Ansaldo Ana Inés, Arguin Martin, Roch Lecours André
Centre de recherche de l'Institut universitaire de gériatrie de Montréal, Montreal, Canada.
Brain Lang. 2002 Aug;82(2):206-22. doi: 10.1016/s0093-934x(02)00017-2.
We examined the role of the right cerebral hemisphere in the recovery from aphasia of HJ, a 50-year-old right-handed and unilingual man who suffered from severe aphasia caused by an extensive left hemisphere (LH) lesion. He was followed-up over 10 months at 4-month intervals, with a lateralized lexical decision task (LDT), an attentional task, and a language battery. Testing started when HJ was 2 months poststroke. In the LDT, words were presented to central vision or lateralized to the left or right visual hemifield. At each test period, we examined the effect of the degree of imageability (high vs. low), and the grammatical class (noun vs. verb) of the targets on HJ's response times and error rates, with left visual field, right visual field, and central vision presentations. The results of the experiment showed that the pattern obtained with the LDT could not be accounted for by fluctuations in attention. There was an interaction of grammatical class with degree of imageability with left visual field displays only. The right hemisphere (RH) was faster with high-imageability words than with low-imageability words, regardless of their grammatical class. There was also an overall RH advantage on response times at 2 and 6 months after onset. This RH predominance coincided with a major recovery of language comprehension and the observation of semantic paralexias, while no major change in language expression was observed at that point. Ten months after onset, the pattern of lateralization changed, and response times for the LDT with either presentation site were equivalent. This LH improvement coincided with some recovery of language expression at the single-word level. The results of this study suggest that, in cases of severe aphasia caused by extensive LH lesions, the RH may play an important role in the recovery process. Furthermore, these results show that the contribution of the two cerebral hemispheres to recovery may vary overtime and affect specific aspects of language.
我们研究了一名50岁右利手且只会说一种语言的男性HJ的右半球在失语症恢复过程中所起的作用。HJ因左侧大脑半球（LH）广泛损伤而患有严重失语症。我们每隔4个月对他进行了为期10个月的随访，采用了侧化词汇判断任务（LDT）、注意力任务和语言测试组。测试在HJ中风后2个月开始。在LDT中，单词呈现在中央视野或向左或右侧视野侧化呈现。在每个测试阶段，我们研究了可想象程度（高与低）以及目标词的语法类别（名词与动词）对HJ反应时间和错误率的影响，包括左视野、右视野和中央视野呈现的情况。实验结果表明，LDT获得的模式无法用注意力波动来解释。仅在左视野显示时，语法类别与可想象程度之间存在交互作用。无论语法类别如何，右半球（RH）对高可想象性单词的反应比对低可想象性单词更快。在发病后2个月和6个月时，右半球在反应时间上也总体占优势。这种右半球优势与语言理解的显著恢复以及语义性错语的观察结果相吻合，而此时语言表达没有观察到重大变化。发病10个月后，侧化模式发生改变，两个呈现部位的LDT反应时间相当。这种左半球功能的改善与单词水平语言表达的一些恢复相吻合。本研究结果表明，在由广泛的左侧大脑半球损伤导致的严重失语症病例中，右半球可能在恢复过程中起重要作用。此外，这些结果表明，两个大脑半球对恢复过程的贡献可能随时间而变化，并影响语言的特定方面。
