Glossary of MS/Medical Terms

This glossary is a compilation of information gathered from several sources. Hope you find what you are looking for! Special thanks to: ThJuland's Dell and MSRevealed Take the time to visit each of these sites you won't be disappointed!
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A B C D E F G H I L M N O P R S T U V W 


Ambulatory: able to walk, not bedridden.

ACTH (adrenocorticotrophic hormone): used for short term treatment of an acute exacerbation (attack), no value as a long term treatment of MS. A substance produced by the brain that regulates the production of steroids by the adrenal gland. This material can be produced artificially and is sometimes recommended by physicians to manage flare-ups of Multiple Sclerosis.

Antibodies: Substances produced by cells in response to stimullating agents such as viruses or bacteria, they are tailor made for a particular antigen. Proteins produced by special cells in the immune system that attack germs, parasites, and other foreign substances in the body.

Amyotrophic Lateral Sclerosis (ALS or Lou Gehrig's Disease): A degenerative disease of the motor neurons, characterized by weakness and atrophy of the muscles. ALS effects most all of the muscles in the body and face. A degenerative process in the motor neurons of the anterior horns and corticospinal tracts. ALS is discovered in middle age and progresses rapidly. A patient given a definitive diagnosis of ALS has a life expectancy from 2-5 years. Studies indicate that a patient who has a general sense of well being and lessened outside stressors will live longer within that 2-5 year life expectancy range. Compared to that of an ALS patient who has overwhelming outside stressors may expire more rapidly within the estimated 2-5 year range.

Anti-inflammatory Drugs: Over-the-counter and prescription medications that are sometimes recommended to decrease inflammation. Aspirin and Ibuprofen are types of over-the-counter anti-inflammatory medications.

Ataxia: A condition that is characterized by an impaired ability to coordinate movement. A staggering gait and poor balance are caused by lesions in the spinal cord or cerebellum. Which is the case in the demyelinating and degenerative nerve tissue that occurs in many Multiple Sclerosis patients. Ataxia is not exclusive to Multiple Sclerosis and may also occur in other disorders such as, the sequela of a birth trauma, congenital disorders, neoplasm, toxi substance, or head injury.

Ataxic speech Abnormal speech characterized by faulty formation of the sounds because of neuromuscular dysfunction.

Autoimmune disease: A process in which the body's immune system causes illness by attacking elements, such as particular cells or materials, that are normal and essential for health. The immune system is the body's defense system against abnormal substances (such as viruses or bacteria) in the body. In autoimmune disorders, the body's defense system attacks substances that are needed by (versus harmful to) the body.


Baclofen: A prescription medication for individuals with Multiple Sclerosis that is recommended for spasticity of muscles. Baclofen is an anti-spasticity agent that is believed to interfere with spinal cord activity that produces abnormal tone in the legs and arms.

biotechnology: biology and genetic engineering applied to science and technology.


CAT scanner: the imaging test,computerized axial tomography, where each image is generated by a computer synthesis of x-ray transmission data obtained in many different directions in a given plane.

central nervous system: the part of the nervous system which in vertebrates consists of the brain and the spinal cord, to which sensory impulses are transmitted and from which motor impulses pass out, and which coordinates the activity of the entire nervous system.

Cerebellum A part of the brain located in the posterior cranial fossa behind the brain stem. There are two lateral cerbellar lobes and a middle section called the vermis. Linking the brain stem are three pairs of peduncles. It's function is responsible for coordinating muscular activity.

Cerebellar Function Disorders: The severity of symptoms seems to depend on the amount of tissue destroyed and not on where the damage is. Among the most characteristic signs of cerebellar damage are the following:
1) Asthenia - This refers to a lack of muscular strength, either during voluntary muscle contraction or in holding posture.
2) Ataxia - Literally "difficulty measuring" this term refers to failure to stop a motion at the intended point with overshoot occurring. Prediction would seem to be faulty here. This term indicates incoordination of muscular activity involving tremor, failure of progression, and failure accurately to perform rapid alternating movements such as tapping a finger. A swaying, unsteady and wide based gait is often the most obvious sign.
3) Fatigability - Muscles on the same side as where cerebellar damage has occurred tire more easily and have slower than normal contraction and relaxzation times, leading to slowed movements.
4) Hypotonia - The muscles feel flabby and offer less resistance to passive displacement. This may be from lack of response to spinal tract input.

