Parkinson's disease (PD) is a slowly progressive, chronic neurological condition affecting a small area of cells in the midbrain known as the substantia nigra. Gradual degeneration of these cells causes a reduction in dopamine, a vital neurotransmitter.
Signs and Symptoms
Decreased levels of dopamine can produce one or more of the classic signs of Parkinson's disease:
- Resting tremor on one side of the body
- Generalized slowness of movement (bradykinesia)
- Stiffness of limbs (rigidity)
- Gait or balance problems (postural dysfunction)
Other symptoms observed in some persons with Parkinson's disease can include:
- Small cramped handwriting (micrographia)
- Lack of arm swing on the affected side
- Decreased facial expression (hypomimia)
- Lowered voice volume (dysarthria)
- Feelings of depression or anxiety
- Episodes of feeling "stuck in place" when initiating a step (freezing)
- Slight foot drag on the affected side
- Increase in dandruff or oily skin
- Less frequent blinking and swallowing
Few patients experience all of these symptoms and some may experience other signs.
- Estimated that up to 1.5 million Americans are affected
- 40,000 to 60,000 new cases are diagnosed each year
- 15% of patients are diagnosed before age 50
- Parkinson's disease affects one of every 100 persons over the age of 60
Thanks to public health strides and healthier lifestyle choices, many people now live well into their eighties, adding to the impression that the incidence of Parkinson's disease is increasing. While there is, as yet no cure for this condition, Parkinson's disease is not a fatal illness and progressive treatments allow many patients to maintain a high level of function throughout their lifetimes.
The cause of Parkinson's disease remains a mystery. What happens is clearer than why it happens in these cases. Cells begin to die in a small deep area of the brain, the substantia nigra. These cells of the substantia nigra manufacture dopamine, a chemical messenger that is necessary for ease of movement. As the cells degenerate, the amount of dopamine in the brain decreases. Symptoms of Parkinson's appear when about 70-80% of these cells die. It is not clear why these cells begin to die in some people but not in others.
Sometimes Parkinson's symptoms can be linked to stroke, or exposure to certain toxins, or use of medications such as those used to treat psychosis and some used for nausea. In these cases, the condition is known as secondary parkinsonism, and the condition may be reversible if the cause can be eliminated.
Most cases of Parkinson's, however, are termed idiopathic, or without a known cause.
Recently, researchers isolated a gene responsible for multiple cases of Parkinson's in a large family. But only 20% of people who have the illness are thought to have a hereditary connection. Some researchers are investigating a possible link between Parkinson's and a person's lifetime exposure to environmental toxins such as pesticides and heavy metals. Others think PD may be the result of the natural aging process gone awry, accelerating the normal brain cell death that occurs as we age. However, most researchers agree that Parkinson's disease is probably the result of a genetic predisposition coupled with a yet unknown environmental factor.
There is no definitive blood test or X-ray to confirm diagnosis. The diagnosis of Parkinson's disease is one of clinical judgment, base on a thorough neurological examination. The diagnosis of Parkinson's based on the person's symptoms, medical history and response to medications. Tests such as magnetic resonance imaging (MRI), and/or blood work can help rule out conditions that may produce similar symptoms such as stroke or a brain tumor. Once a probable diagnosis is established, medications are prescribed, and the diagnosis is confirmed if the symptoms improve.
The goal of treatment is to maximize independence and quality of life for people who have Parkinson's disease. Treatment may include medication, surgery, and rehabilitation therapy.
Medications currently provide the most effective Parkinson's treatment. There are a variety of medications aimed at controlling and alleviating the symptoms. Because every person who has Parkinson's has individual symptoms and responses to medication, treatment is tailored to the individual, and may require a combination of several different medications.
For those whose symptoms do not respond to the usual medical treatments, surgery may be an option. Deep brain stimulation (DBS) surgery involves placement of a wire electrode into a specific area of the brain. This electrode is connected to a stimulator, somewhat like that of a cardiac pacemaker. The stimulator is then implanted beneath the skin under the collarbone. The patient can switch on the stimulator with a hand-held control, sending electronic pulses to the brain to interrupt the signals that cause tremor.
Physical, occupational, or speech therapy combined with modifications in the home environment can help individuals with Parkinson's achieve maximum comfort, safety and independence.
For additional information and resources about Parkinson's Disease, visit the National Parkinson Foundation web site at http://www.parkinson.org/.
Sections of this information were reprinted and adapted, with permission, from the National Parkinson Foundation, Inc. web site.
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