People who received an implant deep within the brain to relieve symptoms of advanced Parkinson's disease made gains that lasted a decade, researchers found in the first study of long-term treatment.

Deep brain stimulation is a surgical intervention that involves the implantation of a "brain pacemaker," which thwarts many key Parkinson's characteristics that erode a patients' quality of life.

The pacemaker works round-the-clock sending high-frequency electronic impulses via electrodes deep into the brain's subthalmic nucleus. The treatment, experts say, is usually pursued when drugs no longer work.

Reporting in the Archives of Neurology, scientists in Italy found in a group of 18 patients who've survived a decade with the devices that deep brain stimulation not only is safe but may hold advantages over conventional drug therapy, which can cause side effects.

For decades, doctors have prescribed the drug levodopa, which is converted into the neurotransmitter dopamine. But treatment can cause a side effect that further impairs movement for Parkinson's patients.

Brain stimulation doesn't trigger more dopamine, doctors say. Rather, it helps normalize brain circuitry that goes awry when dopamine declines.

Dr. Alon Mogilner, director of functional and restorative neurosurgery at North Shore University Hospital in Manhasset, said "patients are being referred earlier in the course of their disease."

Mogilner -- who was not involved in the Italian study -- is following the progress of 400 North Shore patients who've undergone deep-brain stimulation procedures for Parkinson's, dystonia and Tourette's syndrome.

It is not a cure, he said, but the new analysis confirms what doctors in the field long suspected -- deep brain stimulation works for Parkinson's long-term. "It relieves the tremors, the rigidity and the slowness," Mogilner said, referring to some of Parkinson's most debilitating symptoms.

The implant system consists of three parts: a pacemaker, the lead, and an insulated wire that runs from the brain, behind the ear, and down the neck to the pacemaker, which is placed under the collarbone. "It's all internal," Mogilner said. Many patients receive two electrodes placed in different parts of the subthalmic nucleus.

The research, by Dr. Anna Castrioto of Università degli Studi di Perugia, is important because it's the first to show deep brain stimulation effectively treats Parkinson's for at least a decade -- and possibly longer, Mogilner added.

But the procedure is not without problems. Castrioto found some of the initial benefit from high-frequency impulses wore off because of the disorder's progressive nature. American researchers have found other potential problems: infection at the surgical site and cognitive decline in some patients. Still, the Italian team insists deep-brain stimulation helps patients over the long haul.

"Our findings ... support long-term response to stimulation in patients with advanced Parkinson's disease," Castrioto said.

Parkinson's, a neurodegenerative condition that affects 1 in every 100 people in the United States over age 60, is typified by a range of symptoms that arise when dopamine-producing brain cells become impaired or die.

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