Unmet Needs in Children With Attention Deficit Hyperactivity Disorder-Can Transcranial Direct Current Stimulation Fill the Gap? Promises and Ethical Challenges

Transcranial Direct Current Stimulation (tDCS) in Pediatric Populations—– Voices from Typically Developing Children and Adolescents and their Parents

Background

Transcranial direct current stimulation (tDCS) is a brain stimulation technique currently being researched as an alternative or complimentary treatment for various neurological disorders. There is little knowledge about experiences of the participants of tDCS clinical research, especially from pediatric studies.

Methods

An interview study with typically developing minors (n = 19, mean age 13,66 years) participating in a tDCS study, and their parents (n = 18) was conducted to explore their views and experiences and inform the ethical analysis.

Results

Children (10–13 years old) and adolescents (14–18 years old) reported good experiences with the stimulation. Next to financial incentives, main motives to participate in the study were curiosity and the possibility to help develop treatments for children affected by neurological disorders. They could also see a potential of using tDCS in a non-medical setting, especially regarding the provision of equal opportunity, e.g. in education. Parents also presented a positive attitude towards tDCS and their children participation in the basic research study. Nevertheless, their understanding of tDCS was rather poor. Even though many of them understood the techniques, they often did not see the link between the (current) lack of side effects and an absence of longitudinal studies. Parents were also cautious about using tDCS for non-medical/enhancement purposes.

Conclusions

The study findings show a need for more transparent information about the state of the art of tDCS, its function and what it might be able to offer, especially considering the good acceptability of tDCS.

Effects of transcranial direct current stimulation in children and young people with psychiatric disorders: a systematic review

Transcranial direct current stimulation (tDCS) has demonstrated benefits in adults with various psychiatric disorders, but its clinical utility in children and young people (CYP) remains unclear. This PRISMA systematic review used published and ongoing studies to examine the effects of tDCS on disorder-specific symptoms, mood and neurocognition in CYP with psychiatric disorders. We searched Medline via PubMed, Embase, PsychINFO via OVID, and Clinicaltrials.gov up to December 2022. Eligible studies involved multiple session (i.e., treatment) tDCS in CYP (≤ 25 years old) with psychiatric disorders. Two independent raters assessed the eligibility of studies and extracted data using a custom-built form. Of 33 eligible studies (participant N = 517), the majority (n = 27) reported an improvement in at least one outcome measure of disorder-specific symptoms. Few studies (n = 13) examined tDCS effects on mood and/or neurocognition, but findings were mainly positive. Overall, tDCS was well tolerated with minimal side effects. Of 11 eligible ongoing studies, many are sham-controlled RCTs (n = 9) with better blinding techniques and a larger estimated participant enrolment (M = 79.7; range 15-172) than published studies. Although encouraging, the evidence to date is insufficient to firmly conclude that tDCS can improve clinical symptoms, mood, or cognition in CYP with psychiatric disorders. Ongoing studies appear of improved methodological quality; however, future studies should broaden outcome measures to more comprehensively assess the effects of tDCS and develop dosage guidance (i.e., treatment regimens).

Transcranial direct current stimulation (tDCS) combined with cognitive training in adolescent boys with ADHD: a double-blind, randomised, sham-controlled trial

BACKGROUND

Transcranial direct current stimulation (tDCS) could be a side-effect-free alternative to psychostimulants in attention-deficit/hyperactivity disorder (ADHD). Although there is limited evidence for clinical and cognitive effects, most studies were small, single-session and stimulated left dorsolateral prefrontal cortex (dlPFC). No sham-controlled study has stimulated the right inferior frontal cortex (rIFC), which is the most consistently under-functioning region in ADHD, with multiple anodal-tDCS sessions combined with cognitive training (CT) to enhance effects. Thus, we investigated the clinical and cognitive effects of multi-session anodal-tDCS over rIFC combined with CT in double-blind, randomised, sham-controlled trial (RCT, ISRCTN48265228).

METHODS

Fifty boys with ADHD (10-18 years) received 15 weekday sessions of anodal- or sham-tDCS over rIFC combined with CT (20 min, 1 mA). ANCOVA, adjusting for baseline measures, age and medication status, tested group differences in clinical and ADHD-relevant executive functions at posttreatment and after 6 months.

RESULTS

ADHD-Rating Scale, Conners ADHD Index and adverse effects were significantly lower at post-treatment after sham relative to anodal tDCS. No other effects were significant.

CONCLUSIONS

This rigorous and largest RCT of tDCS in adolescent boys with ADHD found no evidence of improved ADHD symptoms or cognitive performance following multi-session anodal tDCS over rIFC combined with CT. These findings extend limited meta-analytic evidence of cognitive and clinical effects in ADHD after 1-5 tDCS sessions over mainly left dlPFC. Given that tDCS is commercially and clinically available, the findings are important as they suggest that rIFC stimulation may not be indicated as a neurotherapy for cognitive or clinical remediation for ADHD.

