potential role for physical exercise in the treatment of attention deficit hyperactivity disorder (ADHD). Suggested effects include the reduction of ADHD core symptoms as well as improvements in executive functions. In the current review, we provide a short overview on the neurophysiological mechanisms assumed to underlie the beneficial effects of exercise. Further, we review the current evidence from experimental studies regarding both acute exercise and long-term interventions in ADHD. While the positive effects observed after acute aerobic exercise are promising, very few well-designed long-term intervention studies have been conducted yet. Moreover, although exercise effects have not yet been studied in borderline personality disorder (BPD), in the end of this paper we derive hypotheses why exercise could also be beneficial for this patient population.

Impact of physical exercise on children with attention deficit hyperactivity disorders: Evidence through a meta-analysis

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) which is characterized by developmentally inappropriate levels of attention, hyperactivity and impulsivity, is considered as the most common neurodevelopmental disorder in childhood. Physical exercise has shown to have several benefits in the improvement of children with ADHD. In this meta-analysis, we aimed to systematically show, with evidence, the impact of physical exercise on children with ADHD.

METHODS

Web of Science, MEDLINE, EMBASE, Google Scholar, Cochrane Central and http://www.ClinicalTrials.gov were the searched sources for studies which were based on the impact of physical exercise on children with ADHD. Relevant endpoints were assessed. This evidence based meta-analysis was carried out by the most relevant RevMan 5.3 software. Due to the involvement of continuous data (mean and standard deviation), weight mean difference (WMD) with 95% confidence intervals (CI) were used to represent the final analysis. A significant level of P ≤ .05 was set and a fixed statistical effect model was used throughout the analysis.

RESULTS

Fourteen studies with a total number of 574 participants with ADHD were included in this evidenced based meta-analysis. Two hundred and seventy six (276) participants were assigned to the physical activity group whereas 298 participants were assigned to the control group. Results of this analysis showed that anxiety and depression were significantly improved with physical activity in these children with ADHD (WMD: -1.84; 95% CI: [-2.65 - (-1.03)], P = .00001). Hyperactive/impulsive symptoms (WMD: -0.01; 95% CI: [-0.32 - 0.29], P = .93) and inattention symptoms (WMD: -0.22; 95% CI: [-0.51 - 0.08], P = .15) were also improved with physical exercise but the results were not statistically significant. This evidence based analysis showed thought problems (WMD: -3.49; 95% CI: [-5.51 - (-1.47)], P = .0007), social problems (WMD: -5.08; 95% CI: [-7.34 - (-2.82)], P = .0001), and aggressive behaviors (WMD: -3.90; 95% CI: [-7.10 - (-0.70)], P = .02) to have significantly been improved in participants with ADHD who were assigned to physical activity group.

CONCLUSIONS

This current meta-analysis showed with evidence, that physical exercise has a major contribution owing to significant improvement in anxiety and depression, aggressive behaviors, thought and social problems among children suffering from ADHD. Therefore, physical exercise should be incorporated in the daily life of children with ADHD. Further future research should be able to confirm this hypothesis.

Effects of Integrated Brain, Body, and Social (IBBS) intervention on ERP measures of attentional control in children with ADHD

A primary goal of this study was to examine the impact of an Integrated Brain, Body, and Social (IBBS) intervention (multi-faceted treatment consisting of computerized cognitive training, physical exercise, and behavior management) on ERPs of attentional control (P3 & N2) in children with ADHD. The secondary goal was to test the differences between children with and without ADHD on ERP and Go/No-Go behavioral measures. A total of twenty-nine participants (M age = 7.14 years; 52% male; 41.4% white) recruited from the IBBS efficacy study comparing IBBS to Treatment-As-Usual (TAU) completed a Go/No-Go task before and after treatment as brain activity was recorded using EEG. Thirty-four matched healthy controls (HC) completed the same EEG procedures at a single time point. Following treatment, the Go P3 latency was significantly earlier for the IBBS group relative to the TAU group. No treatment effects were found on any behavioral measures. Prior to treatment, there was a significant difference between the ADHD group and HC group for the N2 difference wave. Children with ADHD also showed slower reaction times on behavioral measures. Although this pilot study did not reveal robust treatment effects, it suggests that IBBS may prevent the worsening of attentional systems in the brain and larger studies are needed for replication purposes.

