Glossary This glossary is from Parkinson's Disease: The Complete Guide for Patients and Caregivers, by Abraham N. Lieberman, M.D. A Fireside Book published by Simon & Schuster, New York. Used with permission of the author. Glossary Menu A to C D to F G to H I to L M to O P to R S to U X to Z Main Menu A Acetylcholine a chemical which acts as a neurotransmitter. An imbalance between dopamine and acetylcholine results in some Parkinson's disease symptoms. Action tremor a tremor that increases when the hand is moving voluntarily. Agonist a drug which increases neurotransmitter activity by stimulating the dopamine receptors directly. Akinesia no movement. Amantadine (Symmetrel) an anti-Parkinson drug. Anticholinergics anti-Parkinson drugs that block the action of acetylcholine, thereby rebalancing it in relation to dopamine and reducing rigidity and tremor; e.g., Artane, Cogentin. Antihistamines drugs that are often used to relieve cold or allergy symptoms (i.e., Benadryl) but may also be effective in reducing tremor. Ataxia loss of balance. Athetosis slow, involuntary movements of the hands and feet. Atrophy wasting, shrinkage. Autonomic nervous system that part of the nervous system that is responsible for automatic functions, such as the heartbeat, digestion, salivation. Axon the long, hairlike extension of a nerve cell that carries a message to the next nerve cell. B Basal ganglia several large clusters of nerve cells deep in the brain below the cerebral hemispheres; crucial in coordinating motor commands. Include the striatum and the substantia nigra. Bilateral both sides of the body. Biofeedback a behavior modification in which patients are taught to partially control unconscious bodily functions, such as blood pressure or heart rate. Blink rate the number of times per minute that the eyelid automatically closes. A normal rate may be 10 to 30 per minute; for the parkinsonian it may be 0 to 5 per minute. Blepharospasm forced eyelid closure. Blood-brain barrier the protective membrane that separates circulating blood from brain cells. Body scheme the ability to identify body parts or to relate body parts to each other; the ability to sense one's position in space. Bradykinesia slowness of movement. Bradyphrenia slowness of thought processes. Bromocriptine (Parlodel) a dopamine agonist and antiParkinson drug. Bruxism grinding of teeth and clenching of jaw muscles. Buccinator a muscle of the face and cheek. C Central nervous system the brain and the spinal cord. Cerebellum a large structure consisting of two halves (hemispheres) located in the lower part of the brain; responsible for the coordination of movement and balance. Cerebrum consists of two parts (lobes), left and right, which form the largest and most developed part of the brain; initiation and coordination of all voluntary movement take place within the cerebrum. The basal ganglia are located immediately below the cerebrum. Chorea rapid, jerky, dancelike movement of the body. Cortex the outer layer of the cerebrum, densely packed with nerve cells. Top D Dendrite a threadlike extension from a nerve cell that serves as an antenna to receive messages from the axons of other nerve cells. Delusions a condition in which the patient has lost touch with reality and experiences hallucinations and misperceptions. Deprenyl (Eldepryl, selegiline, Jumex) anti-Parkinson drug. Dopa decarboxylase an enzyme present in the body that converts levodopa to dopamine. Dopa decarboxylase inhibitors anti-Parkinson drugs that block the enzyme dopa decarboxylase. Dopamine a chemical substance, a neurotransmitter, found in the brain that regulates movement, balance, and walking. It is the substance that is lost in PD. Dopaminergic a chemical that works like, or has the same effect as, dopamine. Drug holiday a 3- to 14-day withdrawal of levodopa after long-term treatment when side effects of levodopa outweigh benefits; rarely done today because of the severe effects of drug withdrawal. Dyskinesia an involuntary movement including athetosis and chorea. Dysphagia difficulty in swallowing. Dystonia a slow movement or extended spasm in a group of muscles. E Edema tissue swelling due to excessive fluid. Enzyme a substance that speeds up a specific chemical reaction but that is not itself consumed in the reaction. Euphoria a feeling of well-being or elation; may be drug related. Extensor (muscle) any muscle that causes the straightening of a limb or other part. Extrapyramidal system the system of nerve cells, nerve tracts and pathways that connects the cerebral cortex, basal ganglia, thalamus, cerebellum, reticular formation, and spinal