Cohort Group: Multiple Sclerosis  Inclusion Criteria:  18 years old mild to moderate upper lim disability no strong cognitive deficits no concomitant disease that might affect upper limb performance able to follow procedures and to give informed consent  Cohort Group: Healthy Subjects  Inclusion Criteria:  18 years old no cognitive deficits no concomitant disease that might affect upper limb performance and able to follow procedures and to give informed consent