Chapter One Understanding Parkinson's Disease
Alan remembers quite clearly the day he first noticed that his left hand shook. It was a Monday, the day he was to make a sales presentation he'd spent a month preparing. Sitting quietly at his desk, this 54-year-old businessman felt his hand trembling, slightly but persistently. "I put it down to nerves, fatigue, whatever. I'd been feeling depressed and more tired than usual, but otherwise I was in great physical shape. I was only 54. I didn't give it a second thought -- until it kept happening."
For Beth, a 68-year-old retired schoolteacher, the onset of her condition was much more gradual, occurring over the course of more than a year. "I tired easily and moved much more slowly. My gardening chores became more difficult and painful to perform. I thought it was just the price I had to pay for getting on in years," she recalls. "But my husband became alarmed when he saw me dragging my fight leg, and he complained that I wasn't smiling as much and that I seemed to be staring off into space all the time. When I noticed that I was sort of shuffling when I walked, I became alarmed, too."
Both Alan and Beth would later be diagnosed as having Parkinson's disease, a degenerative brain disease suffered by about one million Americans, most over the age of 50, and just slightly more men than women. They would learn that certain cells in a part of the brain known as the substantia nigra were dying -- cells essential to the process of normal human movement. As the cells of the substantia nigra continue to die off, proper movement and balance deteriorate. But neither of them received the diagnosis of Parkinson's on the first visit to a physician.
"My doctor put me through a complete checkup: blood test, chest x-rays, urinalysis, the works," Alan recounts. "He also asked me endless questions about my work routine, what foods I ate, what kind of stress I was under. Because I was feeling so depressed, he referred me to a psychiatrist, whom I saw for about six or seven months. The psychiatrist prescribed antidepressants, but I still wasn't feeling any better. If anything, I felt worse. Then I went to another neurologist, who said, and I quote, 'Well, it doesn't look like Parkinson's disease anyway.' I guess he said this because I didn't have very pronounced symptoms. In fact, my tremor seemed to disappear whenever I went to the doctor! It took about another year and two other neurologists before the diagnosis of PD was confirmed."
Beth's experience was a bit less complicated, but still involved a number of different tests. "Because of my age and because it seemed to be only my right side that felt odd," Beth recalls, "my doctor wanted to rule out the possibility that I'd had a mild stroke without knowing it. He told me up front that a stroke was highly unlikely, mainly because the symptoms seemed to come on gradually and get worse. But he wanted to make sure."
Although Beth's physician suspected PD almost from the start, he knew it was important to nile out the many other conditions -- some common and others quite rare -- that might account for Beth's symptoms (see Appendix II). Many people suffer from symptoms similar to those caused by Parkinson's disease, but do not actually have the disease itself. When a patient suffers from another disease that produces parkinsonian symptoms, he or she is said to have secondary Parkinson's disease. The causes of these diseases range from the rare, including the inherited, to those caused by certain drugs or toxins. Classic Parkinson's disease, in which the cells of the substantia nigra are being destroyed for an as-yet-unknown reason, is usually referred to as primary or "idiopathic" Parkinson's disease.
No simple blood test or x-ray will confirm PD: The diagnosis is arrived at primarily through physician observation, the elimination of other diseases as the cause of the symptoms, and finally the patient's response to drugs known to reduce the effects of Parkinson's disease (discussed in Chapter Four).
Although you may receive the diagnosis of PD directly from your primary-care physician -- many patients do -- both Alan and Beth eventually saw brain specialists as well. Neurologists are trained in the art of deciphering the intricate circuitry of the body's least-understood organ, the brain.
A complete neurological exam is an intense, often time-consuming, but almost never painful, experience. It usually begins with the neurologist taking a thorough medical history. He or she will probably ask what other medical conditions you have and what drugs you may be taking, your history of childhood diseases, and if you have had any accidents that involved head or spinal injury. You also will be asked about your family's medical history, especially that of first-tier relatives such as parents, grandparents, siblings, and children, and second-tier relatives such as aunts, uncles, and cousins. This information may help the neurologist rule out some inherited conditions, such as Wilson's disease, that may resemble Parkinson's disease.
