Effect of the Dorsolateral Prefrontal Cortex Stimulation and Comparing It with Mindfulness Program on Attention and Hyperactivity of Children with Attention-Deficit/Hyperactivity Disorder

Attention deficit and hyperactivity are the two early symptoms in children with Attention–Deficit/Hyperactivity Disorder (ADHD). Mindfulness–based interventions are among the strategies used in various studies in recent years to treat this disorder. Despite promising evidence of their efficacy, no consistent results have been obtained regarding the possible treatment outcome. A recent meta–analysis on the effectiveness of mindfulness–based therapies has shown a moderate reduction in ADHD symptoms. Recent studies highlight the relevance of noninvasive brain stimulation for modulating cortical excitability. On the other hand, transcranial direct current stimulation (tDCS) is a brain stimulation technique by which a weak direct current applied on the scalp modulates cortical excitability by shifting resting neuronal membrane potential. This study aims to compare the effectiveness of mindfulness interventions and transcranial direct electrical stimulation on symptoms of children with ADHD.

This quasi–experimental study employs a pretest–posttest with a 1.5–year follow–up design. It was conducted among children aged 7 to 10 years with ADHD referred to the Children's Psychiatry Clinic in Kermanshah City, Iran. A total of 45 boys and girls were selected to participate in the present study and were randomly assigned to three groups: tDSC stimulation, mindfulness training, and sham stimulation. In the pretest phase, parents completed the standard questionnaire on attention–deficit hyperactivity disorder. The intervention phase was carried out in 15 sessions where the training groups dealt with the desired interventions. Immediately after the 15th stimulation session, the posttest stage and follow–up were conducted in 1 and 6 months. The data was analyzed using the analysis of variance test with repeated measurements (composite analysis of variance) and post hoc Bonferroni test in SPSS version 24 software at a significance level of 0.05.

Analysis of variance with repeated measurement (3 groups x 4 measurement steps) was used to analyze attention deficit and hyperactivity symptoms. Results showed that the main effect of time and group were significant for attention deficit and hyperactivity (p≤0.001). The post hoc Bonferroni test results showed that in both intervention groups, the scores of attention deficit and hyperactivity in the posttest and follow–up stages significantly decreased compared to the pretest (p≤0.001). This decrease was significantly higher in the transcranial brain direct electrical stimulation group than in the mindfulness program group (p≤0.001).

According to the research findings, direct transcranial electrical stimulation of the brain in the dorsolateral prefrontal cortex (DLPFC) region of the brain was superior to the mindfulness program in improving and perpetuating the symptoms of attention deficit. DLPFC hypoactivity is hypothesized to underlie attention deficits, impaired inhibitory control, and executive dysfunction in ADHD. Therefore, the pathophysiological rationale for therapeutic tDCS is to increase DLPFC activation by anodal stimulation.