Sarica A, Valentino P, Nisticò R, et al. - In this diffusion tensor imaging study, researchers assessed the corticospinal tract (CST) diffusion profile in pure lower motor neuron disease (pLMND) individuals who at baseline did not show any clinical or electrophysiological involvement of upper motor neurons (UMN), and in amyotrophic lateral sclerosis (ALS) individuals. In addition to 15 healthy controls, 15 ALS patients with delayed central motor conduction time (CMCT) and 14 pLMND patients with normal CMCT were registered. According to results, ALS individuals displayed wide microstructural anomalies throughout the CST as assessed by fractional anisotropy (FA) reduction and RD increase while pLMND patients exhibited focal FA reduction and a larger AD increase in the cerebral peduncle and posterior limb of the internal capsule as compared with controls. Findings revealed that CST has been impaired in both patients with ALS and pLMND, indicating that DTI metrics was a reliable tool for detecting subtle UMN changes in patients with pLMND, also in the absence of clinical and CMCT abnormalities.