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. Several small but prestigious studies have reported marked improvement in dystonia patients after DBS–encouraging news for the 300,000 North Americans who suffer from the disease. And there are hints that the procedure could rouse people who flit in and out of comas caused by head injuries.
Patients with severe obsessive-compulsive disorder also seem to benefit from deep-brain stimulation. Surgeons already treat the worst cases by destroying the brain cells that have gone awry; DBS would be a less radical alternative. But only a handful of patients with otherwise intractable OCD have resorted to pacemakers thus far–partially because many doctors want to keep it that way. Dogged by stories of 19th-century lobotomies performed with ice picks, 21st-century doctors have treaded lightly. Those who do treat OCD through stimulation are quick to mention the pile of consent forms and FDA clearances that must be signed before surgery. “There’s a lot of stigma associated with this from the old days,” says Ali Rezai, a neurosurgeon at the Cleveland Clinic Foundation.
Still, there’s a major difference between deep-brain stimulation and procedures that burn, remove or otherwise damage parts of the brain: DBS is reversible. “If it doesn’t work, you can just turn off the pacemaker,” Rezai says. And if, by chance, a disease gets worse after treatment, doctors can fine-tune the device from the outside. At the proper current level, improvement is almost always immediate.
It was for Mario Della Grotta. At 33, he had one of the worst cases of OCD doctors had ever seen. He would get caught up in repetitive thoughts for hours, and at one point was washing his hands 70 times a day. In February 2001, he became the first U.S. patient to undergo DBS for psychiatric reasons. Days after treatment, he had improved dramatically, and today his story reads a lot like Art Davis’s. He has gone back to work. He no longer washes his hands compulsively and is even capable of changing his infant daughter’s diapers. All the ethical concerns in the world–all the “preliminary” and “investigational” and “not sure yets”–can’t change that one messy, glorious fact.
