A functional magnetic resonance imaging investigation of prefrontal cortex deep transcranial magnetic stimulation efficacy in adults with attention deficit/hyperactive disorder: A double blind, randomized clinical trial

Noninvasive Brain Stimulation for Neurodevelopmental Disorders: A Systematic Review

Neurodevelopmental disorders (NDDs) affect brain development, leading to diverse cognitive, social, behavioral, and affective impairments. Noninvasive brain stimulation (NIBS) techniques, such as transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), and transcranial photobiomodulation (tPBM), have been investigated as potential treatments for NDDs. The authors of this systematic review evaluated the literature on NIBS in NDDs, including double-blind, sham-controlled, randomized controlled trials. Following PRISMA guidelines and a registered protocol, the authors conducted a comprehensive search in PubMed, Embase, Cochrane Central Register of Controlled Trials, PsycInfo, and Scopus, identifying 23 studies. TMS showed promise for addressing hyperactivity, inattention, and working memory deficits in attention-deficit hyperactivity disorder (ADHD), with outcomes influenced by coil type (H5 vs. H6) and stimulation site (right vs. left dorsolateral prefrontal cortex). tDCS showed potential for improving inattention and executive function in ADHD, with limited effects observed on reducing symptom severity in autism spectrum disorder (ASD) and dyslexia. tPBM offered specific therapeutic benefits in reducing irritability in ASD. Although NIBS generally showed mild, transient adverse effects, isolated seizure events, such as one during TMS in ADHD, highlight the importance of rigorous safety protocols, especially in NDDs with elevated epilepsy risk. This review identified potential benefits of certain NIBS protocols in NDDs; however, high variability in methodologies, sample size limitations, and bias concerns underscore the need for further research to clarify the therapeutic efficacy and safety of NIBS among patients with NDDs.

Effects of repetitive transcranial magnetic stimulation combined with cognitive training for improving response inhibition: A proof-of-concept, single-blind randomised controlled study

BACKGROUND

Impaired response inhibition is a common characteristic of various psychiatric disorders. Cognitive training (CT) can improve cognitive function, but the benefits may be limited. Repetitive transcranial magnetic stimulation (rTMS) is a promising tool to enhance neuroplasticity, and thereby augment the effects of CT. We aimed to investigate the augmentation effects of rTMS on CT for response inhibition in healthy participants.

METHODS

Sixty healthy participants were randomly assigned to two experimental groups: one with prolonged intermittent theta burst stimulation (iTBS) + CT and the other with sham iTBS + CT over four experimental sessions. Prolonged iTBS (1800 pulses) was used to stimulate the right inferior frontal cortex (rIFC) and pre-supplementary motor area (pre-SMA) in a counterbalanced order. Participants completed a Stop Signal training task following iTBS over one brain region, followed by the Go/No-Go training task after iTBS over the other brain region. The Stroop task with concomitant electroencephalography was conducted before and immediately after the intervention.

RESULTS

There were no significant differences between groups in behavioural outcomes on the Stop Signal task, Go/No-Go task, Stroop task or Behavior Rating Inventory of Executive Functioning for Adults. Similarly, analysis of event-related potentials (ERPs) from the Stroop task (N200 and N400) and exploratory cluster-based permutation analysis did not reveal any significant differences between groups. Subgroup analyses revealed that individuals with higher baseline impulsivity exhibited better learning effects in the active group.

CONCLUSIONS

This first proof of concept study did not find evidence that four sessions of active rTMS + CT could induce cognitive or neurophysiological effects on response inhibition in healthy participants. However, subgroup analyses suggests that rTMS combined with CT could be useful in improving response inhibition in individuals with high impulsivity. It is recommended that future proof of concept studies examine its potential in this clinical population.

