Inserting a “pacemaker” into the brain to emit regular pulses of electricity and quell disordered neural activity may sound like a therapy of last resort, but if current experiments show beneficial results the brain surgery may one day be commonplace. But some scientists are cautioning that research on so-called deep brain stimulation may be pressing ahead too quickly, and warn that long-term effects of the surgery are not yet clear.
A growing number of psychiatric researchers are testing the method’s effectiveness on a host of psychiatric disorders. Until recently, deep brain stimulation was approved in the U.S. only to treat certain movement disorders, primarily those of Parkinson’s disease, for which it diminishes tremors and rigidity and improves mobility. To date, more than 60,000 patients worldwide have had the devices implanted [Los Angeles Times]. But now large clinical trials are in the works that will test the use of deep brain stimulation for obsessive compulsive disorder, epilepsy, and depression. Smaller experiments are beginning to assess the therapy’s effectiveness on a wide range of disorders including anorexia, drug addiction, obesity, traumatic brain injury, and Alzheimer’s.
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Parkinson’s patients could one day find relief from their symptoms by wearing a device on the backs of their necks that sends steady pulses of electricity up their spinal cords and into their brains, according to a new study. Researchers tested the technology on lab rats and mice that were nearly immobilized with Parkinson’s-like symptoms, and saw an immediate and dramatic effect. As long as a mild current flows up their spines and into their brains, the animals regain the ability to scamper around their cages, as if they were normal…. [Lead researcher Miguel] Nicolelis added that the procedure was now being tested on monkeys, and “if it succeeds, human clinical trials could begin in the next few years” [The New York Times].
Some Parkinson’s patients have already found relief from their symptoms with deep brain stimulation, in which tiny electrodes are surgically implanted in their brains to make a “brain pacemaker,” but this new experiment was the first to try a less invasive form of neural stimulation. If the findings are confirmed in humans, scientists say, the procedure could dramatically improve treatment for the disease by making electrical therapies safer and more broadly available [Technology Review].
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Deep brain stimulation can now be used to treat obsessive compulsive disorder, or OCD, which causes uncontrollable worries and anxiety in its sufferers. Medtronic’s Reclaim deep-brain stimulation (DBS) device received approval from the Food and Drug Administration after a study of 26 patients with severe OCD that showed a 40 percent reduction in symptoms after a year of deep brain stimulation therapy. All the patients had tried and failed other therapies [Chicago Tribune].
The Reclaim device is implanted under the skin of the chest and then connected to four electrodes in the brain. The electrodes deliver steady pulses of electricity that block abnormal brain signals [AP]; the device is controlled by a battery-run component outside the body. Hooman Azmi, a neurosurgeon at Hackensack University Medical Center, said, “This is essentially like a pacemaker for the brain” [WebMD Health News].
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Implanting a pacemaker-like device in the brains of Parkinson’s patients improves their condition significantly more than medication and physical therapy, a new study has found. The implantation of a deep brain stimulation device gave patients almost five additional hours each day when they were untroubled by the tremors, jerking limbs, and rigidity that characterize Parkinson’s, a movement disorder. But the surgery carries risks: The deep brain stimulation patients also had almost four times the risk of suffering a serious adverse event like depression, infections, falls or heart problems. Although most side effects could be treated, one patient suffered a brain hemorrhage and died [Chicago Tribune].
The electrodes that doctors install — one on each side of the brain — are actually small, insulated wires that are connected to another wire that runs under the skin to a small battery beneath the skin of the torso. The electrodes are implanted into a part of the brain that normally acts as a relay station for messages. In Parkinson’s patients, a flurry of signals jam this message center, sending aberrant signals to muscles and causing tremors, muscle rigidity, paralysis and other problems. The electrodes send out a mild current that inhibits the stream of messages, relieving the clutter and calming muscle problems [Science News]. The procedure has been an accepted treatment for Parkinson’s since regulators first approved it in 1997, but this study is one of the first to systematically compare the surgery’s results to outcomes from other treatments.
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