Measuring Treatment Response in Pharmacological and Lifestyle Interventions Using Electroencephalography in ADHD: A Review

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, hyperactivity, and/or impulsivity with associations to short- and long-term aversive life events. The exact etiology of the disorder is still unknown. ADHD is heterogeneous in symptomology and a single consistent, reliable biomarker has not been found. Quantitative electroencephalography (EEG) has been proposed as a potential way to differentiate those with ADHD from typically developing controls; however, the data on the diagnostic utility of this approach have been variable. Quantitative EEG has been employed in prognostic ways to assess differences in baseline spectral power profiles and pharmacological and nonpharmacological treatment effects on electrocortical activity within the ADHD population. The aim of this review is to summarize the literature investigating the degree of normalization of resting-state EEG profiles in individuals with ADHD through various interventions, including stimulant and nonstimulant medication, exercise, and diet.

Sustained effects of neurofeedback in ADHD: a systematic review and meta-analysis

Neurofeedback (NF) has gained increasing interest in the treatment of attention-deficit/hyperactivity disorder (ADHD). Given learning principles underlie NF, lasting clinical treatment effects may be expected. This systematic review and meta-analysis addresses the sustainability of neurofeedback and control treatment effects by considering randomized controlled studies that conducted follow-up (FU; 2-12 months) assessments among children with ADHD. PubMed and Scopus databases were searched through November 2017. Within-group and between-group standardized mean differences (SMD) of parent behavior ratings were calculated and analyzed. Ten studies met inclusion criteria (NF: ten studies, N = 256; control: nine studies, N = 250). Within-group NF effects on inattention were of medium effect size (ES) (SMD = 0.64) at post-treatment and increased to a large ES (SMD = 0.80) at FU. Regarding hyperactivity/impulsivity, NF ES were medium at post-treatment (SMD = 0.50) and FU (SMD = 0.61). Non-active control conditions yielded a small significant ES on inattention at post-treatment (SMD = 0.28) but no significant ES at FU. Active treatments (mainly methylphenidate), had large ES for inattention (post: SMD = 1.08; FU: SMD = 1.06) and medium ES for hyperactivity/impulsivity (post: SMD = 0.74; FU: SMD = 0.67). Between-group analyses also revealed an advantage of NF over non-active controls [inattention (post: SMD = 0.38; FU: SMD = 0.57); hyperactivity-impulsivity (post: SMD = 0.25; FU: SMD = 0.39)], and favored active controls for inattention only at pre-post (SMD = - 0.44). Compared to non-active control treatments, NF appears to have more durable treatment effects, for at least 6 months following treatment. More studies are needed for a properly powered comparison of follow-up effects between NF and active treatments and to further control for non-specific effects.

Methylphenidate modifies activity in the prefrontal and parietal cortex accelerating the time judgment

Methylphenidate produces its effects via actions on cortical areas involved with attention and working memory, which have a direct role in time estimation judgment tasks. In particular, the prefrontal and parietal cortex has been the target of several studies to understand the effect of methylphenidate on executive functions and time interval perception. However, it has not yet been studied whether acute administration of methylphenidate influences performance in time estimation task and the changes in alpha band absolute power in the prefrontal and parietal cortex. The current study investigates the influence of the acute use of methylphenidate in both performance and judgment in the time estimation interpretation through the alpha band absolute power activity in the prefrontal and parietal cortex. This is a double-blind, crossover study with a sample of 32 subjects under control (placebo) and experimental (methylphenidate) conditions with absolute alpha band power analysis during a time estimation task. We observed that methylphenidate does not influence task performance (p > 0.05), but it increases the time interval underestimation by over 7 s (p < 0.001) with a concomitant decrease in absolute alpha band power in the ventrolateral prefrontal cortex and dorsolateral prefrontal cortex and parietal cortex (p < 0.001). Acute use of methylphenidate increases the time interval underestimation, consistent with reduced accuracy of the internal clock mechanisms. Furthermore, acute use of methylphenidate influences the absolute alpha band power over the dorsolateral prefrontal cortex, ventrolateral prefrontal cortex, and parietal cortex.

