Upper motoreuron lesions (UML) affects people of all ages and conditions and is a major cause of disability in the young. Whereas active exercise is recognised as paramount to restore the lost motor functions, passive mobilisation of the affected limbs is regarded as a means to safeguard muscular tissue properties during a period of disuse and lack of voluntary control, which often characterises the acute and sub-acute phases. The purpose of the present work is to study the cortical reactivity in UML patients who are treated for two weeks with a robotic passive ankle mobiliser, and the clinical effects of this treatment. The rationale is that, if passive mobilisation can affect positively the functional reorganisation at a cortical level, it could be proposed as a suitable tool to maintain afferentation and guide central nervous remapping, thus bridging the period of time when active exercise is impossible due to acute paresis. Preliminary results on 7 patients (aged 15.35±4.36) showed that this therapy is very well tolerated and suggest that its application could specifically improve ankle PROM and plantarflexor muscle length. EEG data showed improved desynchronisation in at least one frequency band in 3 patients of the study, thus confirming the effects of passive mobilisation on the cortical re-organisation of some patients having UML.