The aim of this study is to evaluate the role of cognitive disorders and quality of life in patients with CIS, considered as high risk to develop an MS, treated with interferon Beta. This prospective observational study will include 120 patients, all treated and evaluated annually with neurological extensive examination, ophthalmologic screening (OCT, OF, VEP, VF), auto questionnaire about fatigue (musicol, ELIF), quality of life (SEP-59), and conventional MRI.

Inclusion Criteria:

• Patients older than 18 years,
• Patients with CIS and temporo spatial dissemination for less than one year
• Patient without prior immunomodulatory treatment
• Patient informed of CIS diagnosis and MS according to McDonald criteria,
• Patients with EDSS inferior or egal to 5,5
• Patients usually french-reader and with MMS >24
• Patients informed of study protocol
• Patients agree to sign informed consent
• Patients with affiliation number from social French département.

Exclusion Criteria:

• Secondary progressive MS
• Patient with acute relapse
• Patient already treated with IFN
• corticosteroids less than 15 days
• Patient with severe dépressive disorders
• Patient already included in clinical study
• Patient < 18 years
• Patient with known contra indications for beta interféron
• Every reason with can provoke an interruption of the study, regarding a patient empechment
• Contre indications for MRI or other tests required in the study
• pregnancy or lactation
• patient Under juridic protection

Patient with CIS and temporo spatial dissemination for less than one year without prior immunomodulatory treatment