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Hey, shortwavers, John Hamilton here in the host chair today. In my day job, as NPR's

brain correspondent, I've done a lot of reporting on Parkinson's disease. It's a progressive

disorder that causes difficulty with movement. It affects around a million people in the United States,

and that number is on the rise, in part because our population is getting older.

Parkinson's is the fastest growing out of the neurodegenerative disorders that we deal with

fairly commonly as neurologists. So it's not the most common overall. That would be Alzheimer's disease.

Parkinson's comes in second, but it's very concerning that it's growing so quickly.

Dr. Claire Henscliffe is the chair of neurology at the University of California, Irvine.

She's one of the scientists at the forefront of Parkinson's research. She says the most

visible symptoms of Parkinson's are tremors and

trouble with coordination and balance. Then there's unfortunately the Parkinson's that you don't see.

Cognition, thought processing, memory can be affected. People can have onset of depression or

anxiety, whereas they've never had that before. Or there's a part of the nervous

system called the autonomic nervous system that can get involved. And that affects all sorts of things.

It affects how we digest or food. It can cause constipation. You can get blood pressure fluctuations,

the bladder can be affected. And while people are typically diagnosed around age 50 or 60,

it may start 10, 15, 20 years before we ever pick up a tremor or ever see someone slow down.

Sense of smell can alter, sleep can change. That's when the Parkinson's process in the brain has

...