Fixing Your Brain
When pills fail, electrical implants can mend brains damaged by Parkinson's, stroke, and depression
Energy. In 2000, as part of a clinical trial, Sanderson got such an implant. "A week after the surgery, I was able to hook up my daughter's stereo speakers," says Sanderson. "It seems like a small thing, but days earlier it had been too difficult to think about. In about six months, I started walking every day. I finally felt I had some energy."
About 550 people with this kind of depression now have VNS implants. There are small side effects. The device emits a pulse every five minutes, and many people get hoarse for the 30-second duration because the vagus nerve is near the vocal cords. And as with deep brain stimulation, not everyone benefits; just over half, in fact. Physicians are quick to point out that these people have not been helped by anything else. More important, of those who do respond, 60 to 70 percent hold that better mood--including complete remissions--for at least two years.
Another, more experimental technique for serious depression, which doesn't involve surgery, is transcranial magnetic stimulation, or TMS. In a doctor's office, a small paddle-shaped magnet is held over the patient's left prefrontal cortex, which is tied to mood-control areas. The current produced by the magnet prompts greater activity in these regions. "You can start outside and affect inside," says Mark George, a psychiatrist and TMS expert at the Medical University of South Carolina in Charleston. There have not been a lot of big studies of the technique, which is usually applied for several minutes a day over four weeks. But so far, research shows an improvement that's slightly greater than that seen with antidepressants alone.
Brain repair still has rough edges. For instance, in deep brain stimulation, there's a lot of trial and error in picking pulse voltages and some debate about the optimum sites and even the number of implants. That may be one reason why Pat Brogan is still crippled. And with transcranial magnetic stimulation, even the best brain repairmen admit they are not exactly sure how it exerts its therapeutic effects. "We really need a better understanding of the science," says Sackheim. Plus, insurance companies are balking at paying the $20,000 price tag for VNS, claiming it is investigational despite its FDA approval.
Patients have, however, been able to appeal some of these denials successfully. And if the medical science turns out to support the continuing technical advances, brain fixes will increasingly rely on plugs instead of just pills.
5 WAYS TO REPAIR A BROKEN BRAIN
The brain is electric and doesn't work properly when damaged cells interrupt the circuit connections. New implants can jump-start these circuits with tiny electric currents.
VAGUS NERVE STIMULATION
Resistant depression, epilepsy
Periodic battery-driven pulses from an implant on the nerve travel into the brain and drown out irregular activity.
TRANSCRANIAL MAGNETS
Resistant depression
The left prefrontal cortex leads to an underactive mood area. A magnet outside the head sends a current inside, rousing the region.
DEEP BRAIN STIMULATION
Parkinson's, dystonia, other motion disorders
An electrode wired to an implanted battery overrides abnormal movement signals from this or near- by areas.
BRAINGATE
In quadriplegics, an implant picks up motor control signals and passes them to a computer that commands remote devices.
CORTICAL STIMULATOR
Stroke
Damage in this area causes partial paralysis. An electrode hooked to an implanted battery excites new activity.
VAGUS NERVE
Goes to areas of mood and body control
MOTOR CORTEX
Starts voluntary movements
SUBTHALAMICNUCLEUS
Affects muscle control
PREFRONTAL CORTEX
Affects emotional responses
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