Cerebellum: A part of the brain located in the posterior cranial fossa behind the brain stem. There are two lateral cerbellar lobes and a middle section called the vermis. Linking the brain stem are three pairs of peduncles. Its function is responsible for coordinating muscular activity.

Cognition: 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.

Coordination: An organized working together of muscles and groups of muscles aimed at bringing about a purposeful movement, such as walking or standing.

corticosteroid: a steroid produced by the adrenal cortex.

Cortisone: A steroid hormone recommended to some people with Multiple Sclerosis to reduce acute inflammations in the nervous system.


Decompostion of Movement: inability to sequence properly fine, coordinated acts.

Deep tendon reflexes: The involuntary jerks that are normally produced at certain spots on a limb when the tendons are tapped with a hammer.

Demyelination: Loss of the myelin sheath that normally covers a nerve. The destruction or removal of the myelin covering nerve tissue. The stripping off of the myelin lining of nerve fibers by a disease process. Multiple sclerosis is a demyelinating disease. Other factors, however, can also cause demyelination.

diagnosis: the determination of the nature of a disease.

Diplopia: Double vision, or the simultaneous awareness of two images of the same object that results from the failure of the two eyes to work in a coordinated fashion. Often covering one eye will ease symptoms, by erasing one of the images.

Disability: 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.

Dysarthia: Problems with the clarity or rhythm of speech. Poorly articulated speech resulting from dysfunction of the muscles controlling speech. The content and meaning of the spoken words remain normal.

Dysphagia: A Condition in which the action of swallowing is either difficult to perform, painful or in which swallowed material seems to be held up in its passage to the stomach. It is caused by painful conditions of the mouth and throat, obstruction of the pharynx or esophagus by diseases of the wall or pressure from outside, or by abnormalities of muscular activity of the pharynx or esophagus.

Dysphonia: Disorders of voice quality (including poor pitch control, hoarsness, breathiness, and hypernasality) caused by spasticity, weakness, and incoordination of muscles in the throat and mouth.


efficacy: the extent to which a specific intervention, procedure, regime or service produces a beneficial result under ideal conditions.

Evoked Potentials: Electrical signals recorded from the central nervous system that appear in response to repetitive stimuli, such as a clicking noise, flashing light, or electrical shock. Evoked potentials rely on electroencephalography to record responses.

Exacerbation: An increase in the severity of symptoms. Exacerbations of MS usually involve an increase in definite symptoms, lasting weeks or months. During the attack, numerous individual symptoms may come and go in succession. Acute attacks are usually followed by complete or partial remission (the abatement or diminution of symptoms). A worsening or flare-up of neurologic signs and symptoms (such as numbness, weakness or lost vision), usually associated with inflammation and demyelination in the brain or spinal cord. The opposite of exacerbation is remittance or remission.


fatigue: that state, following a period of mental or bodily activity, characterized by a lessened capacity for work and reduced efficiency of accomplishment, usually accompanied by a feeling of weariness, sleepiness, or irritability.

Fecal Incontinence: Loss of control of bowel movements.

Fibromyalgia (FM): is defined as pain of unknown origin. FM affects approximately six million Americans, four million are women. It is a chronic muscle pain syndrome with poorly understood associations with many other conditions. Although there is no distinctive pathophysiological basis for the syndrome, these patients are readily recognized by their history of widespread body pain and multiple tender-point areas.

Footdrop: Impaired or absent voluntary dorsiflexion of the foot. The normal heel-toe pattern of walking (gait) is disturbed, causing the toes to touch the ground before the heel, resulting in the person tripping and losing balance.


Girdle Sensations: The sensation of feeling a tight band around one's trunk that is sometimes experienced by people with Multiple Sclerosis.

