Is may be Time to Update the Current Definitions of the Types of Multiple Sclerosis

Since 1996, a debate regarding the cause of disability in Multiple Sclerosis (MS) and the accuracy of the current definitions of MS types has not subsided. Recently, many researchers presented evidence supporting that relapses are a significant causative factor of the increased disability in multiple sclerosis (MS), primarily, but not exclusively, indicating that the disease's progression, which is independent of any relapse activity, plays a significant role in the patient's deterioration mainly in adult MS cases, and this gradually becomes the principle pathway with which disabilities compound in MS patients. We propose an updated definition of the types of MS, highlighting the central role of the disease's progression.