Neural correlates of executive function and attention in children with ADHD: An ALE meta-analysis of task-based functional connectivity studies

We conducted a comprehensive meta-analysis of task-based functional MRI studies on executive function and attention in children with attention deficit hyperactivity disorder (ADHD). We searched for studies published before March 20, 2023, in PubMed, Cochrane Library, Web of Science, EBSCO, Embase, and Scopus. The ALE (activation likelihood estimation) method was used to detect differences in brain activation between children with ADHD and comparison children. Fifty-seven (57) studies were included, with 2,231 participants (1,062 children with ADHD). Based on the omnibus meta-analysis findings, significant hypoactivation in children with ADHD relative to comparisons was observed in the frontoparietal network, putamen, insula, cingulate gyrus, and middle temporal gyrus, while ADHD-related hyperactivation was present in the occipital lobe, declive, middle frontal gyrus, and parahippocampal gyrus. This study highlights the critical involvement of the parietal lobe. Results also revealed abnormalities in the frontal lobe and brainstem, suggesting unintegrated primitive reflexes. For stimulant-naive children with ADHD, significant hypoactivation in the right cerebrum was observed compared to controls. Finally, dysfunctional connectivity between the frontoparietal network and the striatum may lead to inefficient working memory, while the cerebellum plays a crucial role in inhibitory control and attention tasks. These findings provide important insights into the pathology of ADHD.

Transcranial magnetic stimulation in attention-deficit/hyperactivity disorder: a systematic review and meta-analysis of cortical excitability and therapeutic efficacy

Background/Objectives

Attention-deficit/hyperactivity disorder (ADHD) currently lacks a universally accepted biomarker or diagnostic test, underscoring the need for objective and effective assessment methods. Transcranial magnetic stimulation (TMS) has emerged as a promising tool for both assessing cortical excitability and providing therapeutic interventions. This study conducted two independent meta-analyses to evaluate: 1) the potential of TMS in assessing cortical excitability, and 2) its therapeutic efficacy in managing ADHD symptoms.

Methods

A systematic search was conducted in EMBASE, MEDLINE, PsycINFO, ClinicalTrials, and PubMed following PRISMA guidelines. The "cortical excitability" meta-analysis included studies comparing TMS-EMG or TMS-EEG neurophysiological measures between ADHD patients and healthy controls. The "therapeutic" meta-analysis focused on randomized controlled trials (RCTs) evaluating repetitive TMS (rTMS) effects on ADHD symptoms. Standardized mean differences (SMDs) were calculated for pooled effect sizes.

Results

In the "cortical excitability" meta-analysis, 17 studies were included, demonstrating significantly reduced short-interval intracortical inhibition (SICI) in ADHD compared to healthy controls (pooled SMD = 0.65, 95% CI: 0.41-0.88, P < 0.00001). No significant differences were observed for motor evoked potentials (MEP), motor thresholds (aMT/rMT), cortical silent period (cSP), ipsilateral silent period (iSP), or intracortical facilitation (ICF). The "therapeutic" meta-analysis, encompassing 8 samples from 7 studies, demonstrated that rTMS significantly improved ADHD symptoms compared to control conditions (pooled SMD = 0.45, 95% CI: 0.19-0.70, P = 0.0006).

Conclusions

This study highlights the potential of TMS as both a diagnostic and therapeutic tool in ADHD. Reduced SICI appears to be a key neurophysiological marker of ADHD, reflecting cortical GABAergic dysfunction. Additionally, rTMS shows promise in alleviating ADHD symptoms, though further studies are needed to confirm long-term therapeutic benefits and optimize stimulation protocols.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42024507867.

Efficacy and Safety of Transcranial Magnetic Stimulation for Attention-Deficit Hyperactivity Disorder: A Systematic Review and Meta-Analysis

BACKGROUND

Transcranial magnetic stimulation (TMS) is a promising neuromodulation technique that has been widely used in neuropsychiatric disorders, but there was no evidence on its effect on the improvement attention-deficit hyperactivity disorder (ADHD).

OBJECTIVE

This systematic review and meta-analysis aimed to investigate the efficacy and safety of TMS in reducing ADHD symptoms.

METHOD

We systematically searched four databases (PubMed, Embase, Web of Science, and Cochrane Library databases) for randomized controlled/crossover trials on the efficacy and safety of TMS on ADHD symptom improvement compared to sham rTMS or non-TMS interventions, published until September 18, 2024. Extracted data from the included studies involved patient characteristics, intervention protocols, and main outcomes. The effect size of the TMS treatment was evaluated using the standardized mean difference (SMD) with a 95% confidence interval (CI), calculated with either a random effects model or fixed effects model depending on the level of heterogeneity.

