MS Glossary

• Ataxia: inability to coordinate muscle movements, particularly wobbliness or unsteadiness while walking; ataxia is a symptom of multiple sclerosis
• Axon: nerve fibers that carry electrical impulses through the brain and spinal cord; they are surrounded by a protective sheath called myelin; in multiple sclerosis the axon can be damaged, causing symptoms such as numbness, tingling, muscle weakness and poor coordination
• Central Nervous System (CNS): the brain, spinal cord and optic nerve; the CNS carries electrical impulses between your brain and your muscles and sensory organs allowing for movement, vision, touch and other senses; multiple sclerosis is a CNS disease
• Demyelination: damage to and loss of myelin, the protective sheath around nerve fibers (axons); demyelination causes the symptoms of multiple sclerosis
• Disease-modifying drugs: medications for multiple sclerosis that can slow down the natural course of the disease; AVONEX is an example of a disease-modifying drug; disease-modifying drugs are different from medications used to treat flare-up symptoms
• Evoked Potentials: a test is used to measure how fast your brain responds to sensory input, such as flashing lights, sounds, or electrical stimulation; it can reveal the presence of brain lesions and is used to help diagnose multiple sclerosis
• Exacerbation (Sometimes called a relapse):an increase in the severity of multiple sclerosis symptoms; in relapsing/remitting MS exacerbations are unpredictable; they can appear and disappear suddenly, leaving behind limited functioning in the affected body part; exacerbations can last days, weeks or months
• Gait: patterns of walking; a change in gait, such as staggered walking with the legs wide apart, can be a symptom of multiple sclerosis
• Immune System: the cells, proteins and processes in your body that help protect it from harmful invaders such as bacteria and viruses; when the immune system attacks healthy tissue, it is called an autoimmune disease; multiple sclerosis is considered an autoimmune disease because the immune system attacks myelin in the brain, spinal cord and optic nerve
• Interferon: a naturally occurring protein that is part of the immune system and helps the body fight off infection; there are three types of interferons (alpha, beta and gamma); interferon beta is used in the treatment of multiple sclerosis
• Lesion: scars and damage to tissue; lesions seen in the brain through magnetic resonance imaging (MRI) can be an indication of multiple sclerosis
• L'hermitte's Sign: a shock-like sensation that extends down the spine and through the limbs caused by bending the neck forward; it is often experienced by people with multiple sclerosis and can be a symptom of the disease
• Magnetic Resonance Imagery (MRI): a noninvasive test that uses a magnetic field and radio waves to produce computerized images of your brain and spinal cord; MRI is used to diagnose multiple sclerosis because it can show brain lesions
• Myelin: a sheath made of fat and protein that surrounds the nerve fibers (axons) of the central nervous system; myelin protects the axons and also helps speed up the signals traveling along the spinal cord and in the brain; in multiple sclerosis, the myelin is damaged, causing a breakdown in electrical impulses, leading to symptoms
• Multiple Sclerosis (MS): a chronic disease of the central nervous system characterized by damage to the protective sheath (myelin) around nerve fibers; symptoms of MS include numbness, tingling, muscle weakness, poor coordination and vision problems
• Neurologist: a physician who specializes in diseases of the central nervous system (brain, spinal cord and optic nerve), including multiple sclerosis; usually a neurologist is the healthcare provider who makes a diagnosis of multiple sclerosis
• Optic Neuritis: an inflammation of the optic nerve, the nerve that controls the eye; can cause double vision, blurred vision or eye pain; is often an early symptom of multiple sclerosis
• Placebo: an inactive substance used in clinical trials as a guideline against which the drug being studied can be measured; a drug must be more effective than the placebo to be considered a useful treatment
• Primary progressive MS: a type of multiple sclerosis in which there are no flare-ups (relapses), but over a period of years, there is gradual loss of physical and cognitive functions; affects about 10% of all people with MS.
• Relapsing-remitting MS: a type of multiple sclerosis that shows clearly defined flare-ups (relapses) with some amount of recovery in between; affects about 80% of all people with MS.
• Relapse (Sometimes called an exacerbation):an increase in the severity of multiple sclerosis symptoms; in relapsing/remitting MS exacerbations are unpredictable; they can appear and disappear suddenly, leaving behind limited functioning in the affected body part; exacerbations can last days, weeks or months
• Sclerosis: scar; used to describe the many lesions or scars in the brain and spinal cord that characterize multiple sclerosis
• Secondary progressive MS: a form of MS in which flare-ups and remissions are common in the in the early-to-mid stage,; but then a more continuous loss of physical and cognitive functions starts to take over; 50% of people with relapsing-remitting MS will develop secondary progressive MS within 10 years of their initial diagnosis.
• Spasticity: stiffness, tightness or contractions in the muscles, most commonly the legs; a symptom of multiple sclerosis

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