Mondo Description A multiple sclerosis that is characterized by steady worsening of neurologic functioning, without any distinct relapses or periods of remission. The rate of progression may vary over time, with occasional plateaus or temporary improvements, but the progression is continuous.

Disease Ontology Description A multiple sclerosis that is characterized by steady worsening of neurologic functioning, without any distinct relapses or periods of remission. The rate of progression may vary over time, with occasional plateaus or temporary improvements, but the progression is continuous.