美国国家公共电台 NPR How Highly Focused Sound Waves Steadied A Farmer's Trembling Hand（在线收听）

RACHEL MARTIN, HOST:

Now we turn to a story of a man whose hands got so shaky, he couldn't eat with a spoon and he struggled to write legibly.

ALAN DAMBACH: My signature was so bad, and my writing was just atrocious.

MARTIN: NPR's Jon Hamilton reports on a new treatment that helped Alan Dambach control the condition known as essential tremor.

JON HAMILTON, BYLINE: Alan Dambach was in his late 50s when he noticed how unsteady his hands had become. Gradually, it got hard for him to fix the machinery at his family's tree farm in western Pennsylvania. And simple things, like eating and drinking, became an adventure.

DAMBACH: Salad bars were a no-no.

HAMILTON: But Dambach says it was his handwriting that finally made him realize he had to do something.

DAMBACH: One day I was over at our business, and I was writing an order. And one of my foremen said, why don't you let me write that for you?

HAMILTON: Dambach didn't have a disease, like Parkinson's. He'd simply inherited genes that made his hands shaky as he got older. The condition is called essential tremor, or familial tremor, and it affects more than 7 million people in the U.S. Dambach tried drugs. They helped for a while. He considered surgery to get an implanted device called a deep brain stimulator.

DAMBACH: And I thought, no way. This isn't going to work for me. I'm still too active.

HAMILTON: Then in his late 60s, Dambach heard about a new treatment called focused ultrasound, and he found a brain surgeon named Howard Eisenberg who was using the technique. Eisenberg is a professor at the University of Maryland. He says Dambach's story is pretty typical of the patients he treats.

HOWARD EISENBERG: So these are people, they don't have just a tremor. It's a disabling tremor. These are people who have actually had to change their lives.

HAMILTON: Focused ultrasound reduces tremors by sending high-frequency sound waves right through the skull to destroy specific areas of brain tissue. Eisenberg says it's an outpatient procedure, but not a trivial one.

EISENBERG: Heating up part of your brain and killing brain cells seems invasive to me, but it doesn't have the same feeling to patients as surgery. There are no incisions. You don't go to the operating room.

HAMILTON: Instead, patients are placed in an MRI scanner to figure out which brain areas to zap. Then they are fitted with a device that can focus sound waves on those areas. Dambach says during his treatment, Eisenberg and his team would administer a burst of ultrasound then bring him out of the MRI tube to see how he was doing.

DAMBACH: They gave me a bottle of water to pretend I was drinking. And every time I came out, it shook less.

HAMILTON: Studies show the treatment generally reduces tremors by at least half. Charlene Aldrich, who works with Eisenberg at the University of Maryland, says that makes a big difference. She shows me the drawings made by several patients who were asked to trace a circular pattern before and after the treatment.

CHARLENE ALDRICH: So you can see here, they cannot stay within the lines. They cannot draw a circle. This is actually a scratch over it. And here, they follow the lines symmetrically like you and I would do.

HAMILTON: The procedure isn't perfect. So far, it's only being used to treat one side of the brain, which means it can only reduce tremor in one hand. Also, there are risks. Some patients experience numbness or problems with balance afterward. And, even though the procedure is approved by the Food and Drug Administration, many insurers still don't cover the cost, which is about $40,000. For Alan Dambach, though, focused ultrasound was the right call. He says at the end of his treatment, he was exhausted.

DAMBACH: But the next day, I had to take the payroll checks to the bank and I had to sign them. I just was so happy my signature was back.

HAMILTON: That was more than a year ago, and Dambach says his signing hand is still rock steady. Jon Hamilton, NPR News.