Graves Disease: an autoimmune thyroid disease characterized by a genetic predisposition, an increased incidence in young women, the presence of thyroid-stimulating immunoglobulins, and an uncertain etiology. The onset occasionally follows a frightening episode in the patient's life or separation from a loved one. On physical examination, the patient has a diffuse goiter with secondary hyperthyroidism, a noninfiltrative/infiltrative ophthalmopathy, and, on occasion, an infiltrative dermopathy.

Gray Matter: The darker colored tissue of the central nervous system, composed mainly of the cell bodies of neurons, branching dendrites, and glial cells (compare white matter). In the brain gray matter forms the cerebral cortex and the outer layer of the cerebellum; in the spinal cord the gray matter lies centrally and is surrounded by white matter.


Hemiparesis: Sensory loss or weakness of the face, arm and leg on one side of the body.

Hemiplegia: Paralysis of one side of the body, including one arm and one leg.


Immune System: The Immune System is a collection of cells and proteins that works to protect the body from potentially harmful, infectious microorganisms(microscopic life-forms), such as Bacteria, Viruses and Fungi. The Immune System plays a role in the control of cancer and other diseases, but also is the culprit in the phenomena of allergies, hypersensitivity and the rejection of transplanted organs and medical implants.

Immunosuppression: Any form of treatment or drug, which slows or inhibits the body's usual immune responses. Some examples used to treat MS are: Cyclosporin, Methotrexate, and Azathioprine.

Impairment: Any loss or abnormality of psychological, physiological, or anatomical structure or function. It is a deviation from the person's usual biomedical state. An impairment is thus any loss of function directly resulting from injury or disease.

Incontinence: The inability to hold urine or stool until urination or defecation is intended.

Inflammation: A tissue's immunological response to injury, characterized by mobilization of white blood cells and antibodies, swelling, and fluid accumulation.

Injection site: the place where there has been the introduction of a medicinal substance or nutrient material into the subcutaneous tissue, the muscular tissue, a vein, artery or other canals or cavities of the body.

Interferon: An interfering protein that neutralizes virus. It is produced by the body's cells in response to foreign nucleic acid, such as viruses. It protects uninfected cells. A protein substance that is produced naturally in the body by the natural killer cells of the immune system in response to a variety of foreign substances, such as viruses and bacteria. These proteins are antiviral cytokins and are also potent immune regulators and growth factors.
Interferons fall into three groups:
Alpha: is produced by Leukocytes in response to Viruses or Nucleic Acids.
Beta: is produced by Fibrobasts in response to Viruses or Nucleic Acids.
Gamma: is produced by Lymphocytes (both T and LGL) in response to immune stimuli. It is produced by activated T-Cells and natural killer cells. A degree of immune activation leads to the production of Gamma, an increase in Antigen Presenting Cell function (APC), activates Macrophages in general, and probably enhances their capacity to act as APC's.

Intramuscular: An intramuscular injection is made into a muscle. Intramuscular injection is the method used in patients receiving Avonex.


Lesion: Any abnormal damage to tissue structure or function. A scar is a lesion. So is cancer, a MS plaque, a stomach ulcer or a pimple.

Lhermitte's Sign: An electrical sensation that runs down the spine and into the limbs that some people with Multiple Sclerosis experience when they flex their necks, such as when tilting their heads.

Lumbar Puncture: A procedure in which cerebrospinal fluid is withdrawn by means of hollow needle inserted into the subarachnoid space in the region of the lower back (usually between the third and the fourth lumbar vertabrae). The fluid thus obtained is examined for diagnostic purposes. This procedure is usually without risk to the patient. Caution: In patients with raised intracranial pressure it may be hazardous and the optic fundi must be examined for the presence of papilledema (swelling of the first part of the optic nerve; the optic disk or optic papilla.) For further information see (Retrobulbar neuritis), Optic Neuritis) on this glossary page. Please discuss this with your health care professional.


