Fixing Your Brain
When pills fail, electrical implants can mend brains damaged by Parkinson's, stroke, and depression
There are those with even more severe paralysis who may be aided by implant technology. Quadriplegics, for instance, often have no movement from the neck down. But an experimental device called a BrainGate offers a little more control. At Massachusetts General Hospital in Boston, two patients have had an electrode grid, about the size of a baby aspirin, planted in a brain area that controls voluntary hand movement. The wires come out to a small plug on the scalp, which, in turn, is connected to a small computer sitting next to the patient's wheelchair. The grid tracks patterns of brain activity as the patient thinks "move to the left" or "move to the right." It turns out those patterns are different, and the computer can tell them apart. It can use the patterns to run devices that move left or right, like a computer screen cursor.
"Within the first three days, I was able to control the cursor. When I think back on it, it was kind of a trip," says Matthew Nagle, 26, the first patient to have the implant. (He had it removed after 13 months because he needed an MRI, which is dangerous with metal in the brain.) Nagle was also able to control a robotic arm on the other side of his room.
Going beyond motion to emotion, brain repairmen have also set their sights on treatment-resistant depression. This is not the blues. This is not a low mood. "This is a living hell," says Charles Conway, a St. Louis University psychiatrist who works with these patients.
Lana Sanderson has passed through this torment. The 55-year-old Seattle resident had been battling depression ever since her 20s. "I just couldn't function,"says Sanderson. "I felt like weights were tied to my legs all the time. Just going across the room was hard, and frankly I didn't even want to try." During bad periods, she was stuck in her house, and she lost her pharmaceutical sales job. And there was the pain, an ache that permeated her body and mind with no obvious cause. "I tried virtually every class of medication available, in every combination. And finally I had ECT." The electroconvulsive therapy--large shocks to the brain, delivered in a hospital--didn't work either. There are about 4 million Americans like Sanderson. Many consider suicide. Quite a few go through with it.
Sanderson finally did get help from vagus nerve stimulation. VNS was originally developed to treat epilepsy in the late 1990s, and about 35,000 epileptics have the implant. One advantage is that it doesn't involve cutting into the skull. Instead, it uses a major highway to the brain called the left vagus nerve, located in the neck. A surgeon places electrical coils around the nerve and hooks them up to a pacemakerlike device, implanted in the skin of the chest. Pulses of electricity travel into the brain, short-circuiting epileptic seizures. Researchers noticed that patients' moods improved, probably because some of these signals stimulated parts of the brain's limbic system, which affects emotions.
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