A chemical messenger released by cholinergic nerves. Normally in many parts of the body, including the brain, and necessary to normal body functioning. There appears to be a reciprocal seesaw relationship between acetylcholine and do pamine and their respective nerve cell systems.

Action Tremor

Rhythmic, involuntary movement of a limb when movement is initiated, e.g., when writing or lifting a cup. Not usually seen in the earlier stages of Parkinson’s.

Adrenaline (epinephrine)

The neurotransmitter of the adrenal gland which is secreted in moments of crisis. It stimulates the heart to beat faster and work harder, increases the flow of blood to the muscles, causes an increased alertness of mind, and produces other changes to prepare the body to meet an emergency.


A chemical or drug that mimics neurotransmitter activity.


Absence of body movements.


Chemical name for biologically active form of Vitamin E.


A drug which stimulates the release of available dopamine in the brain.


Adjective applied to a substance (medication) that reduces the action of acetylcholine.

Anticholinergic Parkinson's Drugs (Artane, Cogentin)

The group of drugs which decreases the action of acetylcholine. The specified drugs may help reduce rigidity, tremor, and drooling in Parkinson’s.


Drugs opposing the actions of histamine; commonly used to treat allergies. Used in the past for Parkinson’s as they sometimes had beneficial effects on symptoms due to their anticholinergic properties.


A derivative of morphine and a dopamine agonist. Currently experimentally used as injectable treatment for severe Parkinson’s.


Loss of balance


Dyskinesias in which there are slow, repetitive, sinuous involuntary movements.

Autonomic Nervous System

The branch of the nervous system that controls internal organs in the body, e.g., heart, lungs.

Basal Ganglia or Nuclei

Deeper structures in the brain, concerned with normal movement and walking. The caudate nucleus, putamen and Substantia Nigra are basal ganglia affected in Parkinson’s.

Benign Essential Tremor

A condition characterised by tremor of the hands, head, voice, and sometimes other parts of the body. Essential tremor often runs in families and is sometimes called familial tremor. It is sometimes mistaken for a symptom of Parkinson’s. However, this is an action tremor and there is no rigidity or bradykinesia.

Beta-Blockers (ß-Blockers)

Drugs which block the action of epinephrine at certain sites. Usually used to treat hypertension and heart disease, they may be effective in the treatment of benign essential tremor.


Occurring on both sides of the body.


Spasmodic blinking or involuntary closing of the eye lids; a type of dystonia.


Slowing down of a movement. Bradykinesia involves slowness of initiating and executing movements and fine motor movements and difficulty in performing repetitive movements. It is a major symptom of Parkinson’s.


The ingredient in Sinemet which prevents the breakdown of the levodopa in the body before it can reach the brain.

Central Nervous System (CNS)

Consists of the brain and spinal cord.


Part of the brain that is involved in coordination.

Cerebral Cortex

The largest part of the brain; responsible for thought, reasoning, memory, sensation, voluntary movement.


A naturally occurring substance which is a precursor of acetylcholine.


A type of dyskinesia (abnormal movement), characterised by continuing, rapid, dance-like movements. May result from high doses of levodopa and/or long term levodopa therapy.


A dyskinesia characterised by choreic and athetoid movements.

Cogwheel Rigidity

Stiffness in the muscles, with a jerky quality when arm and leg joints are repeatedly moved.


Diminished ability of intestinal muscles to move feces (stool), often resulting in very hard stool. A common problem in Parkinson’s.


(Eldepryl, Selegiline, Jumex) A drug that slows the breakdown of chemicals like dopamine by inhibiting the action of certain enzymes. It increases effects of dopamine in the brain.

Dopa Decarboxylase Inhibitors

Drugs that block the conversion of levodopa to dopamine outside the brain.These include carbidopa and benserazide.


A chemical produced by the brain; it assists in the effective transmission of electrochemical messages from one nerve cell to the next. It is deficient in the basal ganglia and Substantia Nigra of a person with Parkinson’s. It governs actions of movement, balance and walking.

Dopamine Agonist

Drugs that mimic the effects of dopamine and stimulate the dopamine receptors.


An adjective used to describe a chemical, a drug, or a drug effect related to dopamine.

Drug Holiday

A 3 to 14 day withdrawal of a drug after long term treatment.

Drug Induced Parkinsonism

Parkinson’s symptoms which have been caused by drugs used to treat other conditions, e.g., neuroleptic drugs, and reserpine, used to be used to treat hypertension.


Speech difficulties caused when the muscles associated with speech are affected.


Abnormal movement of voluntary muscles. Dystonia, athetosis, and chorea are types of dyskinesia.


