Right hemisphere structural adaptation and changing language skills years after left hemisphere stroke.
Right hemisphere structural adaptation and changing language skills years after left hemisphere stroke.
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DOI：
10.1093/brain/awx086
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发表时间：
2017-06-01
期刊：
影响因子：
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通讯作者：
Price CJ
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作者：
Hope TMH;Leff AP;Prejawa S;Bruce R;Haigh Z;Lim L;Ramsden S;Oberhuber M;Ludersdorfer P;Crinion J;Seghier ML;Price CJ
中风后的语言障碍通常被认为在一年内稳定下来。Hope等人报告了令人惊讶的相反证据，表明中风后失语症患者的语言技能在中风后数年仍在继续变化。这些变化与完整的右半球的结构适应有关。具有后天语言缺陷的中风幸存者通常被认为在中风发作的一年内达到“平台期”，之后他们的剩余语言技能将保持稳定。然而，有报告称，患者似乎在数年内康复。在这里，我们分析了28名左半球中风患者的纵向变化，每个人在中风后一年多的时候第一次评估-测试每个病人的口语物体命名技能和获取结构脑扫描两次。随着时间的推移，一些患者的情况似乎有所改善，而另一些则有所下降;这两个方向的变化都与大脑完整右半球的结构适应有关，并且可以预测。与普遍认为这些患者的语言技能是稳定的观点相反，这些结果意味着真实的变化会持续多年。最强的大脑行为关联（“峰值簇”）位于前颞叶和中央前回。使用功能性磁共振成像，我们证实，这两个区域积极参与时，神经正常的控制对象的名称视觉呈现的对象，但似乎都没有参与时，相同的参与者使用手指按下，使语义联想决定相同的刺激。这表明这些区域在未受损的大脑中起着单词检索或发音功能的作用。我们通过参考其他任务中的变化来区分这些解释。与真实的变化发生在这里的说法一致，口语物体命名的变化与其他两个类似任务的变化相关，口语动作命名和书面物体命名，每一个都独立地与相似（重叠）的右半球区域的结构适应相关。书面对象命名的变化，这需要单词检索，但不清晰度，也显着更相关的两个（一）在口头对象命名的变化;和（二）结构适应在两个峰值集群，比在另一个任务的变化听觉单词重复，这需要清晰度，但不单词检索。这表明，口语物体命名的变化反映了单词检索过程水平的变化。令人惊讶的是，鉴于它们在性质上相似的激活特征，前颞区的肥大与行为改善有关，而中央前回的肥大与行为下降有关。我们预测，这两个区域中的一个或两个可能是神经刺激研究（抑制中央前区和/或增强前颞区）的富有成效的目标，旨在鼓励恢复或逮捕下降，即使中风发生后数年。中风后的语言障碍通常被认为在一年内稳定下来。Hope等人报告了令人惊讶的相反证据，表明中风后失语症患者的语言技能在中风后数年仍在继续变化。这些变化与完整的右半球的结构适应有关。
Language difficulties after stroke are commonly thought to stabilise within a year. Hope et al. report surprising evidence to the contrary, showing that the language skills of patients with post-stroke aphasia continue to change even years after stroke. The changes are associated with structural adaptation in the intact right hemisphere. Stroke survivors with acquired language deficits are commonly thought to reach a ‘plateau’ within a year of stroke onset, after which their residual language skills will remain stable. Nevertheless, there have been reports of patients who appear to recover over years. Here, we analysed longitudinal change in 28 left-hemisphere stroke patients, each more than a year post-stroke when first assessed—testing each patient’s spoken object naming skills and acquiring structural brain scans twice. Some of the patients appeared to improve over time while others declined; both directions of change were associated with, and predictable given, structural adaptation in the intact right hemisphere of the brain. Contrary to the prevailing view that these patients’ language skills are stable, these results imply that real change continues over years. The strongest brain–behaviour associations (the ‘peak clusters’) were in the anterior temporal lobe and the precentral gyrus. Using functional magnetic resonance imaging, we confirmed that both regions are actively involved when neurologically normal control subjects name visually presented objects, but neither appeared to be involved when the same participants used a finger press to make semantic association decisions on the same stimuli. This suggests that these regions serve word-retrieval or articulatory functions in the undamaged brain. We teased these interpretations apart by reference to change in other tasks. Consistent with the claim that the real change is occurring here, change in spoken object naming was correlated with change in two other similar tasks, spoken action naming and written object naming, each of which was independently associated with structural adaptation in similar (overlapping) right hemisphere regions. Change in written object naming, which requires word-retrieval but not articulation, was also significantly more correlated with both (i) change in spoken object naming; and (ii) structural adaptation in the two peak clusters, than was change in another task—auditory word repetition—which requires articulation but not word retrieval. This suggests that the changes in spoken object naming reflected variation at the level of word-retrieval processes. Surprisingly, given their qualitatively similar activation profiles, hypertrophy in the anterior temporal region was associated with improving behaviour, while hypertrophy in the precentral gyrus was associated with declining behaviour. We predict that either or both of these regions might be fruitful targets for neural stimulation studies (suppressing the precentral region and/or enhancing the anterior temporal region), aiming to encourage recovery or arrest decline even years after stroke occurs. Language difficulties after stroke are commonly thought to stabilise within a year. Hope et al. report surprising evidence to the contrary, showing that the language skills of patients with post-stroke aphasia continue to change even years after stroke. The changes are associated with structural adaptation in the intact right hemisphere.