MS terms


These are some MS terms to know. Of course, a definition is only part of truly understanding something. If you have any questions at all, talk to your healthcare provider. And, as always, you can reach one of our MS-certified nurses at 1-877-447-3243.
We’re here to help.


Medications capable of preventing or relieving spasms or convulsions.

Lack of coordination and unsteadiness that result from the brain’s failure to regulate the body’s posture and the strength and direction of limb movements. Most often caused by disease activity in the cerebellum or its connections with other parts of the brain.

See Exacerbation.

Autoimmune Disease
Process in which the body’s immune system causes illness by mistakenly attacking healthy cells, organs, or tissues. Multiple sclerosis is believed to be an autoimmune disease, as are systemic lupus, rheumatoid arthritis, scleroderma, and many others. The precise origin and an understanding of how these diseases occur are not yet well known.


Bell’s Palsy
Paralysis of the facial nerve, which can occur as a consequence of MS, viral infection, or other infections. It has acute onset and can be transient or permanent.

Blood-Brain Barrier (BBB)
Semi-permeable cell layer around blood vessels in the brain and spinal cord that prevents large molecules, cells, and potentially damaging substances and disease-causing organisms (eg, viruses) from passing out of the bloodstream into the central nervous system (brain and spinal cord).


Central Nervous System (CNS)
Collective term for the major part of the nervous system that is principally comprised of the brain and spinal cord.

Of long duration, not acute.

Cog Fog
A feeling of confusion or lack of mental clarity brought on by cognition issues related to MS. This cognitive symptom is common in people with MS and is also known as brain fog.

High-level functions carried out by the human brain, including comprehension and use of speech; visual perception and construction; calculation ability; attention (information processing); memory; and executive functions such as planning, problem solving, and self-monitoring.

Combined Bladder Dysfunction
Type of neurogenic bladder dysfunction in MS (also called detrusor-external sphincter dyssynergia—DESD). Simultaneous contractions of the bladder's detrusor muscle and external sphincter cause urine to be trapped in the bladder, resulting in symptoms of urinary urgency, hesitancy, dribbling, and incontinence.

Condition in which bowel movements happen less frequently than is normal for the particular individual, or the stool is small, hard, and difficult or painful to pass.

Permanent shortening of the muscles and tendons adjacent to a joint, which can result from severe, untreated spasticity and interferes with normal movement around the affected joint. If left untreated, the affected joint can become frozen in a fixed position.

Often known as steroids, corticosteroids are an anti-inflammatory medicine prescribed for a wide range of conditions.

Cranial Nerves
Nerves that carry sensory, motor, or parasympathetic fibers to the face and neck. Included among this group of twelve nerves are the optic nerve (vision), trigeminal nerve (sensation along the face), oculomotor nerve (eye movement), facial nerve, auditory nerve, and vagus nerve (pharynx and vocal cords). Evaluation of cranial nerve function is part of the standard neurological exam.


Destruction of the myelin sheath, which surrounds the “axons” or nerve fibers in the central nervous system, that results in interruptions of communications between neurons. Regions of demyelination cause interruptions in the conduction of nerve impulses.

A mood disorder marked especially by sadness, inactivity, difficulty with thinking and concentration, a significant increase or decrease in appetite and time spent sleeping, feelings of dejection and hopelessness, and sometimes suicidal thoughts or an attempt to commit suicide.

Double vision or the simultaneous awareness of two images of the same object that results from a failure of the two eyes to work in a coordinated fashion.

As defined by the World Health Organization (WHO), a disability (resulting from an impairment) is a restriction or lack of ability to perform an activity in the manner of, or within the range considered normal for, a human being.

Disease-Modifying Drugs (DMD)
Disease-modifying therapies have been shown in clinical trials to modify the course of MS.

Double-Blind Clinical Study
A study in which neither the subjects (ie, patients) nor the examining healthcare providers (or attending nurses, or any other research staff) know who is taking the test drug and who is taking a control or placebo agent.

