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Parkinson's Disease

Parkinson's Disease: Glossary

Monday, April 23, 2012 - 14:52

Contributing Author: Guy Slowik FRCS

Here are definitions of medical terms related to Parkinson's disease.

Acetylcholine: A chemical which acts as a chemical messenger. An imbalance between dopamine and acetylcholine results in some symptoms of Parkinson's disease.

Akinesia: Absence of movement

Allograft: Cells taken from one person to transplant into another person (such as using a human fetus for a human brain cell transplantation).

Amantadine (SymmetrelTM): An anti-Parkinson drug.

Amino Acid Decarboxylase (AADC): One of the two main enzymes (the other one being catechol-0-methyltransferase or COMT) that is responsible for the breakdown of levodopa in the bloodstream before it reaches the brain. AADC breaks down levodopa into dopamine before it can cross the blood brain barrier

Anticholinergics: Drugs that block the action of the chemical messenger acetylcholine. This means there's less of acetylcholine, thus providing a better balance between it and dopamine This reduces rigidity and tremor; e.g., ArtaneCogentin.

Antihistamines: Drugs that are often used to relieve cold or allergy symptoms (for example Benadryl) but may also be effective in reducing tremor.

Ataxia: Loss of co-ordinated movement or balance.

Athetosis: Slow, involuntary movements of the hands and feet.

Basal ganglia: The part of the brain that coordinates movement.

Benserazide: The decarboxylase inhibitor that is co-administered with levodopa in MadoparTM or ProlopaTM

Biofeedback: Modifying behavior by teaching someone to partially control unconscious functions of the body, such as blood pressure or heart rate

Bradykinesia: Slowness of movement or difficulty initiating body movement.

Bromocriptine (ParlodelTM): A dopamine agonist, that is, a drug that mimics the action of dopamine

CabergolineTMA dopamine agonist.

carbidopa: A drug that allows more levodopa to get into the brain to be converted into dopamine. It prevents the enzyme AADC from normally breaking down levodopa in the blood. Levodopa therapy today is administered in a combination tablet with carbidopa.

Cogwheeling: A ratchet-like movement in a joint. It is characteristic of Parkinson's disease.

COMT: Stands for catechol-O-methyltransferase. It is one of the two main enzymes responsible for the breakdown of levodopa before it reaches the brain

COMT inhibitor: A drug that inhibits the action of COMT, the enzyme responsible for the breakdown of levodopa in the bloodstream before it reaches the brain. COMT inhibitors improve delivery of levodopa to the brain.

Corpus striatum: Part of the basal ganglia in the brain. It is a relay station receiving information about the position and movement of the body from several different parts of the brain that transmits it to other parts of the brain.

Decarboxylase: An enzyme in the blood and brain that metabolizes levodopa to dopamine.

Decarboxylase inhibitors (DCI): Compounds that prevent the conversion of levodopa to dopamine by decarboxylase for example, carbidopa and benserazide. They increases the amount of levodopa reaching the brain resulting in a 70 percent reduction in the dose of levodopa required to control symptoms.

Dementia A loss of intellectual abilities.

Deprenyl (Eldepryl, selegiline, Jumex): A monoamine-inhibitor used to treat Parkinson's disease. It blocks the enzyme monoamine oxidase B, which normally breaks down dopamine.

Dopamine: One of the many "chemical messengers" in the brain. It carries messages between the various nerves that control movement. Its deficiency in the brains of people with Parkinson's disease is the underlying cause of the symptoms of the disease.

Dopamine agonists: Medications that attempt to mimic the role of dopamine in the brain.

Dopamine receptors: Sites on the nerve cells which are activated by dopamine and some of which are activated by dopamine agonist drugs.

Dyskinesia: abnormal involuntary movement usually seen in the arms and legs, trunk and head. It may result from taking levodopa over a long period of time or in high doses.

Dysphagia: Difficulty in swallowing.

