Glossary of terms
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
A
Acute:
Having rapid onset, usually with recovery, not chronic or long lasting
Aetiology:
The study of the cause of the disease
Antibodies:
Protein substances produced by the human body in response to antigens. The most significant antibodies produced in case of MS are those made by B-lymphocytes.
Antigen:
The protein part of an organism or cell that the body recognises, rightly or wrongly, as foreign, and which therefore stimulates the production of antibodies to mount a defence immune action. Viruses and bacteria are examples of external antigens. When an antigen comes from part of the body, the reaction is known as auto-immunity. MS may be the result of either an external antigen or an autoimmune response.
Anti-viral Agents:
Drugs and other substances, which are used to counteract viruses.
Assistive Devices:
Any tools that are designed, fabricated, and/or adapted to assist a person in performing a particular task, eg: cane, walker, shower chair, adapted kitchen utensils.
Astrocytes:
Spidery or star-shaped cells which hold together the structures in the central nervous system. Astrocytes control the blood brain barrier and are responsible for producing scar tissue when myelin sheaths have been irreparably damaged.
Autoimmune:
A disease occurring when the body misrecognises part of its own tissue as foreign and attacks that tissue causing damage.
Axons:
The fibres that carry messages in the nervous system. They are protected and insulated by myelin sheaths.
B
Babinski reflex:
A neurologic sign in MS in which stroking the outside sole of the foot with a pointe object causes an upward (extensor) movement of the big toe rather than the normal (flexor) bunching and downward movement of the toes.
Benign:
In the medical sense, this tern means mild or not causing serious damage.
Blood-brain Barrier:
A type of filter that prevents some substances but not others into the central nervous system (CNS) from the blood stream.
B-Lymphocytes (B-cells):
A major family of white blood cells that are produced in the bone marrow and circulate in the bloodstream. They are one of the immune system’s weapons in attacking and invading organisms, through their production of antibodies.
Brain Stem:
The part of the central nervous system that houses the nerve centers of the head as well as the centers for respirationand heart control. It extends from the base of the brain to the spinal cord.
C
CAT Scan (CT Scan):
An x-ray technique, which produces images of the body on thin slices rather than presenting a flat view from one perspective.
Caucasian:
A member of the white or light skinned races of humankind.
Central Nervous System (CNS):
Defined as the brain, optic nerves and spinal cord the CNS is the body’s main control system. MS occurs only within this system.
Cerebrospinal Fluid:
The special fluid, which bathes the central nervous system. It can be tapped for analysis using a lumbar puncture – a procedure in which a needle is inserted between lumbar vertebrae and fluid is drawn off.
Cerebrum:
The large, upper part of the brain, which acts as a master control system and is responsible for initiating thought and motor activity.
Chronic:
Long lasting – MS is a chronic condition. The opposite medical term is acute, meaning a condition that is marked by a crisis or sudden onset.
Clinical Finding:
An observation made during a medical examination indicating change or impairment in a physical or mental function.
Cognitive function:
To do with thought processes and intellectual functions such as memory, problem solving, goal setting rather than the emotions.
Contraction:
A shortening of muscle fibers and muscle that produce movement around a joint.
Cranial Nerves:
Nerves that carry sensory or motor fibers to the face and neck. Included among this group of 12 nerves are the optic nerve (vision), trigeminal nerve (sensation along the face), vagus nerve (pharynx and vocal cord). Evaluation of cranial nerve function is part of the standard neurologic exam.
D
Demyelination:
The disease process, in which the myelin sheaths around the nerve fibres in the CNS are attacked, damaged and replaced by scar tissue. There are a number of demyelinating diseases in humans and animals but MS is the most common in humans and does not occur in animals.
Diplopia:
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. Covering one eye will erase one of the images.
Disability:
As defined by the World Health Organisation, a disability (resulting from an impairment) is a restriction or lack of ability to perform an activity in the manner or within the range considered normal for a human being.