Impairment of sensitivity, especially to touch.


In MS, the appearance of new symptoms or the aggravation of old ones, lasting at least twenty-four hours (synonymous with attack, relapse, flare-up, or worsening).


See Exacerbation.

Foot Drop
Condition of weakness in the muscles of the leg caused by poor nerve conduction, which interferes with a person’s ability to extend the ankle and walk with a normal pattern. The toes touch the ground before the heel, causing the person to trip or lose balance.


Contrast medium injected prior to MRI scans. It passes through breaches in the blood-brain barrier and is therefore used to highlight new and active lesions. The usage of gadolinium greatly enhances the sensitivity of a T1-weighted MRI.

A person who specializes in gastroenterology, a branch of medicine concerned with the structure, functions, diseases, and pathology of the stomach and intestines.



Immune System
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells.

Ability to resist infection and to heal. The process may involve acquired immunity (the body's ability to learn and remember a specific infectious agent) or innate immunity (the genetically programmed system of responses that attack, digest, remove, and initiate inflammation and tissue healing).

A reduction in immune response. It may be the means by which a drug achieves its intended effect, but it may also be an unintended side effect. For instance, immunosuppression may cause a drop in infection-fighting blood cells.

Also called spontaneous voiding; the inability to retain control of urine or bowel movements.

The immunologic response of body tissue to injury, characterized by mobilization of white blood cells and antibodies, swelling, and fluid accumulation.

Prolonged and usually abnormal inability to obtain adequate sleep.

Interferons are a family of naturally occurring proteins that are produced by eukaryotic cells in response to viral infection and other biological inducers. Interferons possess immunomodulatory, antiviral, and antiproliferative biological activities. They exert their biological effects by binding to specific receptors on the surface of cells. Three major groups of interferons have been distinguished: alpha, beta, and gamma.

Interferon beta-1a
Interferon beta that has the same amino acid sequence as that produced naturally by the human body. It is obtained in the laboratory via a biotechnological process: the interferon beta gene is inserted into laboratory-grown mammalian cells, which then produce the protein.

Interferon beta-1b
Interferons belong to a family of proteins that occur naturally in the body, helping to regulate the body’s immune system and fight disease. Interferon beta-1b is obtained in the laboratory via a biotechnological process: the interferon beta gene is inserted into bacteria, which then produce the protein. Its amino acid sequence (or protein) structure is identical to the body’s own natural interferon beta.

Intramuscular Injection
Injected into the muscle.

Within a vein; often used in the context of an injection into the vein of a medication dissolved in a liquid.




See Plaque.

Lhermitte’s Sign
Abnormal sensation of electricity or “pins and needles” going down the spine into the arms and legs that occurs when the neck is bent forward.


Magnetic Resonance Imaging (MRI)
Imaging technique based on detection of the response of water molecules to strong magnetic fields. It produces visual images of different body parts without the use of X-rays. MRI allows the neurologist to identify MS lesions in the brain and spinal cord at different stages of their development. T1 scans and T2 scans refer to the different scanning sequences that help distinguish tissue features.

Marcus Gunn Pupil
An abnormal physical examination finding in the pupil of your eye that may result from an episode of optic neuritis.

MRI T1-Weighted Scans
See Magnetic Resonance Imaging.

MRI T2-Weighted Scans
See Magnetic Resonance Imaging.

Multiple Sclerosis (MS)
Presumed autoimmune disease of the central nervous system that is usually first diagnosed in young adults and whose origin is unknown. It damages myelin (nerve fiber insulation) and axons (nerve fibers) in a random and patchy manner, causing a wide range of neurological defects.

Soft, white coating composed of lipids (fats) and protein, surrounding nerve fibers in the central nervous system. A complex natural electrical insulator, myelin serves to speed up the conduction of electrical signals down nerve fibers.


Nerve inflammation, usually with direct nerve damage. Part of a degenerative process.

