Improving Interference Control in ADHD Patients with Transcranial Direct Current Stimulation (tDCS)

Abstract

The use of transcranial direct current stimulation (tDCS) in patients with attention deficit hyperactivity disorder (ADHD) has been suggested as a promising alternative to psychopharmacological treatment approaches due to its local and network effects on brain activation. In the current study, we investigated the impact of tDCS over the right inferior frontal gyrus (rIFG) on interference control in 21 male adolescents with ADHD and 21 age matched healthy controls aged 13–17 years, who underwent three separate sessions of tDCS (anodal, cathodal, and sham) while completing a Flanker task. Even though anodal stimulation appeared to diminish commission errors in the ADHD group, the overall analysis revealed no significant effect of tDCS. Since participants showed a considerable learning effect from the first to the second session, performance in the first session was separately analyzed. ADHD patients receiving sham stimulation in the first session showed impaired interference control compared to healthy control participants whereas ADHD patients who were exposed to anodal stimulation, showed comparable performance levels (commission errors, reaction time variability) to the control group. These results suggest that anodal tDCS of the right inferior frontal gyrus could improve interference control in patients with ADHD.

Transcranial direct current brain stimulation decreases impulsivity in ADHD

“…Other studies showing improvement in working memory performance measured performance following stimulation [44, 89, 90]. Studies showing positive effects of tDCS in ADHD have primarily been conducted in adolescents [37, 45, 47, 91], and it is possible that adults with ADHD respond differently. Differences may also be due to differences in study design such as dosage and treatment duration, or to participant experiences of side effects during stimulation.…”

“…A single session of tDCS targeting the left DLPFC has been shown to improve memory, planning ability, inhibitory control, and neural efficiency during cognitive processing with minimal side effects [33–35]. Some findings suggest that performance improvements may be related to current density; studies utilizing a 1mA dose have shown mixed results in an ADHD population [36, 37], whereas a higher dosage (i.e., 2mA compared to 1mA or sham tDCS) has been shown to improve cognitive performance in both healthy samples and neuropsychiatric populations [31, 38, 39]. Furthermore, concurrent performance of a challenging task to engage the targeted control circuits may offer synergistic effects on tDCS-induced neuroplastic changes, promoting greater functional connectivity between large-scale brain networks and improved neural efficiency resulting in improved performance on objective measures of cognitive control [40–43].…”

“…A second study of adolescents found that 5 days of anodal tDCS over the left DLPFC caused a significant reduction in inattention and impulsivity at end of treatment and 7 days post stimulation [47]. In adults, anodal tDCS to the right DLPFC resulted in improved inattention scores [48] and anodal tDCS over the inferior frontal gyrus reported that tDCS treatment reduced false positive errors on an interference task in male adolescents with ADHD [37]. However, tDCS applied over the left DLPFC in adults with ADHD did not reveal significant differences on a go/no go task following one stimulation session [36].…”

Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines

“…No AEs were seen in young patients, even after tDCS was applied with a higher than usual current density (0.497 mA/cm 2 ) and/or repeated over several days (Breitling et al, 2016; Mattai et al, 2011; Munz et al, 2015; Schneider and Hopp, 2011; Soff et al, 2016). tDCS was applied to some children during sleep without awakening them, and none reported AEs the following morning (Munz et al, 2015; Prehn-Kristensen et al, 2014).…”

Transcranial Direct Current Stimulation for Treatment of ADHD: A Review of the Mechanisms of Action

“…During recent years, different brain stimulation and modulation techniques have been developed for different neuropsychiatric disorders [13][14][15]. Among the brain modulation techniques, transcranial direct current stimulation (tDCS) has shown interesting potentials as an alternative or adjunctive treatment for different psychiatric disorders including ADHD [12,[16][17][18][19][20][21][22][23]. TDCS is a noninvasive, lowcost, easy to use technique where a week direct current is delivered to the scalp through a pair of electrode, through which the flowing current changes the cortical excitability of the neurons and ultimately alters behavior [24].…”