To determine the effect of riluzole up to 50 mg bid on MRI parameters, including T1 lesions load, atrophy of gray and white matter, and 1H-MRSI; and to determine safety of riluzole when administered orally up to 50 mg bid for 2 years in double blinded clinical trial of patients with clinically isolated syndromes (CIS) and at least 2 silent T2-bright areas in the deep white matter. These patients have a high risk of conversion to MS within 2 years and faster rate of atrophy (Dalton 2004).