Brain pacemaker helps Parkinson's, but with risks

[January 07, 2009]  CHICAGO (AP) -- Parkinson's sufferers who had electrodes implanted in their brains improved substantially more than those who took only medicine, according to the biggest test yet of deep brain stimulation. The study, which followed patients for six months, offers the most hopeful news to date for Parkinson's sufferers. The new technique reduced tremors, rigidity and flailing of the limbs and allowed people to move freely for nearly five extra hours a day.

But the research also revealed higher-than-expected risks. About 40 percent of the patients who received these "brain pacemakers" suffered serious side effects, including a surprising number of falls with injuries.

"We had one patient who felt so good he went up to repair his roof, fell down and broke both his legs," said lead author Fran Weaver of Hines Veterans Affairs Hospital, outside Chicago. "Patients are feeling so much better, they forget they still have Parkinson's."

There is no cure for Parkinson's disease, which affects more than 1 million Americans. Patients suffer from increasingly severe tremors and periodically rigid limbs as their brains stop making dopamine, a chemical needed for movement. They can have trouble walking, speaking and writing, and often struggle with depression.

Standard treatments include drugs to stimulate dopamine. But over time, the medicines can produce flailing movements that are as troubling as Parkinson's tremors.

With deep brain stimulation, which was approved by the Food and Drug Administration in 2002 for advanced Parkinson's and had been performed on thousands of patients, a surgeon implants electrodes in the brain, which are then connected to a pacemaker-like device that can be adjusted and turned off and on. That device, implanted under the collarbone or in the abdomen, sends tiny electrical pulses to the brain, disabling overactive nerve cells.

The latest findings were published in Wednesday's Journal of the American Medical Association. The researchers studied 255 people with advanced Parkinson's at seven VA and six university hospitals. Patients were randomly assigned to have surgery plus the standard medication, or medication alone.

After six months, patients visited neurologists who did not know whether they had had surgery or medication. In the surgery group, 86 out of 121 (71 percent) saw meaningful improvements in movement, as scored by the neurologists. In the medication group, 43 out of 134 patients (32 percent) showed meaningful improvements.

In the surgery group, 49 had serious problems, including infections, falls and one death because of complications from the surgery. In the control group, only 15 people encountered serious problems.

Another way to measure gains for Parkinson's patients is the amount of "on" time -- good quality movement time. Recording these times during the day in diaries, patients who had surgery gained, on average, nearly five hours of "on" time each day. Patients who didn't have surgery made no gains in that area.

"It's really brought a lot of freedom back to my life," said surgery patient Sharon Pederson, 51, of Tomales, Calif. She said medication worked well for four or five years but started causing her arms to fling out wildly.

"I would go to brush my hair and the brush would fly across the room," she said. "Once I was eating a yogurt while I was in the car. I came inside and said, 'I had a fight with a container of yogurt.' It was all over the inside of the car."

Surgery not only stopped the flailing but halted an intense sensation that her nerve endings were burning. Her depression also disappeared. The ability to write her normal flowing signature came back, too.

It didn't work for everyone. A few surgery patients (about 3 percent) got worse.

"You don't want to underestimate or overestimate the risks," said Weaver, a specialist in chronic care. "It still is an individual decision between a patient and a physician."

Surgery to implant the electrodes and pacemaker costs about $60,000 and is covered by Medicare and some insurance companies. Medications can cost $5,000 a year. After surgery, patients were able to cut their medications by 23 percent on average.

One-fourth of the people in the study were 70 and older. That age group has been excluded from many prior studies of DBS. In the new study, the older surgery patients were able to control their movements better, but younger ones benefited even more.

Those findings will help older patients make decisions about treatment, said Dr. Michael Okun of the University of Florida, medical director of the National Parkinson Foundation. The information on falls and other problems will help doctors give better advice, he said.

"This study with its careful methodology will help in setting a higher bar for tracking adverse events," said Okun, who was not involved in the study.

Four of the study's 22 co-authors reported financial ties to companies that make devices or drugs for Parkinson's. The lead author said she has no such ties.

The study was funded by the Department of Veterans Affairs and the National Institutes of Health. Minneapolis-based Medtronic Inc., maker of the devices purchased for the study, provided the money for collecting data.

In about six months, more results are expected from the study, which also compared two brain regions for electrode placement.

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On the Net:

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[Associated Press; By CARLA K. JOHNSON]

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