Dystonia: Involuntary spasms of muscle contraction that cause abnormal movements and postures. The dystonia that occurs most frequently in Parkinson's disease is in the foot and is a characteristic of Parkinson's disease.

Entacapone: A COMT inhibitor.

Enzyme: a substance that speeds up a specific chemical reaction but that is not itself consumed in the reaction.

Erythromelalgia: red, warm painful and tender feet

Free radicals: toxic substances that are continuously produced by all cells of the human body.

Genes: The heredity factor that is passed from parents to children that determines the characteristics you inherit from your parents

Globus pallidus: A small part of the brain that regulates muscle tone needed for specific body movements. It is destroyed during the operation known as a pallidotomy

Hormone: a substance secreted by a gland that is transported in the bloodstream to various parts of the body to regulate or modify bodily functions.

Hypomimia: decreased facial expression.

Incontinence: inability to control voiding from the bladder (or bowel).

Levodopa: The main medication used to treat PD. It is converted to dopamine (the chemical messenger which is deficient in someone with Parkinson's disease), when it reaches the brain.

MadoparTMA drug that combines levodopa and benserazide.

Microelectrode recording: The method of recording electrical activity from individual brain cells, using very fine wire electrodes, to improve precision during surgery for Parkinson's disease.

Micrographia: A change in handwriting with the script becoming smaller and more cramped.

Motor fluctuation: Variations in one's ability to control movement during the day, due to fluctuating levels of dopamine in the brain.

Myoclonus: Jerking, involuntary movements of the arms and legs. May occur normally during sleep.

Neuron: A nerve cell.

Neurotransmitter: A chemical messenger that carries messages or signals between the various nerves. Dopamine is a neurotransmitter

On-off effect: This describes the sometimes rapid changes in the ability of medication to control the symptoms of Parkinson's disease.

Off-time: The period during which Parkinsons symptoms are not controlled by medication.

Orthostatic hypotension: A fall in blood pressure when standing; may result in fainting.

Oxidation: A chemical process in which a substance combines with oxygen

Pallidotomy: A surgical procedure in which a group of cells in the brain called, the globus pallidus is destroyed. It is a relay station from which information leaves the site of the basal ganglia (where dopamine is stored).

Pergolide (Permax): An antiparkinson drug.

'Pill rolling' movements: A rhythmical movement of the thumb upon the first two fingers of the hand. A classic and early sign of tremor in Parkinson's disease.

Postural instability: Impaired balance and coordination, which often causes a person to lean forward or backward and to fall easily.

Pramipexole: A new dopamine agonist.

Resting tremor: A tremor of the arm or leg when it is at rest, that is, when it is not moving.

Rigidity: The muscles feel stiff and there is resistance to movement even when another person tries to move the joint.

Ropinirole: A new dopamine agonist

Selegiline: A drug that helps conserve levels of dopamine in the brain by blocking one of the enzymes responsible for dopamine degradation.

SinemetTMAn antiparkinson drug.

Spasm: A condition in which a muscle or group of muscles involuntarily contract.

Substantia Nigra: A part of the brain involved in initiating movement. It is situated near the center of the brain and contains a clump of dark cells that manufacture dopamine.

Stereotactic or stereotaxic surgery: A surgical technique in which surgeons use three dimensional coordinates to locate specific areas of the brain..

TASMARTM(tolcapone): The first in a new class of drugs called COMT inhibitors for the treatment of Parkinson's disease.

Thalamotomy: A surgical operation in which surgeons destroy small areas of the thalamus in the brain in order to alleviate one-sided tremor.

Tremor: The shakiness or trembling, often in a hand (although it may affect the whole or any part of the body), that in Parkinson's disease is usually most apparent when the affected part is at rest.

"Wearing-off" effect: The tendency, as Parkinson's disease progresses, for each dose of levodopa to be effective for shorter and shorter periods of time.

Parkinson's Disease