中文摘要：

目的探索经颅直流电刺激（tDCS）同步吞咽任务对吞咽运动中枢的神经电生理学影响。方法采用自身对照，双盲设计。选取健康受试者20例，先后给予阳极tDCS（a—tDCS）、阴极tDCS（c—tDCS）和虚假tDCS（s—tDCS）三种刺激模式，以吞咽强投射区为靶半球进行干预，并同步完成用力吞咽任务。单脉冲经颅磁刺激分别刺激双侧吞咽皮质代表区，记录tDCS干预前以及干预后5、30、60和90min舌骨上肌群的运动诱发电位（MEP）；采用两因素重复测量的方差分析对数据进行统计学处理。结果tDCS干预因素可影响双侧吞咽运动皮质的兴奋性[同侧，F（2，28）=241．2，P〈0．01；对侧，F（1，20）=29．5，P〈0．01]。时间因素和tDCS干预因素有交互作用[同侧，F（3，46）=25．4，P〈0．01；对侧，F（4，53）=6．6，P〈0．01]。其中s—tDCS对双侧兴奋性的影响差异无统计学意义[同侧，P=0．894；对侧，P=0．354]。与s·tDCS相比，a—tDCS提高了刺激同侧的兴奋性，而不是对侧[同侧，MEP均值差值为21％±2％，95％可信区间为15％～27％，P〈0．01；对侧，MEP均值差值为1％±2％，95％可信区间为-3．4％-6．5％，P〉0．05]。与s-tDCS相比，c—tDCS抑制同侧而增强对侧的皮质兴奋性[同侧，MEP均值差值为-21％4-2％，95％可信区间为-18％～-42％，P〈0．01；对侧，MEP均值差值为20％±3％，95％可信区间为12％～29％，P〈0．01]。结论tDCS同时结合吞咽任务对吞咽运动中枢的影响具有极性依赖性和刺激半球依赖性特征；a—tDCS可以提高同侧吞咽皮质运动区的兴奋性，而c—tDCS则在抑制同侧吞咽运动皮质同时兴奋对侧吞咽皮质区。

英文摘要：

Objective To assess the neurophysiological effects of transcranial direct current stimulation （tDCS） of the motor cortex when swallowing. Methods Twenty healthy volunteers had anodal tDCS （a-tDCS）, cathodal tDCS （c-tDCS） or sham tDCS applied over the hemisphere with stronger suprahyoid projections, effortful swallowing was performed simultaneously. Suprahyoid motor-evoked potentials （MEPs） on both the stimulated and non-stimulated contra-lateral hemisphere were examined immediately before stimulation and 5, 30, 60 and 90 minutes later. The MEPs were normalized and analyzed using two-way repeated measures analysis of variance. Results The tDCS had long-lasting effects on the suprahyoid MEPs bilaterally. There were significant changes in the effect over time. Sham tDCS showed no significant effect. Compared with sham tDCS, a-tDCS significantly increased the excitability of the stimulated hemisphere, but not the non-stimulated projection. Compared with sham tDCS, c-tDCS induced decreased cortical excitability in the stimulated hemisphere but an increase in the non-stimulated projection. Conclusions tDCS during swallowing can alter bilateral swallowing activity in the motor cortex in a polarity-depend- ent and site-dependent way. A-tDCS enhances the excitability of the stimulated hemisphere while c-tDCS inhibits it ipsilaterally but increases it contralaterally.