Recently, celebrities like Selma Blair and Christina Applegate have ignited a more open conversation about multiple sclerosis (MS). This chronic disease affects the central nervous system and causes episodes of inflammation that can affect the brain, optic nerves, and the spinal cord. In this video, Dr. Claire Riley breaks down the four types of MS – clinically isolated syndrome (CIS), relapsing-remitting (RRMS), secondary progressive (SPMS), and primary progressive (PPMS).