Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, North Rhine-Westphalia, Germany.
, Office 117, Wendlingweg 2, 52074, Aachen, Germany.
Sci Rep. 2024 Aug 19;14(1):19197. doi: 10.1038/s41598-024-70065-7.
Deficiencies in response inhibition are associated with numerous mental health conditions, warranting innovative treatments. Transcranial direct current stimulation (tDCS), a non-invasive brain stimulation technique, modulates cortical excitability and has shown promise in improving response inhibition. However, tDCS effects on response inhibition often yield contradictory findings. Previous research emphasized the importance of inter-individual factors that are mostly ignored in conventional meta-analyses of mean effects. We aimed to fill this gap and promote the complementary use of the coefficient of variation ratio and standardized mean effects. The systematic literature search included single-session and sham-controlled tDCS studies utilizing stop-signal task or Go-NoGo tasks, analyzing 88 effect sizes from 53 studies. Considering the impact of inter-individual factors, we hypothesized that variances increase in the active versus sham tDCS. However, the results showed that variances between both groups did not differ. Additionally, analyzing standardized mean effects supported previous research showing an improvement in the stop-signal task but not in the Go-NoGo task following active tDCS. These findings suggest that inter-individual differences do not increase variances in response inhibition, implying that the heterogeneity cannot be attributed to higher variance in response inhibition during and after active tDCS. Furthermore, methodological considerations are crucial for tDCS efficacy.
反应抑制缺陷与许多心理健康状况有关，需要创新的治疗方法。经颅直流电刺激 (tDCS) 是一种非侵入性的大脑刺激技术，可调节皮质兴奋性，并已显示出改善反应抑制的潜力。然而，tDCS 对反应抑制的影响经常产生相互矛盾的发现。先前的研究强调了个体间因素的重要性，而这些因素在传统的平均效应元分析中大多被忽略。我们旨在填补这一空白，并促进变异系数比和标准化平均效应的互补使用。系统文献检索包括单次疗程和假刺激对照的 tDCS 研究，使用停止信号任务或 Go-NoGo 任务，分析了 53 项研究中的 88 个效应量。考虑到个体间因素的影响，我们假设在活跃组与假刺激组之间，方差会增加。然而，结果表明两组之间的方差没有差异。此外，分析标准化平均效应支持了先前的研究，表明在停止信号任务中，而不是在 Go-NoGo 任务中，积极 tDCS 后反应抑制得到改善。这些发现表明，个体间差异不会增加反应抑制的方差，这意味着异质性不能归因于积极 tDCS 期间和之后反应抑制的方差更高。此外，方法学考虑对于 tDCS 的疗效至关重要。
