Positive effects of transcranial direct current stimulation in adult patients with attention-deficit/hyperactivity disorder A pilot randomized controlled study

Cachoeira, Carolina Tosetto; Leffa, Douglas Teixeira; Mittelstadt, Suzana; Mendes, Lorenna Sena Teixeira; Brunoni, André R.; Pinto, Jairo Vinícius; Blazius, Vítor; Machado, Vitoria; Bau, Claiton H.D.; Rohde, Luís Augusto; Grevet, Eugênio H.; Schestatsky, Pedro

doi:10.1016/j.psychres.2016.11.009

Cited by 63 publications

(71 citation statements)

References 39 publications

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“…Dopaminergic agents ameliorate the inattention 28 . It is noteworthy that, similarly to the mode of stimulation used in our study, anodal tDCS to the left DLPFC improved ADHD symptoms in adolescents and adults 29,30 . Considering these facts, our results confirm that tDCS induces dopamine release in the striatum and confirm that the enhanced dopaminergic transmission in the striatum eventually enhances attention.…”

Section: Discussionsupporting

confidence: 73%

Endogenous dopamine release under transcranial direct-current stimulation governs enhanced attention: a study with positron emission tomography

et al. 2019

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Transcranial direct-current stimulation (tDCS) to the dorsolateral prefrontal cortex (DLPFC) has been established as an effective and noninvasive method to modulate cognitive function. Nevertheless, the mechanisms causing those cognitive changes under the tDCS remain largely unknown. We strove to elucidate the cognito-biological relation under the tDCS condition by examining whether the dopamine system activated by tDCS is involved in cognitive changes in human participants, or not. To evaluate the dopamine system, we used [11C]-raclopride positron emission tomography (PET) scanning: 20 healthy men underwent two [11C]-raclopride PET scans and subsequent neuropsychological tests. One scan was conducted after tDCS to the DLPFC. One was conducted after sham stimulation (control). Results of [11C]-raclopride PET measurements demonstrate that tDCS to the DLPFC caused dopamine release in the right ventral striatum. Neuropsychological tests for attentiveness revealed that tDCS to the DLPFC-enhanced participants’ accuracy. Moreover, this effect was correlated significantly with dopamine release. This finding provides clinico-biological evidence, demonstrating that enhancement of dopamine signaling by tDCS in the ventral striatum is associated with attention enhancement.

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Section: Discussionsupporting

confidence: 73%

Endogenous dopamine release under transcranial direct-current stimulation governs enhanced attention: a study with positron emission tomography

et al. 2019

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“…Future tDCS studies should systematically investigate the following lines of research, to reveal the real clinical potential of tDCS for ADHD treatment. First, preliminary data suggest beneficial effects of tDCS on other cognitive dysfunctions in ADHD including cognitive flexibility, problem-solving, selective attention, and hyperactivity symptoms involved in ADHS [6, 70, 109]. Second, based on the findings of this meta-analysis, future tDCS studies on ADHD populations, with a statistically-proven blinding procedure (especially double-blinded trials), are recommended to target the stimulation area based on the symptoms subtypes.…”

Section: Discussionmentioning

confidence: 99%

Transcranial direct current stimulation in attention-deficit hyperactivity disorder: A meta-analysis of neuropsychological deficits

et al. 2019

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Transcranial direct current stimulation (tDCS) is a promising method for altering cortical excitability with clinical implications in neuropsychiatric diseases. Its application in neurodevelopmental disorders especially attention-deficit hyperactivity disorder (ADHD), is in early stage and promising but its effectiveness has not been systematically examined yet. We conducted a meta-analysis on the effectiveness of tDCS on the most studied neuropsychological symptoms of ADHD, which is the first reported meta-analysis of tDCS studies on ADHD. Data from 10 randomized controlled studies (including 11 separate experiments) targeting inhibitory control, and/or working memory (WM) in ADHD were included. Results show that overall tDCS significantly improved inhibitory control. Sub-analyses further show that dorsolateral prefrontal cortex (dlPFC) (but not right inferior frontal gyrus) tDCS and anodal (but not cathodal) tDCS significantly improved inhibitory control with a small effect size. Anodal dlPFC-tDCS had the largest significant effect on inhibitory control with a small-to-medium effect size. Additionally, a significant improving effect of tDCS on inhibitory control accuracy (but not response time) and WM speed (but not accuracy) were found. Overall, this meta-analysis supports a beneficial effect of tDCS on inhibitory control and WM in ADHD with a small-to-medium effect size. TDCS seems to be a promising method for improving neuropsychological and cognitive deficits in ADHD. However, there might be a dissociation between neuropsychological deficits and clinical symptoms of ADHD and therefore, the significance of this meta-analysis for clinical purposes is limited. Future studies should systematically evaluate the role of inter-individual factors (i.e., ADHD subtype, types of the deficit) and stimulation parameters (i.e., site, polarity, intensity, duration, repetition rate) on tDCS efficacy in ADHD population and examine whether benefits are long-term.

