Elsner Bernhard, Kugler Joachim, Pohl Marcus, Mehrholz Jan
Department of Public Health, Dresden Medical School, Technical University Dresden, Fetscherstr. 74, Dresden, Sachsen, Germany, 01307.
Cochrane Database Syst Rev. 2015 May 1(5):CD009760. doi: 10.1002/14651858.CD009760.pub3.
Stroke is one of the leading causes of disability worldwide and aphasia among survivors is common. Current speech and language therapy (SLT) strategies have only limited effectiveness in improving aphasia. A possible adjunct to SLT for improving SLT outcomes might be non-invasive brain stimulation by transcranial direct current stimulation (tDCS) to modulate cortical excitability and hence to improve aphasia.
To assess the effects of tDCS for improving aphasia in people who have had a stroke.
We searched the Cochrane Stroke Group Trials Register (November 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, November 2014), MEDLINE (1948 to November 2014), EMBASE (1980 to November 2014), CINAHL (1982 to November 2014), AMED (1985 to November 2014), Science Citation Index (1899 to November 2014) and seven additional databases. We also searched trials registers and reference lists, handsearched conference proceedings and contacted authors and equipment manufacturers.
We included only randomised controlled trials (RCTs) and randomised controlled cross-over trials (from which we only analysed the first period as a parallel group design) comparing tDCS versus control in adults with aphasia due to stroke.
Two review authors independently assessed trial quality and risk of bias, and extracted data. If necessary, we contacted study authors for additional information. We collected information on dropouts and adverse events from the trials.
We included 12 trials involving 136 participants for qualitative assessment. None of the included studies used any formal outcome measure for our primary outcome measure of functional communication - that is, measuring aphasia in a real-life communicative setting. We did a meta-analysis of six trials with 66 participants of correct picture naming as our secondary outcome measure, which demonstrated that tDCS may not enhance SLT outcomes (standardised mean difference (SMD) 0.37, 95% CI -0.18 to 0.92; P = 0.19; I² = 0%; inverse variance method with random-effects model; with a higher SMD reflecting benefit from tDCS). We found no studies examining the effect of tDCS on cognition in stroke patients with aphasia. We did not find reported adverse events and the proportion of dropouts was comparable between groups.
AUTHORS' CONCLUSIONS: Currently there is no evidence of the effectiveness of tDCS (anodal tDCS, cathodal tDCS and bihemispheric tDCS) versus control (sham tDCS) for improving functional communication, language impairment and cognition in people with aphasia after stroke. Further RCTs are needed in this area to determine the effectiveness of this intervention. Authors of future research should adhere to the CONSORT Statement.
中风是全球致残的主要原因之一，幸存者中失语症很常见。目前的言语和语言治疗（SLT）策略在改善失语症方面效果有限。经颅直流电刺激（tDCS）进行非侵入性脑刺激可能是一种辅助SLT以改善治疗效果的方法，通过调节皮层兴奋性来改善失语症。
评估tDCS对改善中风后失语症患者失语情况的效果。
我们检索了Cochrane中风组试验注册库（2014年11月）、Cochrane对照试验中央注册库（CENTRAL）（Cochrane图书馆，2014年11月）、MEDLINE（1948年至2014年11月）、EMBASE（1980年至2014年11月）、CINAHL（1982年至2014年11月）、AMED（1985年至2014年11月）、科学引文索引（1899年至2014年11月）以及另外七个数据库。我们还检索了试验注册库和参考文献列表，手工检索了会议论文集，并联系了作者和设备制造商。
我们仅纳入了随机对照试验（RCT）和随机对照交叉试验（我们仅将其第一阶段作为平行组设计进行分析），比较tDCS与对照组对中风后失语症成人患者的影响。
两位综述作者独立评估试验质量和偏倚风险，并提取数据。如有必要，我们联系研究作者获取更多信息。我们从试验中收集了关于失访和不良事件的信息。
我们纳入了12项试验，涉及136名参与者进行定性评估。纳入的研究均未使用任何正式的结局指标来衡量我们的主要结局指标——功能性沟通，即在现实生活交流环境中测量失语症。我们对六项试验进行了荟萃分析，66名参与者将正确图片命名作为次要结局指标，结果表明tDCS可能无法增强SLT的效果（标准化均数差（SMD）为0.37，95%可信区间为-0.18至0.92；P = 0.19；I² = 0%；采用随机效应模型的逆方差法；SMD越高表明tDCS有益）。我们未发现研究tDCS对中风失语症患者认知影响的研究。未发现报告的不良事件，且两组间失访比例相当。
目前尚无证据表明tDCS（阳极tDCS、阴极tDCS和双半球tDCS）与对照组（假tDCS）相比，在改善中风后失语症患者的功能性沟通、语言障碍和认知方面有效。该领域需要进一步的随机对照试验来确定这种干预措施的有效性。未来研究的作者应遵循CONSORT声明。
