20 Terms You Should Know If You’re Affected by MS

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8 Feb 2023 | ~11:39 Engagement Time


Kathy Costello , Nurse Practitioner & Roz Kalb , Psychologist


Life with MS often thrusts you into a whirlwind of doctor’s visits, testing, and treatments that may be confusing and frightening. Throughout this time, you’ll hear medical terminology from each healthcare worker you visit, and it may sound like a different language.   

While you can always ask your doctor to repeat themselves or define words you don’t understand, you can also feel more confident during appointments by learning some of the key terms in MS.   

Here are twenty common terms to help you understand MS and better communicate with the medical professionals who participate in your diagnosis and care.

Terms Related to MS and the Central Nervous System

1. Immune system – The immune system consists of many distinct types of cells that can communicate with each other and work together to recognize, fight and destroy pathogens, such as bacteria, viruses, and parasites. The normal immune system can tell the difference between pathogens and normal cells and tissues. However, the immune system can behave abnormally or malfunction and attack normal cells and tissues.

A malfunctioning immune system can cause a variety of autoimmune and immune-mediated diseases such as multiple sclerosis, rheumatoid arthritis, Crohn’s disease, Psoriasis, and many others. Each of these conditions involves different cells of the immune system that cause specific areas of inflammation, damage, and symptoms. 

2. Central Nervous System (CNS) – The central nervous system consists of the brain, spinal cord, and optic (vision) tracts. In MS, the CNS is the target of a malfunctioning immune system.

3. Multiple sclerosis (MS) – MS is a complex immune-mediated disease of the CNS. In MS, the immune system targets cells and tissues in the CNS as if those cells and tissues were a bacteria or virus.  

The errant immune activity can cause inflammation and damage in the CNS. Damage occurs to myelin, the underlying axons and the cells that make myelin, called oligodendrocytes. This causes symptoms that can include things like blurred or double vision, feeling unusually tired, numbness or tingling, weakness, fuzzy thinking, sadness, imbalance, and others. 

4. Myelin – Myelin is a layer of substance wrapped around nerve fibers in the CNS.   

It is often compared to the rubber around an electrical wire. If the rubber insulation is damaged, the appliance or light fixture may work intermittently or not at all.  

Myelin is made up of proteins and fats. Myelin provides support to nerves and allows rapid transmission of electrical impulses. If myelin is damaged, impulses slow and messages are altered or interrupted. In MS, myelin damage usually leads to an array of physical and mental symptoms. 

5. Neuron – The neuron is the basic functional cell of the CNS. Neurons are cells that consist of three basic parts. All three are necessary to transmit signals within the CNS and connect to the peripheral nervous system (nerves outside of the brain and spinal cord) to get messages to organs, muscles, skin, etc.  

The three parts of the neuron are the cell body, dendrites that collect information, and axons that transmit information to other neurons. Many axons within the CNS have myelin wrapped around them to increase the speed of nerve transmission. 

Terms You’ll Hear at the Doctor’s Office

6. MRI – MRI stands for magnetic resonance imaging.  

It is a diagnostic tool that uses a super strong magnet, radio waves and a computer to construct very clear images of internal organs and tissues. The magnet causes water molecules to align in the direction of the magnetic field. Radio waves cause the molecules to move.  

The movement creates a signal that the computer can capture to make images or pictures of body organs, tissues, and abnormalities such as tumors, inflammation, or infections. MRI does not use any radiation. It is especially useful for imaging the CNS to help with making an accurate diagnosis and can be used after diagnosis to check for new disease activity or progression. 

7. Gadolinium – Gadolinium is a contrast material that is used during some MRIs to better visualize certain types of abnormalities–including inflammation, infection, blood vessel abnormalities, and tumors. Gadolinium is given by an intravenous injection (into a vein in the arm or hand).  

In MS, gadolinium is helpful in identifying active inflammation. New or active areas of inflammation identified with a gadolinium-enhanced MRI will appear enhanced (bright white) for about 4 weeks. After that, the new area can be seen on non-contrast MRI images but will no longer be enhanced by gadolinium. While gadolinium is useful, it is not always needed as part of routine monitoring for people with MS.  

8. Lumbar puncture – A lumbar puncture, also known as a spinal tap, is a test used to help the neurologist make an accurate diagnosis. The findings of this test are not specific to MS but can help determine a diagnosis in combination with your symptoms, the neurological examination, the MRI, and several of blood tests.  

During a lumbar puncture procedure, you are usually placed on your side with your knees bent toward your body. An area in your lower back is first injected with a numbing solution. Then a needle is inserted into the space around the spinal cord where spinal fluid is located. Two to three teaspoons of spinal fluid are removed and then sent to a laboratory for testing.  

The testing can identify inflammation, infections, or markers of specific neurological conditions. After a lumbar puncture, you will be asked to remain lying down for about an hour, limit standing or walking until the following day, and asked to drink plenty of fluids. 

9. Optical coherence tomography (OCT) – OCT is a diagnostic test that measures the thickness of structures in the back of the eye that are necessary for vision.  

During an OCT, while you are sitting very still, bright light waves are directed at the retina (the back part of the eye). The structures in that part of the eye reflect light based upon the thickness of their tissues. A detailed representation of the retinal structures is produced that reveals information about the health of the visual system. In MS, OCT is used to measure the thickness of the retinal nerve, which is a marker of optic nerve health as well as the extent of nerve fiber loss and damage within the CNS.  

