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Glossary for Multiple Sclerosis

Learn the terminology of multiple sclerosis (MS), including definitions related to: neurology, symptoms, diagnostic criteria, treatment, immunology, basic science and related disorders.

Benign MS
Benign MS is a type of relapsing-remitting multiple sclerosis in which few relapses occur and result in very little permanent disability. It is thought that between 10 and 20% of people with MS have benign MS.

Glial Cells
Glial cells are brain cells that “support” neurons by providing nutrition for the neurons and insulating them from each other.

Cerebral Cortex
The cerebral cortex is the outer layer of gray matter covering the cerebral hemispheres. It is responsible for higher cognitive functioning.

The cerebellum is the part of the brain responsible for the coordination of movement and balance. It is common for MS lesions to be in the cerebellum, which lead to a variety of symptoms, including weakness, lack of coordination and some types of tremors.

Double-Blinded Trial
A double-blinded trial is a type of clinical trial in which neither the researchers nor the participants know which drugs are being taken.

Open-Label Trial
An open-label trial is a type of clinical trial in which both the researchers and the study participants know which drugs are being taken.

A neuropsychologist is a psychologist who specializes in diagnosing and treating neurobiological causes of brain disorders, such as those that occur as a result of multiple sclerosis (MS).

Intramuscular Injection
An intramuscular (IM) injection is an injection that is given directly into a muscle.

Pyramidal Tracts
Pyramidal tracts are nerve structures that begin in the sensorimotor areas of the cortex and go through the brainstem to the motor neurons of the spinal cord.

Neurons are the basic nerve cells of the nervous system that sends and receives messages between the brain and the body using electrical signals.

Meta-analysis is a statistical technique which combines the results of several studies.

B Cells
B cells are a type of white blood cell that produces and secretes antibodies.

Adherence means taking medications (or following other treatment) as prescribed.

Cerebrospinal Fluid
Cerebrospinal fluid is a clear, colorless fluid which flows around the brain and spinal cord to provide nourishment and protection.

Vestibular System
Vestibular System is made up of the parts of the inner ear and nervous system that control equilibrium, balance and orientation.

Corticospinal Tract
The corticospinal tract consists of nerve structures that begin in the sensorimotor areas of the cortex and go through the brainstem to the motor neurons of the spinal cord.

Synapses are the junctions between neurons.

Salvage Therapy
Salvage therapy is a drug regimen that is used when other treatments have failed.

Side Effect
A side effect is an effect of a drug other than that desired, usually referring to something negative.

In multiple sclerosis (MS), a lesion is an area of the central nervous system that is inflamed or has been demyelinated.

Paraplegia describes complete paralysis and loss of sensation of both legs and can happen in people with multiple sclerosis (MS).

Peripheral Nervous System
The peripheral nervous system includes all nerves other than those of the central nervous system (CNS).

Peripheral Neuropathy
Peripheral neuropathy is damage to the peripheral nervous system that causes pain, numbness, tingling and/or muscle weakness in the extremities.

Oligodendrocytes are a type of glial cell that produces myelin.

Statistical Significance
Statistical significance means the likelihood that a finding or a result is caused by something other than just chance.

Dendrites are the fibers of a brain cell that receive signals from other brain cells.

Progressive Multifocal Leukoencephalopathy (PML)
Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease caused by a type of polyomavirus called the JC virus (JCV). It has been associated with the use of Tysabri for multiple sclerosis (MS) and Crohn's disease.

Neutralizing Antibodies
Neutralizing antibodies are antibodies produced in response to a foreign agent. In people with multiple sclerosis (MS), neutralizing antibodies are often produced in response to disease-modifying treatments.

T Cells
T cells are a type of immune cell that does not produce antibodies, but bind to antigens with receptors on their surfaces.

Meaning "within a vein," refers to inserting a needle directly into a vein in order to administer medications or fluids.

Atrophy refers to shrinkage of muscle tissue or nerve tissue, both common in multiple sclerosis (MS).

The axon is the extension of the neuron that transmits messages. The functioning of axons is affected by multiple sclerosis (MS) through demyelination or through destruction of the axon itself.

Subcutaneous Injection
An injection in which the needle is inserted into the fatty tissue directly below the skin. Several disease-modifying therapies used for multiple sclerosis (MS) are administered by subcutaneous injection.

