Parkinson's disease (PD) is a disease that is linked with the nervous system! It is basically a chronic, progressive disorder that may continue for a longer duration of time, and may take so many years as well. This disease mainly affects a person's muscular coordination.

Here are some of the terms that are related with Parkinson's disease:

1. Chronic:Recurring frequently or something that lasts a long time!
2. Dopamine:A neurotransmitter that helps send signals that control movement.
3. Neurotransmitter:A chemical that helps in transmitting the electrical signals from one brain cell to another.
4. Substantia nigra:A region of the brain that is responsible for controlling the movement.

The symptoms by which PD can be identified include:

• Tremor (shaking), and this type of extreme shaking usually begins in the hands. When it comes to Parkinson's disease, the most general tremor that is linked with it is known as "pill-rolling tremor." as far as its movements are concerned, they are just similar to rolling a pill between the thumb and forefinger. A person can witness these kind of movements thrice in a second or so!
• Slowing down of movements. As PD deals with the nervous system, that is why the person who is suffering from this disease may slow down or even stop in the middle of familiar movements, like the usual day to day activities such as walking, writing etc.
• Muscle rigidity: the person may also suffer some kind of stiffness and his movements may be jerky rather than smooth. If such things happen, then you should immediately take him to doctor!
• Problems with balancing in day to day moments. The patient may have problems with his posture as well. He may also change the way he or she walks to keep from falling over.    
  

Some other symptoms that are accompanied with this disease are:

• Depression
• Changes in the way a person speaks
• Sleep problems, including restlessness and nightmares
• Emotional changes
• Incontinence (loss of bladder control)
• Constipation
• Changes in handwriting
• Dementia (increased problems with mental functions)

It is not mandatory that the person who is suffering from Parkinson's disease will definitely show these symptoms but still a majority of them may show these symptoms.