Department of Human Movement Science, Incheon National University, Incheon, South Korea; Neuromechanical Rehabilitation Research Laboratory, Incheon National University, Incheon, South Korea.
Department of Human Movement Science, Incheon National University, Incheon, South Korea; Division of Sport Science, Incheon National University, Incheon, South Korea; Sport Science Institute & Health Promotion Center, Incheon National University, Incheon, South Korea; Neuromechanical Rehabilitation Research Laboratory, Incheon National University, Incheon, South Korea.
Ageing Res Rev. 2021 Sep;70:101377. doi: 10.1016/j.arr.2021.101377. Epub 2021 Jun 2.
This systematic review and meta-analysis investigated the effects of transcranial direct current stimulation (tDCS) on the cognitive functions of healthy older adults by focusing on the changes in reaction time during cognitive tasks.
A total of 31 studies qualified for this meta-analysis, and we acquired 36 comparisons from the included studies for data synthesis. The individual effect sizes were calculated by comparing the altered reaction time during the performance of a specific cognitive task between the active tDCS and sham groups. In two moderator variable analyses, we examined the potentially different effects of the tDCS protocols on the cognition-related reaction time based on the tDCS protocol used (i.e., online vs. offline tDCS) and the five cognitive domains: (a) perceptual-motor function, (b) learning and memory, (c) executive function / complex attention, (d) language, and (e) social cognition. Meta-regression analyses were conducted to estimate the relationship between demographic and tDCS parameter characteristics and the changes in reaction time.
The random-effects model meta-analysis revealed significant small effects of tDCS on cognition-related reaction time. Specifically, providing online tDCS significantly reduced the reaction time, and these patterns were observed during learning and memory and executive function / complex attention tasks. However, applying offline tDCS failed to find any significant reduction of reaction time across various cognitive tasks. The meta-regression analysis revealed that the effects of tDCS on the reaction time during the performance of cognitive tasks increased for the older people.
These findings suggest that providing online tDCS may effectively improve the ageing-induced reaction time related to specific cognitive functions of elderly people.
本系统评价和荟萃分析通过关注认知任务中反应时间的变化，研究了经颅直流电刺激（tDCS）对健康老年人认知功能的影响。
共有 31 项研究符合荟萃分析的条件，我们从纳入的研究中获得了 36 个比较来进行数据综合。个体效应大小是通过比较在执行特定认知任务时，主动 tDCS 和假刺激组之间的反应时间变化来计算的。在两项调节变量分析中，我们根据所使用的 tDCS 方案（即在线与离线 tDCS）和五个认知领域（a）感知运动功能、（b）学习和记忆、（c）执行功能/复杂注意力、（d）语言和（e）社会认知，检查了 tDCS 方案对与认知相关的反应时间的潜在不同影响。进行了元回归分析，以估计人口统计学和 tDCS 参数特征与反应时间变化之间的关系。
随机效应模型荟萃分析显示，tDCS 对认知相关反应时间具有显著的小效应。具体来说，提供在线 tDCS 显著降低了反应时间，这种模式在学习和记忆以及执行功能/复杂注意力任务中观察到。然而，应用离线 tDCS 未能在各种认知任务中发现反应时间的任何显著降低。元回归分析表明，tDCS 对认知任务执行过程中反应时间的影响随着老年人年龄的增加而增加。
这些发现表明，提供在线 tDCS 可能有效改善老年人与特定认知功能相关的老化引起的反应时间。