Then the doctor performs the physical exam. When a motor (movement) disorder such as Parkinson's disease is suspected, the neurologist will pay special attention to your muscles: how they contract, their strength, and their tone (their resistance to passive movement). The doctor will most likely use the reflex hammer not only in the usual places, such as your knee and elbows, and ankles, but perhaps on your jaw and in other places as well. Every muscle has a reflex, even those that control chewing and swallowing.
Eye movements are studied because the neurologist can tell many things about the function of your nervous system by studying how your eyes move from side to side and up and down. In Parkinson's disease and in some of the diseases that resemble it, there may be a limitation in eye movement -- a subtle limitation of which you may not be aware.
Next, the neurologist often likes to see how you move about, how you open and close your hands, tap your feet, how you stand, walk down a hallway, sit back down in your chair. Many neurologists, especially when they suspect PD, will request a sample of your handwriting. In addition, the doctor will take special note of what we think of as body language: Do you cross your legs often or casually brush hair from your face? How often do you blink? Do you smile, frown, or otherwise show emotion when you are speaking or listening? Even the way you get dressed after the exam is data for the doctor's calculations.
Your memory, your ability to do simple mathematical equations, and the sophistication of your abstract reasoning may also be measured at this time. One test for mental function requires you to spell a five-letter word such as "world" forward and backward. This test requires not only rote learning but the ability to juggle things in your mind, remember them, and rearrange them.
Don't be surprised if the exam involves a bit of philosophy as well. To measure your powers of abstract thinking, the neurologist may ask you to interpret a proverb or cliche: What does "A rolling stone gathers no moss" mean to you? for instance. Of course, no fight or wrong answer exists to such a question, but how you describe your reaction to it may tell the doctor a great deal about the way your brain is functioning.
More than likely, and again to rule out other conditions that may account for your symptoms, other medical tests may be required. One of the most useful is magnetic resonance imaging, or MRI, which has replaced the computerized axial tomogram, otherwise known as the CAT or, preferably, the CT scan. First introduced in 1984, the MRI scan has become an invaluable medical tool. Hundreds of times more detailed than the ordinary x-ray, MRI scanning can be used to see inside any of the body's organs, including the brain.
The MRI scan is a simple, completely painless procedure, although a few rare patients experience claustrophobia after being placed within the scanner. You'll lie flat on a special table as a powerful magnetic field is created around you. Special radio-frequency waves are pulsed through the field. A detector will pick up changes in the field as the radio waves pass through your brain, then feed the data about tissue density into a computer for analysis. A picture of the result is displayed on a computer screen. The test takes about 20 to 30 minutes and will detect any tumors, cysts, abscesses, or other problems that may be causing your motor dysfunction. Invaluable information on previous, unsuspected strokes may also be obtained.
To rule out brain damage from injury or other neurological disorders not detected on the MRI, the neurologist may request that you have an EEG, an electroencephalogram. If you're scheduled for an EEG, expect to perhaps feel a bit sticky (often glue is used on your scalp) but otherwise completely comfortable. Electrodes are attached to your scalp to record your brain's faint electrical activity. In order to measure how your brain reacts to changes, you may be subjected to flashing lights or noise during the exam.
Other tests may also be administered before your doctor or neurologist determines that you are, indeed, suffering from Parkinson's disease. Although these tests may seem tedious and may be costly, remember that there are other diseases that can be confused with PD. Since PD is a lifelong condition, it is important to rule out these other diseases, which may require special treatment.
One test, called the positron emission tomography, or PET, scan, has provided valuable insights into Parkinson's disease. An extremely sophisticated test, the PET scan can actually detect the presence and location of brain chemicals, something once possible only through the removal of the brain for biochemical analysis. In fact, it may be possible for a PET scan to detect a loss of dopamine -- the brain chemical missing or in short supply in the brain of a Parkinson's disease patient -- before symptoms of Parkinson's disease are apparent. Unfortunately, PET scan equipm...
