应用在线经颅直流电刺激探查外侧裂后部对失语症恢复的作用

摘要

Objective: To investigate whether stimulating bilateral posterior perisylvian regions (PPR) with transcranial direct current stimulation (tDCS) could improve language function of aphasia and its possible mechanism.Method: Seven convalescent aphasic patients after stroke were examined with psycholinguistic assessment in Chinese aphasia (PACA). tDCS was applied under three different conditions: tDCS with anodal plate over the left PPR, tDCS with anodal plate over the right PPR, and without stimulation. The language tasks included picture-naming and auditory word-picture matching.Result: The scores of picture naming improved significantly during anodal tDCS over the left PPR(P＜0.05), while the scores of the auditory word-picture matching decreased during anodal tDCS over the right PPR(P＜0.05).Conclusion: Anodal tDCS over the left PPR could improve the naming function of aphasics, while anodal tDCS over the right PPR could decrease the score of auditory word-picture matching and there was no effect on picture naming. The possible mechanism was that anodal tDCS over the left PPR could increase the excitability of associative language cortices, improve the picture-naming ability, while anodal tDCS over the right PPR could interfere with the auditory word comprehension of left hemisphere. This indicates that language recovery of aphasia after stroke can be compensated mainly by the affected hemisphere.%目的:采用汉语失语症心理语言评价(PACA)及在线经颅直流电刺激(tDCS),探查两半球外侧裂后部周围区(PPR)是否可以促进失语症语言功能的改善,以及语言功能恢复的可能机制.方法:利用PACA对7例脑卒中后恢复期失语症患者(基底核区损伤4例,皮质损伤3例)进行语言评价,同时实施在线tDCS.在无刺激、左PPR区和右PPR区阳极刺激三种试验条件下进行失语症评价.语言评价任务为听觉词-图匹配、图命名.结果:阳极刺激左PPR区时,图命名成绩显著改善(P<0.05);而刺激右PPR区时,听觉词-图匹配成绩下降(P<0.05).结论:对恢复期失语症患者采用tDCS阳极刺激左PPR区,可以提高其图命名成绩,而右PPR区阳极刺激降低听觉词-图匹配成绩.其可能机制是阳极刺激左PPR区,使得该区皮质的兴奋性增高,激活相关语言区,从而提高了患者的图命名能力;而右PPR区阳极刺激干扰了左半球的听理解加工,表明脑卒中后失语症的语言恢复以同侧半球代偿为主.