Chhatbar Pratik Y, Ramakrishnan Viswanathan, Kautz Steven, George Mark S, Adams Robert J, Feng Wuwei
Department of Neurology, College of Medicine, Medical University of South Carolina, Charleston, SC, USA.
Department of Public Health Science, College of Medicine, Medical University of South Carolina, Charleston, SC, USA.
Brain Stimul. 2016 Jan-Feb;9(1):16-26. doi: 10.1016/j.brs.2015.09.002. Epub 2015 Sep 7.
Transcranial direct current stimulation (tDCS) has shown mixed results in post-stroke motor recovery, possibly because of tDCS dose differences. The purpose of this meta-analysis was to explore whether the outcome has a dose-response relationship with various dose-related parameters.
The literature was searched for double-blind, randomized, sham-controlled clinical trials investigating the role of tDCS (≥5 sessions) in post-stroke motor recovery as measured by the Fugl-Meyer Upper Extremity (FM-UE) scale. Improvements in FM-UE scores were compared between active and sham groups by calculating standardized mean differences (Hedge's g) to derive a summary effect size. Inverse-variance-weighted linear meta-regression across individual studies was performed between various tDCS parameters and Hedge's g to test for dose-response relationships.
Eight studies with total of 213 stroke subjects were included. Summary Hedge's g was statistically significant in favor of the active group (Hedge's g = 0.61, p = 0.02) suggesting moderate effect. Specifically, studies that used bihemispheric tDCS montage (Hedge's g = 1.30, p = 0.08) or that recruited chronic stroke patients (Hedge's g = 1.23, p = 0.02) showed large improvements in the active group. A positive dose-response relationship was found with current density (p = 0.017) and charge density (p = 0.004), but not with current amplitude. Moreover, a negative dose-response relationship was found with electrode size (p < 0.001, smaller electrodes were more effective).
Our meta-analysis and meta-regression results suggest superior motor recovery in the active group when compared to the sham group and dose-response relationships relating to electrode size, charge density and current density. These results need to be confirmed in future dedicated studies.
经颅直流电刺激（tDCS）在中风后运动功能恢复方面的效果不一，这可能是由于tDCS剂量的差异所致。本荟萃分析的目的是探讨治疗结果与各种剂量相关参数之间是否存在剂量反应关系。
检索相关文献，查找采用双盲、随机、假刺激对照临床试验，研究tDCS（≥5次治疗）对中风后运动功能恢复的作用（通过Fugl-Meyer上肢量表（FM-UE）进行测量）。通过计算标准化均数差（Hedge's g）来比较治疗组与假刺激组FM-UE评分的改善情况，以得出汇总效应量。在各个研究中，对不同的tDCS参数与Hedge's g进行逆方差加权线性荟萃回归，以检验剂量反应关系。
纳入8项研究，共计213例中风患者。汇总的Hedge's g在治疗组中具有统计学意义（Hedge's g = 0.61，p = 0.02），表明有中度效果。具体而言，采用双侧tDCS电极放置方式的研究（Hedge's g = 1.30，p = 0.08）或纳入慢性中风患者的研究（Hedge's g = 1.23，p = 0.02）显示治疗组有显著改善。发现与电流密度（p = 0.017）和电荷密度（p = 0.004）存在正剂量反应关系，但与电流幅度无关。此外，发现与电极大小存在负剂量反应关系（p < 0.001，电极越小越有效）。
我们的荟萃分析和荟萃回归结果表明，与假刺激组相比，治疗组的运动功能恢复更佳，且与电极大小、电荷密度和电流密度存在剂量反应关系。这些结果需要在未来的专门研究中得到证实。
