Parkinson’s disease is a progressive disorder of the nervous system that affects motor skills, cognitive processes and other functions.

About 50,000 Americans are diagnosed with the disease each year. I have it, along with Michael J. Fox and Muhammad Ali.

Symptoms include characteristic shaking that often begins in the hand, possible slowed motion and rigid muscles, impaired posture and balance, among other conditions.

There is no known cure, only medications to treat symptoms, says Dr. Neal Hermnowicz, a neurologist and director of the University of California, Irvine, Movement Disorders Services.

“The specific symptoms don’t follow any predictable course. Individuals ask all the time, ‘How am I going to be in five or 10 years?’ and that diagnosis is not possible on an individual basis,” he says.

Q. Are you seeing more patients now than before?

A. the number of cases is increasing because the population is aging. most people are diagnosed around age 60, and there are more people reaching that age today as boomers age.

Q. Are people more open about having the disease?

A. in the past, they were very quiet. Morris K. Udall (former congressman) and Margaret Bourke White (a well-known photographer) were two who had Parkinson’s. now, with Muhammad Ali and Michael J. Fox, it’s much more in the open. this helps focus research on the disease.

Q. You diagnosed my condition about five years ago. I have a small tremor in my right hand that has gotten just a little more pronounced. You have said I fit a category that may mean I will do well for some years. what are other signs of Parkinson’s?

A. Parkinson’s fits two categories: tremor at the outset or stiffness and walking and balance problems.

Q. and medications?

A. the strategy for treatment largely is directed to replacing the neurotransmitter dopamine. that has been a successful strategy using levadopa, which relieves the symptoms, and other medications, such as Azilect, which seems to delay progress of the disease. But these do not get the brain cell to stop what is happening.

We are treating the symptoms, but the intended future goal is to find the cause.

As one delves deeper, what is striking is the great variety and the fact that symptoms don’t follow any predictable course.

Q. what about surgery?

A. Surgery and deep brain stimulation is an option for some people. There are a lot of options and this is a good thing. as choices increase, we can decide which road do we go down, which procedure do we pursue, on an individual basis.

Q. Michael J. Fox seems to vary between many involuntary movements and some control. What’s happening?

A. Well, he does have dyskinesia, or involuntary movement, as a result of advancement of the disease. He acquired the disease at a young age and has talked about it publicly for 10 years.

Q. What’s the most important treatment, in your opinion?

A. People with Parkinson’s need to stay socially and intentionally engaged.

Of course, that is a good diagnosis for everybody, whether they have Parkinson’s or not.

But it’s most important for Parkinson’s patients not to withdraw socially.

Q. It would be difficult for me to withdraw, I think. what is research going to do?

A. hopefully get those brain cells to stop quitting and to start working properly.

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Jane Glenn Haas writes for the Orange County (Calif.) Register. E-mail her at