Functional imaging studies of neurologically intact adults have demonstrated that the right posterior cerebellum is activated during verb generation, semantic processing, sentence processing, and verbal fluency. Studies of patients with cerebellar damage converge to show that the cerebellum supports sentence processing and verbal fluency. However, to date there are no patient studies that investigated the specific importance of the right posterior cerebellum in language processing, because: (i) case studies presented patients with lesions affecting the anterior cerebellum (with or without damage to the posterior cerebellum), and (ii) group studies combined patients with lesions to different cerebellar regions, without specifically reporting the effects of right posterior cerebellar damage. Here we investigated whether damage to the right posterior cerebellum is critical for sentence processing and verbal fluency in four patients with focal stroke damage to different parts of the right posterior cerebellum (all involving Crus II, and lobules VII and VIII). We examined detailed lesion location by going beyond common anatomical definitions of cerebellar anatomy (i.e. according to lobules or vascular territory), and employed a recently proposed functional parcellation of the cerebellum. All four patients experienced language difficulties that persisted for at least a month after stroke but three performed in the normal range within a year. In contrast, one patient with more damage to lobule IX than the other patients had profound long-lasting impairments in the comprehension and repetition of sentences, and the production of spoken sentences during picture description. Spoken and written word comprehension and visual recognition memory were also impaired, however, verbal fluency was within the normal range, together with object naming, visual perception and verbal short-term memory. This is the first study to show that focal damage to the right posterior cerebellum, leads to language difficulties after stroke; and that processing impairments persisted in the case with most damage to lobule IX. We discuss these results in relation to current theories of cerebellar contribution to language processing. Overall, our study highlights the need for longitudinal studies of language function in patients with focal damage to different cerebellar regions, with functional imaging to understand the mechanisms that support recovery.

中文翻译：

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右侧小脑后内侧局灶性损伤对单词和句子理解和产生的影响

对神经功能完整的成年人的功能成像研究表明，右侧小脑后部在动词生成、语义处理、句子处理和语言流利度期间被激活。对小脑损伤患者的研究表明，小脑支持句子处理和语言流畅性。然而，迄今为止，还没有患者研究调查右小脑后部在语言处理中的特殊重要性，因为：(i) 案例研究提出了影响小脑前部病变的患者（有或没有后部小脑损伤），以及(ii) 分组研究将不同小脑区域病变的患者组合在一起，但没有具体报告右小脑后部损伤的影响。在这里，我们调查了 4 名右小脑后部不同部位（均涉及小腿 II、小叶 VII 和 VIII）的局灶性中风损伤患者的右小脑后部损伤是否对句子处理和语言流畅性至关重要。我们通过超越小脑解剖学的常见解剖学定义（即根据小叶或血管区域）检查了详细的病变位置，并采用了最近提出的小脑功能分区。所有四名患者都经历了中风后持续至少一个月的语言困难，但三名患者在一年内表现在正常范围内。相比之下，一名患者对小叶 IX 的损伤比其他患者更大，在句子的理解和重复方面存在严重的长期损害，以及图片描述过程中口语句子的产生。口语和书面文字理解和视觉识别记忆也受损，但语言流利度在正常范围内，以及对象命名、视觉感知和口头短期记忆。这是第一项表明右小脑后部的局灶性损伤导致中风后语言困难的研究；并且在小叶 IX 受损最严重的情况下，处理障碍仍然存在。我们将这些结果与当前关于小脑对语言处理的贡献的理论进行讨论。总体而言，我们的研究强调需要对不同小脑区域局灶性损伤患者的语言功能进行纵向研究，并通过功能成像来了解支持恢复的机制。