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“…Two studies tested five repeated sessions of 1–2 mA tDCS of 20 min in double-blind sham-controlled studies on either ADHD symptoms alone (Cachoeira et al, 2017 ) or additional cognitive functions (Sotnikova et al, 2017 ). The study in ADHD adults was a randomized double-blind, placebo-controlled clinical trial using sessions of 2 mA stimulation with anodal stimulation of right DLPFC and cathodal stimulation of left DLPFC in 17 adult ADHD patients and found trend-wise significant improvements in overall ADHD symptom scores and a significant improvement in inattention scores after real ( N = 9) relative to sham stimulation ( N = 8); furthermore, all symptom improvements were still significant 2 weeks after stimulation, suggesting longer-term effects (Cachoeira et al, 2017 ). The other study tested five sessions of 1 mA tDCS sessions of 20 min over 5 days in 15 ADHD adolescents in a randomized, double-blinded, sham-controlled crossover study with 2 weeks break between conditions and found significant improvements in inattention symptoms only, which were stronger 7 days later.…”

Section: Transcranial Direct Current Stimulation (Tdcs)mentioning

confidence: 99%

Cognitive Neuroscience of Attention Deficit Hyperactivity Disorder (ADHD) and Its Clinical Translation

Rubia

2018

Front. Hum. Neurosci.

249

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This review focuses on the cognitive neuroscience of Attention Deficit Hyperactivity Disorder (ADHD) based on functional magnetic resonance imaging (fMRI) studies and on recent clinically relevant applications such as fMRI-based diagnostic classification or neuromodulation therapies targeting fMRI deficits with neurofeedback (NF) or brain stimulation. Meta-analyses of fMRI studies of executive functions (EFs) show that ADHD patients have cognitive-domain dissociated complex multisystem impairments in several right and left hemispheric dorsal, ventral and medial fronto-cingulo-striato-thalamic and fronto-parieto-cerebellar networks that mediate cognitive control, attention, timing and working memory (WM). There is furthermore emerging evidence for abnormalities in orbital and ventromedial prefrontal and limbic areas that mediate motivation and emotion control. In addition, poor deactivation of the default mode network (DMN) suggests an abnormal interrelationship between hypo-engaged task-positive and poorly “switched off” hyper-engaged task-negative networks, both of which are related to impaired cognition. Translational cognitive neuroscience in ADHD is still in its infancy. Pattern recognition analyses have attempted to provide diagnostic classification of ADHD using fMRI data with respectable classification accuracies of over 80%. Necessary replication studies, however, are still outstanding. Brain stimulation has been tested in heterogeneously designed, small numbered proof of concept studies targeting key frontal functional impairments in ADHD. Transcranial direct current stimulation (tDCS) appears to be promising to improve ADHD symptoms and cognitive functions based on some studies, but larger clinical trials of repeated stimulation with and without cognitive training are needed to test clinical efficacy and potential costs on non-targeted functions. Only three studies have piloted NF of fMRI-based frontal dysfunctions in ADHD using fMRI or near-infrared spectroscopy, with the two larger ones finding some improvements in cognition and symptoms, which, however, were not superior to the active control conditions, suggesting potential placebo effects. Neurotherapeutics seems attractive for ADHD due to their safety and potential longer-term neuroplastic effects, which drugs cannot offer. However, they need to be thoroughly tested for short- and longer-term clinical and cognitive efficacy and their potential for individualized treatment.

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Positive effects of transcranial direct current stimulation in adult patients with attention-deficit/hyperactivity disorder A pilot randomized controlled study

Cited by 63 publications

References 39 publications

Endogenous dopamine release under transcranial direct-current stimulation governs enhanced attention: a study with positron emission tomography

Endogenous dopamine release under transcranial direct-current stimulation governs enhanced attention: a study with positron emission tomography

Transcranial direct current stimulation in attention-deficit hyperactivity disorder: A meta-analysis of neuropsychological deficits

Cognitive Neuroscience of Attention Deficit Hyperactivity Disorder (ADHD) and Its Clinical Translation

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