One of the major chemicals in the brain, a neurotransmitter that stimulates motor nerves.

Action tremors

Tremors that increase with voluntary movements.


A class of medication, which stimulates the dopamine receptors directly.


Complete or partial loss of muscle movement.

Amantadine (Symmetrel)

A medication initially designed to relieve influenza symptoms but later found to assist with rigidity and other parkinsonian symptoms. May also help to reduce dyskinesias.

Antidepressant (medication):

Medications used to treat depression.


Occurring on both sides of the body (left and right).


Rapid blinking or forced closure of the eyes.


Poverty and slowness of movements.

Central nervous system

The brain and spinal cord.


A drug used in combination with levodopa in the treatment of Parkinson's which prevents levodopa from being metabolized in the body, thus allowing more levodopa to reach the brain.


Refers to increased muscular tone. Regular jerky quality in response to passive movements as if there was a cogged wheel in the joint.


Rapid, jerky, dance-like movements of the body. Dementia: progressive deterioration of mental state.


Chemical produced by the brain; it assists in the effective transmission of electrochemical messages between neurons.

Dopamine agonists

Mimic the effects of dopamine without boosting body's production. This class of drugs is used to postpone levodopa therapy and its side effects.


Abnormal, involuntary movements of voluntary muscles (may involve face, neck, hands, arms, legs, etc.) including twitches, jerks, twisting, or writhing movements.


Difficulty swallowing common in later stages of Parkinson's.


Slow, twisting movements which may involve one limb or several limbs.

Essential tremors

A rapid tremor that, in contrast to the slower, resting tremors of Parkinson's, increases with activity.

Familial tremor

An inherited essential tremor.

Festinating gait

Rapid, uncontrolled shuffling.

Flexion contracture

Permanent bending of parts of the body.


Temporary, involuntary inability to move.

Haloperidol (Haldol)

A tranquilizing medication that can cause Parkinson-like symptoms.


Of unknown cause.


Antiparkinson drug which is changed into dopamine in the brain; usually combined with carbidopa i.e. Sinemet).


Enhance the effect of dopamine by interfering with its breakdown in the brain. May help prevent further damage to cells.


Small handwriting; in Parkinson's, writing may start out normal size and become smaller and smaller. Sometimes an early symptom of Parkinson's.

Off dystonia

An abnormal posturing or cramping when levodopa levels are at their minimum in the bloodstream.

"Off" time

Time during which antiparkinsonian medications are not working well and motor function is poor.

On-Off fluctuation

Fluctuations in response to antiparkinsonian drugs in which patient changes suddenly from a good response "on" to a poor response "off".

Orthostatic hypotension

A drop in blood pressure during rapid changes in body position (e.g. from a sitting position to standing position).

Peak-dose dyskinesia

 A type of dyskinesia which occurs when the dopamine in the brain is supposed to be at its peak; results from too much dopamine in the system.

Postural instability

Loss of balance and coordination. Inability to right oneself when falling down.

Propulsive gait

walking that is propelled forward.

Resting tremor

Tremors of a limb when the body is relaxed.


Increased resistance to passive movement of a limb.



Substantia nigra

An area of the midbrain containing a cluster of black-pigmented nerve cells that produce dopamine.


A rhythmic involuntary movement of a body part.

Wearing off

A fluctuation in response to antiparkinson medications when the medications are losing their effect and parkinsonian symptoms progressively appear. In other words; medication effects end before the next dose is due.