Relating to or involving both nervous stimulation and endocrine secretion.

Psychologist with specialized training in the evaluation of cognitive functions. Neuropsychologists use a number of standardized tests to evaluate specific cognitive functions and identify areas of cognitive impairment. They also may suggest possible treatments for individuals with MS-related cognitive impairment. See Cognition.

The need to urinate during the night.

Rapid, involuntary movements of the eyes in the horizontal or, occasionally, vertical direction.


Optic Nerve
The main nerve leading from the eye to the brain that transmits visual signals to the brain.

Optic Neuritis
Inflammation or demyelination of the optic (visual) nerve with temporary or permanent impairment of vision; associated with pain during the acute phase.


Inactive non-drug compound designed to look just like the test drug. It is administered to control group subjects in double-blind clinical trials (in which neither the researchers nor the subjects know who is getting the drug and who is getting the placebo) as a means of assessing the benefits and risks of a test drug taken by experimental group subjects.

An area of inflamed or demyelinated central nervous system tissue.

Primary Progressive MS (PPMS)
Clinical course of MS that is characterized from the beginning by progressive disease with no plateaus or remissions, or with an occasional plateau and very short-lived, minor improvements.



Involuntary response of the nervous system to a stimulus, such as the stretch reflex, which is elicited by tapping a tendon with a reflex hammer, resulting in a muscle contraction. Abnormal reflexes can be indicative of neurologic damage, including MS, and are therefore tested as part of the standard neurological exam.

See Exacerbation.

Relapsing-Remitting MS (RRMS)/Relapsing MS
Clinical course of MS that is characterized by the occurrence of new symptoms or the worsening of old symptoms (relapses or exacerbations). Symptoms may evolve over several days or weeks and then fully or partially disappear. The pattern of attacks is unpredictable, even in the same person.

Lessening in the severity of symptoms, or a “return” to the level of health equal or similar to the one experienced prior to the last attack.

Repair of damaged myelin. Some myelin repair may occur spontaneously in MS.


Anything that can happen that may present a risk and/or require medical attention—investigation, monitoring, or potential treatment. You might not feel a safety issue at all, so your healthcare provider will test you periodically to monitor for safety concerns.

An abnormal condition in which tissue has become hard, produced by overgrowth of fibrous tissue (scars). The term “multiple sclerosis” refers to multiple scars in the brain.

Secondary-Progressive MS (SPMS)
Clinical course of MS that initially is relapsing MS and then becomes progressive at a variable rate. With SPMS, neurological symptoms worsen progressively. At first, there may still be some relapses; then relapses generally stop completely, and a slow but steady progression of disability takes place.

An involuntary and abnormal contraction of muscle.

Increased muscle tone associated with involuntary muscle contractions, spasms, and stiffness. In multiple sclerosis, spasticity is most prominent in the lower limbs.

See Corticosteroids.

Subcutaneous Injection
Injected under the skin.

Subjectively perceived problem or complaint reported by the patient. In multiple sclerosis, common symptoms include visual problems, fatigue, sensory changes, weakness or paralysis of limbs, tremor, lack of coordination, poor balance, bladder or bowel changes, and psychological changes.


T Cells
Any of several types of white blood cells that develop in the thymus gland and play a role in the control of immune response.

Gradual stepping up of a dose of medicine. It allows the body to adjust and become used to the medicine’s effects, thereby reducing the likelihood and severity of potential side effects that may occur at the beginning of a treatment.

Tolerability is related to how a drug makes you feel—like if there are uncomfortable side effects. Sometimes people can put up with effects like these to meet their treatment goals. Other times, these effects are unbearable, so a change of treatment may be recommended. And occasionally, a side effect can also be a safety issue, too.

Trigeminal Neuralgia
Chronic condition that may cause acute pain in the face caused by demyelination of nerve fibers in the trigeminal nerve root (the nerve responsible for relaying feeling/sensation signals to the brain).







