Three cases of multiple sclerosis, characterized by disorders of superior functions such as memory loss, either isolated (1 case) or as part of a frontal syndrome (2 cases) are reported. The importance of these disorders, often presenting as the main symptoms, their good prognosis and their rarity in adulthood are underlined. From a pathophysiologic point of view, the authors discuss the role of the frontal, near the limbic area, localization of the plaques.