Multiple Sclerosis




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.


Natural steroid hormones or man-made drugs used to suppress inflammation.

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)

These therapies include beta interferons, glatiramer acetate, and immunosuppressants fingolimod (mitoxantrone). 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).


In MS, form of treatment that slows or inhibits the body's natural immune responses, including those directed against the body's own tissues. Examples of immunosuppressive treatments in MS include cyclosporin, methotrexate, and azathioprine.


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 is identical to 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

Interferon beta that is slightly different from the one produced naturally by the human body. It is obtained in the laboratory via a biotechnological process: the interferon beta gene is inserted into bacteria, which then produce the protein. Interferon beta-1b has a slightly different amino acid structure and lacks the glycosylated moiety that is found in 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 mainly affects 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 auto-injection device for use only with Rebif® (interferon beta-1a) and is designed to help make injections easier to manage.


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 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).