RESULT

Eight studies (325 ADHD patients in total) were included in this systematic review and meta-analysis. According to the core symptoms, TMS significantly improved inattention (SMD = -0.94, 95% CI = -1.33 to -0.56, p < 0.001) and hyperactivity/impulsivity (SMD = -0.98, 95% CI = -1.27 to -0.69, p < 0.001) compared to non-TMS interventions after 3-6 weeks of intervention. During the 1-month follow-up, the TMS group still demonstrated a significant improvement in inattention symptoms compared to the non-TMS group (SMD = -0.67, 95% CI = -1.06 to 0.28, p < 0.001). The total symptoms in the TMS group only showed improvement in the 1-month follow-up compared to the non-TMS group. (SMD = -0.48, 95% CI = -0.82 to -0.14, p = 0.005). Only minor adverse events were reported in the included studies, comprising headache and scalp discomfort.

CONCLUSION

TMS significantly improved the inattention, hyperactivity/impulsivity, and total symptom scores in ADHD patients with minor adverse events. Future research should focus on the association between different brain regions and symptoms in ADHD patients, which is crucial for stimulation navigation in TMS interventions. The trial is registered in PROSPERO (PROSPERO registry number: CRD42023473853).

Noninvasive Brain Stimulation for Improving Cognitive Deficits and Clinical Symptoms in Attention-Deficit/Hyperactivity Disorder: A Systematic Review and Meta-Analysis

Objective: Noninvasive brain stimulation (NIBS) is a promising complementary treatment for attention-deficit/hyperactivity disorder (ADHD). However, its efficacy varies due to diverse participant profiles and methodologies. This meta-analysis, registered with PROSPERO (CRD42023457269), seeks to assess NIBS efficacy in improving cognitive deficits and clinical symptoms in individuals with ADHD. Methods: We systematically searched five databases (October 2024) for randomized controlled trials focusing on cognitive functions and clinical symptoms in individuals meeting the DSM/ICD criteria for ADHD. A meta-analytical synthesis was conducted using RevMan 5.4.1. Results: Meta-analyses found significant improvement in inhibitory control, working memory, and inattention in active transcranial direct current stimulation (tDCS) groups compared with sham groups. Conversely, repetitive transcranial magnetic stimulation (rTMS) did not demonstrate significant therapeutic benefits for ADHD symptoms. Additionally, four transcranial random noise stimulation (tRNS) and three transcranial alternating current stimulation (tACS) studies demonstrated promising improvements in executive functions and the alleviation of ADHD symptoms. Conclusions: The findings from this meta-analysis highlight NIBS as a promising adjunctive therapy for managing ADHD, advancing both theoretical knowledge and practical treatment options in this field.

Change in striatal functional connectivity networks across 2 years due to stimulant exposure in childhood ADHD: results from the ABCD sample

Widely prescribed for Attention-Deficit/Hyperactivity Disorder (ADHD), stimulants (e.g., methylphenidate) have been studied for their chronic effects on the brain in prospective designs controlling dosage and adherence. While controlled approaches are essential, they do not approximate real-world stimulant exposure contexts where medication interruptions, dosage non-compliance, and polypharmacy are common. Brain changes in real-world conditions are largely unexplored. To fill this gap, we capitalized on the observational design of the Adolescent Brain Cognitive Development (ABCD) study to examine effects of stimulants on large-scale bilateral cortical networks' resting-state functional connectivity (rs-FC) with 6 striatal regions (left and right caudate, putamen, and nucleus accumbens) across two years in children with ADHD. Bayesian hierarchical regressions revealed associations between stimulant exposure and change in rs-FC of multiple striatal-cortical networks, affiliated with executive and visuo-motor control, which were not driven by general psychotropic medication. Of these connections, three were selective to stimulants versus stimulant naive: reduced rs-FC between caudate and frontoparietal network, and between putamen and frontoparietal and visual networks. Comparison with typically developing children in the ABCD sample revealed stronger rs-FC reduction in stimulant-exposed children for putamen and frontoparietal and visual networks, suggesting a normalizing effect of stimulants. 14% of stimulant-exposed children demonstrated reliable reduction in ADHD symptoms, and were distinguished by stronger rs-FC reduction between right putamen and visual network. Thus, stimulant exposure for a two-year period under real-world conditions modulated striatal-cortical functional networks broadly, had a normalizing effect on a subset of networks, and was associated with potential therapeutic effects involving visual attentional control.

