Rewiring the Brain
Robert Langreth, Forbes Magazine, 03.05.01
Lauri Sandoval tried more than a dozen drugs to treat the deep depression that
darkened most of her adult life. None worked for long. Unable to hold a steady job,
the 42-year-old New Mexico resident had to move in with her mother two years
ago. Then she underwent surgery to implant an experimental device that treats her
blues by transmitting tiny pulses of electricity to nerves in her neck.
Soon, this mini-shock therapy started to work. Today Sandoval is back to working
full time, as a personal assistant to a Hollywood star, and she regularly goes out on
the town with friends. "It's incredible," she says. "I am actually happy. I've never
been able to say that before."
The device that brought her back, made by publicly held Cyberonics in Houston,
Tex., is one of a new generation of pacemaker-style gadgets that use mild electrical
jolts to treat myriad mental and neurological illnesses. While they aren't cures, they
may reduce or eliminate symptoms in severe cases, offering hope to millions of
patients who get no relief from drugs.
The brain, much like a microprocessor inside a computer, uses electrical current to
communicate within itself and with other parts of the body. When that fragile
circuitry goes awry, it can play a role in disorders ranging from depression to
epilepsy to Parkinson's disease. The workings of these natural bioelectric currents
are just beginning to reveal themselves. Researchers are learning that precisely
targeting zaps of barely noticeable pulses to affected areas of the brain can help
restore some normal function to the cerebral circuitry.
Cyberonics' poker-chip-size device, implanted in the chest during surgery, is
approved for treating drug-resistant epilepsy and has moved into final-stage human
tests for the far bigger market of drug-resistant depression. Medical device giant
Medtronic is testing a related technique called deep-brain stimulation, in which
electrodes from a device in the chest are surgically threaded several inches into
the brain to the site of damage. The method is approved for tremor and could win
clearance for Parkinson's disease later this year. A third method avoids surgery
entirely: At a doctor's office, patients wear a magnetic device on their head that
generates gentle therapeutic currents in parts of the brain hit by depression and
schizophrenia.It is being tested by Neotonus of Marietta, Ga., and others.
This new field is "absolutely exploding," says Stanford Miller, a Neotonus vice
president. Adds Cyberonics Chief Executive Robert (Skip) Cummins: "It's a gigantic
opportunity. We are talking about some of the largest medical markets in the world."
Doctors have spent decades using drugs to tweak aberrant brain chemicals, with
only limited success. Of 6 million Americans treated for depression, more than 1
million don't respond to drugs. Among the nation's 2.5 million epileptics, about 10%
can't be helped by chemical therapy. Drugs for Parkinson's disease often work
initially, but their effectiveness eventually fades.
Scientists have long thought electricity might help, but until recently they have been
unable to precisely target particular regions of the brain. Electroshock therapy, the
decades-old treatment of last resort for depression, indiscriminately blasts the
entire head to induce seizures and jar patients out of their blues. While effective, it
can cause severe short-term memory loss.
The new techniques are to shock therapy what laser-guided rifles are to
carpet-bombing—better targeted with less collateral damage. Among the more
promising is Cyberonics' vagus nerve stimulation approach, pioneered by its
cofounder, Jacob Zabara, the company's scientific founder and retired Temple
University physiologist.
The vagus nerve links the brain to major internal organs such as the heart, lungs
and stomach. Until recently researchers thought that it was mainly a one-way
conduit, sending messages from the brain to the body. Zabara realized the
one-way theory might be wrong while watching his wife use breathing techniques
to control her labor pains during the birth of their first child in 1971. He theorized the
pain-dulling effect also owed to feedback from the lungs back up through the vagus
nerve to the brain. Zabara also wondered if the vagus might help regulate other
brain functions, such as nausea or seizures.
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