Terms About Types of MS and Disease Progression

10. Relapse – A relapse is a new MS symptom or symptoms that lasts for at least 24 hours and is not due to another cause (such as a fever). Many symptoms of MS can fluctuate throughout the day, but those fluctuations are not relapses. A relapse is generally a new symptom and is associated with new inflammation that can often be seen on the MRI with the use of the contrast agent, gadolinium. 

11. Relapsing -remitting MS (RRMS) – RRMS is a pattern of the MS disease process with relapses followed by remissions – or periods of time without new or worsening symptoms. During a relapse, new areas of inflammation are likely to appear on an MRI enhanced with gadolinium.  

12. Progression – In MS, progression refers to worsening of MS with accumulation of more disability over time. While most people begin with a relapsing-remitting pattern, over time, there are fewer relapses, less inflammation, but more worsening, or progression over time.  

13. Secondary-progressive MS (SPMS) – SPMS is a pattern of the MS disease process that follows relapsing-remitting MS in most people. MS is a progressive disease, but most people begin the disease with a relapsing-remitting pattern that eventually changes over many years’ time to become more progressive – with gradual worsening of symptoms and accumulation of disability.  

14. Primary progressive MS (PPMS) – PPMS is a pattern of the MS disease process in which gradual progression occurs from the beginning, without any of the remissions that occur in relapsing-remitting MS. Symptoms – most often difficult walking – worsen slowly over time. Inflammation can occur, but with far less frequency than in relapsing-remitting MS. 

Terms About MS Treatment

15. Steroids – Steroids, specifically glucocorticoids are used to treat MS relapses. Glucocorticoids such as prednisone, methylprednisolone and dexamethasone help to accelerate recovery from a relapse. These steroids to not have a long-term benefit but can help people experiencing a relapse feel better sooner rather than later.  

16. Disease modifying treatments (DMT) – DMTs are medications for MS that modify the disease process, which means that they reduce the number of new relapses, reduce new inflammation, and slow disease progression. The sooner these medications are after the diagnosis is made, the greater long-term benefit they are likely to have 

More than 20 DMTs have been approved by the U.S. Food and Drug Administration (FDA) approved for the treatment of MS. DMT’s work by reducing the immune system activity that is producing inflammation and damage in the CNS. Some of the DMT’s are taken by mouth, some are self-injected, and some are given by an intravenous (IV) infusion (into a vein in the arm or hand). DMT’s do have side effects, and although they are generally mild, side effects can sometimes be serious. Only one DMT is taken at a time.  

A DMT is intended to be taken indefinitely, unless it is not controlling your MS effectively, or is causing intolerable side effects or risks. You and your MS provider will discuss the DMTs and choose one that seems best for you. If that medication is not well tolerated, or is not effective for your MS, you and your MS provider will choose a different DMT. See more information about MS DMTs here. 

17. Rehabilitation – Rehabilitation refers to care that helps regain, maintain, or improve physical, mental and/or cognitive function. It includes several types of therapies that are all directed at functional abilities and activities of daily living. Therapies may include: 

  • Physical therapy to improve or maintain mobility, strength, and flexibility, manage pain, prevent disability 
  • Occupational therapy to improve or maintain function and offer tools and strategies to enhance performance of daily activities. This may include physical and cognitive function. 
  • Speech therapy to improve speech, swallowing and/or cognitive function 

18. Exercise and lifestyle physical activity – Exercise is structured and repetitive movement with the goal of improving or maintaining strength, balance, flexibility, and/or overall fitness. Activities such as running, weightlifting, aerobics, and Pilates are all examples of exercise. Lifestyle physical activity is any movement of the muscles. Moving the arms to prepare a meal is an example of lifestyle physical activity.  

Regardless of someone’s limitations, it’s beneficial for everyone to increase physical activity in their everyday lives. Increasing activity can improve mood, strength and endurance, energy, and your ability to participate in usual activities. 

Terms About Common Symptoms

19. Optic neuritis – Optic neuritis translates to “eye inflammation” and refers to inflammation of the optic nerve. The optic nerve transmits visual signals from the back of the eye to the vision center located in the back part of the brain. There, the information can be processed so that we can interpret the image.  

The optic nerve can send signals very rapidly because of the myelin coating around the nerve. The optic nerve is a common location for MS inflammation, which generally occurs in one eye or the other, but never both eyes at the same time. In about one-quarter of people with a diagnosis of MS, optic neuritis is the first symptom that is experienced.  

Symptoms of optic neuritis can include blurred vision, dim vision, or complete loss of vision. In addition, loss of color vision (particularly reds appearing grayish), and difficulty with bright lights are also common. Most people who experience optic neuritis will have return of their vision over several weeks or months. It may not return 100% but can often be close to normal. Bright lights may remain uncomfortable and an elevated body temperature due to heat or fever may cause a temporary blurring of vision that returns to baseline once the body cools down. 

20. Spasticity – Spasticity refers to tightness or stiffness in the muscles, most often the muscles in the legs and back. Damage to nerve pathways in the spinal cord often cause spasticity. People who experience spasticity may also experience spasms – or a sudden onset of muscle tightness. Both spasticity and spasms can be painful and limit mobility. Physical therapy, exercises and sometime medications can help treat spasticity. 

21. Cognition – Cognition refers to all the brain processes needed to learn, understand, reason, remember and use knowledge and information. Impaired cognition is a very common symptom of MS.  


There will certainly be additional terms that you will hear or read that may also need definition or clarification. You can explore common symptoms, treatments, and more in MS A-Z. If you can’t find what you’re looking for, contact us. We’re here to help.