Transcranial photobiomodulation for neurodevelopmental disorders: a narrative review

BACKGROUND

Neurodevelopmental disorders (NDDs) such as autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and Down syndrome (DS) significantly impact social, communicative, and behavioral functioning. Transcranial photobiomodulation (t-PBM) with near-infrared light is a promising non-invasive neurostimulation technique for neuropsychiatric disorders, including NDDs. This narrative review aimed to examine the preclinical and clinical evidence of photobiomodulation (PBM) in treating NDDs.

METHODS

A comprehensive search across six databases was conducted, using a combination of MeSH terms and title/abstract keywords: "photobiomodulation", "PBM", "neurodevelopmental disorders", "NDD", and others. Studies applying PBM to diagnosed NDD cases or animal models replicating NDDs were included. Protocols, reviews, studies published in languages other than English, and studies not evaluating clinical or cognitive outcomes were excluded.

RESULTS

Nine studies were identified, including one preclinical and eight clinical studies (five on ASD, two on ADHD, and one on DS). The reviewed studies encompassed various t-PBM parameters (wavelengths: 635-905 nm) and targeted primarily frontal cortex areas. t-PBM showed efficacy in improving disruptive behavior, social communication, cognitive rigidity, sleep quality, and attention in ASD; in enhancing attention in ADHD; and in improving motor skills and verbal fluency in DS. Minimal adverse effects were reported. Proposed mechanisms involve enhanced mitochondrial function, modulated oxidative stress, and reduced neuroinflammation.

CONCLUSIONS

t-PBM emerges as a promising intervention for NDDs, with potential therapeutic effects across ASD, ADHD, and DS. These findings underscore the need for further research, including larger-scale, randomized sham-controlled clinical trials with comprehensive biomarker analyses, to optimize treatment parameters and understand the underlying mechanisms associated with the effects of t-PBM.

Clinical efficacy of deep transcranial magnetic stimulation (dTMS) in psychiatric and cognitive disorders: A systematic review

Deep transcranial magnetic stimulation (dTMS) has gained attention as an enhanced form of traditional TMS, targeting broader and deeper regions of the brain. However, a fulsome synthesis of dTMS efficacy across psychiatric and cognitive disorders using sham-controlled trials is lacking. We systematically reviewed 28 clinical trials comparing active dTMS to a sham/controlled condition to characterize dTMS efficacy across diverse psychiatric and cognitive disorders. A comprehensive search of APA PsycINFO, Cochrane, Embase, Medline, and PubMed databases was conducted. Predominant evidence supports dTMS efficacy in patients with obsessive-compulsive disorder (OCD; n = 2), substance use disorders (SUDs; n = 8), and in those experiencing depressive episodes with major depressive disorder (MDD) or bipolar disorder (BD; n = 6). However, the clinical efficacy of dTMS in psychiatric disorders characterized by hyperactivity or hyperarousal (i.e., attention-deficit/hyperactivity disorder, posttraumatic stress disorder, and schizophrenia) was heterogeneous. Common side effects included headaches and pain/discomfort, with rare but serious adverse events such as seizures and suicidal ideation/attempts. Risk of bias ratings indicated a collectively low risk according to the Grading of Recommendations, Assessment, Development, and Evaluations checklist (Meader et al., 2014). Literature suggests promise for dTMS as a beneficial alternative or add-on treatment for patients who do not respond well to traditional treatment, particularly for depressive episodes, OCD, and SUDs. Mixed evidence and limited clinical trials for other psychiatric and cognitive disorders suggest more extensive research is warranted. Future research should examine the durability of dTMS interventions and identify moderators of clinical efficacy.

