Transcranial stimulation for ADHD

Igor Dórea Bandeira, Rachel Silvany Quadros Guimarães, João Gabriel Jagersbacher, Thiago Lima 
1. Barretto, Jéssica Regina de Jesus-Silva, Samantha Nunes Santos, Nayara Argollo, Rita Lucena. 

Transcranial Direct Current Stimulation in Children and Adolescents With Attention-Deficit/Hyperactivity Disorder (ADHD): A Pilot Study.  Journal of Child Neurology.  Published online ahead of print.

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Studies investigating the possible benefits of transcranial direct current stimulation on left dorsolateral prefrontal cortex in children and adolescents with attention-deficit hyperactivity disorder (ADHD) have not been performed. This study assesses the effect of transcranial direct current stimulation in children and adolescents with ADHD on neuropsychological tests of visual attention, visual and verbal working memory, and inhibitory control. An auto-matched clinical trial was performed involving transcranial direct current stimulation in children and adolescents with ADHD, using SNAP-IV and subtests Vocabulary and Cubes of the Wechsler Intelligence Scale for Children III (WISC-III). Subjects were assessed before and after transcranial direct current stimulation sessions with the Digit Span subtest of the WISC-III, inhibitory control subtest of the NEPSY-II, Corsi cubes, and the Visual Attention Test (TAVIS-3). There were 9 individuals with ADHD according to Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) criteria. There was statistically significant difference in some aspects of TAVIS-3 tests and the inhibitory control subtest of NEPSY-II. Transcranial direct current stimulation can be related to a more efficient processing speed, improved detection of stimuli, and improved ability to switch between an ongoing activity and a new one.

From the manuscript

The stimulation was performed with 7 × 5 cm (35 cm²) electrodes in saline-soaked sponges and were held in place by elastic bandages (we used the Striat device [Ibramed, Amparo-SP, Brazil] as approved by the Brazilian Health Agency [ANVISA]). The anode was positioned on the left dorsolateral prefrontal cortex (F3 according to the 10-20 system for EEG) and the cathode on the right supraorbital area because previous studies reported that stimulation of left dorsolateral prefrontal cortex can improve parameters in neuropsychological tests and also working memory and attention.Five sessions were held on consecutive days in the presence of a skilled physician for possible complications. In the first minute, a current intensity of 1 mA was maintained and at the second minute the current was increased to 2 mA. In the 29th minute, transcranial direct current stimulation was reduced to 1 mA and held for a further minute. The parameters of electrode array size, current strength, and current duration values were previously tested for their safety in children...

Considering all the participants in all the days of intervention, there were 99 records of adverse effects, of which 5% was related to headache (mild in 100%), 1% to neck pain (mild in 100%), 18.18% to tingling in the anode positioning site (considered mild in 83.33% and moderate in 16.66% of cases), 31.31% to itching (mild in 61.29% and moderate in 38.7% of cases), 24.24% to burning sensation (mild in 41.66% and moderate in the other), 13.13% local redness (mild in 92.3% and moderate in 7.6% of cases), and 1% to mild sleepiness. Sense of shock accounted for 6% of adverse events (mild in all cases)....

Test-retest effect did not occur in this study because of the unpredictable nature of the instruments used. As an open study with a small sample, the results should be interpreted with caution. Furthermore, it is not possible to translate the findings into improved functional gains observed in some tests. The short follow-up time does not allow to determine persistent gains. The fact of having found improvement in some evaluation parameters even with limited sample may mean that further studies may produce results with more supportive evidence, which may enable the strengthening of this new therapeutic approach in children and adolescents with ADHD, especially for those who do not fit in the standard pharmacologic treatment.

There are few published articles on the use of transcranial direct current stimulation in the pediatric population, and this study is perhaps the first to test the potential benefits of this technique in children and adolescents with ADHD through the stimulation of the dorsolateral prefrontal cortex. The results, although not consistent, confirm the safety and tolerability of this technique in children and suggest potential benefits of transcranial direct current stimulation in individuals with ADHD. Double-blind, randomized, sham-controlled trials with larger clinical samples should be performed in the future and aim to achieve more solid levels of evidence; in addition, a follow-up should be considered to evaluate the long-term effects of transcranial direct current stimulation in this population.

The transcranial direct current stimulation seems to improve aspects of selective attention, minimizing attention-deficit spectrum characteristics of ADHD in children and adolescents, both in the segmented analysis of the tasks when in the mean values of the agglomerates of TAVIS-3. The transcranial direct current stimulation appears to reduce the time needed for children and adolescents with ADHD to select new information, as evidenced by the improvement in the standards of the naming step of subtest inhibitory control (NEPSY-II), and appears to reduce the total number of errors when alternating attention is used. There were clinical improvements post–transcranial direct current stimulation compared to baseline in ADHD children, according to the perception of parents. Adverse effects were mild, transient, self-limited, and similar to the ones in the adult population.