Transcranial direct current stimulation does not improve clinical and neurophysiological outcomes in panic disorder: A randomized sham-controlled trial.

AIM: Emerging evidence suggests that transcranial direct current stimulation (tDCS) has anxiolytic effects and may enhance emotional processing of threat and reduce threat-related attentional bias. Panic disorder (PD) is considered to be a fear network disorder along with prefrontal activity alterations. We aim to assess the effect of tDCS on clinical and physiological parameters in PD for the first time. METHODS: In this triple-blind randomized sham-controlled pilot study, 30 individuals with PD were allocated into active and sham groups to receive 10 sessions of tDCS targeting the dorsolateral prefrontal cortex bilaterally at 2 mA for 20-min duration over 2 weeks. The clinical severity, threat-related attentional bias, interoceptive accuracy, and emotional recognition were assessed before, immediately after, and 1 month after tDCS. RESULTS: Active tDCS, in comparison to sham, did not elicit more favorable clinical and neuropsychological/physiological outcomes in PD. CONCLUSION: The present study provides the first clinical and neurobehavioral results of prefrontal tDCS in PD and indicates that prefrontal tDCS was not superior to sham in PD.

Evidence for modulation of planning and working memory capacities by transcranial direct current stimulation in a sample of adults with attention deficit hyperactivity disorder.

BACKGROUND AND OBJECTIVE: Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder that affects up to 2.8% of the adult population. Albeit pharmacological and behavioral therapies alleviate some core symptoms of ADHD, they do not avail cognitive dysfunction adequately. Executive dysfunction has been considered to have a principal role in ADHD and has previously been linked to activity alterations in the prefrontal cortex. Transcranial Direct Current Stimulation (tDCS) is a noninvasive brain stimulation technique that may modulate prefrontal cortex activity and induce neuroplasticity, with preliminary results in ADHD. The aim of the present study is to assess the effect of repeated tDCS on measures of executive functions in adults with ADHD. METHOD: In this randomized double-blind sham-controlled study, 22 adults with ADHD were allocated into two groups and were administered five consecutive sessions of 2 mA active/sham tDCS over the dorsolateral prefrontal cortex (right anodal/left cathodal). A neuropsychological test battery was administered before the first session and immediately after the last session. RESULTS: The maximum number of digits and the total number of correct trials in the Digit Span Backward test increased in the active group (p = 0.017). The total move score in the Tower of London test decreased (p = 0.033), suggesting better planning ability. However, no significant differences were observed on Stroop Test and Trail Making Test after tDCS. DISCUSSION: The present study corroborates the modulating effects of tDCS on planning and working memory in a small group of adults with ADHD. Our results highlighted that cognitive functions are modulable using tDCS in adults with ADHD.