Change in Striatal Functional Connectivity Networks Across Two Years Due to Stimulant Exposure in Childhood ADHD: Results from the ABCD Sample

Widely prescribed for Attention-Deficit/Hyperactivity Disorder (ADHD), stimulants (e.g., methylphenidate) have been studied for their chronic effects on the brain in prospective designs controlling dosage and adherence. While controlled approaches are essential, they do not approximate real-world stimulant exposure contexts where medication interruptions, dosage non-compliance, and polypharmacy are common. Brain changes in real-world conditions are largely unexplored. To fill this gap, we capitalized on the observational design of the Adolescent Brain Cognitive Development (ABCD) study to examine effects of stimulants on large-scale bilateral cortical networks' resting-state functional connectivity (rs-FC) with 6 striatal regions (left and right caudate, putamen, and nucleus accumbens) across two years in children with ADHD. Bayesian hierarchical regressions revealed associations between stimulant exposure and change in rs-FC of multiple striatal-cortical networks, affiliated with executive and visuo-motor control, which were not driven by general psychotropic medication. Of these connections, three were selective to stimulants versus stimulant naive: reduced rs-FC between caudate and frontoparietal network, and between putamen and frontoparietal and visual networks. Comparison with typically developing children in the ABCD sample revealed stronger rs-FC reduction in stimulant-exposed children for putamen and frontoparietal and visual networks, suggesting a normalizing effect of stimulants. 14% of stimulant-exposed children demonstrated reliable reduction in ADHD symptoms, and were distinguished by stronger rs-FC reduction between right putamen and visual network. Thus, stimulant exposure for a two-year period under real-world conditions modulated striatal-cortical functional networks broadly, had a normalizing effect on a subset of networks, and was associated with potential therapeutic effects involving visual attentional control.

A meta-analysis of randomized sham-controlled trials of repetitive transcranial magnetic stimulation for attention deficit/hyperactivity disorder

OBJECTIVE

To investigate the efficacy of repetitive transcranial magnetic stimulation (rTMS) for attention deficit/hyperactivity disorder (ADHD).

METHODS

Randomized sham-controlled trials were identified in major databases from January 1990 to January 2023. The primary outcome was overall improvement in ADHD symptoms. Subgroup analysis focused on the efficacy of rTMS in different brain regions. Secondary outcomes were the association of rTMS with improvement in different ADHD symptoms. Outcomes were expressed as effect size based on standardized mean difference (SMD)(continuous data), and ORs with 95%CI (categorical data).

RESULTS

A meta-analysis of six randomized sham-controlled trials involving 169 participants demonstrated no difference in overall ADHD symptoms between those treated with rTMS and sham controls (SMD = -0.24, p = 0.17). Subgroup analysis revealed that rTMS was more efficacious than sham treatment when targeting the right prefrontal cortex (SMD = -0.49, p = 0.03) but not the left prefrontal cortex (SMD = 0.01, p = 0.67). rTMS treatment was correlated with greater improvement in inattention (SMD = -0.76, p = 0.0002), but not hyperactivity (p = 0.86), impulsivity (p = 0.41), or depression symptoms (p = 0.95). The apparently higher risk of dropout in the rTMS group than the sham control group was not statistically significant (OR = 1.65, p = 0.26).

CONCLUSION

This review found that rTMS only had therapeutic efficacy for ADHD symptoms (particularly inattention) when targeting the right prefrontal cortex. Further large-scale randomized sham-controlled trials are required to verify our findings.

Safety and Efficacy of Deep Transcranial Magnetic Stimulation for Management of Emotional Dysregulation in Children and Adolescents with Externalizing Behavior Disorders: Protocol of a Transdiagnostic Sham Controlled fMRI Study

Background

High-frequency deep transcranial magnetic stimulation (dTMS) on the anterior cingulate cortex (ACC) and medial prefrontal cortex (mPFC) has been known to be effective in modulating emotional experience but not studied in children and adolescents with externalizing behavior disorders (EBDs). We present a novel protocol for a study that aims to assess the safety and efficacy of adjuvant dTMS in managing emotional dysregulation in EBDs in children and adolescents.

Methods

The trial is prospectively registered in the Clinical Trial Registry of India (CTRI) at www.ctri.nic.in with registration number: CTRI/2023/03/050701. In total, 40 subjects with age less than 18 years with EBDs would be randomized into two groups (active and sham dTMS); receiving 15 sessions of high-frequency dTMS, each, over 3 weeks. The subjects and rater would remain blind to treatment allocation. Assessments would be done at baseline and immediately after completion of the treatment using the Child Behavior Checklist (CBCL), Difficulty in Emotional Regulation Scale (DERS), Modified Overt Aggression Scale (MOAS), Affective Reactivity Index (ARI), Barratt's Impulsivity Scale (BIS), Drug Abuse Screening Test (DAST), Children Global Assessment Scale (CGAS), and Clinical Global Impression (CGI). A checklist for side effects will be administered following each session in both groups.

