The Potential of 'Brain Pacemakers'
Implanted Devices May Alter Treatment of Many Disorders
By Rob Stein
Washington Post Staff Writer
Saturday, March 6, 2004; Page A01
A handful of scientists around the world have begun cautiously experimenting
with devices implanted in patients' bodies to deliver precisely targeted
electrical stimulation to the brain in hopes of treating otherwise
hopeless behavioral, neurological and psychiatric disorders.
While stressing that the ethically sensitive research with "brain pacemakers"
has just begun, the scientists say the results so far have been so promising
that it could mark the beginning of a new era in treating often intractable
cases. The approach builds on rapid recent advances in understanding how the
brain works, on high-tech imaging technologies that allow surgeons to pinpoint
targets with unprecedented precision, and on the miniaturization of
computerized electronic devices that can safely be inserted under the skin.
"I believe we have opened up a totally new field of research," said Alim-Louis
Benabid, a neurosurgeon who pioneered the field at the University of Grenoble
in France. "The number of labs which are entering the field is increasing
extremely quickly. We will probably see in the next five to 10 years a number
of exciting new applications."
Brain pacemakers are already widely used to treat Parkinson's disease and
other movement disorders, and now several neurological centers have begun
trying them to relieve several forms of previously untreatable pain, including
rare but excruciating "cluster headaches."
Large trials are planned in Europe and the United States to control the worst
cases of epilepsy. Small pilot studies have begun for patients with the most
devastating, resistant forms of depression and for obsessive-compulsive
disorder, a sometimes disabling psychiatric condition marked by repetitive
thoughts and routines.
French researchers have begun testing on monkeys to see whether the devices
might suppress appetite, and perhaps boost metabolism, in obese people. Some
researchers are thinking about how they might use the technique to overcome
addictions.
The research is shadowed, however, by one of the most reviled episodes of
medical history -- the psychiatric surgery boom of the early and mid-20th
century, when lobotomies and abuses of electroshock therapy became synonymous
with horrendous mistreatment depicted in books and films such as "One Flew
Over the Cuckoo's Nest." The sinister images of mind control conjured up by
the notion of implanting electrodes into people's brains only adds to the
potential for controversy.
Chastened by that dark legacy, the researchers say they are moving exceedingly
carefully, testing the approach only on hopelessly ill people who otherwise
would face irreversible brain surgery or risk side effects from shock therapy,
and creating layers of protections to ensure that all patients are fully
informed and shielded from abuse. Although the procedure carries risks, so far
it appears fairly safe. Moreover, researchers say, the treatment has the
advantage of being able to be simply turned off or removed if it does not work
or if problems occur.
Nevertheless, the research arouses fears of reviving the reckless use of brain
surgery, about the wisdom of poking around in what some consider the font of a
person's humanity, about oversimplifying mental illness as a purely biological
problem, and the temptation to move too quickly to try out new technologies.
"Any time you start messing with the brain and start treating it as,
quote-unquote, just another organ, we're going to have questions of the
propriety of doing this kind of thing," said Raymond De Vries, a medical
sociologist at the Institute for Advanced Study in Princeton, N.J. "This is
the brain. This is the seat of who we are."
Modeled on heart pacemakers routinely implanted in people's chests to
automatically regulate heart rhythms, brain pacemakers were first developed in
the late 1980s to treat Parkinson's, a devastating brain disorder in which
victims inexorably lose control of their muscles.
In a painstaking six-hour procedure, surgeons drill two small holes into a
patient's skull. Then, using computerized scans and electrical monitoring of
the firing of nerve cells to precisely guide them, they carefully thread two
electrodes, each about the diameter of a piece of spaghetti, to specific areas
on each side of the brain, depending on the nature of the disorder.
Because brain surgery is painless, the operation is done while the patient is
conscious so his responses can help guide the surgeons. The electrodes are
attached to wires embedded under the skin that lead down the side of the
patient's head, neck and shoulder to battery-operated, adjustable pacemakers
implanted under the collarbone.
Known technically as "deep brain stimulation," the approach has been used on
tens of thousands of patients with Parkinson's, as well as patients with two
other movement disorders, essential tremor and dystonia. Encouraged by the
success and safety of the treatment for those disorders, researchers began
exploring its potential for other conditions.
About two dozen people worldwide have undergone the procedure in a handful of
small experiments testing brain pacemakers for depression and
obsessive-compulsive disorder, or OCD.
Psychiatrists started with obsessive-compulsive disorder, because OCD can be
so severe and because the brain pathways involved are fairly well understood.
Neurosurgeons are implanting the electrodes into parts of the brain called the
anterior limbs of the internal capsules, which are believed to be relay
stations for signals to and from other parts of the brain that create the
repetitive thoughts.
