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MSA Glossary

Receiving a diagnosis of Multiple System Atrophy means you’re thrust into an unfamiliar and unfriendly world. A helpful way to navigate the landscape is to learn the language. This MSA glossary will help you on this journey.

A Glossary Of Terms Related To MSA


A drug that imitates a neurotransmitter. Dopamine agonists are drugs that imitate the actions of dopamine.


Inability to move (“freezing”) or difficulty in beginning or maintaining a body motion


A drug that blocks the action of acetylcholine, a neurotransmitter in the brain. Anticholinergic drugs are often effective in reducing the tremor of Parkinson’s disease

Antiparkinsonian medication

A medicine used to treat Parkinson’s disease.

Artane (trihexyphenidyl HCL)

An anticholinergic drug that is often effective at reducing parkinsonian tremor. The most common side effects include anxiety, blurry vision, dry mouth, and nausea. It may also cause confusion.


A mobility-impairment condition marked by loss of balance and decreased coordination


Slow, repetitive, involuntary movements, especially in the hands

Basal ganglia

Large clusters of neurons deep within the brain that are responsible for voluntary movements such as walking and movement coordination. Includes the striatum, the subthalamic nucleus, and the substantia nigra

Bilateral surgery

Surgery performed on both sides of the brain

Blood-brain barrier

A thin layer of tightly packed cells separating the central nervous system from the body’s blood stream. This layer blocks the ability of many substances, including certain drugs, from entering the brain.


The slowing down and loss of spontaneous and voluntary movement


The generic name of a dopamine agonist drug that can alleviate Parkinson’s symptoms. The most common brand name is Parlodel.


A drug often used in conjunction with levodopa—as in the drug Sinemet—to increase levodopa’s efficacy by allowing more to reach the brain. Carbidopa also reduces levodopa’s unpleasant side effects such as nausea.

Central Nervous System (CNS)

A term referring to the brain and spinal cord


A general term for nervous disorders characterized by involuntary, random, jerking movements of muscles in the body, face, or extremities

CT (CAT) scan

Computed tomography, a technique that uses a series of X-rays to create image “slices” of the body from different orientations to create a two-dimensional image of the body. The term CAT scan (computed axial tomography) refers to a specific orientation of images.


A jerky or ratchet-like sensation felt by a physician when a patient’s limb is moved around a joint

COMT Inhibitor

A drug that blocks an enzyme (catchol-O-methyltransferase) that breaks down dopamine. COMT inhibitors include entacapone (Comtan) and tolcapone (Tasmar)

DBS (deep brain stimulation)

Application of an electrical current to a deep brain target via an implanted electrode connected to a programmable power source inserted in the chest wall (similar to a cardiac pacemaker)


The generic name of the drug that inhibits the enzyme monoamine oxidase type B (MAO-B), thereby increasing the level of dopamine in the brain. The most common side effects include nausea, dizziness, insomnia, agitation, and confusion.


Identification or naming of a disease by its signs and symptoms


A neurotransmitter chemical produced in the brain that helps control movement, balance, and walking. Lack of dopamine is the primary cause of Parkinson’s symptoms.

dx (dx’d)

Diagnosed (i.e. dx 5 years ago)


Slurred or otherwise impaired speech


Unsteadiness or balance problems


Involuntary, uncontrollable, and often excessive movement. These movements can be lurching, dance-like or jerky, and are distinct from the rhythmic tremor commonly associated with Parkinson’s disease. A common side effect of many drugs used to treat Parkinson’s disease.


Difficulty in swallowing


Abnormal and awkward posture or sustained movements of a hand, foot, or other part of the body; may be accompanied by rigidity and twisting


The brand name for the version of deprenyl made by Somerset Pharmaceuticals


A protein that catalyzes or speeds up chemical reactions

Essential tremor

A fast tremor (about eight cycles per second) that is most pronounced when performing an action such as writing or bringing a hand to a target


A quickening of steps and shuffling after starting to walk


Abrupt and temporary inability of Parkinson’s patients to move that frequently occurs at a boundary such as a door or when exiting a car


Referring to genes, the inherited code (“DNA”) for human structure and function. Hereditary

Genetic predisposition

The inherited genetic pattern that may make some individuals more prone to certain conditions than others with a different genetic makeup

Globus Pallidus

A structure (group of nerve cells) deep in the brain affecting movement, balance, and walking. It is often used as a target for pallidotomy or DBS, two surgical procedures


The variable appearance of a condition


Reduced number of movements


Immobile, expressionless face with reduced blinking


An area of cell damage or cell death


Also called L-dopa, it is the most commonly administered drug to treat Parkinson’s symptoms (its brand name is Sinemet in the United States). Levodopa helps restore levels of dopamine, a chemical messenger in the brain responsible for smooth, coordinated movement and other motor and cognitive functions.

Lewy bodies

Abnormal structures seen in dead or dying dopamine-producing cells of the substantia nigra in Parkinson’s disease. They are frequently the most precise way to diagnose Parkinson’s.


Thin metallic tubes inserted into the brain and guided by stereotactic methods. They are connected to the operating room computer and used to measure the electrical signal from brain cells during surgical procedures, such as pallidotomy.


