Diagnosis and Progression

It’s crucial to understand how doctors assess MS symptoms and how the severity of the disease increases over time. MS is caused by the body’s defense system attacking myelin, the fatty substance surrounding and protecting nerve fibers in the central nervous system.  This disrupts signals traveling to and from the brain causing various symptoms of MS such as weakness.  The immune response or inflammation sometimes damage the nerve themselves, leaving scar tissue or sclerosis, causing permanent damage and disability

This results in a variety of symptoms. Among other things, MS may cause blurred vision, dizziness, tingling and numbness, partial or total paralysis, speech difficulties, hearing loss, blindness, fatigue, depression, elimination problems or memory and cognition difficulties.

But what makes MS so challenging is its unpredictability. Symptoms vary greatly from one person to the next and they frequently wax and wane. What’s more, in some instances, major symptoms may disappear entirely and later a relapse will take place. As a result, getting a handle on the disease is challenging.


Because symptoms of MS frequently mimic other nervous system disorders, doctors usually conduct neurological tests to rule out other possibilities. These tests focus on checking reflexes, sensations, body movements, vision and pupil response, and eye movements. Five types of tests are commonly used to assist with the diagnosis of the condition. These include:

Neurologic Exam and Interview. A physician performs a check on medical history and uses a variety of tests to evaluate cognition, emotional clues, language function and physical abilities, including balance, coordination, vision and other senses. Doctors often rely on the Expanded Disability Status Scale (EDSS) to measure the physical disability associated with MS. By asking a series of questions they’re able to assess where you’re at on the MS spectrum.

Cerebral Fluid Analysis. A spinal tap, also referred to as a lumbar puncture, allows doctors to collect a sample of cerebrospinal fluid (CSF) and and perform various of tests. These tests are to confirm the diagnosis of multiple sclerosis and to evaluate for diseases which may mimic MS. One important test that your doctor may order is oligoclonal bands.  The presence of oligoclonal bands is suggestive of inflammation of the central nervous system, a strong indicator of MS.

MRI Scan.  Magnetic resonance imaging of the brain can detect the lesions, damage from the exacerbation of MS. However, some patients who display a normal MRI may have MS. Others with lesions—particularly the elderly—don’t have MS.

Evoked Potential (EP) Test. These assessments record the nervous system’s electrical response to stimulation across different pathways. The residual damage from MS attacks can be detected by slower neurological response times. This test can detect nerve pathways that a neurologic exam cannot.

Blood test. Although a blood test cannot diagnose MS, it can be used to rule out other conditions that produce similar outcomes, including collagen-vascular diseases, hereditary disorders and HIV.


MS is a challenging disease to diagnose. A doctor must detect damage in two separate areas of the central nervous system, including the brain, spinal cord and optic nerves—and document that the damage occurred at least one month apart. It’s also necessary to rule out all other possible diagnosis. Specific guidelines for using diagnostic tools, including MRIs and VEPs, exist. These steps, referred to as the McDonald Criteria, were created in 2001 and updated in 2010. The Kurtzke Expanded Disability Scale (EDSS) uses whole and half numbers and a ranking from one to 10 to assess the level of disability.

Disease Types and Progression

The National Multiple Sclerosis Society describes four distinct courses of the disease. All can vary across mild, moderate and severe symptoms:

Relapsing-Remitting MS (RRMS). The most common form of the disease (85 percent) experience clearly defined attacks of worsening neurologic function. Relapses and flare-ups occur and they’re followed by recovery periods.

Primary-Progressive MS (PPMS). This form of MS (10 percent) causes steadily worsening neurologic function—without distinct relapses or remissions. Only minor and occasional plateaus and improvements occur.

Secondary-Progressive MS (SPMS). Some patients with relapsing-remitting MS can develop into secondary progressive MS.  Patient no longer have relapses and recovery periods. It is characterized by a steadily worsening state, with or without flare-ups, plateaus or remissions. Historically, about 50 percent of those diagnosed with relapsing-remitting MS developed SPMS within 10 years. However, it isn’t known whether recent treatments reduce progression from RRMS to SPMS.

Progressive-Relapsing MS (PRMS). About 5 percent of those with MS experience PRMS. These individuals experience steadily worsening conditions—with attacks that are clearly identifiable. Some PRMS suffers experience remissions or recoveries following a relapse. Regardless, the disease progresses.

Track your progress with Healthline's MS Assessment Tool.

Related Conditions

Some MS patients also suffer from idiopathic thrombocytopenic purpura (ITP), an autoimmune bleeding disorder that results in abnormally low levels of platelets, creating a condition known as thrombocytopenia. The lack of these specialized blood cells leads to poor clotting and excessive bleeding.

Although there’s no cure for MS, treatments can help manage the condition more effectively. Most people with MS have a normal or near-normal life expectancy, according to the National Multiple Sclerosis Society.