Difficulty in swallowing.


Involuntary spasms of muscle contraction that cause abnormal movements and postures. May appear as a side effect of long term drug treatment in Parkinson’s and may worsen in response to stress.


Inflammation of the brain usually caused by a virus infection.

Encephalitis Lethargica

(Sleeping Sickness) A specific kind of encephalitis which occurred in scattered epidemics throughout the world during the period 1916 to 1926; it usually caused sleepiness, double vision, trouble swallowing, and drooling. Many of those affected developed advanced Parkinsonism as depicted in the movie Awakenings.


(Parsidol/Parsitan) A drug sometimes used in the past for Parkinson’s due to its anticholinergic effects.

Extrapyramidal Nervous System

Refers to the caudate, putamen, and Substantia Nigra. It is affected in Parkinson’s.


Walking in rapid, short, shuffling steps.


A bent, curved posture.


Temporary, involuntary inability to move


A sustained increase of pressure within the eyeball which can injure the optic nerve and cause impaired vision or blindness. Treatment with anticholinergics may exacerbate glaucoma.

Globus pallidus

The inner part of the lenticular nucleus. The lenticular nucleus and the caudate nucleus form the Striatum.

Heimlich Maneuver

A form of first aid for people who are choking.


Abnormally diminished motor activity.


An adjective meaning “of unknown cause”. The usual form of Parkinson’s is idiopathic Parkinson’s.

Intention Tremor

One occurring when the person’s attempts voluntary movement.

Lenticular nucleus

This group of cells along with the caudate nucleus form the Striatum or Corpus Striatum.


The international generic name for the medicinal formulation of L-Dopa. It is contained in Sinemet and Prolopa.

Levodopa-Induced Dyskinesias

A side effect of medication which may occur with prolonged use. These abnormal, involuntary movements may be alleviated by reducing the amount of medication.

Lewy Body

Pink, staining spheres on damaged brain cells; markers for Parkinson’s.

Livido Reticularis

A purplish or bluish mottling of the skin seen usually below the knee and sometimes on the forearm in persons under treatment with the drug amantadine (Symmetrel).


The tendency to have very small handwriting due to difficulty with fine motor movements in Parkinson’s.


A toxic chemical, exposure to which can lead to Parkinson’s.


Jerking, involuntary movement of arms and legs, usually occurring during sleep.


Vital part of the brain comprised of two basal ganglia (caudate and putamen).

Neuroleptic Drugs

(Also called major tranquilizers) A class of drugs which act as dopamine antagonists (by blocking some dopamine receptors). They can aggravate symptoms of Parkinson’s. This class includes Haloperidol (Haldol), and the phenothiazines, e.g., Compazine, Stelazine, Chlorpromazine, etc.


A nerve cell.


A specialized chemical produced in nerve cells that permits the transmission of information between nerve cells.

Nigrostriatal Degeneration

Degeneration of the nerve pathways from Substantia Nigra to the striatum. These pathways are normally rich in dopamine and are those affected in PD.

Norepinephrine (Noradrenalin)

Chemical transmitter found mainly in two areas of the brain involved in governing the involuntary autonomic nervous system.

On-Off Fluctuations

Fluctuations that occur in response to levodopa therapy in which the person’s mobility changes suddenly and unpredictably from a good response (on) to a poor response (off).

Orthostatic Hypotension

A drop in blood pressure during rapid changes in body position (e.g., from sitting to standing).


A symptom of Parkinsonism, especially the postencephalitic form, in which a word or syllable is repeated and the flow of speech is interrupted.


Excision or destruction of the Globus Pallidus, which is part of the Lenticular Nucleus, which is part of the Striatum.


Sensations, usually unpleasant, arising spontaneously in a limb or other part of the body, variously experienced as “pins and needles” or a feeling of warmth or coldness (thermal paresthesias).

Parkinson's Disease

That form of Parkinsonism originally described by James Parkinson as a chronic, slowly progressive disease of the nervous system characterized clinically by the combination of tremor, rigidity, bradykinesia, and stooped posture, and pathologically by loss of the pigmented nerve cells of the Substantia Nigra in the brain.

Parkinson's Facies

A stolid masklike expression of the face, with infrequent blinking; it is characteristic of Parkinson’s.


A clinical state characterised by tremor, rigidity, bradykinesia, stooped posture, and shuffling gait. The more common causes of Parkinsonism are Parkinson’s Disease, striatonigral degeneration, and a reversible syndrome induced by ma jor tranquillizing drugs.

Paralysis agitans

The Latin form of the older, popular term shaking palsy, which was used to designate Parkinson’s in James Parkinson’s time.