Dormant:
Inactive, some viruses are known to lie dormant in the body for long periods of time, subsequently becoming activated. A possible role of viral infections in MS has still not been excluded.
Dysesthesia:
Distorted or unpleasant sensations experienced by a person when the skin is touched.
E
EAE (Experimental Allergic Encephalomyelitis):
An autoimmune demyelinating disease of mice and other small animals, which closely resembles MS in its processes and effects and is therefore used for laboratory study in MS research. However, it is not identical to MS.
Electroencephalography (EEG):
A diagnostic procedure that records, via electrodes attached to various areas of the persons head, electrical activity generated by brain cells.
Epidemiology:
The science of studying diseases in whole populations – a word derived from epidemic.
Evoked responses:
Nerve conduction can be assessed by testing the body’s response to outside stimulating, usually through the eyes or by touch. Such tests can sometimes show evidence of damage to the CNS when there are no obvious symptoms. They measure the magnitude and speed of the condition by detecting small electrical output of nerves.
Exacerbation: (bout, attack)
In MS, an acute recurrence of previous symptoms or the relatively sudden development of new symptoms: both are the result of renewed disease activity in the CNS.
F
Flaccid:
A decrease in muscle tone resulting in loose, "floopy" limbs.
Flexor Spasm:
Involuntary, sometimes painful contractions of the flexor muscles, which pull the legs upward into a clenched position. They often occur during sleep, but can occur when the person is in a seated position.
H
Helper T-lymphocytes:
White blood cells that are a major contributor to the immune system's inflammatory respones against myelin.
I
Idiopathic:
The cause is unknown.
Immunoglobuin (Gamma) (IgG):
A protein made by the B-cells and normally found in the bloodstream, IgG contains antibodies. Raised levels on the CSF are additional evidence in diagnosing MS.
Immunosuppressive Agents (Drugs):
Able to suppress some or all of the functions of the immune system. Drugs, which can do this, are given to people who have organ transplants so the body does not reject the new component. Most of these drugs have been tested for the treatment of MS
Immune System:
The complex system by which the body recognises and destroys antigens. It uses various families of white blood cells made in such organs as the bone marrow and the thymus gland. The study of this system (immunology) is now a very important part of medical science.
Incidence:
In epidemiological terms, the number of new cases of a disease or condition occurring in a given population in a given period – usually a year. It is often mistakenly used instead of the term prevalence e.g.: 2 per 100,000 per year.
Incontinence:
The inability to control passage of urine or feces.
Inflammation:
The body’s response to injury, infection or other attacks. On the skin, this can be seen as redness and swelling. In the CNS an attack on the myelin sheath results on accumulation of white blood cells and fluid, called oedema (swelling)
Interferons:
A group of proteins which are made by cells when infected with a virus, and which can prevent nearby cells from being infected. Different interferons are being tested for there
L
Longitudinal:
Of length or duration, implying on
Lumbar Puncture:
A diagnostic procedure that uses a hollow needle to penerate the spinal canal to remove cerebrospinal fluid for analysis. This procedure is used to examine the cerebrospinal fluid for changes in composition that are characteristic of MS (elevated white cell count, elevated protein content)
Lymphocytes:
Families of white blood cells with different functions in the body’s immune system (see B – and T – lymphocytes) natural killer cells
M
Macrophage:
A white blood cell, which literally eats and disposes of debris in the CNS following tissue damage. The macrophage is made in the bone marrow.
Microglia:
A component cell of the CNS, it helps the macrophage remove damaged tissues after an attack.
Motor nerves:
Nerves, which the brain uses to control movement of muscles.
MRI (Magnetic Resonance Imaging):
A scanning technique for producing images of the body’s internal tissues. Like CAT scanners, MRI scanners provide pictures of a thin slice of the body – but by using magnetic fields and radio waves rather than x-rays. MRI scanning shows the lesions (plaques) of MS, the CAT scan does not.
