Parkinson’s can take a heavy toll

As we watch Pope John Paul struggle in the late stages of Parkinson’s disease, it is clear how devastating Parkinson’s can be. One of the “degenerative” neurological diseases, Parkinson’s gradually steals the body’s ability to perform even the simplest activities. It affects the part of the brain that controls our movements, called the substantia nigrans.

The substantia nigrans makes dopamine, and uses it as a chemical messenger to pass information on down the line to the next way station. All this information gets translated into the smooth movements we do a thousand times a day.

Parkinson’s, for some as yet unknown reason, kills off 80 percent of those dopamine- producing cells. Without dopamine around, the nerve cells at that way station start firing off willy-nilly. The person with Parkinson’s has trouble controlling his movements, and getting dressed in the morning can take an agonizing two hours.

Parkinson’s is generally a disease of late middle age; the average age at diagnosis is 60. Michael J. Fox, another celebrity who has made his struggle with Parkinson’s very public, was just 37 when he was diagnosed. He is one of the 10 percent who are younger than 40 when they are derailed by Parkinson’s.

Like multiple sclerosis, Parkinson’s is not the same in everyone. Some may have rapidly progressive disease; for others the diseases ambles along slowly. Some may be severely disabled; others may have only minor movement difficulties. An equal opportunity disease, Parkinson’s affects men and women in about the same numbers.

Parkinson’s is often difficult to diagnose in its early stages, because the symptoms can be vague and nonspecific. Fatigue and weakness are common. Handwriting may change, taking on a cramped look. The voice may become softer, and it may be difficult to get up out of a chair.

The classic symptom of Parkinson’s is the “pill rolling” tremor, the rhythmic back and forth motion of the thumb and forefinger at a steady three cycles per second. Sufferers note rigidity, slowing down and loss of spontaneous and automatic movement, and loss of balance and coordination. They often walk stoop-shouldered, with bowed head. Because the muscles become increasingly nonresponsive, activities of daily living become more and more difficult.

Dopamine, in the form of levodopa, has been the mainstay of treatment for years. The increased dopamine helps to stabilize movement and control tremors. Newer agents, called dopamine agonists, also help with the first symptoms of Parkinson’s, although perhaps not quite as well as levodopa.

These drugs are not without their down side. They don’t provide a permanent fix for the problem, and must be taken regularly to relieve symptoms. They probably don’t prevent the disease from progressing. These drugs can stimulate other dopamine sensitive areas of the brain, and cause side effects such as nausea, vomiting and hallucinations.

In some people, as the disease progresses, the symptoms start breaking through in what is referred to as “off” states, where the muscles just won’t work. Therapy strives to turn those “off” times into “on” times. A recent study in the British journal The Lancet looked at a drug called rasagiline. Combined with levodopa, the drug reduced off times by about 20 percent. This study only lasted for 18 weeks, so further studies will need to look longer term to see if this drug upholds its promise.

And what about stem cells? Scientists are interested, but the research, threading in and out of the political zeitgeist, is still in its infancy.

It is not often that the whole world can see the final stages of Parkinson’s. But as we watch Pope John Paul’s courageous, but frail demeanor, it is there for all of us to observe. And ironically, as we watch the man who is so adamantly against embryonic stem cell research, we wonder if the cure for this devastating disease lies in their transformative power.