What is Parkinson's disease?

Parkinson's disease, a movement disorder, is a progressive and degenerative neurological disease with four primary symptoms: rigidity (stiffness or inflexibility of the limbs and joints), bradykinesia/akinesia (slowness of movement/absence of movement), tremor (involuntary, regular, rhythmic shaking of a limb, the head, the mouth, the tongue, or the entire body), and postural instability (poor balance and coordination).

The major symptoms of Parkinson's disease are due to abnormalities in structures deep within the brain. These structures form a complex motor circuit that, when operating correctly, allows for smooth, controlled, normal movement.

One of these structures is called the substantia nigra. In Parkinson's disease, cells in the substancia nigra die - for reasons as yet unknown. These cells produce dopamine, a chemical essential for controlling normal movement and muscle function.

As the cells die and less and less dopamine is released, other structures of the motor circuit that process nerve signals are also affected and begin to act abnormally.

Two brain structures affected by the loss of dopamine are the "subthalamic nucleus" (STN) and the "globus pallidus" (GP). Without normal amounts of dopamine, these two structures affect the motor circuit by virtually slowing it down and thus the symptoms of Parkinson's disease appear.

How does Parkinson's disease affect quality of life?
Many Parkinson's patients describe themselves as prisoners within their own bodies.

As Parkinson's progresses, it becomes increasingly disabling, making routine daily activities like bathing, dressing or eating without assistance from others difficult or impossible.

Patients can experience extreme swings in movement control - from periods of virtually normal motor function to episodes of complete immobility - in the span of a few hours.

The disabling effects of Parkinson's disease and the unpredictable onset of side effects from treatment with the drug levodopa may cause many patients to become unwilling or unable to venture outside their homes to work, shop, eat or socialise - everyday activities that most people take for granted. The inability of some advanced Parkinson's patients to care for themselves often leads to a loss of dignity and self-esteem.

How widespread is Parkinson's disease?
Estimates vary, but Parkinson's disease may affect approximately 1.6 million people worldwide. Based on the incidence of the disease, approximately 33'000 people worldwide, could benefit from Deep Brain Stimulation Parkinson's Control Therapy each year.

The average age of onset for Parkinson's disease is 60.

"Young-onset" Parkinson's disease may affect people between the ages of 20 and 40.