Disease processes in PD

Parkinson’s disease, which is commonly referred to as PD or just ‘Parkinson’s’, was named after a London doctor called James Parkinson, who first described the symptoms of the disease in 1817.

PD is a condition of the nervous system (i.e., a neurological condition) that involves a gradual loss of nerve cell function in the brain (known as neurodegeneration). This nerve cell loss leads to a decline in certain aspects of body function, particularly the control of movement although other non-movement symptoms can also occur. Body movements are controlled by nerve cells in the brain that pass messages to one another. These messages are sent using chemicals (neurotransmitters), which pass between the nerve cells and, in healthy people, the messages are carried smoothly (see Figure, below).

Dopamine controls movement

(Click on animation to enlarge.)

One important neurotransmitter that is involved in controlling body movements is called dopamine. In people with PD, there is a lack of dopamine in the brain, and therefore the relay of messages is disturbed, and this creates problems with the control of movement.

The symptoms of PD often appear gradually, usually on one side of the body first, and slowly progress over time. The main physical symptoms of PD are slowness of movement, stiffness, and sometimes tremor and loss of balance, although the type and severity of symptoms vary from person to person. Different symptoms may appear as PD progresses.

Please follow the links at the side of this page to find out more background information about the disease processes in PD, as well as the causes, diagnosis, and symptoms of the condition.