Primary Progressive Multiple Sclerosis (PPMS) is one of four internationally recognised forms of Multiple Sclerosis.

PPMS is characterised by a gradual progression of the disease from its onset with no superimposed relapses and remissions at all. There may be periods of a leveling off of disease activity and there may be good and bad days or weeks.

The following graph, showing level of disability over time, demonstrates two typical courses of PPMS.

PPMS differs from Relapsing/Remitting and Secondary Progressive in that onset is typically in the late thirties or early forties, men are as likely women to develop it and initial disease activity is often in the spinal cord and not in the brain.

Primary Progressive MS often migrates into the brain, but is less likely to damage brain areas than relapsing/remitting or secondary progressive - for example, people with Primary Progressive are less likely to develop cognitive problems.

PPMS is the sub-type of MS that is least likely to show inflammatory (gadolinium enhancing) lesions on MRI scans.

The Primary Progressive form of the disease affects between 10 and 15% of all people with multiple sclerosis.

Other forms of Multiple Sclerosis are:
Relapsing/Remitting Multiple Sclerosis
Secondary Progressive Multiple Sclerosis
Progressive Relapsing Multiple Sclerosis

Secondary Progressive Multiple Sclerosis links:
What is the Course of MS?

MS Glossary
All About Multiple Sclerosis