magnetic resonance imaging (MRI): an MRI produces detailed pictures by using a magnetic field, radio waves and sophistocated computer processing. The body is placed in the magnetic field of the MR machine. Energy in the form of radio waves is then directed to the portion of the body being studied. The MR computer reads the radio waves leaving the body and processes them into picture form (images).
MRI's are a commonly used means of diagnostic testing in Multiple Sclerosis. It allows the technician to give your Dr. the much needed information to determine the course of treatment in your disease. MRI films with enhanced lesional activity that may be present in the brain and spinal areas of the body. This testing will assist your Dr. as an intregral part of your overall health care management. MRI clinics are efficient and extremely helpful as an important diagnostic tool, to the medical community as well as the patients they service. If you do not feel well enough to accurately fill out the medical information forms please bring someone along with you who knows your health history.

methylprednisolone: an anti-inflammatory steroid-like compound capable of significantly influencing intermediary metabolism.

Multiple sclerosis (MS):A chronic disease of the nervous system affecting young and middle-aged adults. The mylelin sheaths surrounding nerves in the brain and spinal cord are damaged, which affects the function of the nerves involved. The course of the illness is characterized by recurrent relapses followed by remissions. The disease affects different parts of the brain and spinal cord, resulting in typically scattered symptoms. These symptoms usually include unsteady gait and shaky movements of the limbs, (ataxia), rapid involuntary movements of the eyes (nystagmus), defects in speech pronunciation (dysarthria), spastic weakness, numbness, tingling in spine (Lhermitte's sign), auditory and cognitive processing dysfunction, retrobulbar neuritis. The underlying cause of the nerve damage remains unknown but evidence points to the patient's abnormal response to a viral infection. Along with the most common symptoms of Multiple Sclerosis, there are many other symptoms that the patient will discover as MS related manifestations in conjuction with viral, bacterial infections, trauma related to stress and or physical injury. When these other manifestations are present, they have a tendancy to exacerbate the already pre existing condition. Therefor adding additional symptomology.

Myalgia: pain in the muscles.

myelin: the fatty insulation of nerve fibers that is damaged in multiple sclerosis.

Myelination: The process in which myelin is laid down as an insulating layer around the axons of certain nerves. Myelination is responsible for the great increase in size during the first year of life, when it grows from about a quarter to three-quarters of the adult size.

Myelitis: An inflammatory disease of the spinal cord. The most usual kind (transverse myelitis) most often occurs during the development of Multiple Sclerosis, but is sometimes a maifestation of encephalomyelitis, when it can occur as an isolated myelitis, when it can occur as an isolated attack. The inflamation spreads more or less completely across the tissue of the spinal cord, resulting in a loss of its normal function to trasmit nerve impulses up and down. It is as though the spinal cord had been severed: parlysis and numbness affects the legs and trunk below the level of the diseased tissue.


National Multiple Sclerosis Society (NMSS): an organization for MS information and support, the NMSS has more than 140 chapters throughout the country, offering programs and services to meet the needs of people with MS and their families.

Necrosis: Is the death or decay of tissue in a part of the body which is the result of loss of blood supply, burning, and other severe injuries.

Nerve Sheath: Coating or coverings of the nerve fibers and nerve tract. They include: Endoneurial, myelin, neurilemma, medullary, and notochordal.

Neuralgia: A severe stabbing like sensation of pain caused by a variety of disorders affecting the central nervous system.

Neuritis Abnormal inflammation of the nerve. Signs of this condition are muscular atrophy, neuralgia hyperthesia, anesthsia, paralysis and abnormal reflexes.

neurological: relating to the various nervous systems.

neurologist: a medical specialist in the diagnosis and treatment of disorders of the neuromuscular system.

Nystagmus: Rapid involuntary movements of the eyes that may be from side to side, up and down, or rotary. Nystagmus may be congenital and associated with poor sight; It also occurs in disorders of the brain responible for eye movements and their coordination. Including also disorders of the organ of balance in the ear or the associated parts of the brain. Common symptom of Multiple sclerosis.


Optic Atrophy: Degeneration of the optic nerve. It may be secondary to disease within the eye or it may follow damage to the nerve itself resulting from injury or inflammation.

Optic Neuritis: Optic Neuritis is the most common symptom that leads to further testing for the diagnosis of Multiple Sclerosis. See Retrobulbar neuritis and Uhthoff's Syndrome for more detailed information on the term, Optic Neuritis . Located within this "Glossary" page in alphabetical order.