Association of Affected Neurocircuitry With Deficit of Response Inhibition and Delayed Gratification in Attention Deficit Hyperactivity Disorder: A Narrative Review

The neural networks that constitute corticostriatothalamocortical circuits between prefrontal cortex and subcortical structure provide a heuristic framework for bridging gaps between neurocircuitry and executive dysfunction in attention deficit hyperactivity disorder (ADHD). “Cool” and “Hot” executive functional theory and the models of dual pathway are supposed to be applied within the neuropsychology of ADHD. The theoretical model elaborated response inhibition and delayed gratification in ADHD. We aimed to review and summarize the literature about the circuits on ADHD and ADHD-related comorbidities, as well as the effects of neurocircuitry on the executive dysfunction in ADHD.

A comparative study on the neurophysiological mechanisms underlying effects of methylphenidate and neurofeedback on inhibitory control in attention deficit hyperactivity disorder

In Attention Deficit Hyperactivity Disorder (AD(H)D), treatments using methylphenidate (MPH) and behavioral interventions like neurofeedback (NF) reflect major therapeutic options. These treatments also ameliorate executive dysfunctions in AD(H)D. However, the mechanisms underlying effects of MPH and NF on executive functions in AD(H)D (e.g. the ability to inhibit prepotent responses) are far from understood. It is particularly unclear whether these interventions affect similar or dissociable neural mechanisms and associated functional neuroanatomical structures. This, however, is important when aiming to further improve these treatments. We compared the neurophysiological mechanisms of MPH and theta/beta NF treatments on inhibitory control on the basis of EEG recordings and source localization analyses. The data show that MPH and theta/beta NF both increase the ability to inhibit pre-potent responses to a similar extent. However, the data suggest that MPH and NF target different neurophysiological mechanisms, especially when it comes to functional neuroanatomical structures associated with these effects. Both treatments seem to affect neurophysiological correlates of a ‘braking function’ in medial frontal areas. However, in case of the NF intervention, inferior parietal areas are also involved. This likely reflects the updating and stabilisation of efficient internal representations in order to initiate appropriate actions. No effects were seen in correlates of perceptual and attentional selection processes. Notably, reliable effects were only obtained after accounting for intra-individual variability in the neurophysiological data, which may also explain the diversity of findings in studies on treatment effects in AD(H)D, especially concerning neurofeedback.

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Neurophysiological mechanisms of methylphenidate (MPH) and neurofeedback (NF) in ADHD are compared.

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Both treatments improve inhibition, but have different underlying neurophysiological mechanisms.

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Both treatments affect the neurophysiological correlates of a ‘breaking function’ in medial frontal areas.

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NF also affects inferior parietal areas and likely the updating of internal representations.

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Distinctive effects are only seen when accounting for intra-individual variability.

The efficacy of Ritalin in ADHD children under neurofeedback training

Current research has shown that neurofeedback (NF) is a viable treatment for attention deficit hyperactivity disorder (ADHD), however having pharmacological approach alongside such stimulants is still inevitable. Therefore, the purpose of this study is the comparison of neurofeedback with Ritalin and without Ritalin in treating children with ADHD. This study was causal-comparative in design. Participants were children aged 5-10 years with ADHD; seven participants were in neurofeedback group with Ritalin and seven in neurofeedback without Ritalin group according to random split and parent's conformation. Clinical Q, Conner's continuous performance test (CPT), and WISC-R were used before and after treatment. For analyzing data, we used descriptive statistical and Mann Whitney U tests. Results showed that even if the two groups were modified in all components, modifications of commission and reaction time of the CPT and F4 theta/alpha of the clinical Q were more accurate in NF with Ritalin treatment rather than the other group. These findings suggest that neurofeedback is efficient in improving some of the behavioral concomitants of ADHD in children whose parents favored non-pharmacological treatment, but Ritalin and neurofeedback combination is more efficient. So, multimodal approach is strongly recommended for ADHD treatment.