MS LifeLines Ambassadors are sponsored by EMD Serono, Inc.


Rebif® (interferon beta-1a) is used to treat relapsing forms of MS to decrease the frequency of relapses and delay the occurrence of some of the physical disability that is common in people with MS.

Important Safety Information

Before beginning treatment, you should discuss the potential benefits and risks associated with Rebif with your healthcare provider.

Rebif can cause serious side effects. Tell your healthcare provider right away if you have any of the symptoms listed below while taking Rebif.

  • Behavioral health problems, including depression and suicidal thoughts. You may have mood problems including depression (feeling hopeless or feeling bad about yourself), and thoughts of hurting yourself or suicide
  • Liver problems or worsening of liver problems, including liver failure. Symptoms may include nausea, loss of appetite, tiredness, dark colored urine and pale stools, yellowing of your skin or the white part of your eye, bleeding more easily than normal, confusion, and sleepiness. During your treatment with Rebif you will need to see your healthcare provider regularly and have regular blood tests to check for side effects
  • Serious allergic and skin reactions. Symptoms may include itching, swelling of your face, eyes, lips, tongue or throat, trouble breathing, anxiousness, feeling faint, skin rash, hives, sores in your mouth, or skin blisters and peels
  • Injection site problems. Symptoms at the injection site may include redness, pain, swelling, color changes (blue or black), and drainage of fluid
  • Blood problems. Rebif can affect your bone marrow and cause low red and white blood cell and platelet counts. In some people, these blood cell counts may fall to dangerously low levels. If your blood cell counts become very low, you can get infections and problems with bleeding and bruising. Your healthcare provider may ask you to have regular blood tests to check for blood problems
  • Seizures. Some people have had seizures while taking Rebif

Rebif will not cure your MS but may decrease the number of flare-ups of the disease and slow the occurrence of some of the physical disability that is common in people with MS.

Do not take Rebif if you are allergic to interferon beta, human albumin, or any of the ingredients in Rebif.

Before you take Rebif, tell your healthcare provider if you have or have had any of the following conditions:

  • mental illness, including depression and suicidal behavior
  • liver problems, bleeding problems or blood clots, low blood cell counts, seizures (epilepsy), or thyroid problems
  • you drink alcohol
  • you are pregnant or plan to become pregnant. It is not known if Rebif will harm your unborn baby. Tell your healthcare provider if you become pregnant during your treatment with Rebif
  • you are breastfeeding or plan to breastfeed. It is not known if Rebif passes into your breast milk. You and your healthcare provider should decide if you will use Rebif or breastfeed. You should not do both

Tell your healthcare provider about all medicines you take, including prescription and over-the-counter medicines, vitamins and herbal supplements.

The most common side effects of Rebif include:

  • flu-like symptoms. You may have flu-like symptoms when you first start taking Rebif. You may be able to manage these flu-like symptoms by taking over-the-counter pain and fever reducers. For many people, these symptoms lessen or go away over time. Symptoms may include muscle aches, fever, tiredness, and chills
  • stomach pain
  • change in liver blood tests

Tell your healthcare provider if you have any side effect that bothers you or that does not go away.

These are not all the possible side effects of Rebif. For more information, ask your healthcare provider or pharmacist.

Call your doctor for medical advice about side effects.

Refer to the Instructions for Use that comes with the Rebif® Rebidose® (interferon beta-1a) autoinjector.

This information is not intended to replace discussions with your doctor. For additional information about Rebif, please consult the Prescribing Information and Medication Guide and talk to your doctor. You can also visit or call, toll-free, 1-877-447-3243. Rebif is available by prescription only.

Rebif, Rebif Rebidose, Rebiject II, MS LifeLines, and the Rebif logo are registered trademarks of EMD Serono, Inc. or its affiliates.

Brought to you by EMD Serono, Inc., the marketer of Rebif in the US.

This information is intended only for residents of the United States.