Motor neuron dysfunctions (MNDys) in Frontotemporal Lobar Degeneration (FTLD) have been consistently reported. Clinical and neurophysiological findings proved a variable range of pathological changes, also affecting the corticospinal tract (CST). This study aims to assess white-matter microstructural alterations in a sample of patients with FTLD, and to evaluate the relationship with MNDys. Fifty-four FTLD patients (21 bvFTD, 16 PPA, 17 CBS) and 36 healthy controls participated in a Diffusion Tensor Imaging (DTI) study. We analyzed distinctive and common microstructural alteration patterns across FTLD subtypes, including those affecting the CST, and performed an association analysis between CST integrity and the presence of clinical and/or neurophysiological signs of MNDys. The majority of FTLD patients showed microstructural changes in the motor pathway with a high prevalence of CST alterations also in patients not displaying clinical and/or neurophysiological signs of MNDys. Our results suggest that subtle CST alterations characterize FTLD patients regardless to the subtype. This may be due to the spread of the pathological process to the motor system, even without a clear clinical manifestation of MNDys.

中文翻译：

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扩散张量成像的皮质脊髓通路参与额颞叶变性的证据。

额颞叶变性（FTLD）中的运动神经元功能障碍（MNDys）已得到一致报道。临床和神经生理学发现证明病理变化范围可变，也影响皮质脊髓束（CST）。这项研究旨在评估FTLD患者样本中的白色物质微观结构改变，并评估其与MNDys的关系。54名FTLD患者（21名bvFTD，16名PPA，17名CBS）和36名健康对照参加了扩散张量成像（DTI）研究。我们分析了跨FTLD亚型的独特且常见的微结构改变模式，包括那些影响CST的亚型，并对CST完整性与MNDys的临床和/或神经生理学迹象之间的关联性进行了分析。大多数FTLD患者在未表现出MNDys临床和/或神经生理学症状的患者中，运动路径的微结构变化与CST改变的患病率很高。我们的结果表明，无论亚型如何，细微的CST改变都是FTLD患者的特征。这可能是由于病理过程扩散到运动系统，即使没有明确的MNDys临床表现也是如此。