The study aims to test a robotic rehabilitation protocol which involves the use of a robotic device (NeReBot) as an alternative to the conventional rehabilitation treatment. NeReBot is a 3-degree-of-freedom robotic device, which can be programmed by the therapist to perform repetitive assistive movements (flexion and extension, adduction and abduction, pronation and supination, circular) of the upper limb (shoulder and elbow), combined with a visual and acoustic display. Acute and subacute stroke patients (≤20 days post-stroke) will be randomized into two groups with a procedure by a computer program: the experimental group (EG) and the control group (CG). Both groups will receive a total daily treatment time of 120 minutes for five days a week and for five weeks. The EG will perform the conventional functional rehabilitation (proprioceptive exercises, verticalization, gait training, paretic hand and wrist mobilization, without mobilizing the proximal paretic arm) and occupational therapy for 80 minutes a day, while the proximal paretic arm will be treated by NeReBot for 40 minutes a day. For the CG, NeReBot therapy is substituted by 40 minutes of conventional mobilization of the proximal paretic arm by the therapist.