A new and experimental deep brain stimulation (DBS) system uses feedback from the brain to fine-tune its signaling in response to signs of dyskinesia, potentially offering a more refined way to ease motor problems in Parkinson’s patients, a small feasibility study reports.
The research, “Adaptive deep brain stimulation for Parkinson’s disease using motor cortex sensing,” was published in the Journal of Neural Engineering. Larger studies of the devices potential effectiveness, as well as its safety, may follow.
DBS is a treatment strategy for people with advanced Parkinson’s disease, whose movement problems do not benefit from medications.
The procedure as now used consists in surgically implanting one or more thin wires into the brain, and an area known as the basal ganglia is constantly stimulated to ease symptoms. Adjustments in intensity are done manually by clinicians in response to changes in symptoms.
While it can be effective, DBS can also cause side effects that include dyskinesia, or uncontrolled movements, which has led to attempts to improve the technique.
In a small and short-term study, two Parkinson’s patients were implanted with an adaptive DBS device. The implant wire was inserted over the primary motor cortex — a key part of the brain that controls movement.
Signals collected from this lead were fed to a computer program embedded in the device, which would determine whether to stimulate the brain — rather than provide continuous stimulation.
“Other adaptive deep brain stimulation designs record brain activity from an area adjacent to where the stimulation occurs, in the basal ganglia, which is susceptible to interference from stimulation current,” Philip Starr, MD, PhD, the study’s senior author at the University of California, San Francisco, said in a news release. “Instead, our device receives feedback from the motor cortex, far from the stimulation source, providing a more reliable signal.”
The computer program was instructed to identify a pattern of brain activity that has been linked to dyskinesia.
Specifically, stimulation was reduced upon identification of dyskinesia-related brain activity, and increased when no dyskinesia was found, in this way minimizing side effects.
Initial results indicated that the adaptive system improved patients’ movement as effectively as traditional, constant DBS set manually by the researchers.
Because the new adaptive approach did not continuously stimulate the brain, it required about 40 percent battery energy over traditional DBS.
“This is the first demonstration of adaptive DBS in Parkinson’s disease using a fully implanted device,” the researchers wrote.
Although researchers were not able to compare the incidence of dyskinesia using either system, they hope that the adaptive system will lead to fewer adverse effects over longer time periods.
“The novel approach taken in this small-scale feasibility study may be an important first step in developing a more refined or personalized way for doctors to reduce the problems patients with Parkinson’s disease face every day,” Nick B. Langhals, PhD, program director at National Institute of Neurological Disorders and Stroke (NINDS) and team leader for the Brain Research through Advancing Innovative Technologies (BRAIN) Initiative.
Because too much stimulation could cause dyskinesia, an adaptive DBS system that responds to brain activity may represent an effective and safer alternative, the investigators believe.
“Here we have demonstrated the feasibility of adaptive [DBS],” Starr said. “We are now planning larger, longer-term trials to determine how effective this system is in managing the symptoms of patients with Parkinson’s.”
Both NINDS and the Brain Initiative supported the study.
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