Parkinson's disease

What causes it?
The exact reason for specific cells of the brain to deteriorate is unknown, and no regular genetic influences had been identified until recent work on twins suggested quite strongly that a genetic influence may, in fact, be greater than was previously thought. In some cases the disease occurs with extraordinarily high incidence in families, especially if it affects young people, and a defective gene has been demonstrated.

It is known that in Parkinson's disease there is a progressive deterioration of certain nerve cells in a specific area of the brain, and this can be demonstrated by the use of modern imaging techniques. These cells are responsible for producing a particular chemical - dopamine. This is one in a chain of chemicals necessary for the proper conduction of the nerve impulses within this area of the brain. If there is a disturbance, then there is inefficient transmission of messages in this area, which is responsible for muscle movements. Consequently, loss of various aspects of muscle function occurs. The exact reason that these specific cells of the brain deteriorate is unknown.

There are other conditions that can produce Parkinson-like features (secondary Parkinsonism):

• Some cases of the 'disease' have been thought to be associated with an exposure to various chemical toxicants, beginning in childhood and continuing throughout life, which are found in the environment.
• Other exposures to such chemicals as pesticides and certain wood preservatives have been researched and recorded as a possible link.
• There are also certain prescribed medications, which, as a side effect, can cause Parkinsonism features; these clear as soon as the medication is discontinued.

What are the symptoms?
There are very many symptoms, and they will not all be found in every person affected. These will include:

• Muscle rigidity and stiffness, difficulty with bending of limbs
• An unstable, stooped or bent-over posture
• General loss of balance
• Variable changes in walking pattern, with characteristic features
• Shaking, tremors and fixed facial expressions
• Slow speech with general speech changes