Primary-progressive MS

About 10-15% of patients with multiple sclerosis (MS) have primary-progressive multiple sclerosis, which is characterized by progressive neurological disability (PPMS). Inflammatory white-matter lesions are less visible, but diffuse axonal loss and microglial activation, as well as cortical demyelination, can be seen in healthy-looking white matter, and quantitative MRI reveals atrophy and intrinsic anomalies in the grey and white matter. People with PPMS are older at onset than those with relapse-onset multiple sclerosis, and a greater percentage of them are memen.




Secondary-progressive MS

The second most common form of multiple sclerosis is secondary progressive multiple sclerosis (SPMS) (MS). There are currently no definitive clinical diagnostic criteria, and research is underway to identify imaging and biochemical biomarkers. Within 15 years, one in every two relapse remitting multiple sclerosis (RRMS) patients will develop SPMS, and up to two-thirds of RRMS patients will develop SPMS after 30 years, resulting in a gradual loss of neurological function and limitations to everyday activities.