Before her operation, Kelly Fahrenkrug was tormented by such thoughts --
pounding, relentless fears of being contaminated by some ominous but amorphous
threat outside her home.
"It's like your own brain torturing you. It's just constant repetitive
thoughts and routines, and being very afraid all the time," said Fahrenkrug,
34, a housewife and mother in Davenport, Iowa.
Today, her obsessive thoughts have quieted. They are not gone. But they are
hushed. Fahrenkrug can do things that once seemed impossible -- run errands,
ferry her daughter around town, entertain friends.
"It just sort of eased up is how I'd describe it. It was gradual. I just
noticed a lift in my mood. I just started to notice things were better," she
said.
Scientists do not understand exactly how electrical stimulation may work. The
brain uses tiny electrical and chemical impulses to transmit messages. The
external stimulation may either turn on or amplify -- or perhaps turn off or
diminish -- certain electrical signals, ameliorating the symptoms.
"The brain is an electrical organ with circuitry that carries messages. It's
like having an orchestra playing a symphony, with various areas playing
different parts. They have to play together," said Ali R. Rezai, director of
functional neurosurgery at the Cleveland Clinic Foundation in Ohio. "In some
cases, some parts aren't playing in synchrony. You hear chaotic music. That's
what's happening -- it's chaotic activity. We can get in there and modulate
that chaotic activity."
While researchers caution that the studies done so far are small and
preliminary, the results appear promising, apparently providing at least some
benefit for about half of OCD patients. Patients experience a reduction in
paralyzing fears, which reduces their compulsion to engage in often
debilitating repetitive routines. In some, improvement has been dramatic,
enabling people who had been incapacitated for years to return to work and
develop personal relationships. The approach appears to be producing similar
results for people devastated by depression.
"It's very exciting," said Andres Lozano, a neurosurgeon at the University of
Toronto working with colleagues at Emory University in Atlanta to test the
approach for depression. "These are patients who have failed all other
therapies."
To rule out the placebo effect, scientists have evaluated some patients when
they were unaware the stimulators were not delivering current. While the
surgery carries risks such as infection and hemorrhage, so far no serious
problems have been reported, the researchers said. Some experts, however, are
troubled by the move to start testing the approach on people with other
disorders, particularly depression, without more preliminary research.
"Our knowledge of the functional anatomy of depression is not as good as it is
for OCD. I'm a little bit more reserved about that and think they should be
waiting a bit more," said Mark S. George, director of the brain-stimulation
laboratory at the Medical University of South Carolina in Charleston. "Our
first rule is to first do no harm, and it would seem that something as
invasive as deep brain stimulation should be tested on animal models for
depression first."
Raj Persaud, a psychiatrist at the Maudsley Hospital in London, said he has
reservations. "Looking at yourself and making the changes that may be
necessary takes some time," he said. "Neurosurgery is the quick fix." But
researchers involved in the work say they are proceeding slowly, only offering
the treatment to people who otherwise would continue to suffer.
"This would be a last resort," said Wayne K. Goodman, a psychiatrist at the
University of Florida, who treated Fahrenkrug.
All the centers testing the procedure have established elaborate programs and
oversight to make sure no patients are accepted for treatment until they have
been thoroughly screened to make sure they have no other options, might
benefit, and are capable of giving informed consent.
"What happened during the era of lobotomy was those techniques were heralded
as miraculous cures for patients," said Benjamin D. Greenberg, a psychiatrist
at Brown University and Butler Hospital in Providence, R.I. "The procedure
over time became applied indiscriminately. The overall consequences were
tragic for many patients. It's all that history that makes us as careful as we
are."
As part of that effort, the researchers have enlisted Joseph J. Fins, a
medical ethicist at the Weill Medical College of Cornell University.
"They are very sensitive to the historical legacy of psychosurgery," Fins
said. "Today's iteration is far more discreet, less toxic and easier to study
than its predecessor."
Given the pivotal role the brain plays in the body, Rezai predicts a much
broader spectrum of patients will eventually benefit.
"I think we're really in the beginning of a new era for the treatment of
neurological and psychological disorders that are intractable to medication
and other treatments," Rezai said.
Eventually, Rezai said, "smart brain pacemakers" will be able to sense
aberrant brain cell firings and correct the problem with "a burst of
therapeutic activity."
"With time, it will become a more routine part of the armamentarium of
therapies for patients," he said. "In the future, neural prostheses and smart
systems for the brain will be applied more and more."
© 2004 The Washington Post Company
http://www.washingtonpost.com/wp-dyn/articles/A34883-2004Mar5.html
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Last Updated on
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