Kumari Nitika, Taylor Denise, Signal Nada
Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand.
Front Hum Neurosci. 2019 Oct 4;13:328. doi: 10.3389/fnhum.2019.00328. eCollection 2019.
Cerebellar transcranial direct current stimulation (ctDCS) appears to modulate motor performance in both adaptation and motor skill tasks; however, whether the gains are long-lasting is unclear. This systematic review aims to evaluate the effect of ctDCS with respect to different time scales of motor learning. Ten electronic databases (CINAHL, MEDLINE, SPORT Discus, Scopus, Web of Science, Cochrane via OVID, Evidence-Based Reviews (EBM) via OVID, AMED: Allied and Complementary Medicine, PsycINFO, and PEDro) were systematically searched. Studies evaluating the effect of ctDCS compared to sham ctDCS on motor learning in healthy individuals were selected and reviewed. Two authors independently reviewed the quality of the included studies using the revised Cochrane's risk-of-bias tool. The results were extracted with respect to the time scale in which changes in motor performance were evaluated. Seventeen randomized controlled trials met the eligibility criteria of which 65% of the studies had a "high" risk-of-bias, and 35% had "some concerns." These studies included data from 629 healthy participants. Of the studies that evaluated the effect of anodal ctDCS during and immediately after the stimulation, four found enhanced, three found impaired, and ten found no effect on gains in motor performance. Of the studies that evaluated the effect of anodal ctDCS after a break of 24 h or more, seven found enhanced, two found impaired, and one found no effect on gains in motor performance. Of the studies that evaluated the effect of cathodal ctDCS across a range of time scales, five found impaired, one found enhanced, and five found no effect on gains in motor performance. In healthy individuals, anodal ctDCS appears to improve short to longer-term motor skill learning, whereas it appears to have no effect on gains in motor performance during and immediate after the stimulation. ctDCS may have potential to improve motor performance beyond the training period. The challenge of the motor task and its characteristics, and the stimulation parameters are likely to influence the effect of ctDCS on motor learning.
小脑经颅直流电刺激（ctDCS）似乎在适应性任务和运动技能任务中均能调节运动表现；然而，这种改善效果是否持久尚不清楚。本系统综述旨在评估ctDCS在不同时间尺度的运动学习方面的效果。我们系统检索了十个电子数据库（CINAHL、MEDLINE、SPORT Discus、Scopus、Web of Science、通过OVID检索的Cochrane图书馆、通过OVID检索的循证医学评论（EBM）、AMED：联合与补充医学、PsycINFO以及PEDro）。选取并综述了评估ctDCS与假刺激相比对健康个体运动学习影响的研究。两位作者使用修订后的Cochrane偏倚风险工具独立评估纳入研究的质量。根据评估运动表现变化的时间尺度提取结果。十七项随机对照试验符合纳入标准，其中65%的研究存在“高”偏倚风险，35%的研究存在“一些疑虑”。这些研究纳入了629名健康参与者的数据。在评估刺激期间及刺激后即刻阳极ctDCS效果的研究中，四项研究发现运动表现改善，三项研究发现运动表现受损，十项研究发现对运动表现增益无影响。在评估24小时或更长时间休息后阳极ctDCS效果的研究中，七项研究发现运动表现改善，两项研究发现运动表现受损，一项研究发现对运动表现增益无影响。在评估不同时间尺度阴极ctDCS效果的研究中，五项研究发现运动表现受损，一项研究发现运动表现改善，五项研究发现对运动表现增益无影响。在健康个体中，阳极ctDCS似乎能改善短期至长期的运动技能学习，而在刺激期间及刺激后即刻对运动表现增益似乎无影响。ctDCS可能具有在训练期之外改善运动表现的潜力。运动任务的挑战性及其特征以及刺激参数可能会影响ctDCS对运动学习的效果。
