The natural course of MS is highly variable, and it is impossible to predict the nature, severity or timing of progression in a given patient. Some people with MS will have a more progressive disease course than others.In some cases, the course of MS over the first five years may provide a clue to the progression of the disease over the next 10 years. Recent studies indicate that 90% of patients with minimal disability five years after onset were still ambulatory at 15 years. It is estimated that at 20 years after diagnosis, about 1/3 of people who receive no treatment may require a wheelchair or other assistive device.With the present immunomodulatory therapies, the goal is to slow the progression of disability. Some people with MS respond quite well and may have no progression over years. For others, the treatment may slow, but not stop the progression. It is important to be proactive and work with your healthcare provider in order to obtain the most appropriate treatment, thus obtaining the highest level of benefit.