A 6-month follow-up of an RCT on behavioral and neurocognitive effects of neurofeedback in children with ADHD

To assess the long-term effects of neurofeedback (NFB) in children with attention deficit hyperactivity disorder (ADHD), we compared behavioral and neurocognitive outcomes at a 6-month naturalistic follow-up of a randomized controlled trial on NFB, methylphenidate (MPH), and physical activity (PA). Ninety-two children with a DSM-IV-TR ADHD diagnosis, aged 7-13, receiving NFB (n = 33), MPH (n = 28), or PA (n = 31), were re-assessed 6-months after the interventions. NFB comprised theta/beta training on the vertex (cortical zero). PA comprised moderate to vigorous intensity exercises. Outcome measures included parent and teacher behavioral reports, and neurocognitive measures (auditory oddball, stop-signal, and visual spatial working memory tasks). At follow-up, longitudinal hierarchical multilevel model analyses revealed no significant group differences for parent reports and neurocognitive measures (p = .058-.997), except for improved inhibition in MPH compared to NFB (p = .040) and faster response speed in NFB compared to PA (p = .012) during the stop-signal task. These effects, however, disappeared after controlling for medication use at follow-up. Interestingly, teacher reports showed less inattention and hyperactivity/impulsivity at follow-up for NFB than PA (p = .004-.010), even after controlling for medication use (p = .013-.036). Our findings indicate that the superior results previously found for parent reports and neurocognitive outcome measures obtained with MPH compared to NFB and PA post intervention became smaller or non-significant at follow-up. Teacher reports suggested superior effects of NFB over PA; however, some children had different teachers at follow-up. Therefore, this finding should be interpreted with caution. Clinical trial registration Train your brain and exercise your heart? Advancing the treatment for Attention Deficit Hyperactivity Disorder (ADHD), Ref. no. NCT01363544, https://clinicaltrials.gov/show/NCT01363544 .

Neurofeedback versus psychostimulants in the treatment of children and adolescents with attention-deficit/hyperactivity disorder: a systematic review

This systematic review aimed to evaluate the efficacy of neurofeedback (NF) compared to stimulant medication in treating children and adolescents with attention-deficit/hyperactivity disorder (ADHD). Included in this review are eight randomized controlled trials that compared an NF condition, either alone or combined with medication, to a medication condition, which was mainly methylphenidate. Outcome measures included behavioral assessments by parents and teachers, self-reports, neurocognitive measures, electroencephalogram power spectra and event-related potentials. When only trials are considered that include probably blinded ratings or those that are sham-NF or semi-active controlled or those that employed optimally titration procedures, the findings do not support theta/beta NF as a standalone treatment for children or adolescents with ADHD. Nevertheless, an additive treatment effect of NF was observed on top of stimulants and theta/beta NF was able to decrease medication dosages, and both results were maintained at 6-month follow-up. This review concludes that the present role of NF in treating children diagnosed with ADHD should be considered as complementary in a multimodal treatment approach, individualized to the needs of the child, and may be considered a viable alternative to stimulants for a specific group of patients. Particularly patients with the following characteristics may benefit from NF treatment: low responders to medication, intolerable side effects due to medication, higher baseline theta power spectra and possibly having no comorbid psychiatric disorders. Future research should prioritize the identification of markers that differentiate responders from nonresponders to NF treatment, the potential of NF to decrease stimulant dosage, the standardization of NF treatment protocols and the identification of the most favorable neurophysiological treatment targets.

