Byline: Mary Carmichael
Art Davis gave up on sleep six months ago. By the end of each day, Parkinson's disease would paralyze his 58-year-old body, leaving him to crawl down the hall to bed and have his wife and children lift him onto the mattress. Once there, he lay awake with pain and cramps for most of the night. But two weeks ago, for the first time in ages, Davis woke up well rested and went for a four-mile walk near his home in Warren, Ohio, as he has several times since then. "It's a miracle," he says. Actually, it's a machine. Davis now has a "brain pacemaker," a generator in his chest wired to four electrodes in his brain that silence the neurons that once malfunctioned and left him prostrate.
Davis's miracle is increasingly commonplace. Fifteen thousand patients worldwide with Parkinson's and another disorder called "essential tremor" have received brain pacemakers in clinical trials over the past decade, and with FDA approval secured in January, many more are sure to follow. But stories like Davis's are just the beginning. Brain pacemakers, or "deep-brain stimulators," are also starting to show promise for treating several other neurological disorders. Though research is sparse and preliminary, the few small studies performed on patients with epilepsy, dystonia (which involves constant, involuntary muscle spasms) and severe obsessive-compulsive disorder have all yielded encouraging results.
The disorders may seem unrelated, but they have the same root cause. They begin when neurons abandon their normal electrical functions and start misfiring wildly, causing either uncontrollable movements (as in Parkinson's) or uncontrollable behaviors (as in OCD). To start stimulation, surgeons first drill into the skull of the patient, who is usually lying awake on the operating table. Once they find the affected area of the brain, they implant the electrodes there. A week later they implant a generator or "pacemaker" into the patient's chest and wire it, through the neck, up to the electrodes in the brain. When the doctors activate the generator, the implanted wires come alive deep within the brain and electrically stun the misfiring nerve cells, which immediately stop transmitting their faulty messages.
Twenty-some epileptics have undergone deep-brain stimulation in studies, with mostly positive results. …