neurons; it is concerned with the regulation of reflex movements such as balance and walking. The extrapyramidal system is damaged in Parkinson's disease. F Festination short, shuffling steps; involuntary speeding up of the gait. Flexor (muscle) any muscle that causes the bending of a limb or other body part. Freezing temporary, involuntary inability to move. Top G Ganglion a cluster of nerve cells. Gray matter the darker-colored tissues of the central nervous system; in the brain, the gray matter includes the cerebral cortex, the thalamus, the basal ganglia, and the outer layers of the cerebellum. H Hormone a substance secreted by a gland that is transported in the bloodstream to various organs in order to regulate or modify bodily functions. Top I Incontinence involuntary voiding of the bladder or bowel. L Levodopa the single most effective anti-Parkinson drug which is changed into dopamine in the brain usually combined with carbidopa (a dopa decarboxylase inhibitor) as Sinemet . Lewy body a pink-staining sphere, found in the bodies of dying cells, that is considered to be a marker for Parkinson's disease. Top M Micrographia a change in handwriting with the script becoming smaller and more cramped. Monoamine oxidase (MAO) an enzyme that breaks down dopamine. There are two types of MAO "A" and "B." In Parkinson's disease, it is beneficial to block the activity of MAO B. MPTP a chemical produced during an attempt to make a synthetic narcotic. MPTP destroys the cells of the substantia nigra cells and produces a disease that mimics Parkinson's disease. Myoclonus jerking, involuntary movements of the arms and legs. May occur normally during sleep. N Neuron a cell specialized to conduct and generate electrical impulses and to carry information from one part of the brain to another. Neurotransmitters chemical substances that carry impulses from one nerve cell to another; found in the space (synapse) that separates the transmitting neuron's terminal (axon) from the receiving neuron's terminal (dendrite). Nigral of or referring to the substantia nigra. Norepinephrine a neurotransmitter found mainly in areas of the brain that are involved in governing autonomic nervous system activity, especially blood pressure and heart rate. On-off phenomena abrupt changes in performance during the day caused by the taking effect or wearing off of anti-parkinson drugs. O Orthostatic hypotension a large decrease in blood pressure upon standing; may result in fainting. Orthostatic hypertension may occur spontaneously in PD or may be related to certain drugs. Top P Palsy paralysis of a muscle or group of muscles. Pergolide (Permax) an anti-Parkinson drug. Peristalsis wavelike contractions that move food through the digestive tract. Pyramidal pathway a collection of nerve tracts that travel from the cerebral cortex through the pyramid of the medulla oblongata in the brainstem to the spinal cord. Within the pyramid of the medulla, fibers cross from one side of the brain to the opposite side of the spinal cord; the pyramidal pathway is intact in Parkinson's disease. R Range of motion the extent that a joint will move from full extension to full flexion. Resting tremor a tremor of a limb that increases when the limb is at rest. Rigidity increased resistance to the passive movement of a limb. Top S Sialorrhea drooling. Sinemet an anti-Parkinson drug. Spasm a condition in which a muscle or group of muscles involuntarily contract. Striatum part of the basal ganglia, it is a large cluster of nerve cells, consisting of the caudate nucleus and the putamen, that controls movement, balance, and walking; the neurons of the striatum require dopamine to function. Substantia nigra a small area of the brain containing a cluster of black-pigmented nerve cells that produce dopamine which is then transmitted to the striatum. Sustention (postural) tremor a tremor of a limb that increases when the limb is stretched. Synapse a tiny gap between the ends of nerve fibers across which nerve impulses pass from one neuron to another; at the synapse, an impulse causes the release of a neurotransmitter, which diffuses across the gap and triggers an electrical impulse in the next neuron. T Tremor a rhythmical shaking of a limb, head, mouth, tongue, or other part of the body. Tyrosine the amino acid from which dopamine is made. W White matter nerve tissue that is paler in color than gray matter because it contains nerve fibers with large amounts of insulating material (myelin). The white matter does not contain nerve cells. In the brain, the white matter lies within the gray layer of the cerebral cortex. X to Z Top Main Menu