Small, cramped handwriting that is a symptom for many Parkinson’s patients


The brand name of a dopamine agonist, pramipexole, made by Pharmacia, which is often used to treat Parkinson’s disease

Monoamine oxidase inhibitors (MAO)

Drugs that enhance the effect of dopamine by preventing enzymes from breaking them down

Movement disorders

Refers to several conditions, many of them neurodegenerative, that prevent normal movement. Some are characterized by either lack of movement (bradykinesia, hypokinesia, etc) or excessive movement (chorea, athetosis, dystonia, tremor). Besides Parkinson’s, other conditions often defined as movement disorders include essential tremor, multiple system atrophy, progressive supranuclear palsy, Huntington’s disease, Tourette’s syndrome and cerebral palsy.

MRI (Magnetic Resonance Imaging)

Three-dimensional images of the brain obtained in a scanner using a powerful magnet

Multiple System Atrophy (Shy-Drager Syndrome)

A degenerative condition characterized by low blood pressure when standing, parkinsonism, rigidity, ataxia, fainting, and incontinence.


Refers to conditions such as Parkinson’s that are characterized by the loss of cells in the central nervous system


A physician specializing in diseases and disorders of the brain, spinal cord, nerves, and muscles, including stroke, Parkinson’s disease, epilepsy, Alzheimer’s disease, and muscular dystrophy


A nerve cell used to transmit information within the central nervous system


A doctor who operates on the brain and central nervous system


A chemical that carries impulses from one neuron to another

On-Off Phenomenon

Sudden loss of activity of levodopa lasting minutes to hours after a brief period of effectiveness. The term also sometimes refers to a cyclical response to medication where the patient can function adequately at times but is too stiff and immobile to

function at other times.

Orthostatic hypotension

Sudden drop in blood pressure (>20 mm Hg systolic) upon standing and accompanied by symptoms such as dizziness, fatigue and syncope..


A surgical procedure in which lesions are produced in the globus pallidus region of the brain in an effort to lessen Parkinson’s symptoms such as tremors, rigidity, and Bradykinesia


Antiquated term referring to paralysis or an uncontrollable shaking of the body. Parkinson’s disease was originally called the “shaking palsy”

Paralysis agitans

Antiquated name for Parkinson’s disease


Generic term referring to slowness and mobility problems that look like Parkinson’s disease. Several conditions, such as multiple system atrophy and progressive supranuclear palsy, and a number of medications produce this appearance.


The brand name for the dopamine agonist bromocriptine that is made by Novartis


Abbreviation for Parkinson’s disease


The generic name of a dopamine agonist used to treat Parkinson’s disease. The brand name is Permax


The brand name for the dopamine agonist pergolide that is made by Eli Lilly

PET scan

An acronym for “positron emission tomography,” an imaging technique used to monitor and produce pictures of metabolic or biochemical activity in the brain


One of the characteristic slower tremors in the fingers of Parkinson’s patients; the alternating movements of the thumb and forefinger give the appearance of rolling a small object between the fingers


The expected future course of an illness

Progressive Supranuclear Palsy

A degenerative disease of unknown cause characterized by problems looking up and down, frequent falls and parkinsonism that is not helped consistently by levodopa


Abnormal stiffness in a limb or other body part. It is most apparent when an examiner moves a patient’s limb — as in cogwheeling.

Shy-Drager Syndrome (Multiple System Atrophy)

A degenerative condition characterized by low blood pressure when standing. It may lead to parkinsonism, rigidity, ataxia, fainting, or incontinence.


The brand name of the most commonly prescribed version of the drug levodopa, made by Du Pont Pharmaceuticals


Brain surgery, guided by brain images from CAT or MRI scans, usually involving a metallic frame bolted to a patient’s head to prevent any movement


Also known as the corpus striatum, it is the largest component of the basal ganglia in the brain and controls movement, balance, and walking

Substantia Nigra

Literally means “black substance.” A part of the basal ganglia, located in the midbrain, that is rich in dopamine-producing nerve cells and the black pigment neuromelanin (hence its name). In Parkinson’s the loss of nerve cells from this region leads to a dopamine deficit and subsequently to Parkinson’s symptoms.

Subthalamic Nucleus (STN)

A nerve center near the substantia nigra. The STN may be targeted for deep brain stimulation (DBS) to reduce Parkinson’s symptoms


The brand name of the COMT inhibitor tolcapone, that is made by Roche Laboratories.


A surgical procedure in which cells in the thalamus are destroyed in an effort to eradicate debilitating tremors.


A mass of gray matter (nerve cells) located deep in the brain that is responsible for motor control and serves as a relay center for sensory signals.


A drug in the COMT inhibitor class that is sometimes prescribed in tandem with levodopa. The drug has been known to cause serious liver problems and has been withdrawn from the Canadian and European markets.


Unwanted rhythmic movements (may be fast or slow) that may affect the hands, head, voice or other body parts.

Trigger Event

An external or environmental factor such as head trauma, exposure to a toxin, or stress that contributes to the development of a condition or disease.

Wearing Off

Loss of effectiveness of Parkinson’s medications between doses. If the effectiveness of a medication does not last until the next dose is due, it “wears off”.

For all references listed in the About MSA section please download the MSA Coalition's "MSA - What You Need to Know"

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