Plaque: The demyelinating scarring of the axons. Which comprise the bulk of the White Matter in the Central Nervous System.(See also - Sclerosis)

Primary Progressive MS: A clinical course of MS characterized from the beginning by progressive disease, with no plateaus or remissions or an occasional plateau and very short-lived, minor improvements.

Progressive/Relapsing MS: A rare type of MS that is steadily progressive from onset but also has clear acute attacks. A clinical course of MS which shows disease progression from the beginning, but with clear, acute relapses, with or without full recovery from each relapse along the way.

Pseudo-exacerbation: A temporary aggravation of disease symptoms, resulting from an elevation in body body temperature or other stressor (ex. an infection, fatigue, constipation), that disappears once the stressor is removed. A pseudo-exacerbation involves only pre-existing symptom flare-up, rather than new disease activity or progression.


Recent Memory: The ability to remember events, conversations, content of reading material or television programs from a short time ago, i.e. an hour or two ago or last night. People with MS-related memory impairment typically experience the greatest difficulity remembering these types of things from the recent past.

Reflex: An 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, or absent reflexes can be indicative of neurological damage, including MS, and are therefore tested as part of the standard neurological exam.

Relapse: return of the manifestations of a disease after an interval of improvement.

Relapsing-remitting multiple sclerosis(RR/MS): people with this kind of MS have exacerbations, which come and go without any regular pattern, followed by periods of remission.

Remission: A decrease in the signs and symptoms of Multiple Sclerosis. The opposite of remission is exacerbation. A lessening in the severity of symptoms or their temporary disappearance during the course of the illness.

Remote Memory: The ability to remember people or events from the distant past. MSers tend to experience few if any problems with their remote memory.

Remyelination: The repair of damaged myelin. Myelin repair usually occurs spontaneously in the early course of MS but very slowly.

Restless leg syndrome: Restless leg syndrome (RLS) is a neurological disorder of of which there is no known cure. Only the relief of some symptoms by various means. The origin of (RLS) still remains unclear. It is however considered to be genetic neurological condition brought on by an imbalance in the brain. Patients describe (RLS) as a tingling or crawling sensation deep within their legs. There is a constant need or moving their legs to relieve the discomfort. The arms are sometimes affected as well. The symptoms are mostly present at night and have been noted to be one the leading cause of sleep disorders and insomnia. Caffiene increases the symptoms associated with (RLS). Treatment: Most commonly prescribed for this condition is Clonazepam (Klonopin) which acts to stabilize the conduction of nerve impulses.

Reticular Formation: Is scattered like a cloud throughout most of the length of the brainstem. This group of nuclei receives nerves which innervate the face. These axons play an important role in arousing and maintaining consciousness. Visual, or acoustical stimuli, and mental activities can stimulate this system to maintain attention and alertness.

Retrobulbar neuritis (Optic neuritis): inflammation of the optic nerve behind the eye, causing increasingly blurred vision. When the inflammation involves the first part of the nerve and can be seen at the optic disk, it is called optic papillitis. Retrobulbar neuritis is one of the symptoms of "Multiple Sclerosis" but it can also occur as an isolated lesion, in the absence of any other involvement of the nervous system, with the patient recovering vision completely.


Sclerosis: Hardening of tissue. In MS, sclerosis is the body's replacement of lost myelin around CNS nerve axons with scar tissue.

Scotoma: A gap or blind spot in the visual field.

Secondary Progressive MS: A clinical course of MS which initially is relapsing- remitting and then becomes progressive at a variable rate, possibly with an occasional relapse and minor remission. MS that begins with a pattern of clear-cut relapses and recovery but becomes steadily progressive over time with continued worsening between occasional acute attacks.

