Study touts brain stimulation for Parkinson’s
Patients with advanced Parkinson’s disease who received deep brain stimulation showed greater improvement in movement and quality of life after six months than those treated with medication, a new study shows.
But the deep brain stimulation patients had an almost four times greater risk of serious side effects such as depression, infections, falls or heart problems. Although most side effects could be treated, one patient suffered a brain hemorrhage and died.
With deep brain stimulation, doctors surgically implant electrodes that send electrical stimulation to specific parts of the brain to reduce involuntary movements and tremors. It is a widely accepted treatment for advanced Parkinson’s disease, but few randomized trials have been conducted comparing treatments.
Previous studies have largely excluded older patients, who account for the majority of those with the disease. About 25% of the more than 250 patients in the new study were 70 or older.
In the study, which appears in this week’s Journal of the American Medical Assn., patients were randomly selected to receive either medication or bilateral deep brain stimulation, with the electrodes implanted into the subthalamic nucleus or the globus pallidus areas of the brain.
Lead study author Frances Weaver said researchers were surprised by the magnitude of the differences in outcomes.
“The amount of time that patients were able to move normally increased by 4.6 hours,” said Weaver, director of the Center for Management of Complex Chronic Care in Hines, Ill. “Our best medical therapy patient, on average, showed no improvement.”
Researchers studied how long patients had good motor control, referred to as “on” time, without experiencing dyskinesia -- the jerky, uncontrolled movements patients develop after long-term use of medications to treat Parkinson’s disease.
The research is the first to show that deep brain stimulation works as well in older patients as it does in younger ones, said Dr. Leo Verhagen, a neurologist and medical director of the movement disorders surgery program at Rush University Medical Center in Chicago.
“It’s a major step forward,” said Verhagen, who was not involved with the study.
Weaver was optimistic about the findings, but said deep brain stimulation was not a panacea.
“It certainly helps a lot of people,” she said, “but it doesn’t address all of the issues of Parkinson’s disease, which is a progressive, degenerative neurological disease -- second only to Alzheimer’s. So other things will continue to get worse, such as memory, speech, writing, information processing and bladder management.”
The study, conducted at seven veterans hospitals and six affiliated academic medical centers across the country from May 2002 to October 2005, required patients to keep diaries documenting their motor and physical functioning throughout the day. The neurologists assessed patients’ motor skills without knowing which patients got which treatment.
Ken Glowienke, 43, of Oswego, Ill., had the surgery last fall -- although not as part of the study -- and said it had worked well.
“Ninety percent of the day I feel very normal and it doesn’t even cross my mind that I have Parkinson’s disease,” he said.
He did experience a complication -- a grand mal seizure a day after the surgery. But he’s OK now.
An unexpected finding of the study was the number of deep brain stimulation patients who suffered falls.
“These are probably patients who were not ambulatory, or were minimally ambulatory, and all of a sudden they are up and around,” said Dr. Roy A.E. Bakay, professor of neurological surgery at Rush and chairman of the safety monitoring committee for the study.
Other downsides of the procedure are costs and the need to replace the stimulator battery when it wears out, which requires another surgery.
In an editorial accompanying the study, neurologist Guenther Deuschl of Schleswig-Holstein University Hospital in Kiel, Germany, said the study left many unanswered questions, including how soon to implant the device and where in the brain to put it.
He also said patients who received deep brain stimulation seemed to lose some verbal fluency, memory and speed in processing information.
A follow-up paper will compare the effectiveness of implanting the stimulator in the subthalamic nucleus or the globus pallidus.
Despite the unknowns, Bakay said the benefits greatly outweighed the risks for many patients, and he expected that more would opt for the surgery.
“I think too many doctors decide on their own if a patient should undergo the surgery when it should be left to the patient and the patient’s family,” he said.
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