Neural Reactivity to Angry Faces Predicts Treatment Response in Pediatric Anxiety

Although cognitive-behavioral psychotherapy (CBT) and pharmacotherapy are evidence-based treatments for pediatric anxiety, many youth with anxiety disorders fail to respond to these treatments. Given limitations of clinical measures in predicting treatment response, identifying neural predictors is timely. In this study, 35 anxious youth (ages 7-19 years) completed an emotional face-matching task during which the late positive potential (LPP), an event-related potential (ERP) component that indexes sustained attention towards emotional stimuli, was measured. Following the ERP measurement, youth received CBT or selective serotonin reuptake inhibitor (SSRI) treatment, and the LPP was examined as a predictor of treatment response. Findings indicated that, accounting for pre-treatment anxiety severity, neural reactivity to emotional faces predicted anxiety severity post- CBT and SSRI treatment such that enhanced electrocortical response to angry faces was associated with better treatment response. An enhanced LPP to angry faces may predict treatment response insofar as it may reflect greater emotion dysregulation or less avoidance and/or enhanced engagement with environmental stimuli in general, including with treatment.

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.

An RCT into the effects of neurofeedback on neurocognitive functioning compared to stimulant medication and physical activity in children with ADHD

Neurofeedback (NFB) is a potential alternative treatment for children with ADHD that aims to optimize brain activity. Whereas most studies into NFB have investigated behavioral effects, less attention has been paid to the effects on neurocognitive functioning. The present randomized controlled trial (RCT) compared neurocognitive effects of NFB to (1) optimally titrated methylphenidate (MPH) and (2) a semi-active control intervention, physical activity (PA), to control for non-specific effects. Using a multicentre three-way parallel group RCT design, children with ADHD, aged 7-13, were randomly allocated to NFB (n = 39), MPH (n = 36) or PA (n = 37) over a period of 10-12 weeks. NFB comprised theta/beta training at CZ. The PA intervention was matched in frequency and duration to NFB. MPH was titrated using a double-blind placebo controlled procedure to determine the optimal dose. Neurocognitive functioning was assessed using parameters derived from the auditory oddball-, stop-signal- and visual spatial working memory task. Data collection took place between September 2010 and March 2014. Intention-to-treat analyses showed improved attention for MPH compared to NFB and PA, as reflected by decreased response speed during the oddball task [η p2  = 0.21, p < 0.001], as well as improved inhibition, impulsivity and attention, as reflected by faster stop signal reaction times, lower commission and omission error rates during the stop-signal task (range η p2  = 0.09-0.18, p values <0.008). Working memory improved over time, irrespective of received treatment (η p2  = 0.17, p < 0.001). Overall, stimulant medication showed superior effects over NFB to improve neurocognitive functioning. Hence, the findings do not support theta/beta training applied as a stand-alone treatment in children with ADHD.

Response inhibition in Attention deficit disorder and neurofibromatosis type 1 - clinically similar, neurophysiologically different

There are large overlaps in cognitive deficits occurring in attention deficit disorder (ADD) and neurodevelopmental disorders like neurofibromatosis type 1 (NF1). This overlap is mostly based on clinical measures and not on in-depth analyses of neuronal mechanisms. However, the consideration of such neuronal underpinnings is crucial when aiming to integrate measures that can lead to a better understanding of the underlying mechanisms. Inhibitory control deficits, for example, are a hallmark in ADD, but it is unclear how far there are similar deficits in NF1. We thus compared adolescent ADD and NF1 patients to healthy controls in a Go/Nogo task using behavioural and neurophysiological measures. Clinical measures of ADD-symptoms were not different between ADD and NF1. Only patients with ADD showed increased Nogo errors and reductions in components reflecting response inhibition (i.e. Nogo-P3). Early perceptual processes (P1) were changed in ADD and NF1. Clinically, patients with ADD and NF1 thus show strong similarities. This is not the case in regard to underlying cognitive control processes. This shows that in-depth analyses of neurophysiological processes are needed to determine whether the overlap between ADD and NF1 is as strong as assumed and to develop appropriate treatment strategies.

