Laboratory for Cognition and Neural Stimulation, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Moss Rehabilitation Research Institute, Einstein Medical Center, Elkins Park, PA, USA.
Laboratory for Cognition and Neural Stimulation, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
Neuromodulation. 2023 Jun;26(4):728-737. doi: 10.1016/j.neurom.2022.12.014. Epub 2023 Feb 8.
Transcranial alternating current stimulation (tACS)-a noninvasive brain stimulation technique that modulates cortical oscillations in the brain-has shown the capacity to enhance working memory (WM) abilities in healthy individuals. The efficacy of tACS in the improvement of WM performance in healthy individuals is not yet fully understood.
OBJECTIVE/HYPOTHESIS: This meta-analysis aimed to systematically evaluate the efficacy of tACS in the enhancement of WM in healthy individuals and to assess moderators of response to stimulation. We hypothesized that active tACS would significantly enhance WM compared with sham. We further hypothesized that it would do so in a task-dependent manner and that differing stimulation parameters would affect response to tACS.
Ten tACS studies met the inclusion criteria and provided 32 effects in the overall analysis. Random-effect models assessed mean change scores on WM tasks from baseline to poststimulation. The included studies involved varied in stimulation parameters, between-subject and within-subject study designs, and online vs offline tACS.
We observed a significant, heterogeneous, and moderate effect size for active tACS in the enhancement of WM performance over sham (Cohen's d = 0.5). Cognitive load, task domain, session number, and stimulation region showed a significant relationship between active tACS and enhanced WM behavior over sham.
Our findings indicate that active tACS enhances WM performance in healthy individuals compared with sham. Future randomized controlled trials are needed to further explore key parameters, including personalized stimulation vs standardized electroencephalography frequencies and maintenance of tACS effects, and whether tACS-induced effects translate to populations with WM impairments.
经颅交流电刺激（tACS）是一种非侵入性脑刺激技术，可调节大脑中的皮质振荡，已显示出增强健康个体工作记忆（WM）能力的能力。tACS 提高健康个体 WM 性能的功效尚未完全了解。
目的/假设：本荟萃分析旨在系统评估 tACS 增强健康个体 WM 的功效，并评估刺激反应的调节因素。我们假设与假刺激相比，活动 tACS 会显着增强 WM。我们进一步假设它将以任务依赖的方式进行，并且不同的刺激参数会影响对 tACS 的反应。
符合纳入标准的十项 tACS 研究提供了整体分析中的 32 项效应。随机效应模型评估了 WM 任务从基线到刺激后的平均变化分数。所包括的研究在刺激参数、被试间和被试内研究设计以及在线与离线 tACS 方面存在差异。
我们观察到活跃 tACS 在增强 WM 性能方面相对于假刺激具有显着、异质和中等的效应量（Cohen's d = 0.5）。认知负荷、任务领域、会话次数和刺激区域显示出活跃 tACS 与增强 WM 行为之间的显着关系，超过了假刺激。
我们的研究结果表明，与假刺激相比，活动 tACS 可增强健康个体的 WM 表现。需要进一步进行随机对照试验，以探索关键参数，包括个性化刺激与标准化脑电图频率以及 tACS 效果的维持，以及 tACS 诱导的效果是否转化为 WM 受损的人群。
