Frontotemporal dementia (FTD) is a heterogeneous group of neurodegenerative brain disorders, primarily affecting the frontal and/or temporal lobes. Three main subtypes are recognised, each with distinct clinical and cognitive profiles: behavioural-variant FTD (bvFTD), semantic dementia (SD), and progressive nonfluent aphasia (PNFA). Subtype-specific cerebellar grey matter atrophy has been associated with cognitive dysfunction in FTD; however, the extent and severity of structural abnormalities in the cerebro-cerebellar circuits in these disorders has not been investigated. This study aimed to identify patterns of cerebellar white matter changes and their relations to cognitive deficits in the main FTD subtypes. Results revealed bilateral cerebellar white matter changes in all FTD subtypes compared with controls, with greater cerebellar white matter changes in bvFTD than SD and PNFA. Both afferent and efferent cerebellar pathways were associated with cognition. The profiles of the involvement of cerebellar pathways in cognition varied across FTD syndromes. In bvFTD, the output pathway of the cerebellum was only associated with measures of episodic memory. The input pathway was associated with measures of attention, working memory, visuospatial, episodic memory, executive function, and emotion. In SD, both the output and input pathways were associated with measures of working memory, language, and emotion. Finally, in PNFA, both the output and input pathway of the cerebellum were associated with attention, language, and executive function. Additionally, the input pathway was associated with working memory, visuospatial, and emotion. This study is the first to identify patterns of cerebellar white matter changes across FTD syndromes, which in turn relate to cognitive deficits. These findings extend our understanding of the cerebro-cerebellar networks and provide new insight into the role of cerebellar white matter in cognition.

中文翻译：

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小脑结构连接性和额颞痴呆的认知贡献。

额颞痴呆（FTD）是一组神经退行性脑部疾病的异质性疾病，主要影响额叶和/或颞叶。识别出三种主要的亚型，每种具有不同的临床和认知特征：行为变异性FTD（bvFTD），语义性痴呆（SD）和进行性非流利性失语症（PNFA）。亚型特异性小脑灰质萎缩已与FTD中的认知功能障碍有关。然而，尚未研究这些疾病中脑小脑回路结构异常的程度和严重性。这项研究旨在确定小脑白质变化的模式及其与主要FTD亚型的认知缺陷的关系。结果显示，与对照组相比，所有FTD亚型的双侧小脑白质都有变化，bvFTD的小脑白质变化比SD和PNFA大。小脑传入和传出通路均与认知有关。在FTD综合征中，小脑通路参与认知的情况各不相同。在bvFTD中，小脑的输出途径仅与情节记忆的测量有关。输入途径与注意力，工作记忆，视觉空间，情景记忆，执行功能和情绪的测量有关。在SD中，输出和输入路径都与工作记忆，语言和情绪的度量相关。最后，在PNFA中，小脑的输出和输入途径都与注意力，语言和执行功能相关。另外，输入途径与工作记忆，视觉空间和情绪有关。这项研究是首次确定跨FTD综合征的小脑白质变化的模式，而FTD综合征又与认知缺陷有关。这些发现扩展了我们对小脑-小脑网络的理解，并提供了对小脑白质在认知中的作用的新见解。