Sjogren's Syndrome: An immunologic disorder in which there is a deficiency of moisture production in the lacrimal, slaivary and other glands. Resulting in abnormally dry eyes, mouth, and other mucous membranes. This condition occurs primarily in women over the age of 40. In some patients only the salivary glands of the eyes and mouth are affected. In others atrophy of the lacrimal glands can lead to more serious problems. With atrophy of the salivary glands resulting in dental disorders, loss of taste and odor sensations, suceptibility to pneumonia, and other respiratory infections. This condition is commonly associated with Rheumatoid Arthritis and Raynaud's Syndrome. Sjogren's Syndrome mimicks some symptoms indicitive of Multiple Sclerosis.

Somatosensory evoked potentials: A painless, diagnostic test that records electrical changes in the brain in response to repeated electrical shocks applied to a peripheral nerve. This test is useful in the diagnosis of MS because it can confirm the presence of a suspected lesion, which was not shown by a MRI scan, or identify the existence of an unsuspected lesion that has not produced any symptoms.

Spasticity: Increased muscle tone - tightness or stiff muscles, usually around a joint. Increased resistance to movement. It refers to the stiffness that can occur in a limb, usually in the leg. Spasticity often accompanies weakness, but it is possible to have spasticity without weakness and to have weakness without spasticity.

Spinal cord: the cord of nervous tissue that extends from the brain lengthwise along the back in the vertebral canal, gives off the pairs of spinal nerves, carries the impulses to and from the brain, and serves as a center for initiating and coordinating many reflex acts.

Symptom: Any evidence of malfunction perceived by a patient. Common symptoms of MS include visual problems, fatigue, sensory changes, weakness or paralysis of limbs, tremor, lack of coordination, poor balance, bladder or bowel changes, and cognitive changes. (Symptoms vary from patient to patient.)


Trigeminal: Pertaining to the three branch trigeminal (fifth cranial) nerve innervating the face, eyes, nose, mouth and jaw.

Trigeminal nerves: The three branches of the trigeminal nerves (see trigeminal neuralgia for further definition) have motor, sensory, and intermediate roots that connect to three areas of the brain. They connect to the fifth and largest cranial nerve. Motor fibers are essential for chewing food and general presentation of the facial appearance in regards to how the nerves interact with the facial muscles. If the trigeminal is affected by degeneration or pressure it may cause facial features to distort from that of their appearance prior to the nerves being affected. It is also responsible for the movement of facial muscles jerking or twitching. Sensory fibers are responsible for the relaying of information; temperature, pain, and touch from the whole front half of the head including the mouth, and also from the meninges.

Trigeminal Neuralgia (Also called Tic douloureux or Prospalgia): A neurologic condition in which the trigeminal facial nerve is affected. "Stablike" pain radiating along a branch of the trigeminal nerve from the angle of the jaw. It is caused by degeneration of the nerve or by pressure on it. These sudden bursts of pain may be momentary and recur in clusters lasting many seconds. Paroxysmal episodes may last for hours. Three branches of the nerve may be affected.


Uhthoff's Syndrome: At the turn of the last century, Wilhelm Uhthoff was a renowned clinical neuro-ophthalmologist and probably the first clinician whose entire career was devoted to this discipline. His achievements are among those that mark the commencement of contemporary neuro-ophthalmology. Uhthoff's symptom of visual loss with exercise is most frequently associated with optic neuritis. The symptom carries a major risk for recurrence of optic neuritis and development and possible diagnosis in many cases often leading to multiple sclerosis. A metabolic by product of exercise increases in body temperature or causes a reversible conduction block in demyelinated optic nerves and results in temporary loss of vision.


Vertigo: A sensation of dizziness, feeling faint, poor balance (sitting or standing), mental confusion, nausea and weakness. Sometimes described in patients as having a sense of "giddiness" while experiencing vertigo.

Virus: the specific agent of an infectious disease. A group of infectious agents which, with few exceptions, are capable of passing through fine filters that retain most bacteria, are usually not visible through the light microscope, lack independent metabolism, and are incapable of growth or reproduction apart from living cells.


White Matter: Also referred to as white substance. White matter is the nerve tissue of the Central Nervous system. It is lighter in color than gray matter because it contains more nerve fibers thus larger amounts of the insulating material myelin. In the brain the white matter lies within the gray layer of the cerebral cortex. In the spinal cord it is in the central core of the gray matter.