HAVE QUESTIONS?1.877.447.3243

Glossary of MS Terms


A medication 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 (e.g., viruses) from passing out of the blood stream 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; a term used to describe a disease that cannot be cured.


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, 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. They are currently the most effective way of modifying the course of MS.

Double-Blind Clinical Study

A study in which neither the subjects (i.e. patients) nor the examining health care professionals (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); usually associated with inflammation and demyelination in the brain and/or spinal cord.


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 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.


Group of immune system proteins—alpha, beta and gamma—that are produced by different cells in the body. All three have antiviral effects but act in different ways to control the activity of the immune system.

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.

L'hermitte'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

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. It is characterized clinically by symptoms that may abate spontaneously in the early years of the disease but often get gradually worse in later years.


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.


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


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 and 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 liabilities 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.

Rebiject II®

Rebiject II is an autoinjection device for use only with Rebif®
(interferon beta-1a).


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 or an increase in the level of disability.


Repair of damaged myelin. Some myelin repair may occur spontaneously in MS but is usually a very slow and uncontrollable process.


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 just 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.


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.

Trigeminal Neuralgia

Lightning-like 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).


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. Rebif is not approved for treatment of chronic progressive MS.

Important safety information

What is the most important information I should know about Rebif?

Rebif will not cure multiple sclerosis (MS) but it has been shown to decrease the number of flare-ups and slow the occurrence of some of the physical disability that is common in people with MS. Rebif can cause serious side effects, so before you start taking Rebif, you should talk with your doctor about the possible benefits of Rebif and its possible side effects to decide if Rebif is right for you. Potential serious side effects include:

  • Depression. Some patients treated with interferons, including Rebif, have become seriously depressed (feeling sad). Some patients have thought about killing themselves and a few have committed suicide. Depression (a sinking of spirits or sadness) is not uncommon in people with multiple sclerosis. However, if you are feeling noticeably sadder or helpless, or feel like hurting yourself or others, you should tell a family member or friend right away and call your doctor as soon as possible. Your doctor may ask that you stop using Rebif. You should also tell your doctor if you have ever had any mental illness, including depression, and if you take any medications for depression
  • Liver problems. Your liver may be affected by taking Rebif and a few patients have developed severe liver injury. Your health care provider may ask you to have regular blood tests to make sure that your liver is working properly. If your skin or the whites of your eyes become yellow or if you are bruising easily you should call your doctor right away
  • Risk to pregnancy. If you become pregnant while taking Rebif you should call your doctor right away. Rebif may cause you to lose your baby (miscarry) or may cause harm to your unborn child. You and your doctor will need to decide whether the potential benefit of taking Rebif is greater than the risks are to your unborn child
  • Allergic reactions. Some patients taking Rebif have had severe allergic reactions leading to difficulty breathing and loss of consciousness. Allergic reactions can happen after your first dose or may not happen until after you have taken Rebif many times. Less severe allergic reactions, such as itching, flushing or skin bumps, can also happen at any time. If you think you are having an allergic reaction, stop using Rebif immediately and call your doctor
  • Injection-site problems. Rebif may cause redness, pain or swelling at the place where an injection was given. Some patients have developed skin infections or areas of severe skin damage (necrosis) requiring treatment by a doctor. If one of your injection sites becomes swollen and painful or the area looks infected and it doesn’t heal within a few days, you should call your doctor. For more information, please see Medication Guide

Who should not take Rebif?

Do not take Rebif if you:

  • Have had an allergic reaction, such as difficulty breathing, flushing, or hives, to another interferon beta or to human albumin

If you have any of the following conditions or serious medical problems, you should tell your doctor before taking Rebif:

  • Depression (a sinking feeling or sadness), anxiety (feeling uneasy or fearful for no reason), or trouble sleeping
  • Liver diseases
  • Problems with your thyroid gland
  • Blood problems, such as bleeding or bruising easily, and anemia (low red blood cells) or low white blood cells
  • Epilepsy
  • Are planning to become pregnant

Tell your doctor about all medicines you take, including prescription and non-prescription medicines, vitamins and herbal supplements. Rebif and other medicines may affect each other, causing serious side effects. Talk to your doctor before you take any new medicines.

What are the possible side effects of Rebif?

  • Flu-like symptoms (fever, chills, sweating, muscle aches and tiredness)
  • Skin reactions. Soreness, redness, pain, bruising, or swelling may occur at the place of injection
  • Depression and anxiety. Some patients taking interferons have become very depressed and/or anxious
  • Liver problems
  • Abdominal pain
  • Blood problems. You may have a drop in the levels of infection-fighting blood cells, red blood cells or cells that help to form blood clots. If the drop in levels is severe, it can lessen your ability to fight infections, make you feel tired or sluggish or cause you to bruise or bleed easily
  • Thyroid problems. Your thyroid function may change. Symptoms of changes in the function of your thyroid include feeling cold or hot all the time, change in your weight (gain or loss) without a change in your diet or amount of exercise you are getting
  • Severe allergic reactions. Allergic reactions are rare and may be associated with difficulty in breathing and loss of consciousness, which require immediate medical attention

Let your doctor know if you have any of these symptoms or feel sad, tired, hot or cold, or experience hives, rashes, bruising, yellowing of the skin, or a change in body weight (gain or loss).

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

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch, or call

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 www.rebif.com or call toll-free 1-877-447-3243. Rebif is available by prescription only.

MS LifeLines is an educational support service for people living with MS and their families. Speakers and MS LifeLines Ambassadors who participate in Talk MS or in live events are sponsored by EMD Serono, Inc. and Pfizer Inc. 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. and Pfizer Inc, the co-marketers of Rebif in the US.

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