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

(DMT) Disease-modifying therapy (not drugs):
Medications for multiple sclerosis that can slow down the natural course of the disease; IM Ifnb-1a x1 per week 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. The examiner places wires on your scalp over the areas of the brain involved in receiving sensory information. Then the examiner provides specific sensory input for testing. For example, you may hear a series of clicks, be asked to look at screen with a checkerboard pattern, and be given mild electrical stimulation to your legs. The wires on your scalp record how fast your brain receives the sensory input. If the brain response is slower than normal, it can be an indication that the myelin in your brain or spinal cord has suffered inflammation or damage due to multiple sclerosis.

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

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

IM ifnb-1a x 1 per week:
Intra muscular Interferon 1a. Administered once a week.

Interferon:
A naturally occurring protein that is part of the immune system and helps the body fight off infection; there are three types of interferon’s (alpha, beta and gamma); interferon alpha and beta are 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

Lhermittes 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

Lumbar Puncture:
See Spinal Fluid Test

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 one of the most important tests used to diagnose multiple sclerosis because it can show brain lesions and scars associated with the disease.

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; 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.

Progressive Relapsing MS (PRMS):
A relatively rare type approximately 5% at onset. People with PRMS experience a steady worsening of the disease with clear, acute relapses with or without recovery. In contrast to RRMS, periods between relapses are characterised by continuing disease progression.

Relapsing-remitting MS (RRMS):
A type of multiple sclerosis that shows clearly defined flare-ups (relapses) with some amount of recovery in between; affects about 85% of all people with MS.

Sclerosis:
Scar; used to describe the many lesions or scars in the brain and spinal cord that characterize multiple sclerosis

Secondary progressive MS (SPMS):
A form of MS in which flare-ups and remissions are common 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

Spinal fluid test:
Also known as a lumbar puncture or spinal tap helps your neurologist see if the fluid that surrounds your central nervous system shows signs of MS. A long, thin needle is inserted between two bones in the lower spine to extract a sample of the colourless fluid.

A laboratory then examines the sample to see if it contains elevated levels of immune system cells that are often seen in people with MS.