Department of Child and Adolescent Psychiatry and Psychotherapy, Otto von Guericke University, Magdeburg, Germany.
Department of Neurology, Otto von Guericke University, Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), Otto von Guericke University, Magdeburg, Germany.
Prog Brain Res. 2021;264:117-150. doi: 10.1016/bs.pbr.2021.01.014.
Impaired executive functions in ADHD are associated with hypoactivity of the right inferior frontal gyrus (IFG). This region was targeted via repetitive applications of anodal, high-definition transcranial direct current simulation (HD-tDCS) on five consecutive days in 33 ADHD patients (10-17years) and in a healthy control group (n=13, only sham). Patients received either sham (n=13) or verum tDCS with 0.5mA (n=9) or 0.25mA (n=11) depending on individual cutaneous sensitivity. During stimulation, participants performed a combined working memory and response inhibition paradigm (n-back/nogo). At baseline, post, and a 4-month follow up, electroencephalography was recorded during this task. Moreover, interference control (flanker task) and spatial working memory (spanboard task) were assessed to explore possible transfer effects. Omission errors and reaction time variability in all tasks served as measures of attention. In the 0.25mA group increased nogo commission errors indicated a detrimental tDCS effect on response inhibition. After the 5-day stimulation, attentional improvements in the 0.5mA group were indicated by reduced omission errors and reaction time variability. Variability improvements were still evident at follow up. In all groups, nogo P3 amplitudes were reduced post-stimulation, but in the 0.5mA group this reduction was smaller than in the 0.25mA group. Results of the current study suggest distinct effects of tDCS with different current intensities demonstrating the importance of a deeper understanding on the impact of stimulation parameters and repeated tDCS applications to develop effective tDCS-based therapy approaches in ADHD.
注意力缺陷多动障碍（ADHD）患者的执行功能受损与右侧下额下回（IFG）的活动不足有关。在 33 名 ADHD 患者（10-17 岁）和 13 名健康对照组（仅假刺激组，n=13）中，通过连续 5 天对该区域进行重复的阳极、高分辨率经颅直流电刺激（HD-tDCS）治疗，以此靶向该区域。患者根据个体皮肤敏感度接受假刺激（n=13）或真刺激（n=9 用 0.5mA，n=11 用 0.25mA）。在刺激过程中，参与者执行一个结合工作记忆和反应抑制的范式（n-回/nogo）。在基线、刺激后和 4 个月的随访中，在进行该任务时记录脑电图。此外，还评估了干扰控制（侧抑制任务）和空间工作记忆（方格板任务），以探索可能的转移效应。所有任务的遗漏错误和反应时变异性均作为注意力的衡量标准。在 0.25mA 组中，nogo 错误增加表明反应抑制的 tDCS 效应具有有害性。在 5 天的刺激后，0.5mA 组的注意力改善表现为减少的遗漏错误和反应时变异性。在随访时，改善仍然明显。在所有组中，nogo P3 振幅在刺激后降低，但在 0.5mA 组中，这种降低比在 0.25mA 组中更小。当前研究结果表明，不同电流强度的 tDCS 具有不同的影响，这表明深入了解刺激参数和重复 tDCS 应用的影响对于开发有效的基于 tDCS 的 ADHD 治疗方法非常重要。
