Benign disease is still an active disease. It occurs in areas of the brain that do not affect the body with physical or cognitive functions. Often these areas of the brain are still unmapped. Benign disease is usually found when it turns to another form and there is evidence that the disease has been active in the past. Sometimes the scarred areas are found when the doctors do an MRI of the brain or spine for another reason and sometimes it is not found until an autopsy is done.
Relapsing - remitting multiple sclerosis is often the most difficult to handle. One feels sick and has one or more symptoms during a relapse. Sometimes these symptoms seem relatively minor (if one is diagnosed) and sometimes they are overwhelming. But between the relapses are stretches of time of varying lengths where one feels well even though one may have some residual disability from prior relapses. Most disturbing about this form of the disease is that one must continually make adjustments during and perhaps for a time after the relapse. And one never know when a relapse will come or what will activate the disease process. A relapse can totally remit or there can be some residual symptoms that do not change until there is another relapse.
Secondary progressive multiple sclerosis is another form of relapsing - remitting disease. This begins as relapsing - remitting MS but changes so that there is also slow progression. There is a slow downhill slide resulting in increased loss of function. At the same time, relapses can occur. A remission improves the symptoms of the relapse but often there is no true recovery of the prior state of health. These symptoms can slowly continue to deteriorate physical or cognitive function.
Primary progressive disease is a slow or more rapid deterioration of physical and/or cognitive function without evidence of any relapse. There is a loss of function from the beginning and that continues at differing rates in different people.
There are sometimes plateaus in both of the progressive forms of the disease. These plateaus can vary in time. But there will be no improvement of symptoms in primary progressive disease.
There is another form of progressive disease sometimes differentiated from primary progressive disease because of the rapid rate of increased disability. It is called malignant progressive multiple sclerosis. This definition has been eliminated from the "official" language but many doctors continue to use it.
Note: Be aware that there is disability caused by the disease itself and disability due to noncompliance with treatment. Physical and occupational therapy can often help with strength and movement even in the most severe cases of the disease. Medications should be discussed with a neurologist who is an expert in the field of multiple sclerosis. The person who is diagnosed with multiple sclerosis needs to become as educated as possible about the disease because it is usually the person with MS who makes the medical decisions with the counsel of the physician.