Parlodel (Bromocriptine)

A dopamine agonist useful in treating all of the primary symptoms of Parkinson’s. It may be used alone or with other antiparkinson medications.

Permax (Pergolide)

A drug similar in action to Parlodel but more potent.

Postural Deformity

Stooped posture.

Postural Instability

Difficulty with balance.

Postural Tremor

Tremor that increases when hands are stretched out in front.


Something that precedes, e.g., a sign or symptom that forewarns of another, such as muscle aching may be the precursor of a tremor.

Progressive Supranuclear Palsy (PSP)

A degenerative brain disorder sometimes difficult to distinguish from Parkinson’s especially in the early stages. PSP symptoms are rigidity and akinesia, difficulty looking up and down, speech and balance problems. Those with PSP often have poor response to antiparkinson medications.


Trade name for the antiparkinson drug composed of levodopa and benserazide. This drug combination contains a ratio of 4 mg. of levodopa to 1 mg. of benserazide (Prolopa 50-12.5, 100-25, 200-50).

Propulsive Gait

Disturbance of gait typical of Parkinsonism in which, during walking, steps become faster and faster with progressively shorter steps that pass from a walking to a running pace and may precipitate falling forward.

Range of Motion

The extent that a joint will move from being fully straightened to completely bent.


A sensory nerve ending that responds to a stimulus.

Resting Tremor

Shaking that occurs in a relaxed and supported limb.

Retropulsive Gait

Walking that is propelled backwards.


Refers in medical usage to a type of muscular stiffness encountered when examining people with Parkinson’s. It is characterized by a constant, even resistance to passive manipulation of the limbs.


Increased discharge of the oily secretion sebum from the sebaceous glands of the skin.

Seborrheic Dermatitis

Inflammation of the skin sometimes associated with seborrhea.

Shaking Palsy

Old popular term which James Parkinson employed to designate the specific disorder we now call Parkinson’s.

Shy-Drager Syndrome

This is a condition in which the symptoms are the result of abnormalities in motor function and problems in the autonomic nervous system. A person with Shy-Drager Syndrome has Parkinsonism, extremely low blood pressure which worsens upon standing, bladder problems, severe constipation, and decreased sweating. This condition is quite rare.


Drooling of saliva.

Side Effect

A drug’s effect that is different from the beneficial effect for which the drug is being taken.


Trade name for the antiparkinson drug that is a mixture of levodopa and carbidopa. This drug combination contains a ratio of levodopa 4 mg. or 10 mg. to carbidopa 1 mg. (Sinemet 100/25, Sinemet 250/25).

Sinemet CR

Controlled-release Sinemet. 200 mg. Levodopa with 50 mg. Carbidopa in a capsule contained in a matrix (outer layer) releasing the drug more slowly in the body. These capsules are not to be taken all at once, but rather in separate doses over the course of a day.

Stereotactic Surgery

Surgical technique that involves placing a small electrode in an area of the brain to destroy a tiny amount of brain tissue.

Striatonigral Degeneration

This is a degeneration of the nerve pathways travelling from the striatum to the Substantia Nigra. People with this degeneration also appear to have Parkinsonism. However, they respond differently to drug therapy than people with Parkinson’s.


Area of brain controlling movement, balance, and walking. Connects to and receives impulses from Substantia Nigra.

Substantia Nigra

Black pigmented area of the midbrain where cells manufacture the neurotransmitter dopamine.

Sustention or Postural Tremor

Tremor that increases when hands are stretched out in front.

Symmetrel (Amantadine)

A drug that releases dopamine and is useful in PD.

Tardive Dyskinesia

This is a movement disorder associated with long-term use of neuroleptic drugs such as Chlorpromazine, Haloperidol, Loxapine, etc. Movements of a person with tardive dyskinesia are similar in appearance to those of a person with levodopa induced dyskinesias, but the causes of the two conditions are different.


Operation in which a small region of the thalamus is destroyed, achieved by stereotactic techniques. Tremor and rigidity in Parkinsonism and other conditions may be relieved by thalamotomy.


Anatomical term designating a mass of grey matter centrally placed deep in the brain near its base and serving as a major relay station for impulses travelling from the spinal cord and cerebellum to the cerebral cortex.


A poisonous substance.


Rhythmic shaking and involuntary movement of part(s) of the body as a result of sequential muscle contractions.


Occurring on one side of the body. Parkinson’s symptoms usually begin unilaterally.

Vomiting Center

Term referring to an area of the brain where the nausea and vomiting reflex may be triggered by some medications.

Modified from the glossary published by The Parkinson’s Society of Southern Alberta

Special thanks to Simon J. Coles