Forthy MS patients affected by gait disturbances and moderate-severe spasticity will be enrolled: 20 out of them in treatment with Sativex (Group A) considered as responders and 20 treated only with the most common antispastic used in MS (Group B). All the 40 subjects, divided into two groups (A: Sativex+Lokomat Training and B: other antispastic+Lokomat Training), will perform a neurorobotic-assisted gait training (RAGT, each session will last at least 45', 3 times per week, for a total amount of 20 treatment's sessions). All patients will undergo a complete blind physical and neurological examination, including evaluation of disability by means of the Expanded Disability Scale (EDDS) and assessment of spasticity using the Modified Ashworth Scale (MAS) and the numerical rating scale (NRS). To clarify the role of Sativex® in improving spasticity gait-related symptoms the following scales will be also administered: ten meters walking test (10wt), Ambulation Index (AI). Quality of life will be evaluated by means of MSQOL 54. The skilled clinician will be blind to the drug treatment.Moreover, some electrophysiological parameters to test cortical excitability will be also evaluated: motor evoked potentials (MEP) amplitude, short intracortical inhibition (SICI) and facilitation (ICF) from the abductor pollicis brevis muscle (APB) of the most affected side. The same assessment will be applied in baseline, at the end of the robotic training (T1) and 30 days after the end of the nerehabilitation training (T2).