Sweat it out? The effects of physical exercise on cognition and behavior in children and adults with ADHD: a systematic literature review

As attention-deficit/hyperactivity disorder (ADHD) is one of the most frequently diagnosed developmental disorders in childhood, effective yet safe treatment options are highly important. Recent research introduced physical exercise as a potential treatment option, particularly for children with ADHD. The aim of this review was to systematically analyze potential acute and chronic effects of cardio and non-cardio exercise on a broad range of functions in children with ADHD and to explore this in adults as well. Literature on physical exercise in patients with ADHD was systematically reviewed based on categorizations for exercise type (cardio versus non-cardio), effect type (acute versus chronic), and outcome measure (cognitive, behavioral/socio-emotional, and physical/(neuro)physiological). Furthermore, the methodological quality of the reviewed papers was addressed. Cardio exercise seems acutely beneficial regarding various executive functions (e.g., impulsivity), response time and several physical measures. Beneficial chronic effects of cardio exercise were found on various functions as well, including executive functions, attention and behavior. The acute and chronic effects of non-cardio exercise remain more questionable but seem predominantly positive too. Research provides evidence that physical exercise represents a promising alternative or additional treatment option for patients with ADHD. Acute and chronic beneficial effects of especially cardio exercise were reported with regard to several cognitive, behavioral, and socio-emotional functions. Although physical exercise may therefore represent an effective treatment option that could be combined with other treatment approaches of ADHD, more well-controlled studies on this topic, in both children and adults, are needed.

Learning curves of theta/beta neurofeedback in children with ADHD

Neurofeedback is widely applied as non-pharmacological intervention aimed at reducing symptoms of ADHD, even though efficacy has not been unequivocally established. Neuronal changes during the neurofeedback intervention that resemble learning can provide crucial evidence for the feasibility and specificity of this intervention. A total of 38 children (aged between 7 and 13 years) with a DSM-IV-TR diagnosis of ADHD, completed on average 29 sessions of theta (4-8 Hz)/beta (13-20 Hz) neurofeedback training. Dependent variables included training-related measures as well as theta and beta power during baseline and training runs for each session. Learning effects were analyzed both within and between sessions. To further specify findings, individual learning curves were explored and correlated with behavioral changes in ADHD symptoms. Over the course of the training, there was a linear increase in participants' mean training level, highest obtained training level and the number of earned credits (range b = 0.059, -0.750, p < 0.001). Theta remained unchanged over the course of the training, while beta activity increased linearly within training sessions (b = 0.004, 95% CI = [0.0013-0.0067], p = 0.005) and over the course of the intervention (b = 0.0052, 95% CI = [0.0039-0.0065], p < 0.001). In contrast to the group analyses, significant individual learning curves were found for both theta and beta over the course of the intervention in 39 and 53%, respectively. Individual learning curves were not significantly correlated with behavioral changes. This study shows that children with ADHD can gain control over EEG states during neurofeedback, although a lack of behavioral correlates may indicate insufficient transfer to daily functioning, or to confounding reinforcement of electromyographic activity.

CLINICAL TRIALS REGISTRATION

This trial is registered at the US National Institutes of Health (ClinicalTrials.gov, ref. no: NCT01363544); https://clinicaltrials.gov/show/NCT01363544 .

The neuronal mechanisms underlying improvement of impulsivity in ADHD by theta/beta neurofeedback

Neurofeedback is increasingly recognized as an intervention to treat core symptoms of attention deficit hyperactivity disorder (ADHD). Despite the large number of studies having been carried out to evaluate its effectiveness, it is widely elusive what neuronal mechanisms related to the core symptoms of ADHD are modulated by neurofeedback. 19 children with ADHD undergoing 8 weeks of theta/beta neurofeedback and 17 waiting list controls performed a Go/Nogo task in a pre-post design. We used neurophysiological measures combining high-density EEG recording with source localization analyses using sLORETA. Compared to the waiting list ADHD control group, impulsive behaviour measured was reduced after neurofeedback treatment. The effects of neurofeedback were very specific for situations requiring inhibitory control over responses. The neurophysiological data shows that processes of perceptual gating, attentional selection and resource allocation processes were not affected by neurofeedback. Rather, neurofeedback effects seem to be based on the modulation of response inhibition processes in medial frontal cortices. The study shows that specific neuronal mechanisms underlying impulsivity are modulated by theta/beta neurofeedback in ADHD. The applied neurofeedback protocol could be particularly suitable to address inhibitory control. The study validates assumed functional neuroanatomical target regions of an established neurofeedback protocol on a neurophysiological level.