An intravenous infusion (IV) is a method of administering drugs and/or fluids through a needle is inserted directly into a vein. In multiple sclerosis (MS), IVs are used to administer corticosteroids, some disease-modifying therapies (such as Tysabri) and contrast material for MRI scans.

Experimental Autoimmune Encephalomyelitis (EAE)
Experimental autoimmune encephalitis (EAE) is the experimental form of multiple sclerosis (MS) that scientists use in laboratory animals to study different aspects of the disease or test drugs.

Central Nervous System (CNS)
The central nervous system is made up of the brain, the spinal cord and the optic nerve.

Gadolinium-Enhanced Lesion
A gadolinium-enhanced lesion appears on an MRI scan as a bright spot and is an indication of active inflammation.

T2-Weighted Lesions
T2-weighted lesions in MS are areas that appear as bright spots on MRI scans and indicate areas where myelin has been damaged or destroyed.

T1-Weighted Lesions
T1-weighted lesions in MS are areas that appear dark on MRI scans and indicate areas of permanent damage.

Lipoatrophy in MS is a loss of fat right under the skin and is caused by use of Copaxone (glatiramer acetate).

Uhthoff's Sign
Uhthoff's sign is a symptom of multiple sclerosis (MS) in which a person's vision becomes blurred when the body's temperature increases.

The thalamus is the part of the brain which processes sensory information, as well as being involved in other functions such as memory and emotions. Multiple sclerosis can cause a lesion on the thalamus which can cause tremor and spasticity.

Blood-Brain Barrier
The blood-brain barrier is the layer of cells in the capillaries of the central nervous system (CNS) which act as a filter between the bloodstream and the CNS. In multiple sclerosis, the blood-brain barrier allows immune cells into the CNS, which then attack the myelin.

Brain Stem
The brain stem is the part of the brain which controls involuntary functions such as breathing and heart rate. Multiple sclerosis lesions on the brain stem can cause vertigo and other symptoms.

Basal Ganglia
The basal ganglia are large clusters of nerve cells in the brain which help with movement. Multiple sclerosis can cause a lesion on the basal ganglia which can cause tremor and other symptoms.

Secondary-Progressive Multiple Sclerosis
Secondary-progressive multiple sclerosis is a type of MS that some people originally diagnosed with relapsing-remitting MS develop.

In multiple sclerosis areas of the brain or spinal cord that have been damaged form plaques.

Optic Neuritis
Optic neuritis is a common symptom of multiple sclerosis in which a person develops vision problems. These problems are usually in one eye and reversible.

Myelin is a layer of fats and proteins that protect nerve cells. In multiple sclerosis, the myelin is damaged in the brain or on the spinal cord, causing a range of symptoms.

MRIs - Magnetic Resonance Imaging
Magnetic Resonance Imaging scans (MRIs) are one of the most useful tools in diagnosing and monitoring MS.

Disease-Modifying Drugs
Disease-modifying drugs can help slow the progression of MS.

Multiple sclerosis symptoms occur because of a process called "demyelination" in which the outer coating of nerve cells is damaged.

Corticosteroids are a type of medication used to shorten the duration and severity of MS relapses and manage some symptoms.

Autoimmune disease
Multiple sclerosis is thought to be an autoimmune disease in which the cells of the immune system attack myelin in the brain and spinal cord.

Placebos and Clinical Trials
A placebo is a substance with no known therapeutic value that is used in a control group. Placebos are made to look like the medication being tested so study participants and study staff cannot tell a difference.

Clinical Trial Protocol
A protocol is the set of procedures to be followed in a clinical trial. In an MS clinical trial, the protocol should include carefully monitoring all patients for side effects and changes in MS symptoms and progression.

Control Group for Clincal Trials
In MS clinical trials, the control group either receives current standard treatment or a placebo. This is done to compare the results of the control group to that of the new therapy.

Informed Consent in Clinical Trials
Informed consent is one of the most important parts of a clinical trial. All participants in the trial must understand the procedures, as well as potential risks and benefits of participation before they enroll in the trial. This process is called informed consent.

Lumbar Puncture
The lumbar puncture is a diagnostic test for multiple sclerosis using cerebral spinal fluid.

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