The second part is an open controlled study, in which we measure motion detection threshold in MS patients with oscillopsia due to pendular nystagmus and in a group of control subjects. The objective of this part is to determine whether patients with pendular nystagmus develop adaptation to oscillopsia using increased threshold of motion detection. We plan to test the effect of visuo-motor rehabilitation on this threshold in patients with oscillopsia due to pendular nystagmus.