Complementary and Alternative Medicine Use by ADHD Patients: A Systematic Review

OBJECTIVE

This study aimed to review the prevalence of complementary and alternative medicine (CAM) use and its different used types, characteristics of the studied cohorts, the reasoning for CAM use, and possible predictive factors for its use amongst ADHD patients.

METHOD

The Web of Science Core Collection, PubMed, and Scopus were searched from inception to 10 February 2022. All of the original papers published in English which report data on CAM use by patients with ADHD were included.

RESULTS

Twelve original researches including 4,447 patients were included. The prevalence of CAM use varied from 7.5% to 67.6%. The most-reported CAM modalities were dietary modifications and natural products. Moreover, higher parental education should be considered as a predictive factor for CAM use.

CONCLUSION

CAM use by ADHD patients seems to be prevalent. Healthcare providers should be trained about the most commonly used CAM therapies and their possible adverse events.

Digitalized transcranial electrical stimulation: A consensus statement

OBJECTIVE

Although relatively costly and non-scalable, non-invasive neuromodulation interventions are treatment alternatives for neuropsychiatric disorders. The recent developments of highly-deployable transcranial electric stimulation (tES) systems, combined with mobile-Health technologies, could be incorporated in digital trials to overcome methodological barriers and increase equity of access. The study aims are to discuss the implementation of tES digital trials by performing a systematic scoping review and strategic process mapping, evaluate methodological aspects of tES digital trial designs, and provide Delphi-based recommendations for implementing digital trials using tES.

METHODS

We convened 61 highly-productive specialists and contacted 8 tES companies to assess 71 issues related to tES digitalization readiness, and processes, barriers, advantages, and opportunities for implementing tES digital trials. Delphi-based recommendations (>60% agreement) were provided.

RESULTS

The main strengths/opportunities of tES were: (i) non-pharmacological nature (92% of agreement), safety of these techniques (80%), affordability (88%), and potential scalability (78%). As for weaknesses/threats, we listed insufficient supervision (76%) and unclear regulatory status (69%). Many issues related to methodological biases did not reach consensus. Device appraisal showed moderate digitalization readiness, with high safety and potential for trial implementation, but low connectivity.

CONCLUSIONS

Panelists recognized the potential of tES for scalability, generalizability, and leverage of digital trials processes; with no consensus about aspects regarding methodological biases.

SIGNIFICANCE

We further propose and discuss a conceptual framework for exploiting shared aspects between mobile-Health tES technologies with digital trials methodology to drive future efforts for digitizing tES trials.

Transcranial direct current stimulation in attention-deficit/hyperactivity disorder: A meta-analysis of clinical efficacy outcomes

BACKGROUND

Evidence for the application of transcranial direct current stimulation (tDCS) in the clinical care of attention-deficit/hyperactivity disorder (ADHD) is limited. Therefore, we aimed to summarize study results using meta-analyses of measures of the cardinal symptoms of ADHD.

METHODS

We conducted a systematic literature search (PubMed/pubpsych/PsychInfo/WOS) until 01/05/2020 for randomized controlled trials (RCTs) evaluating tDCS vs. control condition in patients with ADHD. A random effects meta-analysis of symptom-related outcomes was performed separately for data on the immediate effect and follow-up. Subgroup- and metaregression analyses for patient characteristics and tDCS parameters were included.

RESULTS

Meta-analyzing 13 studies (n=308, age=23.7±13.3), including 20 study arms, tDCS had an immediate effect on overall symptom severity, inattention, and impulsivity, but not on hyperactivity. Results were significant in children and adolescents (8 studies, n=133, age=12.4±3.0). Follow-up data (3 days-4 weeks after stimulation) suggested an ongoing beneficial effect regarding overall symptom severity and a delayed effect on hyperactivity.

DISCUSSION

TDCS seems to be a promising method to treat clinical symptoms in ADHD with long-lasting effects. Still, more research considering the individual neuropsychological and anatomical dispositions of the subjects is needed to optimize tDCS protocols and efficacy. Safety issues of tDCS treatment in children and adolescents are addressed.

Transcranial direct-current stimulation and pediatric attention deficit hyperactivity disorder (ADHD)-Findings from an interview ethics study with children, adolescents, and their parents

INTRODUCTION

Transcranial direct current stimulation (tDCS) is a brain stimulation technique for an alternative or complementary treatment for various neurological disorders, including pediatric ADHD. However, little is known about the experiences of participants undergoing tDCS treatments in clinical trials. Exploration of their views on the matter is an important contribution to the societal debate on ethical issues of tDCS, allowing for a responsible translation into clinical practice and timely identification of potential challenges.

METHODS

in-depth interviews study with children with ADHD undertaking tDCS and their parents (n=32).