Result

Data shall be analyzed utilizing the statistical software Statistical Package for Social Sciences for outcome variables as defined for the purpose of the study. Safety of dTMS in young subjects as assessed by TMSens_Q and reduction in scores of DERS would be primary outcome variables. Functional Magnetic Resonance Imaging (fMRI) task-based assessment of the difference in activation of mPFC and ACC at baseline and after application of dTMS and reduction in scores of BIS, ARI, MOAS, CGI, and CGAS would be measured as secondary outcome variables.

Conclusion

The study's results are going to provide insight into potential role of dTMS in addressing emotional dysregulation in EBDs in children and adolescents adding one more tool to the armamentarium.

Abnormal Structure and Function of Parietal Lobe in Individuals With Attention Deficit Hyperactivity Disorder (ADHD): A Systematic Review Study

Introduction

Abnormal brain structure and function have been reported in individuals with attention deficit hyperactivity disorder (ADHD). This study investigated the parietal lobe structure and function alteration in individuals with ADHD.

Methods

In this systematic review, we searched English papers in accordance with the PRISMA (the preferred reporting items for systematic reviews and meta-analyses) approach. Studies were published between January 2010 and May 2021. Our search was conducted in two parts. Our first search was in July 2020, and our final search was in June 2021. A literature search identified 20 empirical experiments.

Results

Functional magnetic resonance imaging (MRI) studies generally reported low activity and poor connectivity; structural MRI studies reported less gray matter in this lobe, and an echo study reported atrophy. In addition, electroencephalographic studies reported less connectivity of the parietal lobes in ADHD. Furthermore, the transcranial direct current stimulation intervention has shown that activation of this lobe improves attention and executive functions in children with ADHD. Finally, a deep transcranial magnetic stimulation study has demonstrated that activation of this lobe improves working memory.

Conclusion

Functional and structural alteration of the parietal cortex has been reported in ADHD, which has a causal relationship with cognitive impairments. In sum, all included studies reported abnormal structure, function, or connectivity of the parietal lobe or improvement of cognitive functions with parietal lobe stimulation.

Efficacy of Repetitive Transcranial Magnetic Stimulation (rTMS) Combined with Psychological Interventions: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

(1) Background: Psychological interventions are effective in alleviating neuropsychiatric symptoms, though results can vary between patients. Repetitive transcranial magnetic stimulation (rTMS) has been proven to improve clinical symptoms and cognition. It remains unclear whether rTMS can augment the efficacy of psychological interventions. (2) Methods: We examined the effects of rTMS combined with psychological interventions on clinical, functional, and cognitive outcomes from randomized controlled trials conducted in healthy and clinical populations. We searched PubMed, EMBASE, Cochrane Library, and PsycINFO databases up to April 2023. (3) Results: Twenty-seven studies were ultimately included. Compared to sham rTMS combined with psychological interventions, active rTMS combined with psychological interventions significantly improved overall clinical symptoms (k = 16, SMD  =  0.31, CIs 0.08 to 0.54, p  <  0.01). We found that 10 or more sessions of rTMS combined with cognitive behavioural therapy significantly improved clinical outcomes overall (k = 3, SMD  =  0.21, CIs  0.05 to 0.36, Z = 2.49, p  <  0.01). RTMS combined with cognitive training (CT) significantly improved cognition overall compared to sham rTMS combined with CT (k = 13, SMD  =  0.28, CIs 0.15 to 0.42, p  <  0.01), with a significant effect on global cognition (k = 11, SMD  =  0.45, CIs 0.21 to 0.68, p  < 0.01), but not on the other cognitive domains. (4) Conclusion: The current results provide preliminary support for the augmentation effects of active rTMS on clinical and cognitive outcomes across diverse populations. Future clinical trials are required to confirm these augmentation effects for specific psychological interventions in specific clinical populations.

