Akathesia: Restlessness somewhat relieved by standing and moving about.

Akinesia: Literally, not- moving. In general, reduced or absent movement. People with PD blink, swallow and move less than others.

Anhedonia: The inability to enjoy or experience pleasure.

Anticholinergic: Medications that block the action of acetylcholine, an important neurotransmitter; benztropine (Cogentin), trihexiphenidyl (Artane) procyclidine (Kemadrine) and Akineton.

Apathy: Indifference, or not caring, having reduced emotions and dulled interest.

Bradykinesia: Gradual loss of spontaneous movement; slowness of movement. This is often the most disabling of symptoms.

Cholinesterase inhibitors: These medications increase acetylcholine in the brain by preventing the enzyme from breaking it down . These work in the opposite way of anti- cholinergic drugs. These are used alot in Alzheimer's disease and other dementing illnesses including PD, and may help memory, concentration and mood: donepezil (Aricept), galantamine (Reminyl) and rivastigmine (Exelon).

Cognition: Ability to think,  understand and solve problems.

COMT inhibitors: catechol-O-methyltransferase inhibitors increase the bioavailability of levodopa in the brain and subsequent conversion into dopamine by reducing the peripheral metabolism of levodopa; used to extend benefits of levodopa, lessen fluctuations, particularly ‘wearing off’. Side effects include difficulty performing voluntary muscle functions, excessive muscle activity, nausea, diarrhea, and discolored urine.

Corpus striatum: a part of the brain that helps regulate motor activities.

Cryothalamotomy: a surgical procedure in which a supercooled probe is inserted into a part of the brain called the thalamus in order to stop tremors.

Dementia: loss of intellectual abilities.

Dopamine: a chemical messenger, or neurotransmitter, deficient in the brains of Parkinson's disease patients, that transmits impulses from one nerve cell to another.

Dopamine Agonist: Stimulates dopaminergic terminals within the striatum; benefits include a longer half- life that results in less pulsatile stimulation of dopaminergic receptors. Usually given in combination with levodopa- containing medications. Side effects include nausea, vomiting, anorexia, malaise, positional low blood pressure- orthostatic hypotension, and psychiatric reactions.

Dyskinesias: abnormal involuntary movements that can result from long-term use of high doses of levodopa.
Festination: a symptom characterized by small, quick forward steps.

Hypotension: Low blood pressure; postional hypotension may be due to low tone in blood vessels allowing the blood to rush away from the brain when bringing the head up suddenly, may cause fainting.

Lewy body: A ball of proteins lodged within cells, visible microscopically, and usually present in PD.

MAO inhibitors: monoamine oxidase inhibitors. Dopamine is a component of MAO. Non- specific MAO inhibitors are known for provoking hypertensive crises when combined with tyramine– rich foods, typically cheese or red wine.  Selegiline, developed in the late 1960s has MAO-B class of enzymatic activity inhibitor; in the brain MAO-B preferentially metabolizes dopamine. The inhibitor slows reuptake of dopamine, and increases its production. Side effects may be caused by its metabolites, yielding excitement, irritability and anxiety. Most side effects are not brought on by the drug itself, but by increasing the effects of levodopa, yielding nausea, vomiting and dizziness.

On-off effect: a change in the patient's condition, with sometimes rapid fluctuations between uncontrolled movements and normal movement, usually occurring after long-term use of levodopa and probably caused by changes in the ability to respond to this drug.

Pallidotomy: a surgical procedure in which a part of the brain called the globus pallidus is lesioned in order to improve symptoms of tremor, rigidity, and bradykinesia.

Parkinsonism: a term referring to a group of conditions that are characterized by four typical symptoms—tremor, rigidity, postural instability, and bradykinesia.

Postural instability: impaired balance and coordination, often causing patients to lean forward or backward and to fall easily.

Punding: Repetitively sorting, organizing, catagorizing for hours without any true purpose. The activity is associated with intense concentration, and provides the subject  feelings of calm or peace. Interruptions are not welcomed.

Retropulsion: the tendency to step backwards if bumped from the front or upon initiating walking, usually seen in patients who tend to lean backwards because of problems with balance.

Rigidity: a symptom of the disease in which muscles feel stiff and display resistance to movement even when another person tries to move the affected part of the body, such as an arm.

Substantia nigra: movement-control center in the brain where loss of dopamine-producing nerve cells triggers the symptoms of Parkinson's disease; substantia nigra means "black substance," so called because the cells in this area are dark.

Tremor: shakiness or trembling, often in a hand, which in Parkinson's disease is usually most apparent when the affected part is at rest.

Wearing-off effect: the tendency, following long-term levodopa treatment, for each dose of the drug to be effective for shorter and shorter periods.