DAVID MARKS, MD: Do they occur in the same parts of the body each time?
STEVEN GALETTA, MD: No, I think it's a random type of event in many people. For instance, it could occur the first time in the optic nerve. The next time, it might be an event that occurs in the spinal cord.
DAVID MARKS, MD: Is this the only kind of MS that there is?
STEVEN GALETTA, MD: That's the early stage of MS and it accounts for 85 percent of patients in the earliest stages of multiple sclerosis. That is, they have an event that occurs and then it often remits. There are other stages of MS -- secondary progressive MS -- really is characterized by episodes that have occurred and now disability starts to accumulate over time. So the patients had a number of attacks and now they may have trouble walking, for instance. That's secondary progressive MS, and there are more rare forms of MS in which the course is a steady downhill course and we refer to that form of MS as a "primary progressive MS."
DAVID MARKS, MD: If a person has the first event, can they be diagnosed with MS?
STEVEN GALETTA, MD: By clinical definition, we have traditionally required that a patient have a clinical attack, say optic neuritis, and then separated by a month they have a second attack. So MS -- to fulfill the clinical standard definition of MS required two episodes of clinical attacks separated by a month.