Maintaining Your Health on Mackinac
Parkinson's Disease, a Chronic Neurological Condition
By Yvan Silva, M.D.

Parkinson's disease is a neurological disorder. It affects the brain and the nervous system and leads to inability to control motor activity. More than half a million Americans are affected. Overt signs are tremors and speech problems. Walking and physical activities become impaired. Affected individuals become frustrated with these difficulties. Current goals in management are to minimize these disabilities and help gain independence with activities of daily living.

Parkinson's disease is caused by a decrease in a chemical known as dopaminethat that facilitates communication between nerve cells. When production levels fall to about 60 to 80 percent of normal, symptoms start to become evident. Gradual and progressive loss of motor functions ensues. Dopamine facilitates the transmission of signals from the brain to the muscles impediments to this process lead to shaking and trembling instead of steady, smooth and deliberate movements that are the norm. It is not known what leads to the failure of normal dopamine production. Most people with this condition begin to manifest symptoms later in life, although symptoms may appear as early as age 40. Men are affected more often than women and about 12 percent of people with Parkinson's have a family history of this condition. The risk of developing Parkinson's is known to increase with age.

Early signs of the disease may appear and continue before it seriously affects life. Difficulty with normal activities of daily living, such as slowness of movement, becomes apparent. There is slowing of movement such as getting up and out of a chair or getting from one place to another. This bradykinesia may gradually affect all motion. Tremor begins in the hands and a pillrolling like motion between the thumb and forefinger becomes noticeable. Tremor is more apparent at rest and may diminish with purposeful movements. It may not be present during sleep. Progression of tremor later extends to the lower extremities. Yet, tremor may not be a prominent symptom in one-third of Parkinson's sufferers.

Speech problems ensue, loss of voice strength, slowness of speech, and lack of clarity. Anxiety and depression are common. Posture and balance become impeded. It becomes difficult to sit or stand up straight. Stooping and leaning forward with a gait that is slow and shuffling becomes obvious. Memory loss and signs of dementia may develop with progression of the condition. About 25 percent of people with Parkinson's may develop dementia in the later stages. Facial expression becomes less and less expressive and masklike; handwriting becomes cramped and less legible; hands begin to lose their grip and the individual may stay in one position for longer periods of time than usual.

Parkinson's disease manifests itself variably. As the disease progresses, not all sufferers exhibit all the signs and symptoms. There is progression in these broad categories tremor, rigidity, postural instability, and bradykinesia to varying degrees.

While there is still no cure, there have been advances in the development of new drugs and other treatment options. The right medications tailored to the stage of the disease are instituted. Not all respond equally, and changes in the mix and dosages of medications are important to monitor. There are three broad categories of medications. Their functions are to replace dopamine, function as agonists to dopamine, or extend the action of dopamine. Since the 1960s, a medication that is converted to dopamine in the brain, levodopa, has helped people to lessen symptoms, especially with motion, and to help people function independently for longer than before possible. The dopamine agonists and extenders are used in combinations or at various times and are very useful. There are, as usual, side effects to reckon with, singly as well as in combinations.

There are recent developments also in the role of surgery in Parkinson's. The placement of a wire into the hypothalamus, at the base of the brain, connected to an electrical stimulator similar to a heart pacemaker is a relatively new treatment under investigation. For more than four decades a surgical procedure called pallidotomy has been used to help control symptoms, especially tremor. The pallidum, an area deep in the brain, is ablated by heat generated at the tip of the wire that is placed surgically in that area. It has been effective in patients when indicated.

Parkinson's disease is a condition that has been known for a long time. Although no specific

cause has been determined and no specific cure is available, this complex problem with a variable mix of symptoms is being addressed in several new, and some controversial, methods of research. Development of new drugs to improve neurochemical transmission continues. The transplantation of fetal tissue to replace dopamine-producing nerve tissues has been done, with mixed results. Insertion of a gene into the affected area of the brain is also being researched. At this time, people with symptoms that may be indicative of Parkinson's disease should seek early medical consultation, evaluation, and treatment.

Dr. Silva is a professor of surgery at Wayne State University and a resident of Woodbluff on Mackinac Island.