A meta-analysis on the therapeutic efficacy of repetitive transcranial magnetic stimulation for cognitive functions in attention-deficit/hyperactivity disorders

BACKGROUND

Therapeutic efficacies of repetitive transcranial magnetic stimulation (rTMS) for improving cognitive functions in patients with deficit/hyperactivity disorder (ADHD) remained unclear. The aim of this meta-analysis was to investigate the therapeutic efficacy of rTMS focusing on different cognitive performances.

METHODS

Major databases were searched electronically from inception to February 2023 by using keywords mainly "rTMS" and "ADHD" to identify randomized controlled trials (RCTs) that investigated the therapeutic efficacy of rTMS for improving cognitive functions assessed by standardized tasks in patients with ADHD. The overall effect size (ES) was calculated as standardized mean difference (SMD) based on a random effects model.

RESULTS

Meta-analysis of five RCTs with 189 participants (mean age of 32.78 and 8.53 years in adult and child/adolescent populations, respectively) demonstrated that rTMS was more effective for improving sustained attention in patients with ADHD compared with the control groups (SMD = 0.54, p = 0.001).Our secondary analysis also showed that rTMS was more effective for improving processing speed than the control groups (SMD = 0.59, p = 0.002) but not for enhancing memory or executive function.

CONCLUSIONS

Our results supported the therapeutic efficacy of rTMS for improving sustained attention and processing speed. However, the limitation of available data warrants further studies to verify these findings.

The therapeutic role of repetitive transcranial magnetic stimulation in children with attention deficit/hyperactivity disorder in Egypt a randomized sham controlled clinical trial

Background

Repetitive transcranial magnetic stimulation showed some evidence for improving symptoms of ADHD along with its relative safety, thus could serve as a treatment strategy or an alternative to stimulant medication. Accordingly, 60 children with ADHD were assessed, and 30 participants were allocated to the rTMS group and received 15 sessions of rTMS over the right dorsolateral prefrontal cortex combined with Atomoxetine 1.2 mg/kg/day. The other 30 participants were allocated to the Sham group and received 15 sessions of sham rTMS and atomoxetine 1.2 mg/kg/day. Clinical assessments of ADHD symptoms and severity were done and compared at 3 points, before treatment, after receiving 15 sessions of rTMS and follow-up 1 month after the last rTMS session, using Conner’s Parent Rating Scale-Revised-Long form, Children’s Global Assessment Scale, and Clinical Global Impression.

Results

The two groups show significant improvement in the T scores of all CPRS subscales, CGI and CGAS. However, the rTMS group had a significantly more improvement than the sham group in inattention, total ADHD severity, CGI, and CGAS after rTMS and continued to the follow-up after 1 month.

Conclusions

rTMS is an efficacious intervention for treating ADHD, and combined rTMS and atomoxetine is superior to atomoxetine alone in improving attention deficit symptoms and total ADHD symptoms severity.

Trial registration

PACTR, PACTR202110558451583. Registered 25 June 2021. Approved 29 October 2021- Retrospectively registered, https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=15968.

Functional changes in prefrontal cortex following frequency-specific training

Numerous studies indicate a significant role of pre-frontal circuits (PFC) connectivity involving attentional and reward neural networks within attention deficit hyperactivity disorder (ADHD) pathophysiology. To date, the neural mechanisms underlying the utility of non-invasive frequency-specific training systems in ADHD remediation remain underexplored. To address this issue, we created a portable electroencephalography (EEG)-based wireless system consisting of a novel headset, electrodes, and neuro program, named frequency specific cognitive training (FSCT). In a double-blind, randomized, controlled study we investigated the training effects in N = 46 school-age children ages 6-18 years with ADHD. 23 children in experimental group who underwent FCST training showed an increase in scholastic performance and meliorated their performance on neuropsychological tests associated with executive functions and memory. Their results were compared to 23 age-matched participants who underwent training with placebo (pFSCT). Electroencephalogram (EEG) data collected from participants trained with FSCT showed a significant increase in 14-18 Hz EEG frequencies in PFC brain regions, activities that indicated brain activation in frontal brain regions, the caudate nucleus, and putamen. These results demonstrate that FSCT targets specific prefrontal and striatal areas in children with ADHD, suggesting a beneficial modality for non-invasive modulation of brain areas implicated in attention and executive functions.