RESULTS

Children reported overall good experiences with the stimulation, although they found participation in the clinical study very tiring and time consuming. Their responses to the actual effects of the stimulation were mixed. Parents were very keen for their children to participate in the study as they saw it as a promising and safe alternative to medication. Even though many of them understood the techniques, they often did not see the link between the (current) lack of side effects and an absence of longitudinal studies. Unlike children, interviewed parents were cautious about using tDCS for non-medical/enhancement purposes.

DISCUSSION

There is a need for more transparent information about the state of the art of tDCS, its function and what it actually might be able to offer. It is especially important in order to prevent unrealistic hopes and to make sure that future pediatric patients and their carers are more aware of the potential side-effects and long-term effects of tDCS.

Potential targets for the treatment of ADHD using transcranial electrical current stimulation

Attention deficit hyperactivity disorder (ADHD) is a psychiatric disease with a prevalence of 2%-7.5% among the population. It is characterized by three core symptoms: hyperactivity, impulsivity, and inattention. Although the majority of ADHD patients respond to a combination of psychotherapy and standard pharmacotherapy with Methylphenidate, there is a significant minority of patients that do not respond to these substances. Additionally, the treatment with Methylphenidate can cause a variety of side effects like insomnia, headache, decreased appetite, and xerostomia. It would be favorable to have an alternative treatment-option that could circumnavigate the shortcomings of traditional pharmacological treatments. Recent results show that transcranial electrical stimulation (tES) might offer a promising approach. Since research has shown that ADHD is associated with various alterations in brain activity, brain stimulation methods targeting different facets of neuronal functions are currently under investigation. In this article, we briefly review different tES techniques like transcranial random noise stimulation (tRNS), transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS) and explain the modes of action of these brain stimulations. We will specifically focus on transcranial alternating current stimulation (tACS) as a potential method of treating ADHD.

First Epileptic Seizure and Initial Diagnosis of Juvenile Myoclonus Epilepsy (JME) in a Transcranial Direct Current Stimulation (tDCS) Study– Ethical Analysis of a Clinical case

We discuss an epileptic incident in an undiagnosed 13-year old girl participating in a clinical study investigating the effects of transcranial direct current stimulation (tDCS) in healthy children and adolescents. This incident poses important research ethics questions with regard to study design, especially pertaining to screening and gaining informed consent. Potential benefits and problems of the incident also need to be considered. The ethical analysis of the case presented in this paper has been informed by an in-depth interview conducted after the incident with the child and the accompanying parent. We discuss the ethical implications of the epileptic incident, the need for improving screening procedures for studies with minors and for providing more effective communication. This case also underscores the problem of undetected teenage epilepsy in neuropsychological clinical studies and the necessity of raising more awareness of this issue. Since research in tDCS is an active and expanding field, we conclude with providing some recommendation that could ensure that future research on tDCS, or other therapies and neuro-interventions where there is a risk of triggering an epileptic seizure, take into account the specifics of teenage epilepsy and the need for more thorough provision of information during the process of gaining informed consent.

Transcranial Direct Current Stimulation in ADHD: A Systematic Review of Efficacy, Safety, and Protocol-induced Electrical Field Modeling Results

Transcranial direct current stimulation (tDCS) is a promising method for altering cortical excitability with clinical implications. It has been increasingly used in neurodevelopmental disorders, especially attention-deficit hyperactivity disorder (ADHD), but its efficacy (based on effect size calculations), safety, and stimulation parameters have not been systematically examined. In this systematic review, we aimed to (1) explore the effectiveness of tDCS on the clinical symptoms and neuropsychological deficits of ADHD patients, (2) evaluate the safety of tDCS application, especially in children with ADHD, (3) model the electrical field intensity in the target regions based on the commonly-applied and effective versus less-effective protocols, and (4) discuss and propose advanced tDCS parameters. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses approach, a literature search identified 14 empirical experiments investigating tDCS effects in ADHD. Partial improving effects of tDCS on cognitive deficits (response inhibition, working memory, attention, and cognitive flexibility) or clinical symptoms (e.g., impulsivity and inattention) are reported in 10 studies. No serious adverse effects are reported in 747 sessions of tDCS. The left and right dorsolateral prefrontal cortex are the regions most often targeted, and anodal tDCS the protocol most often applied. An intensity of 2 mA induced stronger electrical fields than 1 mA in adults with ADHD and was associated with significant behavioral changes. In ADHD children, however, the electrical field induced by 1 mA, which is likely larger than the electrical field induced by 1 mA in adults due to the smaller head size of children, was sufficient to result in significant behavioral change. Overall, tDCS seems to be a promising method for improving ADHD deficits. However, the clinical utility of tDCS in ADHD cannot yet be concluded and requires further systematic investigation in larger sample sizes. Cortical regions involved in ADHD pathophysiology, stimulation parameters (e.g. intensity, duration, polarity, and electrode size), and types of symptom/deficit are potential determinants of tDCS efficacy in ADHD. Developmental aspects of tDCS in childhood ADHD should be considered as well.