Tracking the Transition: How SPMS is Confirmed

Confirming the transition from Relapsing-Remitting Multiple Sclerosis (RRMS) to Secondary Progressive Multiple Sclerosis (SPMS) is a process of observation over time. Because MS is highly variable, doctors cannot rely on a single snapshot; instead, they look for a sustained “downward slope” in function that happens independently of relapses, while actively ruling out other causes of worsening ^[1][2].

The Search for a Definitive Test

A common source of frustration for patients is the lack of a “yes or no” test for SPMS. There is currently no single blood test or MRI finding that can definitively mark the day you transition ^[1][3]. While an MRI might show a lack of new inflammatory lesions (the “spots” seen in RRMS), it cannot by itself confirm SPMS ^[3]. The diagnosis remains a clinical judgment based on your history, your symptoms, and standardized physical exams performed over several months ^[4].

What Your Doctor is Tracking

To make an objective diagnosis, neurologists use several standardized assessments to measure your “functional systems.” Comparing these scores over 3 to 6 months helps distinguish true progression from temporary fluctuations ^[1][3].

• Expanded Disability Status Scale (EDSS): This is a common tool used to rank your overall disability on a scale from 0 to 10 ^[5]. A transition is sometimes suspected if your score increases by 1.0 point (if your previous score was 5.0 or lower) or 0.5 points (if it was 5.5 or higher) and stays at that new level for at least 3 to 6 months. However, EDSS is weighted heavily toward walking and can miss cognitive or hand-function changes ^[3][1].
• Timed 25-Foot Walk (T25FW): This measures your walking speed. A consistent worsening of 20% or more in your walking time is often considered a sign of progression in research studies ^[6][7].
• 9-Hole Peg Test (9HPT): This tracks manual dexterity and coordination. Like the walking test, a 20% increase in the time it takes to complete the task can indicate a shift in upper-body function ^[6][7].
• Symbol Digit Modalities Test (SDMT): This is a brief cognitive screen that measures how quickly you process information. Because cognitive slowing can happen even if your physical walking ability is stable, this test is an essential part of tracking progression ^[8][9].

The Concept of PIRA

A key term you may hear is Progression Independent of Relapse Activity (PIRA). In RRMS, disability usually follows a relapse (an “attack”). In SPMS, the focus shifts to PIRA—disability that accumulates slowly while you are not having a relapse ^[2][10]. If your scores on the tests above are worsening during a quiet period where no new relapses or MRI lesions are appearing, it can support a transition to SPMS, though PIRA can also occur during relapsing MS ^[11].

Ruling Out Other Causes

Before confirming SPMS, your doctor must ensure that your worsening isn’t caused by something other than the MS progression itself. This “ruling out” process is vital because many of these factors are treatable.

When to Contact Your Care Team Urgently

It is important to know the difference between slow progression and an urgent medical issue. Do not wait for your next appointment if you experience:

• A new or clearly worsening neurologic symptom lasting more than 24 hours (especially without fever or heat).
• Sudden, severe weakness, vision loss, or trouble speaking.
• An inability to pass urine.
• Signs of a severe infection (high fever, flank pain, severe redness/skin breakdown).

Because SPMS is diagnosed retrospectively, your “real-world” observations are just as important as the clinical tests. Keep a simple log of changes you notice over 6-month periods. Focus on specific functional changes: “I used to be able to walk to the end of the block without stopping, but for the last four months, I have to stop halfway,” or “I find I am making more mistakes at work because I can’t process information as fast as I did last year.” Sharing these concrete examples helps your doctor see the pattern of progression ^[3][13].