Understanding Parkinson's Disease

    It all started in 1991, when Hollywood actor Michael J. Fox noticed a twitch in his little finger while working in Florida. Within six months, the tremor spread to his left hand, and his shoulder was achy and stiff.

    A neurologist diagnosed Fox as having Parkinson's disease. In the United States, it afflicts some one million Americans including former heavyweight champion Muhammad Ali, the Reverend Billy Graham and Attorney General Janet Reno.

    "It was incomprehensible," said the star who shot to fame in the 1980s television series Family Ties. "But from the beginning, I wasn't frantic. I was pretty methodical. I'm not crying 'What a tragedy' because it is not. It's a reality, a fact."

    "I think I can help people by talking," he said, noting that hiding his condition had become burdensome. "There are a billion tricks I can do to hide (my disease)," he admitted. "I've done interviews the entire time, and later the writer describes me as nervous."

    There are a few reliable data of global prevalence or morbidity of Parkinson's disease, but it is known to affect all ethnic groups. The Geneva-based World Health Organization (WHO) says there are an estimated four million people suffering from the disease around the globe.

    "Parkinson's disease affects about one in every 250 people over 40 years old and about one in every 100 people over 65 years old," according to The Merck Manual of Medical Information.

    The condition was first established as a clinical entity in 1817 by a London physician, James Parkinson (1755-1824), in his Essay on the Shaking Palsy.

    Later, in the 1860s, the French neurologist Pierre Marie Charcott (1853-1940) called the condition "Parkinson's disease," in honor of the essay author.

    Today, 183 years after it was first published, Parkinson's essay continues to be recognized throughout the world as the classic description of the disease.

    But what causes this disease? The home edition of the Merck manual shares this information: "Deep within the brain is an area known as the basal ganglia. When the brain initiates an action such as lifting an arm, nerve cells in the basal ganglia help smooth the movements and coordinate changes in posture.

    The basal ganglia processes signals and transmits messages to the deep-lying thalamus (area in the brain concerned with many bodily functions, often called the seat of the emotions), which relays the processed information back to the cerebral cortex.

    All these signals are transmitted by chemical neurotransmitters as electrical impulses along nerve pathways and between nerves. The main neurotransmitter of the basal ganglia is dopamine.

    For example, antipsychotic drugs used to treat severe paranoia and schizophrenia block the action of dopamine on nerve cells. In addition, an illegal, street-synthesized form of opiate known as N-MPTP can cause severe Parkinson's disease.

    The expression of Parkinson's disease varies enormously and no two people will have exactly the same symptoms, according to the United Nations health agency. However, the three main symptoms, which are based as a basis for diagnosis, are tremor, rigidity, and bradykinesia.

    * Tremor is often the first sign to be noticed, although it is estimated that about 25 percent of people with Parkinson's disease do not have tremor. The tremor usually occurs at rest and lessens with voluntary movements. It is commonly experienced in the hands and arms, often on one side, but many affect any part of the body.

    * Rigidity results from a sustained increase in muscle contraction and may cause muscle pain and stiffness. Clinically, it may be felt as an intermittent ("cog-wheel") or sustained ("lead pipe") resistance to movement when passively putting a limb throughout its range of movement.

    * Bradykinesia means slowness or poverty of movement. In an unaffected person, automatic movements occur involuntarily and subconsciously.

    People with Parkinson's disease experience an increasing poverty of such spontaneous activity. This accounts for symptoms such as the stooped posture, drooling of saliva and a shuffling gait.

    In addition to the three main symptoms, loss of communication skills is likewise particularly common. "Speech often becomes soft, mumbling and monotonous in tone," the WHO notes. "There is often reduced facial expression, resulting in a typical 'masking face' and limited body language.

    Many people also have problems with their handwriting which becomes small and cramped, making it very difficult to read."

    These communication problems can seriously affect the social and emotional life of both the person with Parkinson's disease and his or her family.

    Research has shown that the loss of non-verbal skills has a negative impact on people's perception of an individual's abilities. Because of reduced body language, people with Parkinson's disease are often erroneously labeled unintelligent, uncooperative, and difficult.

    Although some people with Parkinson's disease in the later stages may become mentally confused or demented, most retain their intellectual facilities while living in a body which is becoming increasingly disabled.

    "This, in itself, can contribute to the boredom, social isolation, and depression commonly experienced by sufferers," the WHO says.