Table 1.

Changes in multiple sclerosis disease-course (or “type”) descriptions

1996 Disease-course definitions	2013 Disease-course definitionsa
N/A	New course added: Clinically isolated syndrome (CIS)—referring to a first episode of inflammatory demyelination in the central nervous system that could become MS if additional activity occurs
Relapsing remitting multiple sclerosis (RRMS)—episodes of acute worsening of neurologic functioning with total or partial recovery and no apparent progression of disease	RRMS—episodes of acute worsening of neurologic functioning (new symptoms or the worsening of existing symptoms) with total or partial recovery and no apparent progression of disease; RRMS can be further characterized as:
	Active—showing evidence of new relapses, new gadolinium enhancing lesions and/or new or enlarging T2 lesions on MRI over a specified time period OR Not active—showing no evidence of disease activity	AND	Worsening—defined as increased disability confirmed over a specified time period following a relapse OR Stable—defined no evidence of increasing disability over a specified time period following a relapse
Primary progressive MS (PPMS)—steadily worsening neurologic function from the beginning without any distinct relapses or remissions	PPMS—steadily worsening neurologic function from the onset of symptoms without initial relapses or remissions; PPMS can be further characterized as:
	Active—showing evidence of new relapses, new gadolinium-enhancing lesions and/or new or enlarging T2 lesions on MRI over a specified time period OR Not active—showing no evidence of disease activity	AND	With progression—evidence of disease worsening on an objective measure of change,b confirmed over a specified period of time, with or without relapses OR Without progression—no evidence of disease worsening on an objective measure of changeb over a specified period of time
Secondary progressive MS (SPMS)—progressive, with or without relapses	SPMS—following an initial relapsing remitting course, the disease becomes more steadily progressive, with or without relapses; SPMS can be further characterized as:
	Active—showing evidence of new relapses, new gadolinium enhancing lesions and/or new or enlarging T2 lesions on MRI over a specified time period OR Not active—showing no evidence of disease activity	AND	With progression—evidence of disease worsening on an objective measure of change,b confirmed over a specified period of time, with or without relapses OR Without progression—no evidence of disease worsening on an objective measure of changeb over a specified period of time
Progressive relapsing MS (PRMS)—steadily worsening neurologic function from the beginning with occasional relapses	Course eliminated: PRMS—individuals who were previously diagnosed with progressive relapsing MS would now be considered primary progressive: active (at the time of relapses or new MRI lesions) or not active

Based on data from the National Multiple Sclerosis Society.

MRI, Magnetic resonance imaging.

^aLublin et al. (2014).

^bFor example, the Expanded Disability Status Scale (EDSS).