Abstract

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique, which has been increasingly used as an investigational tool in neuroscience. In social and affective neuroscience research, the prefrontal cortex has been primarily targeted, since this brain region is critically involved in complex psychobiological processes subserving both Șhotș and Școldș domains. Although several studies have suggested that prefrontal tDCS can enhance neuropsychological outcomes, meta-analyses have reported conflicting results. Therefore, we aimed to assess the available evidence by performing an umbrella review of meta-analyses. We evaluated the effects of prefrontal active vs sham tDCS on different domains of cognition among healthy and neuropsychiatric individuals. A MeaSurement Tool to Assess Systematic Reviews 2 was employed to evaluate the quality of meta-analyses, and the GRADE system was employed to grade the quality of evidence of every comparison from each meta-analysis. PubMed/MEDLINE, PsycINFO and the Cochrane Database of Systematic Reviews were searched, and 11 meta-analyses were included resulting in 55 comparisons. Only 16 comparisons reported significant effects favoring tDCS, but 13 of them had either very low or low quality of evidence. Of the remaining 39 comparisons which reported non-significant effects, 38 had either very low or low quality of evidence. Meta-analyses were rated as having critically low and low quality. Among several reasons to explain these findings, the lack of consensus and reproducibility in tDCS research is discussed.

中文翻译：

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前额叶 tDCS 认知效应的循证综合评价

摘要

经颅直流电刺激 (tDCS) 是一种非侵入性脑刺激技术，已越来越多地用作神经科学的研究工具。在社会和情感神经科学研究中，前额叶皮层一直是主要目标，因为这个大脑区域与复杂的心理生物学过程密切相关，服务于热域和冷域。尽管几项研究表明前额叶 tDCS 可以增强神经心理学结果，但荟萃分析报告了相互矛盾的结果。因此，我们旨在通过对荟萃分析进行综合审查来评估可用的证据。我们评估了前额叶主动与对健康和神经精神病学个体不同认知领域的假 tDCS。采用 MeaSurement Tool to Assess Systematic Reviews 2 来评估荟萃分析的质量，并采用 GRADE 系统对来自每个荟萃分析的每次比较的证据质量进行分级。检索了 PubMed/MEDLINE、PsycINFO 和 Cochrane 系统评价数据库，并纳入了 11 项荟萃分析，结果进行了 55 次比较。只有 16 项比较报告了有利于 tDCS 的显着影响，但其中 13 项的证据质量非常低或低。在报告非显着影响的其余 39 项比较中，38 项的证据质量非常低或低。荟萃分析被评为极低和低质量。在解释这些发现的几个原因中，