BENIGN - After one or two attacks with complete recovery, this form of MS does not worsen with time and there is no permanent disability. Benign MS can only be identified when there is minimal disability 10-15 years after onset and initially would have been categorized as relapsing-remitting MS. Benign MS tends to be associated with less severe symptoms at onset. Frequency - approximately 20%.
RELAPSING-REMITTING - In this form of MS there are unpredictable relapses (exacerbations, attacks) during which new symptoms appear or existing symptoms become more severe. This can last for varying periods (days or months) and there is partial or total remission (recovery). The disease may be inactive for months or years. Frequency - approximately 25%.
SECONDARY-PROGRESSIVE - For some individuals who initially have relapsing-remitting MS there is the development of progressive disability later in the course of the disease, often with superimposed relapses. Frequency - approximately 40%.
PRIMARY-PROGRESSIVE - This form of MS is characterized by a lack of distinct attacks, but with slow onset and steadily worsening symptoms. There is an accumulation of deficits and disability in which may level off at some point or continue over months and years. Frequency - approximately 15%.
DIAGNOSIS - There is no single test available to clearly identify MS, although Magnetic Resonance Imaging (MRI) is currently the most sensitive diagnostic test. The diagnostic process usually takes a period of time and is based on cumulative symptoms and tests and a good patient medical history.