Have you ever been to a football or soccer match? In a good game, the team works together as one, with the players complementing each other and anticipating their teammates' moves. But watching a match on television gives you a completely different view, as the camera tends to focus on the skills of each individual player. It's not until the camera pans out that you can get a feel for how the whole team functions.

It's a similar situation when you try to understand or assess MS. However closely you look at one aspect of the disease, you can only ever see part of the picture, because MS has so many different facets and manifestations - so many team members working together. You have to zoom out to get the whole picture.

As there is no single concrete way to predict the course of MS, neurologists use combined information from a number of different indicators to give them an idea of how the disease might progress. So what are the indicators they look at? Well, there are three well-established measures of disease activity: relapses, physical changes (disability), and lesions detected by magnetic resonance imaging (MRI). Your neurologist may have already mentioned one or all of these to you. As research moves forward and our understanding of MS and the brain increases, we are also learning more about the value of monitoring changes in the size of the brain.

Let's take a look at each of these indicators.


Relapses are also known as exacerbations or flares/flare-ups. Let's be real, no one likes relapses! They can stop you in your tracks with unexplained weakness, vision problems, numbness or tingling, and feeling light-headed or dizzy. So what's happening here? Relapses are experienced when damage in the brain caused by MS prevents or disrupts nerve signals so they can't be transmitted properly. The number, type, and severity of symptoms, and the length of time they last differs not just from person to person, but also from relapse to relapse.

Neurologists use the frequency with which relapses occur (relapse rate) as a measure of MS disease severity. The most common way to measure relapse rate is by counting your relapses and then calculating the average number experienced each year since you were diagnosed. This calculation is referred to as annualized relapse rate, or ARR.

Relapses are a useful method in assessing the potential progression of disability. In fact, the time between relapses and also the level of recovery after a relapse are related to the overall loss of ability, particularly for relapses that happen early on in the disease. However, there are also other important factors that moderate and impact progression. Therefore, physicians also directly assess the progression of disability, or physical changes, in addition to monitoring lesions and whole brain changes, as we'll explain below.

Physical changes

As with relapses, the physical symptoms of MS affect people in different ways at different times. Relapses can be painful, inconvenient, and scary, but they can be followed by complete or partial recovery, especially in those with the relapsing-remitting form of MS. Studies have indicated that some relapses are followed by incomplete recovery, leading to accumulation of disability. Disability, unfortunately, is usually permanent, and can be the most life-changing aspect of MS.

There is no single way to see how well your central nervous system is working. However, a test known as the Expanded Disability Status Scale (EDSS) uses a number of assessments of the different functional areas of the central nervous system (the areas that govern the ability to walk or talk, for example) to measure disability.

Following these assessments, an EDSS score can be calculated. The score is a disability rating, on a scale of 0 to 10, at half-point intervals. Different numbers indicate the level of disability, so for example, a score of 6 would indicate that the person with MS must use a cane when walking.

Magnetic resonance imaging (MRI) and lesions

Magnetic resonance imaging, or MRI, is important to neurologists, as it is the only method of observing disease activity before external physical symptoms appear. It is an imaging technique that can be used to look inside almost any part of the body - in MS, images of the brain and spinal cord - much like an X-ray allows doctors to see pictures of bones. Unlike X-rays, however, MRI scans use a strong magnetic field to create detailed images of the amount of water in the tissue. Damaged areas of the brain, known as lesions, show up because they have higher water content than healthy brain tissue.

MRI is used in both MS diagnosis and to monitor MS disease progression. Researchers are continuing to look into how MRI may help in identifying disease changes and predict long-term outcomes.

Having an MRI scan is a safe and painless procedure, and there's usually no specific preparation required beforehand although it can be a little uncomfortable if you suffer from claustrophobia. The MRI scanner is essentially a large tube, open at both ends, in which you lie on a flat bed. During the scan the radiographer will see you on a monitor, and is able to talk to you via an intercom. Loud tapping or banging noises will occur from time to time, as the electric current in the scanner is turned on and off, so you'll be given earplugs or headphones to wear. The process is usually over in a relatively short space of time (30 minutes or so).

Brain changes

Everybody's brain shrinks as they get older (yes, really!). For people with MS, it's been found that this reduction in brain size can happen at a faster rate.

The impact of this reduction in brain size isn't immediately obvious and can differ from person to person. This is because the brain has a remarkable ability to compensate for damage by creating new connections - imagine that a road is blocked and you need to find an alternative route to your destination. One symptom you may become aware of is feeling tired (yes, this can be yet another contributor to the dreaded MS fatigue!). Due to the extra effort your brain has to make, you might find yourself more easily distracted or have difficulty multitasking or concentrating, while others with MS may appear totally unaffected.

By measuring brain changes over time using MRI, neurologists are able to monitor how the disease is progressing. The ultimate goal in instituting treatment as early as possible is to suppress and reduce early attacks that are believed to eventually contribute to long term loss of function.

That's a lot of tests...

All these assessments may seem a little bit daunting. MS itself is enough to deal with, right? But it is really important that you continue to see your neurologist, MS nurse, or any other health care professional in your personal MS army, according to the schedule they set for you - these four indicators, taken together, will help your neurologist to understand how you are progressing and the results of these tests will give you knowledge about your MS. And knowledge, as they say, is power.