Myelin:
The many-layered sheath composed mainly of fats and protein, which are wrapped around nerve fibres. They insulate the fibres from one another and aid conduction. Myelin is damaged in MS thus interfering with nerve impulse.
Myelin Basic Protein:
A protein, which forms an important part of the myelin sheath. It has proved significant in both inducing and protection again EAE, but this effect has not yet been demonstrated in MS in humans.
N
Natural Killer (NK) Cells:
A group of lymphocytes made in the bone marrow. As their name implies, they destroy other cells, which have been identified as faulty. They are part of the body’s immune defence system.
Nerve Cells:
Tiny structures which form the main component of grey matter. The billions of nerve cells in the brain are the starting point for messages carried along nerve axons (fibres) and both cell and fibre are part of the same structure.
Nervous System:
The body’s complex message system is made up of the CNS, the peripheral nerves (e.g.: those leading from the CNS to the limbs) and the autonomic nerves (which control the heart beat, blood pressure and other functions not under conscious control)
Neurogenic:
Arising from, or with a neurological basis.
Neurologist:
A physician specialising in disease of the nervous system and usually the clinician who will make the definitive diagnosis of MS.
O
Occupational Therapist (OT):
Occupational Therapist assess functioning in activities of everyday living that are essential for independent living, including dressing, bathing, grooming, meal preparation, writing, driving.
Oedema or Oedema:
A medical term to describe an abnormal builds up of fluid in body tissues usually after injury or infection. Sometimes oedema is visible as swelling in the skin. It is also part of the inflammatory process in MS.
Oligdendrocytes (Oligodendroglia):
Cells in the CNS, which is responsible for making and then maintaining the myelin sheath.
P
Paresthesia:
A sensation of burning, prickling, tingling or creeping on the skin that is often seen in MS.
Pathogen:
An agent causing disease.
Plaques:
The essential lesion in the brain in MS caused by loss of myelin in a small zone of nervous tissue.
Prevalence:
In epidemiology, the number of cases in a given population at a given time. Often confused with incidence, e.g. incidence might be 2 per 100,000 per year and prevalence 60 per 100,000 populations. The prevalence of MS in Ireland is at least 100 per 100,000 populations.
Progressive:
Used in medicine to describe a condition or disease, which gets worse over time. In MS, there is the primary progressive form, that is progressive from the outset, and the secondary progressive form in which progression follows relapsing/remitting MS.
R
Remitting (relapsing/remitting):
A term used to describe a disease in which symptoms come (relapse) and then go (remissions). Most people with MS experience such a pattern of symptoms in the early stages of the disease.
Remyelination:
The opposite process to demyelination. Some evidence exists to show that myelin can be repaired in the CNS by a process not yet understood. Remyelination (and even growth of fibres) is commonly observed in the peripheral nerves and the possibility of encouraging this in the CNS is being actively explored for its obvious potential to correct some of the damage caused by MS.
S
Sclerosis:
Scarring of tissue within the body.
Sensory nerves:
Those nerves which convey information, back to the brain about the environment outside and inside the body.
Symptomatic:
Of or related to symptoms. Some researchers are trying to find ways to ease the symptoms of MS; that is, to provide successful symptomatic treatments, which do not, however, alter the disease process itself.
T
T-lymphocytes (T-cells):
White blood cells produced by the thymus gland in the upper chest. There are many different types of T-cells, all with different jobs in the immune system.
Trigeminal neuralgia:
Brief attacks of severe pain involving the trigeminal nerve. Pain is usually felt in the region of the cheek or jaw.
U
Urinary Frequency:
Need or urge to urinate more frequently than normal due to small hyperactive bladder.
Urinary Hesitancy:
The inability to void urine spontaneously even though the urge to do so is present.
Urinary Urgency:
The inability to postpone urination once the need to void has been felt.
V
Vertigo:
A dizzying sensation of the environment spinning, often accompanied by nausea and vomiting.
Virus:
A tiny organism, which can exist only in other living cells and is capable of causing disease.