Glossary of Terms

Acetylcholine (noun): a chemical messenger (transmitter) released by cholinergic nerves in the striatum area of the brain. It is involved in many brain functions, such as memory and control of motor activity. There appears to be an interplay between the actions of acetylcholine and dopamine.

Action tremor (noun): a tremor that occurs or increases when the hand is moving voluntarily

Adjunctive (adjective): supplemental or secondary (but not essential) to the primary agent. Sometimes used to describe medications used to enhance levodopa therapy

Agonist (noun): a chemical or drug that enhances the activity of a neurotransmitter such as dopamine

Akinesia (noun): delay in initiating movement; inability to move; "freezing"

Ancillary (adjective): auxiliary; serving as an aid

Antioxidant (noun): an agent that prevents the loss of oxygen in chemical reactions

Anxiolytic (noun): an agent or a class of medications that reduce anxiety

Apoptosis (noun): a form of cell death in which cells shrink and disappear. Sometimes referred to as "cell suicide". In Parkinson disease, some scientists believe that the nerve cells in the substantia nigra portion of the brain die by apoptosis.

Ataxia (noun): loss of balance

Athetosis (noun): slow, involuntary movements of the hands and feet

Autonomic nervous system (noun): the system that controls involuntary body functions

Blepharospasm (noun): involuntary clinching of the eyelid

Blood-brain barrier (noun): the protective membrane that separates the bloodstream from brain tissue

Bradykinesia (noun): slowness of movement

Bradyphrenia (noun): slowness in thought processing

Chorea (noun): excessive involuntary movements, ranging from twisting or writhing to flailing movements of the extremities

Cogwheeling (noun): a ratchet-like movement in the joints, characteristic of Parkinson disease

Delusion (noun): false, fixed, idiosyncratic belief, not substantiated by sensory or objective evidence

Dementia (noun): a broad complex of symptoms such as disorientation, confusion, memory loss, impaired judgment, and alterations in mood and personality -- which symptoms can arise from a variety of causes

DNA (deoxyribonucleic acid) (noun): the basic chemical substance that makes up the gene

Dysarthria (noun): low voice volume or muffled speech

Dyskinesia (noun): abnormal, involuntary body movements that can appear as jerking, fidgeting, twisting, and turning movements; frequently induced by medications taken by Parkinson patients. Dystonia, athetosis, and chorea are forms of dyskinesias

Dysphagia (noun): difficulty in swallowing

Dystonia (noun): involuntary spasms of muscle contraction which cause abnormal movements and postures

Endogenous (adjective): originating internally; developing from within, rather than caused by external factors; the opposite of exogenous

Essential tremor (ET) (noun): a condition more common than Parkinson disease, which often includes shaking of the hands or head, and an unsteady quality of the voice

Etiology (noun): the causes or origins of a disease. The etiology of Parkinson disease is not known.

Exogenous (adjective): originating externally; arising from external rather than internal factors; the opposite of endogenous

Festination (noun): short, shuffling steps

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

Freezing (noun): temporary, involuntary inability to take a step or initiate movement

Glutamate (noun): a salt or ester of glutamic acid, related to the hydrolysis of proteins

Half life (noun): the time taken for the concentration of a drug in the bloodstream to decrease by one half. Drugs with a shorter half life must be taken more frequently.

Hallucinosis (noun): a state of experiencing hallucinations

Hydrophilic (adjective): capable of uniting with or taking up water

Hypomimia(noun): decreased facial expression due to rigidity of facial muscles

Idiopathic (adjective): of unknown origin

Lewy bodies (noun): pink-staining spheres found in nerve cells, considered to be a pathological marker for Parkinson disease

Livido reticularis (noun): purplish or bluish mottling of the skin caused by certain medications taken by Parkinson patients

Micrographia (noun): small, cramped handwriting

Myoclonus (noun): abrupt, jerking movements of the arms or legs, usually occurring during sleep

Neuroleptics (noun): drugs that block dopamine receptors, usually prescribed to treat psychiatric symptoms

Neuron (noun): a cell that generates or conducts electrical impulses to carry information from one part of the brain to another

Neurotransmitter (noun): a biochemical substance (such as dopamine, acetylcholine, or norepinephrine) that carries impulses from one nerve cell to another

Neurotrophic factors (noun): substances that prevent nerve cells from committing apoptosis

Norepinephrine (noun): chemical transmitter involved in regulating the involuntary nervous system

Off-On phenomena (noun): sudden, unpredictable changes in motor performance by patients on levodopa therapy

Orthostatic hypotension (noun): a drop in blood pressure upon standing; can cause fainting

Palsy (noun): paralysis of a muscle group

Pathogenesis (noun): the production or development of a disease

PET (positron emission tomography) (noun): an imaging method that allows one to visualize brain dopamine systems following the injection of a radioactive analog of levodopa (fluorodopa)

Pharmacodynamics (noun): the study of the relationship of drug concentration to drug effect -- what the drug does to the body

Pharmacokinetics (noun): the study of the absorption, distribution, metabolism, and excretion of drugs -- what the body does to the drug

Postural tremor (noun): the rhythmic shaking of the hands with arms outstretched

Resting tremor: characteristic tremor that occurs as one of the primary symptoms of Parkinson's Disease, typically present in arm, leg, lips, chin or tongue.  Occurs or exacerbates when at rest; decreases with active motions.

Rigidity (noun): increased resistance noted to the passive movement of a limb

Sialorrhea (noun): drooling; increased salivation

Striatum (noun): the area of the brain that controls movement, balance, and walking

Substantia nigra (noun): area of the brain where cells produce dopamine

Wearing-off phenomena (noun): waning of the effects of a dose of levodopa prior to the scheduled time for the next dose, resulting in decreased motor performance