The earliest clinical presentation of relapsing-remitting MS (RRMS) is the clinically isolated syndrome (CIS), that is, a single attack of a single symptom. During a CIS, there is a subacute attack suggestive of demyelination but the patient does not fulfill the criteria for diagnosis of multiple sclerosis. Several studies have shown that treatment with interferons during an initial attack can decrease the chance that a patient will develop MS.The primary aims of therapy are returning function after an attack, preventing new attacks, and preventing disability.