Many of the terms associated with Parkinson's disease are unfamiliar to anyone without a medical degree. Below are some of the words that you may run across in researching about Parkinson's, with simple definitions to make it easier to understand.
A
Acetylcholine
Acetylcholine is a chemical messenger made by your nerves. Some medicines that are used to treat Parkinson's work by stopping acetylcholine from doing its job.
Action Tremor
A tremor of one of your limbs when you start doing something like writing or picking something up. It usually appears in the later stages of Parkinson's disease.
Agonist
A drug or chemical that mimics the action of a neurotransmitter like dopamine. Dopamine agonists are one of the first medical treatments used with Parkinson's disease. They work by tricking the brain into thinking that they are dopamine. Akinesia
Inability to move (freezing) or difficulty in producing bodily movements.
Amantadine
A medication used to treat Parkinson's disease. It stimulates the brain and triggers the release of dopamine. It may be used alone or together with L-dopa. vodopa.
Anticholinergics
A family of medications used to treat the tremors associated with Parkinson's disease. They inhibit the actions of chemical messengers like acetylcholine and relieve tremors.
Ataxia
Lose of balance and coordination.
Athetosis
Repetitive, slow movements that are not under your control, particularly in the hands. A symptom of Parkinson's disease.
Atypical Parkinsonisms
Conditions that are related to Parkinson's disease and have some of the same symptoms, but have their own symptoms that distinguish them from Parkinson's disease.
Autonomic Nervous System
The part of the nervous system that operates automatically, without conscious thought. The Autonomic nervous system controls things like breathing, sweating and your heart rate.
B
Basal Ganglia
A group of nerve cells at the base of your brain that control voluntary movements like walking.
Benign Essential Tremor
A condition that is sometimes mistaken for Parkinson's disease. It has some of the same symptoms, particularly tremors in the hands, head and voice, but it's a different kind of tremor than is usually found in Parkinson's disease, and it isn't accompanied by rigidity of slowness.
Bilateral
Occurring on both sides of the body.
Blood-brain barrier
A sort of `brain filter', the Blood-brain barrier is a layer of cells that between the brain and the blood stream. It blocks many substances from entering the brain.
Blepharospasm
Spastic blinking or forced closing of the eyelids, sometimes seen in cases of Parkinson's disease.
Bradykinesia
Slowed movements characteristic of Parkinson's disease. It's one of the five main symptoms of the disease
Brainstem
The lowest part of the brain, located at the top of the spinal cord. Parts of the brain stem are responsible for most automatic muscle movements
Bromocriptine
The generic name of a dopamine agonist
C
Carbidopa
A drug that is used with levodopa (L-dopa) to help the body use L-dopa more efficiently. Carbidopa blocks the breakdown of L-dopa in the body before it reaches the brain.
Central Nervous System
The brain and spinal cord are the central nervous system
Cerebellum
The largest part of the brain; responsible for thought, reasoning, memory, sensation, voluntary movement.
Chorea
Random involuntary movements of the type often seen in Parkinson's disease as a result of too much medication.
Cognitive Function
The ability to organize information in the brain; thinking, remembering and planning are all parts of cognitive function
Cogwheel Rigidity
Rigidity is one of the five major symptoms of Parkinson's disease. It's characterized by muscle stiffness with a jerky quality when the arm or leg joints are moved. d.
COMT Inhibitor
A class of drugs used to fight parkinsonism by blocking an enzyme that breaks down L-dopa in the intestinal tract and allows more L-dopa to reach the brain. COMT inhibitors include entacapone (Comtan) and tolcapone (Tasmar).

=> Recommended Parkinson’s Disease Resource: All About Parkinson’s